Storm Drainage
Neutrality remake campaign: from-scratch field derivation per authoring cheatsheet; project parameters and derived dispositions
Showing changes from Rev 6
to Rev 7
in Storm Drainage.
−---
−title: Storm Drainage
−category: Sitework
−toc_depth: 3
−description: >
− When to use: Site storm water collection and conveyance for commercial, institutional, and industrial building projects, including curb inlets, grate inlets, combination inlets, area drains, yard drains, storm sewer mains and laterals, manholes, junction structures, headwalls, flared end sections, outfalls, and connections to municipal storm systems or on-site detention and retention facilities. Covers gravity storm drainage piping on the site side of the building from the first structure downstream of any building roof drain leader connection out to the public right-of-way, including pipe materials (reinforced concrete, HDPE corrugated, PVC profile-wall, PVC SDR sewer, ductile iron), structures, castings, excavation and bedding, installation, connection to existing systems, testing, and acceptance.
− Not intended for: Roof drainage piping that runs vertically through the building (governed by the adopted plumbing code and outside the site utility scope); sanitary drain, waste, and vent piping inside the building or building sewer (see [[sync/sanitary-waste-and-vent-piping]]); building-perimeter foundation drainage and footing drains (see [[sync/foundation-drainage]]); subsurface agricultural drainage; storm water quality treatment devices and detention/retention basin earthwork and structural design (those are designed by the civil engineer of record and may reference this standard for the piping that connects to them); roadway pavement and aggregate base course (see [[sync/aggregate-base-course]]); culverts under state DOT roadways (governed by the state DOT standard specifications); and dewatering or temporary construction stormwater controls (see [[sync/earthwork]] and the project SWPPP).
−---
−
−# Scope {toc}
−
−## This standard covers the materials, fabrication, installation, testing, and acceptance of site storm drainage systems that collect surface runoff from paved and unpaved site areas, convey it through gravity piping and structures, and discharge it either to a municipal storm sewer, to an on-site stormwater management facility, or to a permitted outfall. {note}
−## The scope begins at the throat of each curb inlet, the rim of each grate or area drain, and the first downstream structure or fitting receiving a roof drain leader from the building, and ends at the project-defined point of connection to the public storm system or to the inlet structure of the on-site stormwater facility. {note}
−
−## Storm drainage is the scope most directly responsible for the long-term flood performance of the site; under-sized or poorly graded storm systems fail by overtopping, ponding, surcharging back into adjacent properties, and gradually filling with sediment until what was designed as a 10-year system performs at the 2-year level, and errors in alignment, invert elevations, bedding, and joint integrity propagate forward as settlement at pavement repairs, exfiltration into adjacent utility trenches, and infiltration of groundwater that consumes the design capacity. {note}
−
−## The civil drawings carry essentially all of the design-specific information for storm drainage — pipe sizes, slopes, invert elevations, structure rim and invert schedules, manhole types, and inlet types are drawing-driven for nearly every project — and this standard governs the means and methods, the material requirements, and the installation and testing protocols within which the drawings operate. {note}
−
−## Design Responsibility {toc}
−### This standard does not include the hydrologic or hydraulic design of the storm drainage system. {note}
−### The civil engineer of record establishes the design storm, runoff calculation method (rational method, NRCS curve number method, or hydrograph-based methods such as HydroCAD or SWMM), pipe sizing, inlet capacities, and structure schedules. {note}
−
−### The Contractor shall install the system as designed.
−
−### The Contractor shall report to the Engineer of Record any condition that would prevent the designed system from being constructed as drawn — including conflicts with other utilities, inadequate cover, insufficient slope, or differing site conditions at the trench bottom.
−
−### Work under this standard shall be coordinated with [[sync/earthwork]] for trench excavation, dewatering, and backfill, with [[sync/foundation-drainage]] for the building-perimeter system that may discharge to storm structures, and with [[sync/aggregate-base-course]] for pavement structure that drains into curb inlets and area drains and that bears on completed storm trench backfill.
−
−# Referenced Standards {toc}
−
−## Materials, manufacturing, installation, and testing shall comply with the latest adopted edition of the following standards.
−
−## Where contract documents, adopted codes, or referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
−
−## Standards Table {toc}
−
−| Standard | Title |
−|----------|-------|
−| ASTM C76 | Standard Specification for Reinforced Concrete Culvert, Storm Drain, and Sewer Pipe |
−| ASTM C361 | Standard Specification for Reinforced Concrete Low-Head Pressure Pipe |
−| ASTM C443 | Standard Specification for Joints for Concrete Pipe and Manholes, Using Rubber Gaskets |
−| ASTM C478 | Standard Specification for Circular Precast Reinforced Concrete Manhole Sections |
−| ASTM C923 | Standard Specification for Resilient Connectors Between Reinforced Concrete Manhole Structures, Pipes, and Laterals |
−| ASTM C990 | Standard Specification for Joints for Concrete Pipe, Manholes, and Precast Box Sections Using Preformed Flexible Joint Sealants |
−| ASTM D2321 | Standard Practice for Underground Installation of Thermoplastic Pipe for Sewers and Other Gravity-Flow Applications |
−| ASTM D3034 | Standard Specification for Type PSM Poly(Vinyl Chloride) (PVC) Sewer Pipe and Fittings |
−| ASTM D3212 | Standard Specification for Joints for Drain and Sewer Plastic Pipes Using Flexible Elastomeric Seals |
−| ASTM F477 | Standard Specification for Elastomeric Seals (Gaskets) for Joining Plastic Pipe |
−| ASTM F679 | Standard Specification for Poly(Vinyl Chloride) (PVC) Large-Diameter Plastic Gravity Sewer Pipe and Fittings |
−| ASTM F949 | Standard Specification for Poly(Vinyl Chloride) (PVC) Corrugated Sewer Pipe With a Smooth Interior and Fittings |
−| ASTM F1417 | Standard Practice for Installation Acceptance of Plastic Non-Pressure Sewer Lines Using Low-Pressure Air |
−| ASTM F2306 | Standard Specification for 12 in. to 60 in. Annular Corrugated Profile-Wall Polyethylene (PE) Pipe and Fittings for Gravity-Flow Storm Sewer and Subsurface Drainage Applications |
−| AASHTO M294 | Standard Specification for Corrugated Polyethylene Pipe, 300- to 1500-mm (12- to 60-in.) Diameter |
−| AASHTO M252 | Standard Specification for Corrugated Polyethylene Drainage Pipe (3 in. to 10 in.) |
−| AASHTO M306 | Standard Specification for Drainage, Sewer, Utility, and Related Castings |
−| ASTM A48/A48M | Standard Specification for Gray Iron Castings |
−| ASTM A536 | Standard Specification for Ductile Iron Castings |
−| AASHTO HS-20 / HS-25 | Standard Highway Loadings for Bridge and Culvert Design (referenced for casting and structure live load) |
−| ASTM C150 | Standard Specification for Portland Cement |
−| ASTM C913 | Standard Specification for Precast Concrete Water and Wastewater Structures |
−| EPA NPDES CGP | Construction General Permit (National Pollutant Discharge Elimination System) |
−
−### State DOT standard specifications (e.g., FDOT, Caltrans, TxDOT, NJDOT) and local public works manuals are referenced as concept where work connects to public infrastructure. {note}
−
−### The specific governing edition shall be confirmed with the Authority Having Jurisdiction (AHJ) and the public works department or utility owner before work in the right-of-way begins.
−
−### Local stormwater management permitting requirements — including any municipal separate storm sewer system (MS4) program requirements — shall be identified by the Contractor as part of pre-construction planning.
−
−### The SWPPP shall comply with the project's coverage under the EPA Construction General Permit or the state-equivalent NPDES permit.
−
−# Submittals {toc}
−
−## Action Submittals {toc}
−
−### The Contractor shall submit the following for the Engineer of Record's review and acceptance prior to procurement, fabrication, or installation of any portion of the storm drainage system:
−
−- Product data for all pipe and fitting materials, indicating the manufacturer, the applicable ASTM or AASHTO standard, the class or pipe stiffness (PS) where applicable, the wall thickness or SDR, the joint type, the gasket material and the applicable joint standard (ASTM C443, C990, D3212, or F477)
−- Product data and shop drawings for precast manholes, junction structures, inlets, and headwalls, including the manufacturer's standard sections and adjustments, eccentric/concentric cone configurations, base type (monolithic or separate), pipe connection details (cast-in resilient connectors per ASTM C923 or core-drilled with boot), reinforcement schedules, lift-and-set hardware, and AASHTO HS-20 or HS-25 load rating
−- Casting product data for all frames, grates, covers, and lids, indicating the casting standard (ASTM A48 for gray iron or ASTM A536 for ductile iron), the AASHTO M306 listing, the load rating, the clear opening dimensions, and any local public works pattern conformance where the casting is at or within the public right-of-way
−- Bedding and backfill material gradations conforming to ASTM D2321 Class I or Class II as specified, including sieve analyses for each source proposed
−- Trench excavation and dewatering plan where storm drainage trenches will exceed 5 feet in depth or where groundwater is anticipated; this submittal may reference and incorporate the project earthwork submittal under [[sync/earthwork]] for the same trench work
−- Pipe joint testing plan, including the proposed method (low-pressure air per ASTM F1417, hydrostatic, or joint-by-joint pressure test for large-diameter pipe), the test pressures and durations, the testing agency and equipment, and the sections to be tested
−- Deflection testing plan for all flexible pipe (HDPE and PVC), including the timing relative to backfill placement and the mandrel sizes for each pipe diameter being installed
−- Connection details and any required permits or utility owner approvals for connection to existing storm systems or to municipal infrastructure
−- Working storm drainage plan (record-set markup) that the Contractor maintains and updates daily, showing actual horizontal and vertical alignments of pipe and structures as installed
−
−```datasheet
−label: Action Submittals Required
−type: checkbox
−options:
− - "Pipe and fitting product data with applicable standard, class, and joint type"
− - "Precast manhole and structure shop drawings with load rating"
− - "Frame, grate, and cover casting product data with AASHTO M306 listing"
− - "Bedding and backfill material gradations (ASTM D2321 classification)"
− - "Trench excavation and dewatering plan"
− - "Pipe joint testing plan"
− - "Deflection testing plan (flexible pipe)"
− - "Existing-system connection details and utility owner approvals"
− - "Working record-set markup procedure"
−default: "Pipe and fitting product data with applicable standard, class, and joint type"
−```
−
−### Below-grade work for which submittals are pending shall not be installed.
−
−## Closeout Submittals {toc}
−
−### Prior to substantial completion the Contractor shall provide:
−
−- As-built storm drainage record drawings showing the installed plan and profile of all pipe, including station and offset to permanent reference points, finished rim elevation and all pipe invert elevations at every structure, every casting model number installed, every pipe size and material installed by reach, and any deviations from the contract documents
−- Field test reports for all pressure or air tests, leakage tests, deflection tests, and structure vacuum tests, signed by the testing technician, with pass/fail determination for each pipe reach and structure
−- Manufacturer warranties for castings, precast structures, and any specialty products
−- Final cleanout / flushing certification confirming that pipe and structures have been cleared of debris, sediment, and construction materials before turnover to the Owner or to the AHJ
−- AHJ acceptance documentation where the system connects to public storm infrastructure or where the local jurisdiction issues a separate acceptance for the on-site storm system
−
−```datasheet
−label: Closeout Submittals Required
−type: checkbox
−options:
− - "As-built storm drainage record drawings with rim and invert elevations"
− - "Field test reports (pressure/air, leakage, deflection, vacuum)"
− - "Manufacturer warranties for castings, structures, and specialty products"
− - "Final cleanout / flushing certification"
− - "AHJ acceptance documentation"
−default: "As-built storm drainage record drawings with rim and invert elevations"
−```
−
−# Quality Assurance {toc}
−
−## Installer Qualifications {toc}
−
−### Storm drainage piping and structures shall be installed by a contractor with verifiable experience on at least three projects of comparable size and complexity within the preceding five years.
−
−### Personnel installing gasketed joints (concrete, HDPE, or PVC) shall be familiar with the manufacturer's recommended joint assembly procedure, including gasket installation, lubricant application, and home-mark verification.
−
−### Installation of large-diameter reinforced concrete pipe — 36 inches and larger — shall be performed by personnel experienced with the rigging, jointing, and bell-and-spigot home requirements of that pipe size.
−
−### Pipe installation crews working on RCP for the first time on a project shall demonstrate joint assembly on the first three sections in the presence of the Engineer's inspector before proceeding with production work.
−
−## Listing and Marking {toc}
−
−### All pipe, fittings, gaskets, castings, and precast structures shall bear the manufacturer's identification, the applicable standard designation, and the production date or batch number sufficient to trace each item to its certification documents.
−
−### Unmarked pipe or structures shall be rejected and removed from the project regardless of supplier documentation.
−
−### Castings used at or within the public right-of-way shall bear the AASHTO M306 mark, the foundry identification, and any local public works pattern number required by the utility owner.
−
−### Castings without the M306 mark shall not be installed in vehicular areas.
−
−## Pre-Installation Conference {toc}
−
−### Prior to beginning storm drainage installation the Contractor shall participate in a pre-installation conference attended by the Contractor's superintendent for site utilities, the Owner's geotechnical engineer of record, the civil engineer of record, the AHJ inspector (where required), and the testing agency.
−
−### The conference shall review the pipe materials and joint types, the bedding and backfill requirements, the testing program, the inspection hold points, the procedures for connection to existing systems, and the protocols for dealing with differing site conditions.
−
−## Inspection Hold Points {toc}
−
−### The Contractor shall provide the Engineer of Record and the AHJ inspector with not less than 24 hours' notice before each of the following inspection hold points, and no work past a hold point shall proceed until the inspection is completed and released:
−
−- Trench bottom and bedding placement, before pipe installation
−- Pipe alignment, slope, and joint assembly, before initial backfill
−- Structure base placement, before structure sections are stacked
−- Structure pipe penetrations and resilient connector seating, before grouting or sealing
−- Backfill compaction in the pipe zone, before pavement subgrade preparation
−- Final pipe testing (air, hydrostatic, or joint test) and deflection testing for flexible pipe
−- Casting setting and grade, before final pavement placement
−
−# Pipe Materials {toc}
−
−## Primary Material Selection {toc}
−
−### The pipe material for each reach shall be as indicated on the storm drainage plan, profile, and pipe schedule.
−
−### Where the drawings permit more than one material for a given reach, the Contractor shall submit the proposed material for that reach for the Engineer's acceptance.
−
−### The Contractor shall not mix materials within a continuous reach between structures without an approved transition fitting.
−
−### Different materials may be used in different reaches of the same system where the drawings so indicate.
−
−## Primary Material Datasheet {toc}
−
−```datasheet
−label: Primary Storm Sewer Pipe Material
−type: select
−drawing_ref: true
−options:
− - "Reinforced concrete pipe (RCP) per ASTM C76, gasketed bell-and-spigot joints per ASTM C443"
− - "HDPE dual-wall corrugated pipe per AASHTO M294 Type S / ASTM F2306, gasketed joints per ASTM D3212"
− - "PVC profile-wall pipe per ASTM F949, gasketed joints per ASTM D3212"
− - "PVC SDR 35 sewer pipe per ASTM D3034, gasketed joints per ASTM D3212"
− - "PVC large-diameter sewer pipe per ASTM F679, gasketed joints per ASTM D3212"
− - "Ductile iron pipe (specialty applications, see drawings)"
−default: deferred
−```
−
−### Material selection is a civil engineering decision, not a means-and-methods decision, and is established by the civil drawings; the narrative that follows describes the conditions under which each material is appropriate so that the Contractor can recognize and report mismatches between drawn material and field condition. {note}
−
−## Reinforced Concrete Pipe (RCP) {toc}
−
−### Reinforced concrete pipe conforming to ASTM C76 is the long-standing standard for large-diameter storm sewers, public storm mains, and any reach where high structural strength, long service life, and tolerance to heavy live loads with shallow cover are required. {note}
−### RCP is available in five classes (Class I through Class V) reflecting increasing strength designations under the three-edge bearing test. {note}
−
−### The class for each reach shall be as indicated on the pipe schedule and shall be chosen by the civil engineer based on cover depth, live load, trench width, and bedding class.
−
−```datasheet
−label: RCP Strength Class
−type: select
−drawing_ref: true
−options:
− - "Class II (0.01-in. crack 1000-D, ultimate 1500-D)"
− - "Class III (0.01-in. crack 1350-D, ultimate 2000-D)"
− - "Class IV (0.01-in. crack 2000-D, ultimate 3000-D)"
− - "Class V (0.01-in. crack 3000-D, ultimate 3750-D)"
−default: "Class III (0.01-in. crack 1350-D, ultimate 2000-D)"
−```
−
−### Class III RCP is the most commonly specified class for typical commercial site storm drainage with cover depths of approximately 3 to 12 feet and HS-20 live loading, while Class IV and Class V are used where cover is shallow, where trench widths exceed the standard installation envelope, or where unusually heavy live loading is anticipated; the class designation reflects the structural design assumption of the civil engineer. {note}
−
−### The Contractor shall not substitute a lower class than indicated under any circumstances.
−
−### RCP joints shall be gasketed bell-and-spigot or single-offset joints with confined O-ring or profile gaskets conforming to ASTM C443.
−
−### Mortar-only joints, mastic-only joints, and "tongue and groove" joints without a gasket are not acceptable for new storm drainage construction.
−
−### The gasket creates the watertight seal; any mortar or external sealant is supplemental and does not substitute for the gasket. {note}
−
−### The Contractor shall verify that the gasket has been seated correctly in its groove before stabbing the joint, shall apply lubricant per the manufacturer's instructions, and shall confirm that the joint is fully home — typically verified by a paint mark or stencil on the spigot indicating the design home depth.
