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Storm Drainage

Rev7
IssuedAug 29, 2026
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1 Scope

NOTE 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. (1.1)
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. (1.2)
NOTE The following are outside this standard and are governed elsewhere: (1.3)
  • 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
NOTE 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. (1.4)
1.5 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.
1.6 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.
1.7 Work under this standard shall be coordinated with EarthworkEarthworkResolves to the current adopted revision.sync/earthwork for excavation and backfill, with Erosion And Sediment ControlErosion and Sediment ControlResolves to the current adopted revision.sync/erosion-and-sediment-control for protection of the system during construction, and with Aggregate Base CourseAggregate Base CourseResolves to the current adopted revision.sync/aggregate-base-course for the pavement structure bearing on completed storm trenches.

2 Referenced Standards

2.1 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.
2.2 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
2.3 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.
NOTE 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. (2.4)

3 Submittals

3.1 Action Submittals

3.1.1 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
Action Submittals Requiredcheckbox
☐ 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
3.1.2 Storm drainage below grade shall not be installed in any area for which the action submittals covering that work remain unaccepted.

3.2 Closeout Submittals

3.2.1 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
Closeout Submittals Requiredcheckbox
☐ 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

4 Quality Assurance

4.1 Installer Qualifications

4.1.1 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.
4.1.2 Personnel assembling gasketed joints shall be trained in the joint manufacturer's assembly procedure, including gasket seating, lubricant application, and home-mark verification.
4.1.3 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.
NOTE 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. (4.1.4)

4.2 Product Identification and Marking

4.2.1 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.
4.2.2 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.
4.2.3 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.

4.3 Preinstallation Conference

4.3.1 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.
4.3.2 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.

4.4 Inspection Hold Points

4.4.1 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
4.4.2 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.

5 System Watertightness and Joint Performance

NOTE 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. (5.1)
5.2 The joint performance class for the storm drainage system shall be as indicated in the datasheet.
Storm Sewer Joint Performance Classselect
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
NOTE 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. (5.3)
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. (5.4)
5.5 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.
5.6 Mortar and external sealing bands are supplementary to a gasketed joint and shall not be substituted for the gasket.
5.7 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.

6 Pipe Materials

6.1 Permitted Materials

6.1.1 The pipe materials permitted on the project shall be as indicated in the datasheet.
Permitted Storm Sewer