−
−## HDPE Corrugated Dual-Wall Pipe {toc}
−
−### High-density polyethylene corrugated dual-wall pipe conforming to AASHTO M294 Type S (12 in. and larger) or AASHTO M252 (3 in. through 10 in.), and to ASTM F2306 for the 12-in. through 60-in. size range, is widely used for site storm drainage in private development where cover depth, live load, and pipe size are within the range supported by the AASHTO design specifications. {note}
−
−### The minimum pipe stiffness (PS) of HDPE corrugated dual-wall pipe shall be specified, increased above the AASHTO minimum where cover depth, live load, or pipe size requires higher stiffness.
−
−```datasheet
−label: HDPE Pipe Stiffness (PS) Minimum
−type: radio
−unit: psi at 5 percent deflection
−options:
− - "46 psi (AASHTO M294 / ASTM F2306 minimum, Type S)"
− - "Higher PS as specified by civil engineer for deep cover or surcharge"
−default: "46 psi (AASHTO M294 / ASTM F2306 minimum, Type S)"
−```
−
−### HDPE is a flexible pipe — its performance depends on the soil envelope around it, and proper bedding and haunching are critical to long-term shape stability. {note}
−
−### HDPE joints shall be bell-and-spigot joints with elastomeric gaskets conforming to ASTM F477 and meeting the watertight performance requirements of ASTM D3212.
−
−### The HDPE gasket shall be factory-installed in the bell.
−
−### Joints relying solely on a slip-fit or on a snap-ring without a continuous gasket are not acceptable for storm drainage applications connected to permanent infrastructure.
−
−### The Contractor shall confirm the HDPE joint type and gasket configuration against the product submittal and shall use only the manufacturer's recommended lubricant.
−
−### HDPE pipe shall be installed in accordance with ASTM D2321 with embedment material conforming to ASTM D2321 Class I or Class II crushed stone or gravel placed to the depths specified in the Bedding and Pipe Zone Backfill section of this standard.
−
−### The maximum allowable installed deflection of HDPE pipe shall be 5 percent of the nominal inside diameter, measured by mandrel pull-through not earlier than 30 days after final backfill and final cover load have been placed.
−
−## PVC Sewer and Profile-Wall Pipe {toc}
−
−### Polyvinyl chloride pipe is acceptable for storm drainage in the configurations indicated on the drawings, in any of the following standards: {note}
−
−- ASTM D3034 SDR 35 (4-in. through 15-in. nominal), solid-wall gasketed sewer pipe
−- ASTM F679 (18-in. and larger), solid-wall gasketed large-diameter sewer pipe
−- ASTM F949 (4-in. through 36-in.), corrugated/profile-wall PVC pipe with smooth interior
−
−### The PVC pipe type and governing ASTM standard for storm drainage shall be specified for each pipe size range indicated on the drawings.
−
−```datasheet
−label: PVC Pipe Type for Storm Drainage
−type: select
−drawing_ref: true
−options:
− - "SDR 35 solid wall (ASTM D3034) — 4 in. through 15 in."
− - "Large-diameter solid wall (ASTM F679) — 18 in. and larger"
− - "Profile-wall (ASTM F949) — 4 in. through 36 in."
−default: deferred
−```
−
−### PVC pipe joints shall be bell-and-spigot integral gasketed joints conforming to ASTM D3212, with gaskets conforming to ASTM F477.
−
−### Solvent cement joints are not permitted for buried storm sewer service.
−
−### The storm system is subject to differential thermal and ground movement that solvent-cement joints do not accommodate, and the gasketed joint is the recognized standard for buried gravity sewer. {note}
−
−### The Contractor shall verify that all PVC pipe delivered to the site is rated for the storm sewer service — the pipe shall be marked with the applicable ASTM standard and shall not be DWV or Schedule 40 pressure pipe re-purposed as a sewer material.
−
−### PVC pipe is, like HDPE, a flexible pipe and is subject to the same maximum installed deflection limit of 5 percent.
−
−### PVC pipe shall be installed in accordance with ASTM D2321 with the same bedding and pipe-zone embedment requirements as HDPE.
−
−## Ductile Iron Pipe — Specialty Applications {toc}
−
−### Ductile iron pipe is occasionally used for storm drainage in specialty locations: under heavy equipment foundations, under building footings where structural drawings require it, in seismic regions where high joint deflection tolerance is needed, or where the storm system crosses sanitary or pressure utilities at constrained vertical separation. {note}
−
−### Where ductile iron is specified, the pipe material, joint type, lining, and class shall be as indicated on the drawings.
−
−### The requirements of this standard for bedding, jointing, testing, and structure connection apply to ductile iron pipe.
−
−# Structures {toc}
−
−## Manholes and Junction Structures {toc}
−
−### Storm drainage manholes and junction structures shall be furnished by the type and size indicated on the structure schedule and detailed below.
−
−```datasheet
−label: Manhole Type
−type: select
−drawing_ref: true
−options:
− - "Precast circular concrete (ASTM C478), monolithic base"
− - "Precast circular concrete (ASTM C478), separate precast base"
− - "Cast-in-place concrete structure per drawings"
−default: "Precast circular concrete (ASTM C478), monolithic base"
−```
−
−```datasheet
−label: Minimum Manhole Inside Diameter — by Largest Pipe Connection
−type: select
−drawing_ref: true
−options:
− - "48-in. manhole — pipes up to 24 in."
− - "60-in. manhole — pipes 27 in. through 36 in."
− - "72-in. manhole — pipes 42 in. through 48 in."
− - "84-in. manhole or larger — pipes 54 in. and larger"
−default: deferred
−```
−
−### Storm drainage manholes shall be circular precast reinforced concrete structures conforming to ASTM C478.
−
−### Cast-in-place concrete structures may be used where indicated on the drawings, typically for unusual geometries (junction structures with multiple inlet pipes at varying elevations, energy dissipation structures, or weir structures within the storm system).
−
−### Brick or masonry block manholes shall not be used for new storm drainage construction unless specifically required to match existing infrastructure under a renovation scope.
−
−### Manhole barrel diameter, riser sections, eccentric or concentric cone, top slab type, and adjustment ring stack shall be as indicated on [[drawing: the structure schedule and manhole details]].
−
−### Standard interior barrel diameters for storm drainage manholes are 48 inches and 60 inches, while larger diameters (72-inch, 84-inch, 96-inch) are used at junction structures, at structures with large incoming pipes, or where personnel access for cleaning and inspection requires it. {note}
−
−### Manhole sizing is a function of the largest pipe entering or leaving the structure, the angle between pipes at the junction, and the maintenance access required; under-sized manholes cannot accommodate the bench shaping required to direct flow smoothly between inlet and outlet pipes, with the result being hydraulic loss at the structure and accelerated sediment deposition. {note}
−
−### The Contractor shall verify the structure size on the schedule against the pipe sizes converging at that structure before fabricating or ordering precast components.
−
−## Pipe Connections to Structures {toc}
−
−### The connection method for every pipe entering or leaving a structure shall be as detailed below.
−
−```datasheet
−label: Pipe-to-Structure Connection
−type: radio
−drawing_ref: true
−options:
− - "Cast-in resilient connector (ASTM C923) at precast fabrication"
− - "Field-cored opening with boot-type resilient connector (ASTM C923)"
− - "Cast-in-place structure with rigid penetration and flexible gasket sleeve"
−default: "Cast-in resilient connector (ASTM C923) at precast fabrication"
−```
−
−### Every pipe entering or leaving a precast manhole or junction structure shall be connected by either a cast-in-place resilient connector conforming to ASTM C923, or by a core-drilled opening fitted with a boot-type resilient connector also conforming to ASTM C923.
−
−### Direct mortared pipe penetrations through a precast structure wall without a resilient connector are not acceptable.
−
−### The dissimilar thermal and mechanical movement of pipe and structure cracks rigid mortar seals and causes both exfiltration of storm flow and infiltration of groundwater. {note}
−
−### The cast-in resilient connector is the preferred method because it provides factory quality control on the seal-to-structure interface, while the core-drilled-and-boot method is acceptable for field connections that were not anticipated at precast fabrication, provided the core hole is drilled cleanly with a diamond core barrel and the boot is sized correctly for the pipe outside diameter. {note}
−
−## Manhole Joints {toc}
−
−### Joints between precast manhole sections (base to riser, riser to riser, riser to cone, cone to top slab) shall be sealed with butyl rubber preformed flexible joint sealant conforming to ASTM C990, or with confined O-ring rubber gaskets conforming to ASTM C443 where the manhole sections are manufactured for gasketed joints.
−
−### Mortar-only manhole section joints are not acceptable for new construction.
−
−### The preformed sealant or gasket provides the watertightness that mortar alone cannot maintain through ground movement and freeze-thaw cycles. {note}
−
−## Manhole Step and Ladder {toc}
−
−### The manhole step or ladder system shall be as detailed below.
−
−```datasheet
−label: Manhole Step Material
−type: radio
−drawing_ref: true
−options:
− - "Copolymer polypropylene plastic over steel reinforcing bar (ASTM C478)"
− - "Cast-in steel reinforcing bar — coated"
− - "Fixed steel ladder (manholes 20 ft and deeper)"
−default: "Copolymer polypropylene plastic over steel reinforcing bar (ASTM C478)"
−```
−
−### Manhole steps shall be plastic-coated steel reinforcing bar or copolymer polypropylene plastic conforming to ASTM C478 step requirements, embedded in the precast sections in accordance with the section drawings.
−
−### Step spacing shall not exceed 16 inches vertically.
−
−### Manholes deeper than 20 feet shall include a fixed steel ladder in lieu of cast-in steps where required by OSHA confined space entry provisions or local regulation.
−
−### The ladder design shall be reviewed by the Engineer of Record before installation.
−
−## Inlets {toc}
−
−### Inlet selection is established by the civil drawings based on inlet location, gutter or sheet flow conditions, and the inlet's intended hydraulic capacity. {note}
−### The principal inlet types used in commercial site work are: {note}
−
−- **Curb inlet:** A vertical opening in the back of curb, with no grate in the gutter line. Curb inlets accept gutter flow through the vertical opening and are resistant to clogging by leaves and debris. They are the preferred inlet type on continuous-grade gutters where vehicular tire interaction with grates would be a concern.
−- **Grate inlet:** A horizontal opening in the gutter line covered by a cast iron or ductile iron grate. Grate inlets accept gutter flow primarily through the grate openings; they have high capacity per linear foot when the grate is clear, but capacity drops substantially when the grate becomes partially blocked by debris.
−- **Combination inlet:** A curb inlet and a grate inlet acting together at the same location, providing both the high capacity of the grate and the debris-tolerance of the curb opening. Combination inlets are appropriate at sag locations where ponding would result if the grate clogged.
−- **Area drain / yard drain:** A small precast or cast-in-place inlet with a grate, located in a paved area or landscaped low point to drain a localized area.
−- **Trench drain:** A linear surface drain used to collect sheet flow across a paved area, typically at vehicular entrances, loading docks, or wide pedestrian plazas.
−
−### The inlet type shall be specified for each location based on grade condition, drainage configuration, and surface type.
−
−```datasheet
−label: Inlet Type by Location
−type: select
−drawing_ref: true
−options:
− - "Curb inlet — continuous grade"
− - "Grate inlet — gutter line"
− - "Combination inlet — sag location"
− - "Area drain / yard drain — paved low point"
− - "Area drain / yard drain — landscaped low point"
−default: deferred
−```
−
−### Area drains in vehicular areas shall use the same casting load class as the surrounding pavement.
−
−### Trench drains shall be specified separately from this standard where used.
−
−### Inlet structure dimensions, throat or grate opening size, sump depth (if any), and pipe connection elevations shall be as indicated on [[drawing: the inlet schedule and inlet details]].
−
−### The Contractor shall not substitute one inlet type for another without the Engineer's approval.
−
−### The civil engineer of record has computed inlet capacities based on the design gutter flow and the rating curves for the specified inlet type, and substitution alters the hydraulic capacity assumed in the design. {note}
−
−### Inlet capacity calculations are typically performed using HEC-22 or equivalent methods, which assume that grates are not clogged, but field experience indicates that grates in tree-lined or leaf-heavy areas can lose 30 to 50 percent of theoretical capacity in fall and spring; the civil engineer applies a clogging factor in the design, and the Contractor's responsibility is to install the specified inlet correctly and to assist the Owner with the operations and maintenance information needed to keep grates clear. {note}
−
−## Junction Structures and Inline Cleanouts {toc}
−
−### Where two or more pipes meet at angles that exceed the standard manhole bench geometry, a junction structure shall be provided as indicated.
−
−### Junction structures shall be cast-in-place reinforced concrete or precast box structures sized to accommodate the converging pipe inverts with smooth, swept channels that direct flow from each incoming pipe to the outgoing pipe with minimum hydraulic loss.
−
−### The junction structure interior shall be benched in mortar above the spring line of the largest pipe to provide a walkable maintenance surface.
−
−### Inline cleanouts (lateral cleanouts on individual roof drain or area drain lateral connections) shall be brought to grade with a cast iron or PVC riser and a watertight access plug.
−
−### Cleanouts shall be installed at every change of direction greater than 45 degrees on lateral pipe runs and at every 100 feet of straight run on pipe smaller than 18 inches.
−
−## Headwalls, Flared End Sections, and Outfalls {toc}
−
−### The outfall termination type shall be as detailed below.
−
−```datasheet
−label: Outfall Termination
−type: select
−drawing_ref: true
−options:
− - "Cast-in-place concrete headwall with wingwalls"
− - "Precast concrete headwall"
− - "Precast concrete flared end section (RCP)"
− - "HDPE / PVC flared end section (manufacturer's standard)"
− - "Riprap apron downstream of pipe end — no headwall"
−default: deferred
−```
−
−### Where storm drainage discharges to an open swale, ditch, or detention/retention basin, a headwall or flared end section shall be provided at the outfall to control erosion, anchor the pipe end, and provide a clean transition between the pipe and the open channel.
−
−### Headwalls shall be cast-in-place reinforced concrete or precast as indicated.
−
−### Flared end sections shall be precast concrete (for RCP) or metal/polymer (for HDPE and PVC) of the manufacturer's standard configuration matching the pipe.
−
−### A riprap apron, an energy dissipator (e.g., a stilling basin or a baffled outlet), or a combination thereof shall be provided downstream of any outfall where the outlet velocity at the design flow exceeds the permissible velocity of the receiving channel.
−
−### Riprap gradation and apron dimensions shall be as indicated on the drawings.
−
−### Under-sizing the riprap apron causes scour at the pipe outlet that progressively undermines the headwall and the last pipe joint. {note}
−
−# Castings {toc}
−
−## All inlet frames, manhole frames, manhole covers, inlet grates, and area drain grates ("castings") shall be gray iron conforming to ASTM A48 or ductile iron conforming to ASTM A536, listed in accordance with AASHTO M306.
−
−## Castings shall be free of visible defects (cracks, cold shuts, blowholes, inclusions), shall be machined at mating surfaces where required to seat the cover or grate flat in the frame without rocking, and shall bear the foundry identification and the AASHTO M306 mark.
−
−## Casting Material {toc}
−
−```datasheet
−label: Casting Material
−type: radio
−drawing_ref: true
−options:
− - "Gray iron per ASTM A48 (Class 35B typical for street castings)"
− - "Ductile iron per ASTM A536 (Grade 70-50-05 typical for heavy-load castings)"
− - "Mix — ductile iron lid or grate with gray iron frame (cost-effective for H-25 loading)"
−default: "Gray iron per ASTM A48 (Class 35B typical for street castings)"
−```
−
−### Gray iron conforming to ASTM A48 Class 35B is the standard material for the majority of street and parking lot castings, providing good compressive strength and excellent wear and corrosion resistance for the load class typical of HS-20 vehicular loading, while ductile iron conforming to ASTM A536 (commonly Grade 65-45-12 or 70-50-05) is used where loads exceed HS-20, where impact loading is anticipated (e.g., at airport service roads, intermodal facilities, or heavy industrial yards), or where the engineer specifies the higher tensile and yield strength of ductile iron; a common cost-effective configuration is a gray iron frame with a ductile iron lid or grate, where the heavier-loaded element that takes the wheel load gets the more expensive material. {note}
−
−## Casting Load Class {toc}
−
−```datasheet
−label: Casting Load Rating
−type: select
−drawing_ref: true
−options:
− - "Light duty — pedestrian / non-traffic only"
− - "Medium duty — light vehicular (parking lot, driveway)"
− - "H-20 / HS-20 — standard highway loading"
− - "H-25 / HS-25 — heavy highway loading"
− - "Heavy industrial — airport, intermodal, container yard"
−default: "H-20 / HS-20 — standard highway loading"
−```
−
−### The casting load class shall match the live load applicable to the location.
−
−### HS-20 is the standard for typical commercial parking and drives, HS-25 is used for state DOT roadways and routes carrying heavy truck traffic, and pedestrian-only castings (e.g., in non-traffic plazas) use lighter-class castings; under-rated castings in vehicular areas can crack under repeated heavy axle loads and become safety hazards. {note}
−
−### The Contractor shall confirm that pedestrian-class castings are not located on a fire-lane or service-vehicle route where vehicular load is intermittent but real.
−
−## Self-Sealing Covers and Bolted Lids {toc}
−
−### The cover restraint type shall be as detailed below.
−
−```datasheet
−label: Bolted or Gasketed Manhole Cover
−type: radio
−drawing_ref: true
−options:
− - "Not required — non-flood-prone location"
− - "Gasketed self-seating cover (storm surcharge possible)"
− - "Bolted lid with stainless steel fasteners (flood plain or flood-prone)"
−default: "Not required — non-flood-prone location"
−```
−
−### Where castings are subject to occasional surcharge — at sag inlets in low-lying areas, at structures within a flood plain, or where the storm system is designed to surcharge to grade during the extreme event — covers shall be self-sealing (gasketed seat) or bolted in place to prevent the cover from being displaced by surcharge pressure.
−
−### Bolted lids shall use stainless steel or hot-dip galvanized fasteners.
−
−### Carbon steel fasteners corrode within the manhole environment and become unusable within a few years. {note}
−
−## Adjustment Rings {toc}
−
−### The casting-to-structure adjustment method shall be as detailed below.
−
−```datasheet
−label: Casting-to-Structure Adjustment Method
−type: radio
−options:
− - "Precast concrete adjustment rings — mortared between rings and to frame"
− - "Precast HDPE / recycled rubber adjustment rings"
− - "Mortared brick (where permitted by utility owner)"
− - "Custom precast riser (where adjustment exceeds 12 in.)"
−default: "Precast concrete adjustment rings — mortared between rings and to frame"
−```
−
−### Adjustment between the top of the precast structure cone or top slab and the bottom of the cast iron frame shall be made with precast concrete adjustment rings, precast HDPE or recycled rubber adjustment rings, or with mortared brick — as permitted by the local utility owner.
−
−### The total height of adjustment shall not exceed 12 inches without the Engineer's approval.
−
−### Where more than 12 inches of adjustment is needed, a custom riser section shall be specified.
−
−### Tall stacks of adjustment rings are inherently unstable under traffic loading and tend to settle, dislocate, and leak. {note}
−
−### The Contractor shall set the cast iron frame on a continuous mortar bed at the top adjustment ring, with the inside face of the frame flush with the inside face of the structure, and with the top of the frame matched to the finished pavement or grade.
−
−### Castings set proud of pavement create plowing and pedestrian-trip hazards, and castings set low cause water to pond around the rim and accelerate pavement deterioration. {note}
−
−# Excavation and Trench Preparation {toc}
−
−## General Trench Requirements {toc}
−
−### Trench excavation for storm drainage piping shall conform to the requirements of [[sync/earthwork]] for trench excavation, dewatering, slope stability, and shoring or trench protection.
−
−### In case of conflict between this standard and [[sync/earthwork]], the more stringent requirement governs.
−
−### Trench width at the springline of the pipe shall be the minimum needed for safe worker access, pipe installation, and joint assembly, plus the haunching room required by the pipe manufacturer and ASTM D2321 for flexible pipe.
−
−### Minimum trench width at the springline shall be the pipe outside diameter plus 16 inches (8 inches on each side) for pipes up to 24 inches in diameter, and shall be confirmed against the manufacturer's installation manual for larger sizes.
−
−### Excessive trench width increases bedding and backfill quantities and, for rigid pipe, increases the bedding factor required to carry the live load. {note}
−
−### The trench bottom shall be excavated to the pipe invert grade minus the bedding thickness, on a uniform longitudinal slope matching the design pipe slope without dips, sags, or reverse gradient.
−
−### Where the trench bottom is over-excavated below design grade — whether by accident or to remove an unsuitable zone — the over-excavation shall be backfilled with compacted granular bedding material to the design bedding bottom elevation, with the geotechnical engineer's concurrence on the lift thickness and compaction requirement.
−
−## Trench Bottom Stability {toc}
−
−### Where the trench bottom is soft, the stabilization method shall be as detailed below.
−
−```datasheet
−label: Trench Bottom Stabilization (where soft)
−type: select
−options:
− - "Over-excavate and replace with compacted crushed stone working layer — 12 in. minimum"
− - "Over-excavate, place geotextile, then crushed stone — soft cohesive subgrade"
− - "Controlled low-strength material (CLSM) foundation course"
− - "Not required — competent native bearing"
−default: "Not required — competent native bearing"
−```
−
−### The bottom of every storm drainage trench shall be observed by the geotechnical engineer of record (or the Owner's designated inspector) before bedding is placed, to confirm that the trench bottom is competent and uniform.
−
−### Soft, wet, or pumping trench bottom conditions shall be remediated before bedding is placed.
−
−### Remediation options include over-excavation and replacement with crushed stone, geotextile separation with granular fill, or — where conditions warrant — a flowable fill foundation course as directed by the geotechnical engineer. {note}
−
−### The Contractor shall not place pipe directly on bedded mud, on standing water, or on disturbed loose material.
−
−### The bedding-to-pipe load transfer assumed in the pipe design is destroyed if the bedding is bedded on unstable material, with the result being differential settlement that breaks joints and creates sags in the completed pipe. {note}
−
−### The geotechnical engineer's documentation of trench bottom acceptance for each reach shall be retained in the project record.
−
−## Dewatering {toc}
−
−### Trenches that extend below the groundwater table shall be dewatered continuously throughout pipe installation, bedding and pipe-zone backfill placement, and until enough cover has been placed to resist pipe flotation.
−
−### Dewatering shall conform to the requirements of [[sync/earthwork]].
−
−### The Contractor shall not place pipe in standing water.
−
−### Placing pipe in standing water causes bedding washout under the pipe, gasket contamination at the joints, and uncontrolled buoyancy that displaces pipe alignment. {note}
−
−### Dewatering discharge shall be conducted through sediment-control measures (sediment bag, settling basin, or other approved BMP) and shall comply with the project NPDES permit and any local stormwater discharge requirements.
−
−### Discharge of dewatering flow directly to the newly-installed storm system shall be avoided where practical, and shall be filtered if necessary.
−
−# Bedding and Pipe Zone Backfill {toc}
−
−## Bedding Class {toc}
−
−### The bedding class for each reach shall be as detailed below.
−
−```datasheet
−label: Bedding Class
−type: select
−drawing_ref: true
−options:
− - "ASTM D2321 Class I — open-graded crushed stone (preferred for flexible pipe)"
− - "ASTM D2321 Class II — clean coarse-grained, well-graded sand or gravel"
− - "ASTM D2321 Class III — coarse-grained with fines"
− - "Class B bedding (rigid pipe — granular shaped to pipe bottom)"
− - "Class A bedding (rigid pipe — concrete cradle, special applications)"
−default: "ASTM D2321 Class I — open-graded crushed stone (preferred for flexible pipe)"
−```
−
−### Pipe bedding shall be classified in accordance with ASTM D2321 for flexible pipe (HDPE, PVC) and in accordance with the bedding factor convention of the rigid pipe industry for RCP.
−
−### The bedding class for each reach shall be as indicated on the trench detail or the pipe schedule.
−
−### Class I (open-graded crushed stone, typically 3/4 in. or 1/2 in. clean) is the preferred bedding for flexible pipe because it does not require compaction beyond placement and self-consolidation, achieves predictable shape stability in the haunch zone, and provides drainage that prevents migration of fines from the surrounding soil, while Class II (clean, well-graded sand or gravel) is acceptable where Class I material is not available locally but requires careful placement and compaction to achieve the required density in the haunches. {note}
−
−## Bedding Thickness {toc}
−
−### The granular bedding course shall extend from the trench bottom to the underside of the pipe at the full design pipe slope, with a thickness as indicated below and as shown on the trench detail.
−
−```datasheet
−label: Bedding Course Thickness (Below Pipe)
−type: range
−unit: in
−drawing_ref: true
−options:
− min: 4
− max: 12
− setpoints: [4, 6, 9, 12]
−default: 6
−```
−
−### A 4-inch minimum bedding course is the typical default for pipes up to 24 inches in diameter on competent native subgrade, while larger pipes and pipes installed in soft subgrade conditions require thicker bedding (6 inches to 12 inches) to distribute the pipe load and to prevent point bearing on residual rock or hard spots in the trench bottom. {note}
−
−### The bedding course shall be shaped to match the bottom of the pipe at the spring line for rigid pipe so that the pipe bears uniformly along its full length, and shall be left level for flexible pipe (which is supported in the haunch by Class I or Class II material worked in after pipe placement).
−
−## Pipe Zone (Haunching) Backfill {toc}
−
−### The pipe zone is the region of the trench from the top of the bedding to a point 6 to 12 inches above the top of the pipe. {note}
−### This zone provides the primary structural support for flexible pipe. {note}
−
−### The pipe zone shall be filled with the same Class I or Class II material as the bedding, placed in lifts and worked into the haunches with shovel slicing or rod tamping for the lower haunches, and compacted in subsequent lifts up to the top of the pipe zone.
−
−```datasheet
−label: Pipe Zone Backfill Material
−type: radio
−drawing_ref: true
−options:
− - "Same as bedding — Class I (3/4-in. or 1/2-in. clean crushed stone)"
− - "Same as bedding — Class II (clean sand or gravel)"
− - "Native suitable material — for rigid pipe only, with Engineer approval"
−default: "Same as bedding — Class I (3/4-in. or 1/2-in. clean crushed stone)"
−```
−
−### Heavy compaction equipment shall not operate directly over the pipe until at least 12 inches of cover has been placed and compacted in lifts.
−
−### Vibratory compaction over flexible pipe with insufficient cover produces large dynamic loads on the pipe and can crush or deflect the pipe beyond the acceptable 5 percent limit. {note}
−
−### The Contractor shall use hand-operated plate compactors or jumping jack tampers within the pipe zone, transitioning to heavier equipment only after enough cover has been placed to protect the pipe.
−
−```datasheet
−label: Pipe Zone Backfill Compaction
−type: select
−unit: percent of Standard Proctor maximum dry density
−options:
− - "Class I crushed stone — placed by self-consolidation, no compaction required"
− - "Class II sand or gravel — 90 percent (general)"
− - "Class II sand or gravel — 95 percent (under structures or pavements)"
− - "Per geotechnical engineer"
−default: "Class I crushed stone — placed by self-consolidation, no compaction required"
−```
−
−## Minimum and Maximum Cover {toc}
−
−### The minimum cover over the top of the pipe shall be as detailed below.
−
−```datasheet
−label: Minimum Cover Over Top of Pipe (HS-20 Pavement)
−type: select
−unit: in
−drawing_ref: true
−options:
− - "12 in. (RCP Class III or higher)"
− - "18 in. (HDPE / PVC under pavement)"
− - "24 in. (heavy duty / HS-25)"
− - "Per pipe manufacturer for selected pipe class"
−default: "Per pipe manufacturer for selected pipe class"
−```
−
−### Minimum cover from the top of the pipe to the finished surface shall be as indicated on the drawings and shall not be less than the manufacturer's published minimum for the pipe material, pipe class or stiffness, and applicable live load.
−
−### Typical minimum cover values are: reinforced concrete pipe, 12 inches under HS-20 loading for Class III and higher classes; HDPE dual-wall pipe, 12 inches in unpaved areas and 18 inches under HS-20 pavement for PS 46 Type S pipe; and PVC sewer pipe (SDR 35, F949, F679), 12 inches in unpaved areas and 18 inches under HS-20 pavement. {note}
−
−### Maximum cover shall not exceed the pipe manufacturer's published maximum for the pipe class and trench configuration.
−
−### Deep cover applications (typically deeper than 16 to 20 feet, depending on pipe size and class) require structural review by the civil engineer of record and may require a higher pipe class or a different pipe material.
−
−### The Contractor shall not exceed the maximum cover shown on the drawings without the Engineer's review.
−
−## Trench Backfill Above the Pipe Zone {toc}
−
−### Trench backfill from the top of the pipe zone to the underside of pavement or finished grade shall conform to the trench backfill requirements of [[sync/earthwork]] for the applicable area: structural fill compacted to 95 percent of Modified Proctor under pavements and within 5 feet of structures, and general site fill compacted to 90 percent of Standard Proctor in unpaved areas remote from structures.
−
−### Backfill in the pavement zone (typically the upper 18 to 36 inches below pavement subgrade) is the source of most pavement settlement and longitudinal cracking observed over utility trenches, and inadequate compaction in the upper trench backfill is the single most common storm drainage installation deficiency that affects the rest of the project. {note}
−
−### Trench backfill compaction shall be tested by the geotechnical engineer at the frequencies specified in [[sync/earthwork]], and any failing test shall result in scarification and re-compaction.
−
−# Pipe Installation {toc}
−
−## Pipe Laying and Alignment {toc}
−
−### The alignment verification method shall be as detailed below.
−
−```datasheet
−label: Pipe Alignment Verification Method
−type: select
−drawing_ref: true
−options:
− - "Pipe laser — required for grade verification on continuous reaches"
− - "Transit and offset stakes"
− - "String line and grade boards"
−default: "Pipe laser — required for grade verification on continuous reaches"
−```
−
−### Pipe shall be laid in the trench beginning at the downstream end and progressing upstream, with bells (or hub ends, depending on pipe type) facing upstream.
−
−### This orientation places the spigot into the bell with the flow direction, so that any minor joint imperfection does not collect debris and so that joint home depth marks are visible from the upstream end. {note}
−
−### Each pipe section shall be aligned to the design center line and grade before the joint is made.
−
−### Once the joint is home, alignment adjustment requires re-jointing.
−
−### Pipe alignment shall be checked with a laser, transit, or string line set to the design center line.
−
−### Pipe grade shall be verified by transferring grades from offset stakes or from a laser receiver mounted in the pipe.
−
−### Pipe-to-pipe alignment shall be such that no joint is deflected beyond the manufacturer's permissible deflection limit; permissible deflection at gasketed joints typically ranges from 1.5 to 5 degrees depending on pipe size and joint type.
−
−### Where the design alignment requires a deflection exceeding the joint's permissible limit, a fitting shall be used in place of a deflected joint, or the alignment shall be reviewed by the Engineer.
−
−### A pipe laser is the standard method for verifying both alignment and grade on storm sewer reaches and is required for any reach longer than 100 feet.
−
−### Hand-leveling and string-line methods are acceptable only for short reaches between structures and shall be checked against the design invert at each structure before joints are made.
−
−## Joint Assembly — Gasketed Pipe (RCP, HDPE, PVC) {toc}
−
−### Before the spigot is inserted, the bell or hub of each pipe shall be inspected so that the bell is clean of debris, the gasket groove is confirmed to have the gasket correctly seated all the way around the circumference, and any contamination on the gasket is removed.
−
−### Lubricant approved by the pipe manufacturer shall be applied to the gasket and to the spigot in accordance with the manufacturer's installation instructions.
−
−### The use of incompatible lubricants (e.g., petroleum-based products on EPDM gaskets) is not acceptable and will degrade the gasket.
−
−### The spigot shall be inserted into the bell using equipment appropriate for the pipe size and weight: a come-along or chain hoist with a softener strap for small pipe, a hydraulic puller for large RCP, or a slip-fit assembly for HDPE and PVC where the pipe is light enough to be pushed home by hand or with light mechanical assistance.
−
−### The spigot shall be advanced until the home-mark on the spigot is at the bell face or until the spigot shoulder contacts the bell, whichever applies to the joint design.
−
−### The joint shall not be over-inserted past the home mark.
−
−### Over-insertion can roll or pinch the gasket and create a leak path. {note}
−
−### After each joint is assembled, the Contractor shall check the joint home depth around the full circumference using a feeler gauge or by reaching into the bell where access permits.
−
−### Any joint that does not seat fully shall be disassembled, the gasket inspected and re-seated (or replaced if damaged), and the joint re-made before backfill proceeds.
−
−## Joint Assembly — Mechanical Couplings {toc}
−
−### The joining method at material transitions shall be as detailed below.
−
−```datasheet
−label: Pipe Joining at Material Transitions
−type: select
−drawing_ref: true
−options:
− - "Manufacturer's listed transition coupling for the specific OD pair"
− - "Compression repair coupling with stainless steel band (small repair only)"
− - "Cast-in-place concrete collar (RCP transitions only)"
−default: "Manufacturer's listed transition coupling for the specific OD pair"
−```
−
−### Where mechanical couplings are used at transitions (between dissimilar pipe materials, at field cut-ins, or at connections to existing piping), the coupling shall be of a type listed for the materials being joined, with the gasket sized for the actual outside diameters of the pipes — not for the nominal diameters.
−
−### Concrete pipe outside diameters, HDPE outside diameters, and PVC outside diameters differ for the same nominal size, so using a coupling sized for one material on another will result in over-compressed or under-compressed gaskets and joint failure. {note}
−
−## Cutting Pipe to Length {toc}
−
−### Pipe may be cut to length to meet structures or to make field adjustments.
−
−### Cuts shall be square (perpendicular to the pipe axis), shall be deburred and chamfered on the spigot end to allow gasket entry without rolling the gasket, and shall not damage the bell of the upstream pipe.
−
−### For RCP, cutting shall be performed with a diamond saw; flame-cutting and impact methods that crack the concrete are not acceptable.
−
−### For HDPE and PVC, cuts shall be made with a saw or pipe cutter producing a clean perpendicular face.
−
−## Sag and Belly Avoidance {toc}
−
−### The completed pipe shall have a uniform grade matching the design invert elevations at each structure.
−
−### Sags ("bellies") in the pipe between structures collect sediment, reduce capacity, and cannot be cleaned with conventional rodding equipment, and sags discovered after backfill placement are difficult and expensive to correct, so the time to catch them is during pipe laying, before backfill. {note}
−
−### The Contractor shall verify the as-laid invert at each joint and shall report any deviation from grade exceeding the manufacturer's installation tolerance to the Engineer.
−
−## Connection to Existing Storm Systems {toc}
−
−### Coordination for connection to an existing system shall address the items listed below.
−
−```datasheet
−label: Connection to Existing System — Coordination
−type: checkbox
−options:
− - "Utility owner pre-construction coordination meeting completed"
− - "Bypass pumping plan (where required for in-service systems)"
− - "Downstream sediment protection installed before cut-in"
− - "AHJ inspection scheduled for connection witnessing"
− - "As-built record updated with connection station and invert"
−default: "AHJ inspection scheduled for connection witnessing"
−```
−
−### Where the work connects to an existing manhole, inlet, or pipe, the Contractor shall coordinate with the utility owner and the Engineer in advance to confirm the connection method, the AHJ requirements, any flow-bypass needs during the cut-in, and the inspection hold points.
−
−### Core-drilling into existing precast structures is the preferred method for new pipe connections; the core shall be drilled with a diamond core barrel sized for the new pipe with appropriate annular clearance for a resilient connector boot.
−
−### Cut-ins on existing in-service pipe shall be performed only with the utility owner's approval and only after the Contractor has a plan for managing flows during the work — including bypass pumping if required.
−
−### The Contractor shall protect downstream systems from sediment and construction debris introduced during the cut-in by installing temporary inlet protection or a downstream sediment trap before the cut-in begins.
−
−# Structure Installation {toc}
−
−## Base Placement {toc}
−
−### Precast manhole bases shall be set on a compacted granular bedding course (typically 6 to 12 inches of Class I or Class II material) shaped to provide a level, uniform bearing surface at the design invert elevation of the lowest pipe.
−
−### Cast-in-place bases shall be placed on a bedding course, with reinforcement and pipe penetration formwork installed before concrete placement.
−
−### The base shall be set level and at the elevation that places the lowest pipe invert at the design value.
−
−### The base elevation shall be verified before pipe is connected to the structure.
−
−### Small adjustments in base elevation propagate into structure barrel height and frame elevation and are very expensive to correct once riser sections are stacked. {note}
−
−## Riser, Cone, and Top Slab Installation {toc}
−
−### Precast riser sections shall be lifted and set with the lifting hardware specified by the manufacturer (typically lift inserts cast into the riser).
−
−### The joint between sections shall be cleaned, the preformed butyl sealant (ASTM C990) or the O-ring gasket (ASTM C443) placed in the joint, and the upper section lowered onto the lower section so that the sealant or gasket is uniformly compressed around the full circumference.
−
−### The Contractor shall verify that the upper section seats fully before releasing the load on the crane.
−
−### Eccentric cones shall be oriented with the offset on the side opposite the inflow pipe where possible, so that the manhole ladder or step alignment is over solid bench.
−
−### The cone-to-top-slab joint and the cone-to-frame interface shall be sealed in the same manner as the section-to-section joints.
−
−## Bench and Channel Construction {toc}
−
−### The manhole bench and channel construction shall be as detailed below.
−
−```datasheet
−label: Manhole Bench / Channel Construction
−type: select
−drawing_ref: true
−options:
− - "Cast-in-place concrete bench, hand-formed channel"
− - "Cement mortar bench, hand-troweled smooth"
− - "Factory-formed channel insert (where available for the pipe pattern)"
−default: "Cement mortar bench, hand-troweled smooth"
−```
−
−### The bench inside the manhole shall be shaped to direct flow smoothly from each inlet pipe to the outlet pipe with minimum hydraulic loss.
−
−### The channel through the bench shall be the full inside diameter of the largest pipe (or the outlet pipe) at the springline elevation, with the bench sloped at 1 inch per foot from the channel edge toward the outside wall to drain.
−
−### Bench material shall be cement mortar, cast-in-place concrete, or factory-formed channel inserts.
−
−### Smooth, hard-troweled mortar resists abrasion and is easier to maintain than rough, hand-floated material. {note}
−
−### The channel through the manhole shall be at full pipe diameter at the inverts and shall not present a step, lip, or change of section that would catch debris.
−
−### Manhole inverts shall match the pipe invert elevations exactly.
−
−### A manhole channel that sits below the pipe invert creates a sump that collects sediment, and a channel that sits above the pipe invert restricts flow. {note}
−
−## Drop Connections {toc}
−
−### Where an incoming pipe enters the manhole at an elevation more than 24 inches above the outlet invert, an external or internal drop connection shall be provided as indicated on the drawings, so that flow is conveyed from the high inlet to the outlet without spilling onto the manhole bench.
−
−### External drops (a vertical pipe outside the manhole barrel connecting the inlet pipe to a low connection into the manhole) are preferred for sanitary applications, while in storm applications internal drops (a vertical pipe inside the manhole) are acceptable and are commonly used. {note}
−
−## Setting Frames and Castings {toc}
−
−### After backfill around the structure has been compacted to grade, the frame shall be set on the structure with adjustment rings as described in the Castings section above.
−
−### The frame shall be set level, square, and at the elevation that places the top of the casting at finished pavement or grade.
−
−### Mortar joints between the structure top, the adjustment rings, and the frame shall be smooth on the inside of the structure (so as not to interfere with future re-grading or replacement of the frame), and shall be installed without voids that would allow infiltration.
−
−### Where the frame is set in advance of final pavement placement, the Contractor shall protect the frame and the structure rim during paving operations.
−
−### Where the frame is set in advance of final pavement placement, the Contractor shall coordinate frame setting with pavement placement so that the frame is set to final grade as the pavement is placed around it, or so that the frame is temporarily protected by a steel plate and re-set to final grade after paving, because pavers driving over an unsupported frame can rock the frame loose.
−
−# Testing {toc}
−
−## Pipe Leakage and Joint Testing {toc}
−
−### The pipe leakage test method shall be as detailed below.
−
−```datasheet
−label: Pipe Leakage Test Method
−type: select
−options:
− - "Low-pressure air test per ASTM F1417 (PVC and HDPE)"
− - "Hydrostatic test (head pressure)"
− - "Joint-by-joint pressure test (large-diameter RCP only)"
− - "Vacuum test (manholes and select structures)"
− - "Not required — confirm AHJ acceptance criteria"
−default: "Low-pressure air test per ASTM F1417 (PVC and HDPE)"
−```
−
−### All storm drainage pipe shall be tested for leakage after pipe-zone backfill is complete and before final trench backfill is closed above the pipe zone.
−
−### The test method shall be one of the following, as indicated on the drawings or directed by the Engineer.
−
−### The low-pressure air test per ASTM F1417 is the standard production test for PVC and HDPE storm sewer reaches between structures, with the reach plugged at both manholes using test plugs rated for the test pressure and physically restrained against blow-out, air introduced gradually to the test pressure (typically 3.5 psi above any backpressure from groundwater), and the pressure drop measured over the test hold period specified in ASTM F1417 for the pipe size and length. {note}
−
−### Test plugs and end caps shall be confirmed rated for the test pressure before pressurizing.
−
−### The hydrostatic test (water column or head test) is acceptable for any pipe material and is the reference method for pipe and joint leakage, with the reach plugged at the downstream end, filled with water from the upstream manhole to a head of 2 to 5 feet above the upstream pipe crown, and held without makeup water for not less than 1 hour so that any drop in water level indicates leakage; the hydrostatic test is impractical where the upstream invert is below grade with no manhole available as the water column, and where freezing weather precludes water testing. {note}
−
−### Joint-by-joint pressure testing — pressurizing only the individual joint annulus with a packer testing device — is used on large-diameter RCP (typically 48 inches and larger) where reach-length water testing is impractical, and the test is performed with specialized equipment per the device manufacturer's procedure and is observed by the Engineer or AHJ inspector. {note}
−
−## Manhole Vacuum Testing {toc}
−
−### The manhole vacuum test requirement shall be as detailed below.
−
−```datasheet
−label: Manhole Vacuum Test
−type: radio
−options:
− - "Required — all storm drainage manholes per ASTM C1244 procedure"
− - "Required — manholes with cast-in resilient connectors per ASTM C923"
− - "Not required — confirm AHJ acceptance criteria"
−default: "Required — all storm drainage manholes per ASTM C1244 procedure"
−```
−
−### Precast manholes shall be vacuum tested to confirm watertight construction of the structure joints, the pipe-to-structure connections, and the cone and top slab seals.
−
−### The vacuum test shall be performed after the structure is complete and before exterior backfill is placed (where possible) or, where backfill must be placed before the casting is set, after the casting is set but before final paving over the structure.
−
−### The vacuum test plug is sealed at the top of the cone, the manhole evacuated to 10 inches of mercury (approximately 5 psi), and the pump valved off, with the vacuum held for the duration specified in the procedure (typically 1 minute for manholes up to 12 feet deep, longer for deeper structures) and a maximum allowable pressure rise of 1 inch of mercury. {note}
−
−### A manhole that fails the vacuum test shall be inspected for the leak path — typically at a section joint, a pipe connector, or the cone seal — and the leak shall be sealed by re-tightening the joint, regrouting, or applying an approved external sealant.
−
−### A manhole that fails the vacuum test shall be re-tested until it passes.
−
−## Deflection Testing of Flexible Pipe {toc}
−
−### The maximum deflection limit for flexible pipe shall be as detailed below.
−
−```datasheet
−label: Deflection Test — Mandrel Limit
−type: radio
−options:
− - "5 percent maximum deflection (standard for storm sewer flexible pipe)"
− - "7.5 percent maximum deflection (where permitted by AHJ for storm-only)"
− - "Per pipe manufacturer's installation manual"
−default: "5 percent maximum deflection (standard for storm sewer flexible pipe)"
−```
−
−### All HDPE and PVC pipe shall be deflection-tested by mandrel pull-through after final backfill has been placed and the trench has been left undisturbed for at least 30 days, or after the final cover load (including pavement) has been placed, whichever is later.
−
−### The 30-day wait permits the soil envelope around the pipe to equilibrate to its post-construction shape, and testing too soon after backfill can produce passing results that fail later. {note}
−
−### The mandrel shall be a go/no-go device sized to the minimum allowable inside diameter at the specified deflection limit (5 percent or 7.5 percent of the nominal inside diameter).
−
−### The mandrel shall be pulled through the reach by hand or with light mechanical aid, without using a winch or other force that could damage the pipe.
−
−### If the mandrel cannot be pulled through with reasonable manual force, the pipe has failed the deflection limit and the cause shall be investigated.
−
−### Common causes of excessive deflection are inadequate haunch compaction, premature loading by heavy equipment, or use of unsuitable bedding material. {note}
−
−### Pipe failing the deflection test shall be repaired by removing and re-bedding the affected reach, by installing a structural liner approved by the Engineer, or by replacement of the affected reach.
−
−### The Contractor shall not abandon a failed deflection result by "rounding up" the mandrel or by using a smaller mandrel than required by the specification.
−
−## Test Reporting {toc}
−
−### Test results — pass and fail — shall be documented on testing forms that include the reach identification (upstream and downstream structure numbers), pipe material and size, test method, test pressure or head, hold time, start and end pressure or water level readings, and the names of the Contractor's test foreman and the witnessing inspector.
−
−### Failed tests shall not be re-tested without first identifying and correcting the cause of failure.
−
−### Both the failure and the successful retest shall be recorded.
−
−# Cleaning {toc}
−
−## After all testing is complete and before the system is turned over to the Owner or the AHJ, the entire storm drainage system is cleaned of debris, sediment, mortar droppings, and any construction materials. {note}
−
−## Cleaning shall be performed by jet-flushing, by mechanical bucketing, or by other methods suited to the pipe size and configuration.
−
−```datasheet
−label: Final System Cleaning Method
−type: select
−options:
− - "Jet flushing with water — vacuum recovery of debris"
− - "Mechanical bucket cleaning (large-diameter pipe)"
− - "Manual cleanout (small structures and areas)"
− - "Per AHJ acceptance requirement"
−default: "Jet flushing with water — vacuum recovery of debris"
−```
−
−## Sediment removed during cleaning shall be disposed of off-site or, where the project has an on-site stormwater facility, at an Owner-approved location.
−
−## Inlet sumps, manhole benches, and the inverts of all structures shall be flushed and inspected to confirm clean condition.
−
−## Inlet grates and frames shall be cleaned of construction debris and tested for free seating in the frame.
−
−## The Contractor shall not turn the system over with inlet protection bags or temporary sediment controls still in place.
−
−## Inlet protection bags and temporary sediment controls shall be removed at closeout.
−
−## Inlet protection bags and temporary sediment controls were appropriate during construction but reduce hydraulic capacity below design value. {note}
−
−## After cleaning, the Contractor shall conduct a final walk-through inspection with the Engineer and the AHJ inspector (where required), opening each structure to verify clean condition.
−
−## Any sediment, debris, or visible damage discovered shall be addressed before final acceptance.
−
−# Pre-Treatment and Water Quality Structures {toc}
−
−## Where the project includes pre-treatment or water quality structures within the storm drainage system — including oil-water separators, hydrodynamic separators, gross particle separators, sand filters, or bioretention discharge structures — those structures are typically proprietary devices governed by the manufacturer's installation instructions and the civil drawings. {note}
−
−## The pipe and structure installation provisions of this standard apply to the pipe connections into and out of the device.
−
−## The device itself shall be installed per the manufacturer's instructions and the civil details.
−
−## Oil-water separators are required by local stormwater regulations or by the NPDES MS4 program for runoff originating in vehicular fueling, vehicle service, or industrial yard areas. {note}
−
−## Where required, the separator shall be located upstream of the storm system connection to the public infrastructure and shall be sized per the manufacturer's procedure for the contributing drainage area and the design storm.
−
−## The Contractor shall not omit a specified water-quality structure.
−
−```datasheet
−label: Pre-Treatment / Water Quality Structures Included
−type: checkbox
−options:
− - "Oil-water separator (typically required at fueling, vehicle service, or industrial yard areas)"
− - "Hydrodynamic separator (gross debris removal upstream of detention)"
− - "Gross particle / debris separator"
− - "Sediment forebay (within or upstream of detention basin)"
− - "Bioretention discharge structure"
− - "Not included — confirm SWPPP / MS4 program requirements"
−default: "Not included — confirm SWPPP / MS4 program requirements"
−```
−
−## Omitting a specified water-quality structure creates a downstream permit violation and an Owner liability that survives the warranty period. {note}
−
−# Acceptance {toc}
−
−## Final acceptance of the storm drainage system shall require:
−
−- Completion of all testing (pipe leakage, deflection, manhole vacuum) with passing results on every reach and every structure
−- AHJ inspection and release of any portion of the system connected to public infrastructure
−- Submission of complete as-built drawings showing installed pipe alignments, structure rim and invert elevations, casting types, and any deviations from design
−- Final cleaning of pipe and structures with confirmation by walk-through inspection
−- Removal of all temporary construction stormwater controls within the storm system (inlet protection, sediment traps, bypass pumping equipment)
−- Submission of all closeout documentation listed in the Submittals section
−
−```datasheet
−label: Acceptance Documentation Required
−type: checkbox
−options:
− - "Pipe leakage test reports — all reaches"
− - "Deflection test reports — all flexible pipe reaches"
− - "Manhole vacuum test reports — all structures"
− - "As-built record drawings with rim and invert schedule"
− - "AHJ acceptance documentation"
− - "Final cleaning certification"
− - "Casting and structure warranty documentation"
−default: "Pipe leakage test reports — all reaches"
−```
−
−## The Contractor shall remain responsive to defect reports throughout the warranty period.
−
−## The Owner's acceptance of the storm drainage system at substantial completion does not waive the Contractor's warranty obligations or the Contractor's liability for latent defects discovered after acceptance, and storm drainage defects that affect site hydraulics often do not become apparent until the first significant rainfall event after acceptance. {note}
−
−# Warranty {toc}
−
−## The warranty period for the storm drainage system shall be as selected below.
−
−```datasheet
−label: Storm Drainage Warranty Period
−type: select
−options:
− - "1 year from substantial completion"
− - "2 years from substantial completion"
− - "Per AHJ or utility owner requirement (typically 1 to 2 years)"
−default: "1 year from substantial completion"
−```
−
−## The Contractor shall warrant the storm drainage system, including all pipe, joints, structures, castings, bedding and backfill, and connections, against defects in materials and workmanship for the project warranty period beginning at substantial completion.
−
−## Warranty obligations include correction of leaks, settlement at pavement repairs over trenches, excessive pipe deflection developing after acceptance, casting movement or rocking, and structure rim settlement.
−
−## Settlement at pavement repairs over storm trenches is a particularly common warranty item, because even properly installed trench backfill consolidates slightly over the first one or two seasonal cycles, and pavement that was at grade at the time of paving often sags visibly at a year or two after completion. {note}
−
−## The Contractor's warranty shall cover settlement when it can be attributed to trench backfill consolidation and not to subgrade conditions outside the trench.
−
−## Manufacturer warranties for castings, precast structures, and proprietary water-quality devices shall be passed through to the Owner as part of the closeout documentation.
−
−## Where a manufacturer warranty extends beyond the Contractor's installation warranty, the Contractor shall assign the manufacturer warranty to the Owner at closeout.
−
−## The warranty does not relieve the Contractor of liability for non-conforming installation discovered after the warranty period.
−
−## Pipe installed at incorrect slope, structures with leaking joints concealed by exterior backfill, castings under-rated for the load class of the location, or pipe materials substituted from the specified standard remain the Contractor's responsibility as latent defects whenever discovered. {note}
+---
+title: Storm Drainage
+category: Sitework
+description: >
+ When to use: Gravity storm sewer collection and conveyance on the site, for commercial, institutional, industrial, and multi-family projects. Covers storm sewer mains, laterals, and fittings in reinforced concrete, corrugated thermoplastic, solid-wall and profile-wall PVC, corrugated metal, and ductile iron; catch basins, curb and grate inlets, area drains, manholes, and junction structures; frames, grates, and covers; trench excavation, pipe embedment, and backfill within the pipe zone; outfall end treatments and scour protection; connection to an existing or municipal storm system; and the leakage, deflection, and video acceptance testing of the completed system.
+ Not intended for: Roof drains, leaders, and horizontal storm piping on or within the building up to the point of connection (see [[sync/roof-drainage]]); detention, retention, infiltration, and water-quality treatment facilities and their outlet control structures (see [[sync/stormwater-management-systems]]); perforated underdrains, edge drains, and drainage blankets (see [[sync/subdrainage]]); building-perimeter footing drains (see [[sync/foundation-drainage]]); linear trench drains and interior floor drains (see [[sync/trench-drains-and-interceptors]]); water, sanitary, and dry utilities (see [[sync/site-utilities]] and [[sync/sanitary-sewer-systems]]); mass excavation, general fill, and trench backfill above the pipe zone (see [[sync/earthwork]]); shoring and construction dewatering (see [[sync/excavation-support-and-dewatering]]); temporary construction stormwater controls and the SWPPP (see [[sync/erosion-and-sediment-control]]); pavement and aggregate base over completed trenches (see [[sync/aggregate-base-course]]); and the hydrologic and hydraulic design of the storm system itself, which is the work of the civil engineer of record.
+---
+
+# Scope {toc}
+
+## This standard governs the materials, installation, testing, cleaning, and acceptance of the gravity storm sewer system that collects surface runoff from the site and conveys it to a point of discharge. {note}
+
+## The scope begins at the throat of each curb inlet, at the rim of each grate inlet or area drain, and at the first structure or fitting receiving a roof drain leader, and ends at the point of connection to the public storm system, to an on-site stormwater management facility, or at a permitted outfall. {note}
+
+## The following are outside this standard and are governed elsewhere: {note}
+
+- Sizing of pipe, inlets, and structures, and the hydraulic and hydrologic design that produces those sizes
+- Selection and design of detention, retention, infiltration, and water-quality treatment facilities
+- Grading, surface contours, and the overland flow paths that deliver runoff to the inlets
+- Pavement structure and aggregate base over completed storm trenches
+- Temporary construction stormwater controls, inlet protection during construction, and the SWPPP
+
+## Storm drainage governs the long-term flood performance of the site, and its defects are expensive to reach after the pavement is down: an under-bedded pipe settles into a sag that no rodding equipment can clear, a leaking structure joint bleeds fines out of the surrounding soil until the pavement above it dishes, and a casting set proud of grade is struck by every plow that passes. {note}
+
+## The Contractor shall install the system at the alignment, slope, and invert elevations shown, and shall not adjust them to suit field conditions without the written direction of the Engineer of Record.
+
+## The Contractor shall report to the Engineer of Record any condition that prevents the system from being built as drawn, including utility conflicts, insufficient cover, insufficient slope, and a trench bottom that differs from the geotechnical report.
+
+## Work under this standard shall be coordinated with [[sync/earthwork]] for excavation and backfill, with [[sync/erosion-and-sediment-control]] for protection of the system during construction, and with [[sync/aggregate-base-course]] for the pavement structure bearing on completed storm trenches.
+
+# Referenced Standards {toc}
+
+## Materials, fabrication, installation, and testing shall comply with the latest adopted edition of each of the following unless a specific edition is cited in the Contract Documents.
+
+## Where the Contract Documents, the adopted code, the utility owner's standards, and the referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
+
+| Standard | Title |
+|----------|-------|
+| ASTM A48/A48M | Gray Iron Castings |
+| ASTM A536 | Ductile Iron Castings |
+| ASTM A760/A760M | Corrugated Steel Pipe, Metallic-Coated, for Sewers and Drains |
+| ASTM A929/A929M | Steel Sheet, Metallic-Coated by the Hot-Dip Process, for Corrugated Steel Pipe |
+| ASTM B745/B745M | Corrugated Aluminum Pipe for Sewers and Drains |
+| ASTM C76 | Reinforced Concrete Culvert, Storm Drain, and Sewer Pipe |
+| ASTM C443 | Joints for Concrete Pipe and Manholes, Using Rubber Gaskets |
+| ASTM C478 | Circular Precast Reinforced Concrete Manhole Sections |
+| ASTM C506 | Reinforced Concrete Arch Culvert, Storm Drain, and Sewer Pipe |
+| ASTM C507 | Reinforced Concrete Elliptical Culvert, Storm Drain, and Sewer Pipe |
+| ASTM C655 | Reinforced Concrete D-Load Culvert, Storm Drain, and Sewer Pipe |
+| ASTM C877 | External Sealing Bands for Concrete Pipe, Manholes, and Precast Box Sections |
+| ASTM C913 | Precast Concrete Water and Wastewater Structures |
+| ASTM C923 | Resilient Connectors Between Reinforced Concrete Manhole Structures, Pipes, and Laterals |
+| ASTM C924 | Testing Concrete Pipe Sewer Lines by Low-Pressure Air Test Method |
+| ASTM C969 | Infiltration and Exfiltration Acceptance Testing of Installed Precast Concrete Pipe Sewer Lines |
+| ASTM C990 | Joints for Concrete Pipe, Manholes, and Precast Box Sections Using Preformed Flexible Joint Sealants |
+| ASTM C1103 | Joint Acceptance Testing of Installed Precast Concrete Pipe Sewer Lines |
+| ASTM C1244 | Concrete Sewer Manholes by the Negative Air Pressure (Vacuum) Test Prior to Backfill |
+| ASTM C1433 | Precast Reinforced Concrete Monolithic Box Sections for Culverts, Storm Drains, and Sewers |
+| ASTM C1479 | Installation of Precast Concrete Sewer, Storm Drain, and Culvert Pipe Using Standard Installations |
+| ASTM D2321 | Underground Installation of Thermoplastic Pipe for Sewers and Other Gravity-Flow Applications |
+| ASTM D2487 | Classification of Soils for Engineering Purposes (Unified Soil Classification System) |
+| ASTM D3034 | Type PSM Poly(Vinyl Chloride) (PVC) Sewer Pipe and Fittings |
+| ASTM D3212 | Joints for Drain and Sewer Plastic Pipes Using Flexible Elastomeric Seals |
+| ASTM F477 | Elastomeric Seals (Gaskets) for Joining Plastic Pipe |
+| ASTM F679 | Poly(Vinyl Chloride) (PVC) Large-Diameter Plastic Gravity Sewer Pipe and Fittings |
+| ASTM F794 | Poly(Vinyl Chloride) (PVC) Profile Gravity Sewer Pipe and Fittings Based on Controlled Inside Diameter |
+| ASTM F949 | Poly(Vinyl Chloride) (PVC) Corrugated Sewer Pipe With a Smooth Interior and Fittings |
+| ASTM F1417 | Installation Acceptance of Plastic Non-Pressure Sewer Lines Using Low-Pressure Air |
+| ASTM F2306 | Annular Corrugated Profile-Wall Polyethylene (PE) Pipe and Fittings for Gravity-Flow Storm Sewer and Subsurface Drainage |
+| ASTM F2736 | Polypropylene (PP) Corrugated Single Wall and Double Wall Pipe, 6 in. to 30 in. |
+| ASTM F2764 | Polypropylene (PP) Corrugated Double and Triple Wall Pipe and Fittings, 30 in. to 60 in. |
+| ASTM F2881 | Polypropylene (PP) Dual Wall Pipe and Fittings for Non-Pressure Storm Sewer Applications |
+| AASHTO M36 | Corrugated Steel Pipe, Metallic-Coated, for Sewers and Drains |
+| AASHTO M196 | Corrugated Aluminum Pipe for Sewers and Drains |
+| AASHTO M218 | Steel Sheet, Zinc-Coated (Galvanized), for Corrugated Steel Pipe |
+| AASHTO M252 | Corrugated Polyethylene Drainage Pipe, 3 in. to 10 in. Diameter |
+| AASHTO M274 | Steel Sheet, Aluminum-Coated (Type 2), for Corrugated Steel Pipe |
+| AASHTO M294 | Corrugated Polyethylene Pipe, 12 in. to 60 in. Diameter |
+| AASHTO M306 | Drainage, Sewer, Utility, and Related Castings |
+| AASHTO M330 | Polypropylene Pipe, 12 in. to 60 in. Diameter |
+| AASHTO LRFD | LRFD Bridge Design Specifications (Section 12, Buried Structures) |
+| ASCE 15 | Direct Design of Buried Precast Concrete Pipe Using Standard Installations |
+| AWWA C104 | Cement-Mortar Lining for Ductile-Iron Pipe and Fittings |
+| AWWA C111 | Rubber-Gasket Joints for Ductile-Iron Pipe and Fittings |
+| AWWA C151 | Ductile-Iron Pipe, Centrifugally Cast |
+| AWWA C153 | Ductile-Iron Compact Fittings |
+| 29 CFR 1926 Subpart P | Excavations |
+| 40 CFR 122 | EPA National Pollutant Discharge Elimination System Permit Program |
+
+## The governing edition, the local public works manual, and any municipal separate storm sewer system program requirements shall be confirmed with the Authority Having Jurisdiction and the utility owner before any work in the public right-of-way begins.
+
+## State department of transportation standard specifications frequently govern the portion of a site storm system that connects to or crosses a state route, and those specifications carry their own casting patterns, pipe material lists, and acceptance tests that can differ from the requirements of this standard. {note}
+
+# Submittals {toc}
+
+## Action Submittals {toc}
+
+### The Contractor shall submit the following for the Engineer of Record's review and acceptance before any pipe, structure, or casting is procured or fabricated:
+
+- Product data for each pipe and fitting material, identifying the governing product standard, the strength class or pipe stiffness, the wall thickness or dimension ratio, the joint type, and the gasket material and its governing standard
+- Shop drawings for precast manholes, junction structures, inlets, and headwalls, showing barrel diameter, section heights, base type, top configuration, reinforcement, pipe opening locations and connector type, lifting hardware, and load rating
+- Product data for every frame, grate, and cover, identifying the casting alloy and grade, the AASHTO M306 proof-load listing, the clear opening, the legend, and any utility owner pattern number
+- Gradation test results for each proposed bedding and embedment material source, classified in accordance with ASTM D2321
+- Testing plan identifying the leakage test method, test pressures or heads, hold times, mandrel sizes, video equipment, the independent testing agency, and the reaches and structures to be tested
+- Connection details, permits, and utility owner approvals for each connection to an existing or public storm system
+- Procedure for maintaining the record-set markup of installed alignments, inverts, and materials
+
+```datasheet
+label: Action Submittals Required
+type: checkbox
+options:
+ - "Pipe and fitting product data with governing standard, class, and joint type"
+ - "Precast structure shop drawings with load rating and pipe openings"
+ - "Casting product data with AASHTO M306 listing and legend"
+ - "Bedding and embedment gradation test results"
+ - "Testing plan with methods, pressures, hold times, and agency"
+ - "Existing-system connection details and utility owner approvals"
+ - "Record-set markup procedure"
+```
+
+### Storm drainage below grade shall not be installed in any area for which the action submittals covering that work remain unaccepted.
+
+## Closeout Submittals {toc}
+
+### Before substantial completion the Contractor shall submit the following:
+
+- Record drawings showing installed plan and profile, station and offset from permanent reference points, finished rim elevation and every pipe invert at each structure, casting type installed at each location, pipe material and size by reach, and every deviation from the Contract Documents
+- Signed field test reports for every leakage test, deflection test, and structure test, showing the reach or structure identification and a pass or fail determination for each
+- Video inspection recordings and logs where video inspection is required
+- Manufacturer warranties for castings, precast structures, and manufactured end treatments, assigned to the Owner
+- Certification that the system has been cleaned and that all temporary inlet protection and sediment controls within the system have been removed
+- Authority Having Jurisdiction acceptance documentation for any portion of the system connected to public infrastructure
+
+```datasheet
+label: Closeout Submittals Required
+type: checkbox
+options:
+ - "Record drawings with rim and invert elevations by structure"
+ - "Signed field test reports with pass or fail by reach and structure"
+ - "Video inspection recordings and logs"
+ - "Assigned manufacturer warranties"
+ - "Cleaning and temporary-control removal certification"
+ - "Authority Having Jurisdiction acceptance documentation"
+```
+
+# Quality Assurance {toc}
+
+## Installer Qualifications {toc}
+
+### The Contractor performing storm drainage work shall have completed not fewer than three projects of comparable pipe size, depth, and structure count within the preceding five years, and shall submit those project references on request.
+
+### Personnel assembling gasketed joints shall be trained in the joint manufacturer's assembly procedure, including gasket seating, lubricant application, and home-mark verification.
+
+### The first three joints of each pipe material and size installed on the project shall be assembled in the presence of the Engineer of Record's inspector, and production work in that material and size shall not proceed until those joints are accepted.
+
+### The demonstration joint requirement catches the systematic errors — wrong lubricant, gasket rolled at the same point on every joint, home mark ignored — at three joints instead of at the leakage test, when the reach is backfilled and the pavement is scheduled. {note}
+
+## Product Identification and Marking {toc}
+
+### Pipe, fittings, gaskets, castings, and precast structures shall bear the manufacturer's identification, the governing product standard designation, and a production date or lot number sufficient to trace the item to its certification records.
+
+### Pipe, structures, or castings that cannot be traced to certification records shall be rejected and removed from the site, and the cost of removal and replacement shall be borne by the Contractor.
+
+### Castings installed within the public right-of-way shall additionally bear the foundry identification, the AASHTO M306 proof-load marking, and any pattern number required by the utility owner.
+
+## Preinstallation Conference {toc}
+
+### Before storm drainage installation begins the Contractor shall convene a preinstallation conference attended by the Contractor's site utility superintendent, the civil engineer of record, the geotechnical engineer of record, the testing agency, and the Authority Having Jurisdiction's inspector where that inspector's attendance is required by the permit.
+
+### The conference shall review pipe materials and joint assembly, the embedment and compaction requirements, dewatering and flotation control, the testing program and acceptance criteria, the inspection hold points, the procedure for connecting to existing systems, and the procedure for reporting differing site conditions at the trench bottom.
+
+## Inspection Hold Points {toc}
+
+### The Contractor shall give the Engineer of Record and the Authority Having Jurisdiction's inspector not less than 24 hours' notice before each hold point listed below, and shall not proceed past a hold point until the inspection has been performed and released in writing:
+
+- Trench bottom, before bedding is placed
+- Bedding surface and pipe alignment, grade, and joints, before embedment is placed
+- Structure foundation, before the base section is set
+- Pipe penetrations and resilient connectors at each structure, before exterior backfill
+- Embedment compaction in the pipe zone, before final backfill
+- Leakage testing, deflection testing, and video inspection
+- Frame and casting elevation, before final pavement placement
+
+### Where an inspection is not performed within 24 hours of the scheduled time through no fault of the Contractor, the Contractor may proceed past the hold point after notifying the Engineer of Record in writing, and the Owner shall bear the cost of any later uncovering required to inspect that work.
+
+# System Watertightness and Joint Performance {toc}
+
+## The joint performance class establishes what the pipe joints, structure joints, and pipe-to-structure connections are required to do, and every material article in this standard is written against it. {note}
+
+## The joint performance class for the storm drainage system shall be as indicated in the datasheet.
+
+```datasheet
+label: Storm Sewer Joint Performance Class
+type: select
+options:
+ - "Watertight - joints qualified by laboratory hydrostatic test"
+ - "Silt-tight - joints qualified against passage of fine-grained soil"
+ - "Soil-tight - joints qualified against passage of coarse-grained soil"
+default: "Watertight - joints qualified by laboratory hydrostatic test"
+```
+
+## A watertight joint is qualified by a laboratory hydrostatic test of the joint assembly and is the class assumed by the leakage tests in this standard; silt-tight and soil-tight classes limit the passage of soil through the joint but admit water, and systems built to those classes are accepted on video inspection and alignment rather than on a leakage test. {note}
+
+## Storm systems in fill, in expansive or dispersive soils, above a shallow water table, or discharging within a wellhead protection area carry the highest consequence from a leaking joint, because the leak moves soil rather than only water and the surface expression is a pavement failure or a sinkhole rather than a wet spot. {note}
+
+## Where the joint performance class is watertight, mortar-only joints, mastic-only joints, un-gasketed tongue-and-groove joints, and un-gasketed coupling bands shall not be used.
+
+## Mortar and external sealing bands are supplementary to a gasketed joint and shall not be substituted for the gasket.
+
+## Where the joint performance class is silt-tight or soil-tight, the Contractor shall submit the joint manufacturer's qualification test report demonstrating the class claimed for the specific joint and pipe size proposed.
+
+# Pipe Materials {toc}
+
+## Permitted Materials {toc}
+
+### The pipe materials permitted on the project shall be as indicated in the datasheet.
+
+```datasheet
+label: Permitted Storm Sewer Pipe Materials
+type: checkbox
+options:
+ - "Reinforced concrete pipe per ASTM C76"
+ - "Reinforced concrete elliptical or arch pipe per ASTM C507 or ASTM C506"
+ - "Precast reinforced concrete box sections per ASTM C1433"
+ - "Corrugated polyethylene pipe per AASHTO M294 and ASTM F2306"
+ - "Corrugated polypropylene pipe per AASHTO M330"
+ - "Solid-wall PVC sewer pipe per ASTM D3034"
+ - "Large-diameter solid-wall PVC sewer pipe per ASTM F679"
+ - "Profile-wall PVC sewer pipe per ASTM F949 or ASTM F794"
+ - "Corrugated steel pipe per AASHTO M36"
+ - "Corrugated aluminum pipe per AASHTO M196"
+ - "Ductile iron pipe per AWWA C151"
+```
+
+### The pipe material, size, slope, and invert elevations for each reach shall be as indicated on [[drawing: the storm drainage plan and profile]].
+
+### The datasheet establishes which materials may appear anywhere on the project; the plan and profile establishes which of them is used in a given reach, and a material shown on the drawings but not permitted in the datasheet shall be reported to the Engineer of Record before it is ordered. {note}
+
+### The Contractor shall not change pipe material within a reach between two structures.
+
+### Where the drawings permit more than one material for a reach, the Contractor shall submit the proposed material for that reach for the Engineer of Record's acceptance before ordering.
+
+### Material choice on a storm system is driven by the strength available at the required cover, the abrasion and chemical environment, the tolerance of the surrounding soil to joint leakage, the available trench width, and the maintenance practices of whoever will own the system, and those factors point different directions on different reaches of the same project. {note}
+
+## Reinforced Concrete Pipe {toc}
+
+### Requirements in this article apply where reinforced concrete pipe is permitted in the datasheet.
+
+### Reinforced concrete pipe shall conform to ASTM C76, and elliptical, arch, and box sections shall conform to ASTM C507, ASTM C506, and ASTM C1433 respectively.
+
+### Concrete pipe is a rigid pipe: it carries load in the pipe wall rather than by transferring it to the surrounding soil, so its capacity is set at the plant by the strength class and is adjusted in the field only through the bedding, which changes how the reaction under the pipe is distributed. {note}
+
+### The strength class of reinforced concrete pipe for each reach shall be as indicated in the datasheet.
+
+```datasheet
+label: Reinforced Concrete Pipe Strength Class
+type: select
+drawing_ref: "the storm drainage pipe schedule"
+options:
+ - "Class I per ASTM C76"
+ - "Class II per ASTM C76"
+ - "Class III per ASTM C76"
+ - "Class IV per ASTM C76"
+ - "Class V per ASTM C76"
+ - "Special design D-load per ASTM C655"
+default: deferred
+```
+
+### The Contractor shall not substitute a lower strength class than the class indicated for a reach.
+
+### The installation type for reinforced concrete pipe shall be as indicated in the datasheet.
+
+```datasheet
+label: Concrete Pipe Installation Type
+type: select
+drawing_ref: "the storm drainage trench and bedding details"
+options:
+ - "Type 1 per ASTM C1479"
+ - "Type 2 per ASTM C1479"
+ - "Type 3 per ASTM C1479"
+ - "Type 4 per ASTM C1479"
+ - "Concrete cradle"
+ - "Concrete encasement"
+default: deferred
+```
+
+### The strength class and the installation type are selected together, because the ASTM C1479 standard installations trade compaction effort in the haunch against required pipe strength for the same fill height, and installing a Type 3 bedding under pipe whose class was set for a Type 1 installation removes strength the design counted on. {note}
+
+### Reinforced concrete pipe joints shall be single-offset or bell-and-spigot joints with a confined O-ring or profile rubber gasket conforming to ASTM C443.
+
+### The Contractor shall verify that the gasket is seated in its groove around the full circumference before the spigot is stabbed.
+
+### The Contractor shall advance the spigot until the home mark on the spigot reaches the face of the bell, and shall verify the joint gap around the full circumference with a feeler gauge after assembly.
+
+### A concrete joint that does not close around the full circumference shall be pulled apart, the gasket inspected and replaced if rolled or damaged, and the joint remade before embedment is placed.
+
+## Corrugated Thermoplastic Pipe {toc}
+
+### Requirements in this article apply where corrugated polyethylene or corrugated polypropylene pipe is permitted in the datasheet.
+
+### Corrugated polyethylene pipe shall conform to AASHTO M294 Type S or ASTM F2306 in sizes 12 in. and larger and to AASHTO M252 in sizes 10 in. and smaller, and shall have a smooth interior liner.
+
+### Corrugated polypropylene pipe shall conform to AASHTO M330, ASTM F2881, ASTM F2736, or ASTM F2764 for the size supplied, and shall have a smooth interior liner.
+
+### Polypropylene has a higher flexural modulus and a higher heat-deflection temperature than polyethylene at the same profile, so a polypropylene pipe reaches a given pipe stiffness in a shallower profile and holds it at higher summer stockpile temperatures; polyethylene is more forgiving of impact at low temperature. {note}
+
+### The minimum pipe stiffness for corrugated thermoplastic pipe shall be as indicated in the datasheet.
+
+```datasheet
+label: Corrugated Thermoplastic Pipe Minimum Pipe Stiffness
+type: text
+unit: psi at 5% deflection
+derived: "the nominal pipe diameter and the minimum pipe stiffness tabulated for that diameter in the governing product standard"
+default: derived
+```
+
+### Minimum pipe stiffness in AASHTO M294 and AASHTO M330 is tabulated per diameter and decreases as diameter increases, so a single stiffness value applied across a system either under-specifies the small pipe or is unbuildable in the large pipe; where the design requires more than the tabulated minimum for a diameter, the higher value is stated for that diameter alone. {note}
+
+### Corrugated thermoplastic pipe joints shall be bell-and-spigot joints with a gasket conforming to ASTM F477, and where the joint performance class is watertight the joint shall be qualified to ASTM D3212.
+
+### The gasket shall be factory-installed on the spigot or in the bell.
+
+### Split couplers, snap-together bands, and external wrap-only couplings shall not be used where the joint performance class is watertight.
+
+### Corrugated thermoplastic pipe shall be installed in accordance with ASTM D2321.
+
+## Solid-Wall and Profile-Wall PVC Pipe {toc}
+
+### Requirements in this article apply where solid-wall or profile-wall PVC sewer pipe is permitted in the datasheet.
+
+### Solid-wall PVC sewer pipe shall conform to ASTM D3034 in sizes 4 in. through 15 in. and to ASTM F679 in sizes 18 in. and larger.
+
+### Profile-wall PVC sewer pipe shall conform to ASTM F949 or ASTM F794 for the size supplied.
+
+### The dimension ratio of solid-wall PVC sewer pipe shall be as indicated in the datasheet.
+
+```datasheet
+label: Solid-Wall PVC Sewer Pipe Dimension Ratio
+type: select
+options:
+ - "SDR 35"
+ - "SDR 26"
+ - "SDR 23.5"
+ - "SDR 21"
+default: "SDR 35"
+```
+
+### A lower dimension ratio is a thicker wall and a stiffer pipe, and is specified where cover is deep, where the pipe is under a heavily loaded pavement, or where the embedment cannot be relied on to provide the side support that a thinner-walled pipe needs. {note}
+
+### PVC sewer pipe joints shall be integral bell-and-spigot joints with a gasket conforming to ASTM F477, and where the joint performance class is watertight the joint shall be qualified to ASTM D3212.
+
+### Solvent-cement joints shall not be used on buried storm sewer.
+
+### A solvent-cement joint is rigid and cannot accommodate the differential settlement, thermal movement, and beam action a buried gravity line sees, so it concentrates movement at the joint until the pipe cracks rather than distributing it as a gasketed joint does. {note}
+
+### The Contractor shall verify that PVC pipe delivered to the site carries the sewer pipe standard designation, and shall not install drain-waste-vent pipe, Schedule 40 pressure pipe, or irrigation pipe as storm sewer.
+
+### PVC sewer pipe shall be installed in accordance with ASTM D2321.
+
+## Corrugated Metal Pipe {toc}
+
+### Requirements in this article apply where corrugated steel or corrugated aluminum pipe is permitted in the datasheet.
+
+### Corrugated steel pipe shall conform to AASHTO M36 or ASTM A760, and corrugated aluminum pipe shall conform to AASHTO M196 or ASTM B745.
+
+### The metallic coating on corrugated steel pipe shall be as indicated in the datasheet.
+
+```datasheet
+label: Corrugated Steel Pipe Metallic Coating
+type: select
+options:
+ - "Zinc-coated per AASHTO M218"
+ - "Aluminum-coated Type 2 per AASHTO M274"
+ - "Aluminum-zinc alloy coated"
+ - "Zinc-coated with a polymer coating on both surfaces"
+ - "Zinc-coated with an asphalt coating and paved invert"
+```
+
+### Corrugated metal pipe service life is governed by the coating, the effluent and soil resistivity, and the pH at the pipe, and the coating is selected against those site conditions rather than against the pipe size or the load. {note}
+
+### The Contractor shall not install corrugated metal pipe where the soil resistivity or pH determined by the geotechnical investigation falls outside the range published for the selected coating, and shall report such a condition to the Engineer of Record before installing that reach.
+
+### Corrugated metal pipe shall be joined with coupling bands of the same base metal and coating as the pipe, and the band shall engage the same number of corrugations on each side of the joint.
+
+### Where the joint performance class is watertight, coupling bands shall include a gasket or sleeve qualified for that class by the band manufacturer.
+
+### Field-cut ends, damaged coating, and bolt holes shall be repaired with a coating compatible with the base metal before backfill.
+
+### Aluminum and steel components shall not be placed in direct contact in the same buried assembly, and dissimilar-metal contact shall be isolated with a gasket or dielectric sleeve.
+
+## Ductile Iron Pipe {toc}
+
+### Requirements in this article apply where ductile iron pipe is permitted in the datasheet.
+
+### Ductile iron pipe shall conform to AWWA C151, fittings shall conform to AWWA C110 or AWWA C153, and push-on or mechanical joints shall conform to AWWA C111.
+
+### Ductile iron is specified on storm systems where the pipe must carry a structural load no gravity pipe class covers, where it passes beneath a footing or an equipment pad, where vertical separation from a pressure utility is below the code minimum, or where restrained joints are required at a crossing. {note}
+
+### The interior lining of ductile iron storm pipe shall be as indicated in the datasheet.
+
+```datasheet
+label: Ductile Iron Pipe Interior Lining
+type: select
+options:
+ - "Cement-mortar lining with a bituminous seal coat per AWWA C104"
+ - "Cement-mortar lining without a seal coat per AWWA C104"
+ - "Amine-cured epoxy lining"
+ - "Ceramic epoxy lining"
+ - "Unlined"
+default: "Cement-mortar lining with a bituminous seal coat per AWWA C104"
+```
+
+### The bedding, embedment, joint assembly, structure connection, and testing requirements of this standard apply to ductile iron pipe.
+
+## Fittings and Manufactured Branches {toc}
+
+### Fittings shall be of the same material, class or stiffness, and joint type as the pipe they serve, and shall be furnished by the pipe manufacturer or qualified by the pipe manufacturer for use with that pipe.
+
+### Field-fabricated branch connections, saddles cut into the pipe barrel, and mitered elbows assembled on site shall not be used unless the pipe manufacturer publishes a procedure for them and the Engineer of Record accepts that procedure in writing.
+
+### A field-cut branch removes hoop reinforcement or profile wall at the one location where the pipe is already carrying a stress concentration, and the resulting failure appears as a longitudinal crack at the branch years after the reach passed its acceptance tests. {note}
+
+# Drainage Structures {toc}
+
+## Manholes and Junction Structures {toc}
+
+### Structure locations, types, rim elevations, and pipe invert elevations shall be as indicated on [[drawing: the storm structure schedule]].
+
+### The construction of storm drainage manholes and junction structures shall be as indicated in the datasheet.
+
+```datasheet
+label: Manhole and Junction Structure Construction
+type: select
+options:
+ - "Precast circular reinforced concrete sections per ASTM C478"
+ - "Precast rectangular reinforced concrete box sections per ASTM C1433"
+ - "Cast-in-place reinforced concrete"
+default: "Precast circular reinforced concrete sections per ASTM C478"
+```
+
+### Brick and concrete masonry unit structures shall not be used for new storm drainage construction unless the Contract Documents require them to match an existing structure being extended.
+
+### The base configuration of precast structures shall be as indicated in the datasheet.
+
+```datasheet
+label: Precast Structure Base
+type: select
+options:
+ - "Monolithic precast base with the first riser cast integrally"
+ - "Separate precast base slab with a gasketed riser joint"
+ - "Cast-in-place base slab beneath precast risers"
+default: "Monolithic precast base with the first riser cast integrally"
+```
+
+### Minimum manhole inside diameter shall be not less than the value tabulated below for the largest pipe connecting to the structure.
+
+| Largest connecting pipe | Minimum inside diameter |
+|---|---|
+| Up to 24 in. | 48 in. |
+| 27 in. through 36 in. | 60 in. |
+| 42 in. through 48 in. | 72 in. |
+| 54 in. through 60 in. | 84 in. |
+| Larger than 60 in. | As determined by the Engineer of Record for the pipe arrangement |
+
+### Where pipes converge at a structure at an included angle less than 90 degrees, or where three or more pipes enter the structure, the inside diameter shall be increased one tabulated size above the value required for the largest pipe.
+
+### The tabulated diameters are the sizes at which the wall openings, the gasket seats around them, and the bench between them will physically fit; an undersized structure forces the openings to overlap, leaves no material between them to seal against, and cannot be benched to turn the flow. {note}
+
+### The Contractor shall verify structure size against the pipe sizes and angles converging at that structure before precast components are ordered.
+
+## Structure Top and Access {toc}
+
+### The top configuration of precast structures shall be as indicated in the datasheet.
+
+```datasheet
+label: Precast Structure Top Configuration
+type: select
+derived: "the structure depth, the barrel diameter, and the clearance required above the largest pipe crown"
+options:
+ - "Eccentric cone"
+ - "Concentric cone"
+ - "Flat reinforced top slab"
+default: derived
+```
+
+### A cone requires vertical room between the crown of the highest pipe and the underside of the frame to develop its taper, so shallow structures and structures with large pipes take a flat top slab, and the choice follows the geometry rather than a preference. {note}
+
+### Eccentric cones shall be oriented with the vertical face on the side opposite the largest inflow pipe, so that the access opening is above solid bench.
+
+### The access provision within manholes and junction structures shall be as indicated in the datasheet.
+
+```datasheet
+label: Manhole Access Provision
+type: select
+options:
+ - "Copolymer polypropylene encased steel steps per ASTM C478"
+ - "Cast-in steel steps with a protective coating"
+ - "Fiberglass-reinforced polymer steps"
+ - "Fixed ladder anchored to the barrel wall"
+ - "No steps or ladder"
+```
+
+### Owners split on this decision: cast-in steps make routine inspection a one-person task, and they also become the liability when a corroded or loose step fails under a maintenance worker, which is why many owners now prohibit steps entirely and enter structures on portable equipment. {note}
+
+### Where steps are provided, vertical spacing shall not exceed 16 in. and the lowest step shall be not more than 24 in. above the bench.
+
+### Where a fixed ladder is provided, its design shall be submitted to the Engineer of Record for acceptance before fabrication.
+
+### Structures deeper than 20 ft shall be provided with a fixed ladder or an intermediate landing where the Authority Having Jurisdiction or the Owner's confined-space entry program requires one.
+
+## Pipe Connections to Structures {toc}
+
+### The connection of each pipe entering or leaving a structure shall be as indicated in the datasheet.
+
+```datasheet
+label: Pipe-to-Structure Connection
+type: select
+options:
+ - "Cast-in resilient connector per ASTM C923"
+ - "Field-cored opening with a boot-type resilient connector per ASTM C923"
+ - "Flexible waterstop cast into a cast-in-place structure wall"
+ - "Grouted rigid connection"
+default: "Cast-in resilient connector per ASTM C923"
+```
+
+### Where the joint performance class is watertight, the grouted rigid connection shall not be used.
+
+### Pipe and structure move differently under load and temperature, and a rigid grouted annulus has no capacity to absorb that difference, so it cracks and then works as a two-way path: storm flow out, groundwater and the soil it carries in. {note}
+
+### Field-cored openings shall be cut with a diamond core barrel sized for the boot and the pipe outside diameter, shall not sever more reinforcement than the structure manufacturer permits, and shall be located and sized in accordance with the structure manufacturer's written instructions.
+
+### The Contractor shall submit the structure manufacturer's written acceptance for any field-cored opening within 12 in. of a structure joint or of another opening.
+
+### The annular space at every pipe connection shall be sealed on both the interior and exterior faces of the structure wall.
+
+## Structure Joints {toc}
+
+### The joint between precast structure sections shall be as indicated in the datasheet.
+
+```datasheet
+label: Precast Structure Section Joint
+type: select
+options:
+ - "Preformed flexible butyl joint sealant per ASTM C990"
+ - "Confined O-ring rubber gasket per ASTM C443"
+ - "Profile rubber gasket per ASTM C443 with an external sealing band per ASTM C877"
+ - "Cement mortar"
+default: "Preformed flexible butyl joint sealant per ASTM C990"
+```
+
+### Where the joint performance class is watertight, the cement mortar joint shall not be used.
+
+### Joint surfaces shall be clean and dry before the sealant or gasket is placed, and the upper section shall be lowered so that the sealant or gasket compresses uniformly around the full circumference.
+
+### The Contractor shall confirm that the upper section is fully seated before the lifting load is released.
+
+### Excess butyl sealant extruded into the interior of the structure shall be trimmed flush.
+
+## Bench and Channel {toc}
+
+### The bench and flow channel within each manhole and junction structure shall be as indicated in the datasheet.
+
+```datasheet
+label: Manhole Bench and Channel Construction
+type: select
+options:
+ - "Cement mortar bench with a hand-troweled channel"
+ - "Cast-in-place concrete bench with a formed channel"
+ - "Factory-formed channel base section"
+ - "Flat bottom without a bench"
+default: "Cement mortar bench with a hand-troweled channel"
+```
+
+### The channel shall be the full inside diameter of the outlet pipe at the invert and shall carry that section continuously from each inlet pipe to the outlet pipe without a step, lip, or change of section.
+
+### Channel inverts shall match the pipe inverts shown for that structure.
+
+### A channel set below the pipe invert becomes a sump that fills with sediment until it is the invert, and a channel set above the pipe invert holds water back into the upstream reach; either error costs capacity that cannot be recovered without rebuilding the structure. {note}
+
+### The bench shall slope from the channel edge to the structure wall at not less than 1 in. per foot.
+
+### Where two or more pipes enter a structure, the channel shall turn each inflow into the outflow direction on a swept curve rather than a square intersection.
+
+## Drop Connections {toc}
+
+### Where an inflow pipe invert is more than 24 in. above the outlet pipe invert, a drop connection shall be provided.
+
+### The drop connection configuration shall be as indicated in the datasheet.
+
+```datasheet
+label: Drop Connection Configuration
+type: select
+options:
+ - "External drop outside the structure barrel"
+ - "Internal drop inside the structure barrel"
+ - "Prefabricated drop assembly furnished with the structure"
+```
+
+### An external drop keeps the barrel clear for entry and inspection but adds a buried assembly that cannot be seen once backfilled; an internal drop is visible and repairable from inside but takes up entry room and is exposed to the debris a storm system carries. {note}
+
+### Flow shall be conveyed from the inflow pipe to the structure invert without discharging onto the bench.
+
+## Inlets and Catch Basins {toc}
+
+### Inlets accept surface runoff into the system, and the type at each location follows the surface condition there: a curb opening keeps the collection surface out of the wheel path and stays open when leaves cover the gutter, a grate collects sheet flow across the full width but loses capacity as it blinds over, and a combination of the two is used at a sag where there is no downstream inlet to catch what the first one misses. {note}
+
+### The inlet type, throat or grate dimensions, and pipe connection elevations at each location shall be as indicated on [[drawing: the inlet schedule and inlet details]].
+
+### The Contractor shall not substitute one inlet type for another.
+
+### Inlet capacity is computed for the gutter flow produced by [[parameter: design-storm-frequency]] using the rating curve of the specific inlet type and its clogging allowance, and a substitution changes the capacity the design counted on at that location. {note}
+
+### The construction of inlets and catch basins shall be as indicated in the datasheet.
+
+```datasheet
+label: Inlet and Catch Basin Construction
+type: select
+options:
+ - "Precast reinforced concrete per ASTM C913"
+ - "Precast reinforced concrete box sections per ASTM C1433"
+ - "Cast-in-place reinforced concrete"
+ - "Precast polymer concrete"
+default: "Precast reinforced concrete per ASTM C913"
+```
+
+### The sediment sump depth below the outlet pipe invert shall be as indicated in the datasheet.
+
+```datasheet
+label: Sediment Sump Depth Below Outlet Invert
+type: range
+unit: in
+min: 0
+max: 36
+step: 3
+```
+
+### A sump traps the grit and sand that would otherwise settle in the pipe, and some jurisdictions require one for that reason; it also holds standing water between storms, which breeds mosquitoes and turns anaerobic, and it adds a structure the Owner has to vacuum on a schedule or it fills and stops working. {note}
+
+### Inlets in vehicular areas shall be provided with castings of the load rating required for that area by this standard.
+
+# Castings {toc}
+
+## Frames, grates, covers, and lids shall be listed in accordance with AASHTO M306, which qualifies a casting by a 40,000 lbf proof load applied through a 9 in. by 9 in. pad, with cracking or permanent deformation as cause for rejection.
+
+## Castings shall be free of cracks, cold shuts, blowholes, and inclusions, and mating surfaces shall be machined so that the cover or grate seats without rocking.
+
+## Castings shall not be installed in a vehicular area unless they bear the AASHTO M306 mark.
+
+## Casting Alloy {toc}
+
+### The casting alloy shall be as indicated in the datasheet.
+
+```datasheet
+label: Casting Alloy
+type: select
+options:
+ - "Gray iron per ASTM A48"
+ - "Ductile iron per ASTM A536"
+ - "Ductile iron grate or cover set in a gray iron frame"
+ - "Fiber-reinforced composite"
+ - "Fabricated steel"
+default: "Gray iron per ASTM A48"
+```
+
+### Gray iron carries compression well and damps vibration, which is why it dominates street castings; ductile iron carries tension and impact, which matters where wheel loads exceed highway loading or where the casting takes repeated impact, and pairing a ductile grate with a gray iron frame puts the tougher metal only where the wheel actually lands. {note}
+
+### Composite castings are specified where theft of metal castings is a recurring problem, where the casting must not conduct, or where a lighter cover reduces the injury risk to maintenance staff, and they carry a lower impact rating than iron at the same proof load. {note}
+
+## Casting Load Rating {toc}
+
+### The minimum casting load rating in vehicular areas shall be as indicated in the datasheet.
+
+```datasheet
+label: Minimum Casting Load Rating in Vehicular Areas
+type: select
+options:
+ - "H-10 light vehicular loading"
+ - "H-20 or HS-20 highway loading"
+ - "H-25 or HS-25 highway loading"
+ - "Aircraft or container-handling loading"
+default: "H-20 or HS-20 highway loading"
+```
+
+### Castings outside vehicular areas shall be rated for the loads actually imposed at that location, and shall be not less than H-10 rated wherever a fire lane, service drive, or maintenance vehicle route crosses the structure.
+
+### The Contractor shall report to the Engineer of Record any location where a casting shown as pedestrian-rated falls on a fire lane or service vehicle route.
+
+### Fire lanes across plazas are the recurring failure: the surface reads as pedestrian, the casting is specified to match, and the structure is then crossed a few times a year by an apparatus heavier than anything in the parking lot. {note}
+
+## Covers, Grates, and Restraint {toc}
+
+### The restraint and sealing of manhole covers shall be as indicated in the datasheet.
+
+```datasheet
+label: Manhole Cover Restraint
+type: select
+options:
+ - "Standard seated cover without restraint"
+ - "Gasketed self-sealing cover"
+ - "Bolted cover with stainless steel fasteners"
+ - "Locking or pick-resistant cover"
+default: "Standard seated cover without restraint"
+```
+
+### Covers on structures within a flood hazard area, at sag locations subject to ponding, and on reaches designed to surcharge shall be gasketed or bolted so that surcharge pressure cannot displace them.
+
+### Bolted covers shall use stainless steel or hot-dip galvanized fasteners.
+
+### Carbon steel fasteners in a structure that alternates between wet and humid seizes within a few seasons, and the cover then has to be cut open by the crew that came to inspect it. {note}
+
+### The legend cast into storm drainage covers shall be as indicated in the datasheet.
+
+```datasheet
+label: Storm Drainage Cover Legend
+type: select
+options:
+ - "STORM"
+ - "STORM SEWER"
+ - "STORM DRAIN"
+ - "DRAIN"
+default: "STORM SEWER"
+```
+
+### Where the utility owner requires a specific cover pattern and legend for structures it will accept, that pattern and legend shall govern over the datasheet selection for those structures.
+
+### Grates in bicycle and pedestrian routes shall have bar openings oriented and spaced so that a bicycle tire cannot enter the opening.
+
+### Grates in accessible routes shall comply with the adopted accessibility standard for opening width and orientation.
+
+## Adjustment to Grade {toc}
+
+### The method of adjusting the casting to finished grade shall be as indicated in the datasheet.
+
+```datasheet
+label: Casting Grade Adjustment Method
+type: select
+options:
+ - "Precast concrete grade rings set in mortar"
+ - "Polyethylene or recycled rubber grade rings"
+ - "Mortared brick courses"
+ - "Custom-height precast riser section"
+ - "Frame set directly on the structure without adjustment"
+default: "Precast concrete grade rings set in mortar"
+```
+
+### The maximum height of the grade adjustment stack shall be as indicated in the datasheet.
+
+```datasheet
+label: Maximum Grade Adjustment Stack Height
+type: range
+unit: in
+min: 0
+max: 24
+setpoints: [0, 6, 8, 12, 16, 24]
+default: 12
+```
+
+### Where the adjustment required at a structure exceeds the maximum stack height, a custom-height riser section shall be furnished rather than additional rings.
+
+### Every ring in the stack adds two mortar joints, and each joint is a hinge under traffic; a tall stack works loose, admits water behind the frame, and settles as a unit, taking the pavement around the casting with it. {note}
+
+### The frame shall be set on a continuous mortar bed on the top ring, with its inside face flush with the inside face of the structure and no mortar projecting into the structure.
+
+# Outfalls and End Treatments {toc}
+
+## The end treatment at each outfall shall be as indicated in the datasheet.
+
+```datasheet
+label: Outfall End Treatment
+type: select
+drawing_ref: "the outfall details"
+options:
+ - "Cast-in-place concrete headwall with wingwalls"
+ - "Precast concrete headwall"
+ - "Precast concrete flared end section"
+ - "Metal or thermoplastic end section matched to the pipe"
+ - "Riprap apron without a headwall"
+default: deferred
+```
+
+## An end treatment anchors the last pipe joint against the uplift and drag of discharge, retains the embankment at the pipe opening, and presents a defined edge between the pipe and the channel; without one, the discharge undercuts the last joint and the pipe walks out of the bank one storm at a time. {note}
+
+## Riprap gradation, apron dimensions, and bedding or filter fabric beneath the apron shall be as indicated on [[drawing: the outfall scour protection details]].
+
+## Scour protection, an energy dissipation structure, or both shall be provided at any outfall where the discharge velocity at the design flow exceeds the permissible velocity of the receiving channel.
+
+## Cast-in-place headwall and wingwall footings shall bear below [[parameter: frost-depth]] and on undisturbed or engineered fill approved by the geotechnical engineer of record.
+
+## The end treatment shall be constructed before the receiving channel is put into service, and the Contractor shall protect the pipe outlet from erosion until the end treatment is complete.
+
+## The provision of a safety grate or trash rack at outfalls shall be as indicated in the datasheet.
+
+```datasheet
+label: Outfall Safety Grate or Trash Rack
+type: select
+options:
+ - "Provided at every outfall discharging to an open channel or basin"
+ - "Provided at outfalls accessible from a public area or a pedestrian route"
+ - "Not provided"
+```
+
+## A safety grate keeps people and large debris out of a pipe that a child can walk into, and it is also the first thing to blind over in a storm, so where one is provided the Owner acquires a structure that has to be cleared before every major event. {note}
+
+## Where a safety grate or trash rack is provided, its net open area shall be not less than four times the cross-sectional area of the pipe it covers, and it shall be hinged or removable for cleaning.
+
+# Trench Excavation and Foundation {toc}
+
+## Trench Dimensions {toc}
+
+### Trench excavation, sloping, benching, shoring, and worker protection shall conform to [[sync/earthwork]] and [[sync/excavation-support-and-dewatering]], and to 29 CFR 1926 Subpart P.
+
+### Trench width at the pipe springline shall be not less than the pipe outside diameter plus 16 in., and not less than the minimum width published by the pipe manufacturer for the pipe size supplied.
+
+### Trench width at the pipe springline shall not exceed the maximum trench width used in the design of the pipe for that reach.
+
+### Trench width matters in both directions and for opposite reasons: too narrow and there is no room to work embedment into the haunch, which is where a flexible pipe gets its support; too wide and a rigid pipe carries more of the soil prism above it than the installation type assumed. {note}
+
+### The trench bottom shall be excavated to the design pipe invert less the bedding thickness, on a uniform grade matching the design slope, without dips, high spots, or reverse gradient.
+
+### Where the trench bottom is over-excavated below the design bedding elevation, the over-excavation shall be brought back to grade with compacted bedding material at the Contractor's expense, and shall not be brought back to grade with excavated native material.
+
+## Trench Foundation {toc}
+
+### The trench bottom of every reach shall be observed by the geotechnical engineer of record or the Owner's designated inspector, and released in writing, before bedding is placed.
+
+### Pipe shall not be placed on a trench bottom that is soft, pumping, frozen, or covered with standing water, and shall not be placed on disturbed or loose material.
+
+### Where the trench bottom is unsuitable, the foundation shall be stabilized as indicated in the datasheet before bedding is placed.
+
+```datasheet
+label: Trench Foundation Stabilization Where the Bottom Is Unsuitable
+type: select
+options:
+ - "Over-excavate and replace with compacted crushed stone"
+ - "Over-excavate, place a separation geotextile, and replace with crushed stone"
+ - "Over-excavate and replace with controlled low-strength material"
+ - "Geogrid reinforcement beneath a crushed stone working platform"
+```
+
+### The depth of over-excavation and the stabilization method at each occurrence shall be as directed by the geotechnical engineer of record, and shall be documented in the project record for that reach.
+
+### The whole load path assumed for the pipe runs through the bedding into the trench bottom, so a soft foundation does not merely settle: it lets the bedding deform, which unloads the haunch, which lets the pipe deflect and the joints open at the low point of the reach. {note}
+
+### Where crushed stone is placed against a fine-grained trench bottom or fine-grained trench walls, a separation geotextile shall be placed between them.
+
+### Without separation, the fines migrate into the voids in the stone under repeated loading, the stone loses the interlock the bedding depends on, and the pipe settles into the space the migrated fines vacated. {note}
+
+## Groundwater and Flotation {toc}
+
+### Trenches whose bottom lies below [[parameter: seasonal-high-groundwater-elevation]] shall be dewatered continuously, in accordance with [[sync/excavation-support-and-dewatering]], from before excavation of the pipe zone until sufficient backfill is in place to resist flotation.
+
+### The groundwater level shall be maintained not less than 12 in. below the trench bottom throughout pipe laying, embedment placement, and embedment compaction.
+
+### Dewatering discharge shall be conducted through the sediment controls required by [[sync/erosion-and-sediment-control]] and shall comply with the project's NPDES permit.
+
+### Dewatering discharge shall not be routed into the newly installed storm system until that system has been tested and accepted.
+
+### Empty thermoplastic and corrugated metal pipe below the water table will float, and a floated pipe does not simply rise: it lifts between fixed structures into a reverse grade, opens joints at the ends of the floated segment, and displaces the embedment that was holding it. {note}
+
+### Where dewatering is interrupted before sufficient cover is placed, the Contractor shall ballast the pipe with water or place additional cover before the groundwater is allowed to recover.
+
+# Pipe Embedment and Backfill {toc}
+
+## Embedment Material {toc}
+
+### The embedment material for flexible pipe, comprising the bedding, the haunch, and the initial backfill to the top of the pipe zone, shall be as indicated in the datasheet.
+
+```datasheet
+label: Flexible Pipe Embedment Material Class
+type: select
+options:
+ - "ASTM D2321 Class IA open-graded clean angular crushed stone"
+ - "ASTM D2321 Class IB dense-graded processed angular stone and sand"
+ - "ASTM D2321 Class II clean coarse-grained sand and gravel"
+ - "ASTM D2321 Class III coarse-grained soil with fines"
+default: "ASTM D2321 Class IA open-graded clean angular crushed stone"
+```
+
+### Class IA material develops its support on placement and light working rather than on compactive effort, which is what makes it forgiving in the haunch, the one location under a flexible pipe that no compactor can reach; Class II and Class III materials will reach the same support but only if they are placed in thin lifts and actually compacted there. {note}
+
+### Class IV and Class V materials as classified by ASTM D2321, including silt, clay, and organic soils, shall not be used as embedment for flexible pipe.
+
+### The bedding course thickness below the pipe shall be as indicated in the datasheet.
+
+```datasheet
+label: Bedding Course Thickness Below the Pipe
+type: range
+unit: in
+min: 3
+max: 18
+setpoints: [3, 4, 6, 9, 12, 18]
+default: 4
+```
+
+### The bedding course thickness shall be not less than 6 in. where the trench bottom is rock, cemented material, or a stabilized foundation course.
+
+### Bedding beneath rigid pipe shall be shaped to the bottom of the pipe so that the pipe bears uniformly along its full length, and bell holes shall be excavated at each joint so that no pipe bears on its bell.
+
+### Bedding beneath flexible pipe shall be placed and struck level to the design grade, and the pipe shall be supported by embedment worked into the haunch after the pipe is laid rather than by a shaped bed.
+
+## Placement and Compaction {toc}
+
+### Embedment shall be placed simultaneously on both sides of the pipe and shall be worked into the haunch beneath the pipe springline by shovel slicing or rodding before compaction of the lift.
+
+### Embedment shall be placed in lifts not exceeding 8 in. of loose thickness up to the top of the pipe zone.
+
+### The pipe zone extends from the top of the bedding to a plane 12 in. above the crown of the pipe. {note}
+
+### The minimum compaction of Class II and Class III embedment materials shall be as indicated in the datasheet.
+
+```datasheet
+label: Minimum Embedment Compaction for Class II and Class III Materials
+type: range
+unit: '% of maximum standard Proctor dry density'
+min: 85
+max: 100
+setpoints: [85, 90, 95, 100]
+default: 90
+```
+
+### Class IA embedment shall be placed and consolidated by working and light tamping, and a Proctor-referenced compaction requirement shall not be applied to it.
+
+### An open-graded angular stone has no meaningful Proctor curve, so a percent-of-Proctor acceptance criterion cannot be tested on it; acceptance is by placement method, lift thickness, and the working of the haunch. {note}
+
+### Compaction equipment shall not be operated directly over the pipe until at least 12 in. of compacted cover is in place above the crown.
+
+### Hand-operated plate compactors or rammers shall be used within the pipe zone.
+
+### A vibratory roller delivers a dynamic load far above the wheel load the pipe was designed for, and applying it over thin cover deflects a flexible pipe or cracks a rigid one at the moment when nothing above the pipe is yet distributing the load. {note}
+
+## Cover Limits {toc}
+
+### The minimum cover over the crown of the pipe shall be as indicated in the datasheet.
+
+```datasheet
+label: Minimum Cover Over the Pipe Crown
+type: text
+unit: in
+derived: "the pipe material and strength class or stiffness, the design live load at that location, and the minimum cover published for that combination in the product standard or the manufacturer's fill height tables"
+default: derived
+```
+
+### Cover over the pipe crown shall not exceed the maximum fill height published for the pipe material, class or stiffness, and installation type of that reach.
+
+### Where the design cover exceeds the published maximum for the pipe indicated, the Contractor shall report the condition to the Engineer of Record before installing that reach.
+
+### Construction traffic shall not cross a reach until the cover in place meets the minimum cover for construction loading published by the pipe manufacturer, and the Contractor shall provide temporary cover, matting, or bridging at construction crossings where it does not.
+
+### The construction load case usually governs, not the finished condition: the pipe reaches its design cover only after paving, while the loaded haul trucks cross it during backfill, when the cover is thinnest. {note}
+
+## Final Backfill {toc}
+
+### Trench backfill above the pipe zone shall conform to the requirements of [[sync/earthwork]] for the area in which the trench falls, and this standard does not restate those requirements.
+
+### Trench backfill compaction shall be tested at the frequency required by [[sync/earthwork]], and material failing that test shall be removed or scarified and recompacted at the Contractor's expense.
+
+### Backfill in the upper portion of a utility trench is the single most common source of the longitudinal pavement cracking and dishing that appears over storm trenches in the first years of service, and it is the part of the storm drainage scope least likely to be inspected, because the pipe below it has already passed its tests. {note}
+
+# Pipe Installation {toc}
+
+## Laying and Alignment {toc}
+
+### Pipe shall be laid beginning at the downstream end of each reach and progressing upstream, with bells facing upstream.
+
+### Laying upstream places the spigot into the bell in the direction of flow, so the joint presents no shoulder to catch debris, and it leaves the home mark visible from the upstream side where the crew is working. {note}
+
+### The method of verifying pipe alignment and grade shall be as indicated in the datasheet.
+
+```datasheet
+label: Pipe Alignment and Grade Verification Method
+type: select
+options:
+ - "Pipe laser set to the design invert and slope"
+ - "Robotic total station"
+ - "Transit and offset grade stakes"
+ - "String line and batter boards"
+default: "Pipe laser set to the design invert and slope"
+```
+
+### Each pipe section shall be brought to the design line and grade before the joint is closed.
+
+### Once a gasketed joint is home, correcting alignment requires disassembling the joint, so the check belongs before the joint is made rather than after. {note}
+
+### The as-laid invert shall be verified at each joint, and any deviation from the design invert exceeding the pipe manufacturer's installation tolerance shall be reported to the Engineer of Record before embedment is placed over that joint.
+
+### Joint deflection shall not exceed the deflection published by the joint manufacturer for that pipe size and joint type.
+
+### Where the design alignment requires more deflection than the joint permits, a manufactured fitting shall be used, or the alignment shall be referred to the Engineer of Record.
+
+### The completed reach between structures shall hold a uniform grade with no sag.
+
+### A sag holds standing water and the sediment that settles out of it, and once the reach is backfilled and paved there is no way to correct one short of excavating the reach; the sag is created during laying and can only be caught during laying. {note}
+
+## Joint Assembly {toc}
+
+### The bell and gasket seat of each pipe shall be cleaned of soil and debris immediately before the joint is assembled.
+
+### Lubricant supplied or approved in writing by the pipe manufacturer shall be applied to the gasket and the spigot in accordance with the manufacturer's instructions.
+
+### Petroleum-based lubricants, grease, and detergents shall not be applied to elastomeric gaskets.
+
+### A petroleum lubricant swells and softens most elastomeric gasket compounds, and the joint that passed its test on the day it was made loses its seal over the following months as the compound degrades. {note}
+
+### The spigot shall be advanced until the home mark reaches the bell face or until the spigot shoulder contacts the bell, whichever the joint design specifies, and shall not be driven past that point.
+
+### Over-insertion rolls or pinches the gasket out of its seat, which produces a leak path that no external sealing can reliably close. {note}
+
+### Joints shall be assembled with equipment appropriate to the pipe weight, and pipe shall not be pulled home with excavator bucket pressure applied directly to the pipe barrel or bell.
+
+## Cutting Pipe {toc}
+
+### Field cuts shall be square to the pipe axis, and the cut spigot end shall be deburred and chamfered so that the gasket enters without rolling.
+
+### Reinforced concrete pipe shall be cut with a diamond saw, and shall not be cut by flame, impact, or percussion methods.
+
+### Thermoplastic pipe shall be cut with a saw or pipe cutter producing a clean perpendicular face, and corrugated pipe shall be cut at the location within the corrugation specified by the pipe manufacturer.
+
+### Corrugated metal pipe field cuts shall be recoated in accordance with the coating manufacturer's instructions before backfill.
+
+### A cut end that has not been rebuilt to the joint geometry the gasket needs shall not be used at a gasketed joint, and the pipe shall be replaced or a manufactured coupling shall be used.
+
+## Transitions and Couplings {toc}
+
+### The method of joining dissimilar pipe materials, field cut-ins, and connections to existing pipe shall be as indicated in the datasheet.
+
+```datasheet
+label: Joining Method at Material Transitions
+type: select
+options:
+ - "Manufactured transition coupling listed for the specific outside diameter pair"
+ - "Compression repair coupling with a stainless steel shear band"
+ - "Cast-in-place concrete collar"
+ - "Transition through a drainage structure"
+default: "Manufactured transition coupling listed for the specific outside diameter pair"
+```
+
+### Transition couplings shall be sized to the actual outside diameters of both pipes.
+
+### Concrete, corrugated thermoplastic, solid-wall PVC, and ductile iron pipe of the same nominal size have different outside diameters, so a coupling sized from the nominal size over-compresses one gasket and under-compresses the other, and the joint leaks from the day it is buried. {note}
+
+### Where the joint performance class is watertight, the coupling shall be qualified to that class for both materials being joined.
+
+## Locating and Identification {toc}
+
+### The provision for locating buried nonmetallic storm sewer shall be as indicated in the datasheet.
+
+```datasheet
+label: Locating Provision Over Nonmetallic Pipe
+type: select
+options:
+ - "Detectable marking tape above the pipe zone"
+ - "Tracer wire attached along the pipe"
+ - "Detectable marking tape and tracer wire"
+ - "No locating provision"
+```
+
+### Where tracer wire is provided, it shall be continuous through each reach and shall be brought to an accessible termination inside a structure at each end of the reach.
+
+### Where detectable marking tape is provided, it shall be placed 12 in. to 18 in. above the pipe crown, centered over the pipe, and shall be legible as storm sewer.
+
+## Connections to Existing Systems {toc}
+
+### The Contractor shall coordinate every connection to an existing or public storm system with the utility owner and the Engineer of Record before the work, and shall confirm the connection method, flow management during the cut-in, and the inspection to be witnessed.
+
+### The Contractor shall verify the invert, size, material, and condition of the existing pipe or structure at each point of connection before ordering materials for that connection.
+
+### Connections into an existing precast structure shall be made by core drilling with a diamond core barrel and a resilient connector, and shall not be made by breaking out the structure wall.
+
+### Cut-ins on an in-service pipe shall be made only with the utility owner's written approval and only after the Contractor's flow management plan for that cut-in has been accepted.
+
+### Temporary sediment protection shall be installed downstream of every connection before the connection is opened, and shall remain until the new work upstream of it has been cleaned and accepted.
+
+### The point of connection to the public storm system shall be as indicated on [[drawing: the civil utility plan]].
+
+# Structure Installation {toc}
+
+## Foundation and Base {toc}
+
+### Structure bases shall be set on a compacted granular foundation course not less than 6 in. thick, extending not less than 12 in. beyond the structure footprint on all sides, and struck level at the elevation that places the lowest pipe invert at its design elevation.
+
+### The base elevation shall be verified and released before any pipe is connected to the structure.
+
+### A structure base set high or low propagates through every riser and into the frame elevation, and the error surfaces at paving, when it is corrected by adding grade rings rather than by resetting the base. {note}
+
+### Structure foundations shall bear below [[parameter: frost-depth]] where the structure is set in frost-susceptible soil.
+
+### Cast-in-place bases shall be placed on the granular foundation course with reinforcement and pipe opening formwork in place, in accordance with [[sync/cast-in-place-concrete]] and [[sync/concrete-reinforcement]].
+
+## Setting Sections and Frames {toc}
+
+### Precast sections shall be lifted with the hardware cast in by the manufacturer and shall not be lifted by chains passed through pipe openings or by slings around the barrel.
+
+### Structures shall be backfilled uniformly around the full perimeter, in lifts of the same thickness on all sides, so that the structure is not displaced by unbalanced pressure.
+
+### Exterior backfill against structures shall meet the compaction required by [[sync/earthwork]] for the area, and shall not be placed until the structure has been tested where testing is required before backfill.
+
+### The frame shall be set level and square, with the top of the casting at the elevation of the finished pavement or grade at that location.
+
+### Where the frame is set before final pavement placement, the Contractor shall protect the frame and structure rim during paving operations, or shall set the frame to final grade as the surrounding pavement is placed.
+
+### A frame set proud of the pavement is caught by plows and snags pedestrians, and a frame set low ponds water at the rim, which saturates the pavement edge and accelerates its failure. {note}
+
+### Castings shall be reset where the finished elevation differs from the surrounding pavement or grade by more than the tolerance stated in the Contract Documents, at the Contractor's expense where the deviation results from the Contractor's work.
+
+# Testing and Acceptance {toc}
+
+## Pipe Leakage Testing {toc}
+
+### The pipe leakage test method shall be as indicated in the datasheet.
+
+```datasheet
+label: Pipe Leakage Test Method
+type: select
+options:
+ - "Low-pressure air test per ASTM F1417 for thermoplastic pipe"
+ - "Low-pressure air test per ASTM C924 for concrete pipe"
+ - "Hydrostatic exfiltration test per ASTM C969"
+ - "Infiltration measurement per ASTM C969"
+ - "Joint-by-joint packer test per ASTM C1103"
+ - "No leakage test"
+```
+
+### Leakage testing shall be performed after embedment is complete and before final backfill closes the trench above the pipe zone.
+
+### Test plugs and end caps shall be rated for the test pressure and shall be mechanically restrained against blow-out before the reach is pressurized.
+
+### An air test plug that releases at 4 psi in a 36 in. pipe carries roughly the energy of the pipe's cross-sectional area times that pressure, and the plug leaves the pipe end at a speed that has killed test crews; restraint and a cleared work area are not optional refinements of the procedure. {note}
+
+### Where groundwater stands above the pipe crown, the air test gauge pressure shall be increased by 0.433 psi for each foot of water above the crown, and the elevation used shall be measured at the time of test rather than taken from [[parameter: seasonal-high-groundwater-elevation]].
+
+### The infiltration test shall be used only where groundwater stands above the pipe crown for the full length of the reach at the time of test.
+
+### The joint-by-joint packer test shall be used where the reach length, diameter, or absence of an upstream structure makes a full-reach test impractical, and shall be performed with the packer manufacturer's procedure and witnessed by the Engineer of Record.
+
+### A reach that fails the leakage test shall be repaired and retested until it passes, and the Contractor shall bear the cost of the repair and of every retest of that reach.
+
+### The Contractor shall identify and correct the cause of a failure before retesting, and shall record both the failure and the passing retest.
+
+## Structure Leakage Testing {toc}
+
+### The structure leakage test method shall be as indicated in the datasheet.
+
+```datasheet
+label: Structure Leakage Test Method
+type: select
+options:
+ - "Negative air pressure vacuum test per ASTM C1244"
+ - "Hydrostatic exfiltration test"
+ - "Visual inspection for infiltration only"
+ - "No structure leakage test"
+```
+
+### The vacuum test shall be performed after the structure is complete and before exterior backfill is placed, in accordance with ASTM C1244.
+
+### The structure shall be evacuated to 10 in. of mercury, the pump valved off, and the time for the vacuum to fall to 9 in. of mercury measured against the minimum time tabulated in ASTM C1244 for the structure diameter and depth.
+
+### ASTM C1244 is a before-backfill test, and running it after backfill inverts what it proves: the surrounding soil holds the joints closed under the applied vacuum, so a structure that would leak under service conditions can pass. {note}
+
+### A structure that fails shall have the leak path located, sealed by regrouting, re-seating the joint, or applying an external sealing band per ASTM C877, and shall be retested until it passes.
+
+### Where a structure is retested more than twice, the Engineer of Record may require the structure to be removed and rebuilt, and the Contractor shall bear that cost where the failure results from the Contractor's work.
+
+## Deflection Testing {toc}
+
+### The maximum allowable installed deflection of flexible pipe shall be as indicated in the datasheet.
+
+```datasheet
+label: Maximum Allowable Installed Pipe Deflection
+type: range
+unit: '%'
+min: 3
+max: 7.5
+setpoints: [3, 5, 7.5]
+default: 5
+```
+
+### Every reach of thermoplastic and corrugated metal pipe shall be deflection tested by mandrel pull-through after final backfill is in place and the trench has stood undisturbed not less than 30 days, or after the final cover load including pavement is in place, whichever occurs later.
+
+### The 30-day wait lets the soil envelope reach its post-construction state, and a mandrel pulled the week after backfill can pass a reach that will fail the same test a season later. {note}
+
+### The mandrel shall be a rigid, non-adjustable, odd-numbered-leg go or no-go device sized to the pipe inside diameter less the allowable deflection.
+
+### The mandrel shall be pulled by hand or with light mechanical assistance, and shall not be pulled with a winch or any force capable of deforming the pipe.
+
+### The Contractor shall not modify a mandrel, substitute a smaller mandrel, or ream the pipe to pass a reach.
+
+### A reach that fails the deflection test shall be uncovered and re-bedded, relined with a structural liner accepted by the Engineer of Record, or replaced, at the Contractor's expense.
+
+### Excessive deflection almost always traces to the haunch: embedment that was dumped rather than worked under the pipe, a lift thickness that could not be compacted, or heavy equipment crossing before the cover was there to spread it. {note}
+
+## Video Inspection {toc}
+
+### The extent of post-installation video inspection shall be as indicated in the datasheet.
+
+```datasheet
+label: Post-Installation Video Inspection Extent
+type: select
+options:
+ - "All storm sewer mains and laterals"
+ - "All storm sewer mains"
+ - "Reaches selected by the Engineer of Record"
+ - "No video inspection"
+```
+
+### Video inspection shall be performed after final cleaning, with the pipe free of standing water except where the camera is submerged-rated and the water depth is recorded.
+
+### The video record shall be continuously referenced to distance from the starting structure and shall identify each structure, joint, service connection, and defect observed.
+
+### Video inspection is the only acceptance method that finds the defects the other tests cannot see - a sag that holds water, an intruding gasket, a lateral protruding into the barrel, a joint offset - and it is also the record the Owner uses as the baseline for every future inspection of the system. {note}
+
+### Defects identified in the video record shall be corrected and the affected reach re-inspected, at the Contractor's expense where the defect results from the Contractor's work.
+
+## Test Records {toc}
+
+### Every test, whether passing or failing, shall be recorded on a report identifying the reach or structure, the pipe material and size, the test method, the test pressure or head, the hold time, the start and end readings, the date, and the names of the Contractor's test supervisor and the witnessing inspector.
+
+### Test reports shall be submitted within five working days of the test.
+
+### The Contractor shall not remove or replace a failing test report with the report of a subsequent passing test.
+
+## Final Acceptance {toc}
+
+### Final acceptance of the storm drainage system shall require passing results on every required test for every reach and every structure, video records where video inspection is required, complete record drawings, removal of all temporary controls within the system, final cleaning, and the acceptance of the Authority Having Jurisdiction for any portion connected to public infrastructure.
+
+### Acceptance shall not waive the Contractor's warranty obligations or the Contractor's liability for latent defects.
+
+### Storm drainage defects are frequently invisible at acceptance and appear at the first significant rainfall that loads the system, which may be months after the Owner has taken the site. {note}
+
+# Cleaning and Turnover {toc}
+
+## The completed system shall be cleaned of sediment, debris, mortar droppings, and construction materials after all testing is complete and before turnover.
+
+## The final cleaning method shall be as indicated in the datasheet.
+
+```datasheet
+label: Final System Cleaning Method
+type: select
+options:
+ - "Hydraulic jet flushing with vacuum recovery of debris"
+ - "Mechanical bucket cleaning"
+ - "Manual removal from structures"
+default: "Hydraulic jet flushing with vacuum recovery of debris"
+```
+
+## Debris and sediment removed during cleaning shall be captured at the downstream end of the reach being cleaned and shall not be flushed into the downstream system, into a stormwater management facility, or to the outfall.
+
+## Sediment removed during cleaning shall be disposed of off site or at a location approved by the Owner in writing.
+
+## Inlet sumps, structure benches, and structure inverts shall be flushed and left free of standing sediment.
+
+## Grates and covers shall be cleaned of construction debris and shall be verified to seat in their frames without rocking.
+
+## Temporary inlet protection, sediment bags, and construction sediment traps within the storm system shall be removed at turnover.
+
+## Temporary inlet protection left in place at turnover reduces the inlet capacity below its design value at exactly the moment the Owner begins relying on it, and it is the item most often found still installed at the first post-occupancy storm. {note}
+
+## The Contractor shall conduct a final walk-through with the Engineer of Record, opening each structure to verify clean condition, and shall correct any deficiency found before final acceptance.
+
+# Delivery, Storage, and Handling {toc}
+
+## Pipe, fittings, structures, and castings shall be handled with slings, forks, or lifting hardware appropriate to the product, and shall not be dropped, rolled off a truck bed, or dragged.
+
+## Pipe shall be stored on level ground, blocked against rolling, and stacked no higher than the pipe manufacturer's published stacking limit.
+
+## Gaskets and lubricant shall be stored in their original containers, out of direct sunlight, away from petroleum products and ozone-generating equipment, and within the temperature range published by the gasket manufacturer.
+
+## Ozone and ultraviolet exposure attack elastomeric compounds directly, and a gasket that spent a season on an open pallet can fail in service without ever showing damage at the moment it was installed. {note}
+
+## Thermoplastic pipe stored on site longer than the exposure period published by the pipe manufacturer shall be covered with an opaque covering that permits air circulation.
+
+## Pipe, fittings, and structures shall be inspected for damage on delivery and again immediately before installation, and damaged material shall be removed from the site rather than repaired in place unless the manufacturer publishes a repair procedure and the Engineer of Record accepts it.
+
+## Pipe interiors shall be kept free of debris during storage and installation, and open pipe ends shall be closed at the end of each work day.
+
+## An open pipe end left overnight is how construction debris, animals, and washed-in sediment enter a reach that will later be tested and accepted with them still inside. {note}
+
+# Warranty {toc}
+
+## The warranty period for the storm drainage system shall be as indicated in the datasheet.
+
+```datasheet
+label: Storm Drainage System Warranty Period
+type: range
+unit: years
+min: 1
+max: 5
+setpoints: [1, 2, 3, 5]
+default: 1
+```
+
+## The Contractor shall warrant the storm drainage system, including pipe, joints, structures, castings, embedment, and connections, against defects in materials and workmanship for the warranty period beginning at substantial completion.
+
+## Warranty obligations shall include correction of leaking joints, pipe deflection developing after acceptance, settlement of pavement over storm trenches, structure rim settlement, and castings that rock or move in their frames.
+
+## Where the Contractor repairs or replaces work under the warranty, the repaired work shall carry a warranty running from the date of the repair for the full warranty period or for the remainder of the original period, whichever ends later.
+
+## The Contractor shall bear the cost of the warranty repair itself and of restoring the pavement, curb, landscape, and surface finishes disturbed by that repair to the condition documented in the preconstruction condition record for that area.
+
+## The Contractor's warranty shall cover pavement settlement over a storm trench where the settlement is attributable to consolidation of the trench backfill, and shall not cover settlement attributable to subgrade conditions outside the trench.
+
+## Where the parties disagree whether settlement is attributable to trench backfill, the Engineer of Record shall make the initial determination.
+
+## Trench backfill consolidates through the first seasonal cycles even when it was placed correctly, so pavement that was flush at paving often shows a visible depression along the trench line a year later, and the question in every case is whether the depression reflects consolidation of properly placed backfill or a lift that was never compacted. {note}
+
+## Manufacturer warranties for castings, precast structures, and manufactured end treatments shall be assigned to the Owner at closeout.
+
+## The warranty period shall not limit the Contractor's liability for non-conforming work discovered after it expires.
+
+## Pipe laid at an incorrect slope, a structure joint that was never sealed, a casting under-rated for its location, and a pipe material substituted from the one specified are non-conforming work whenever they are discovered, not defects that expire with the warranty. {note}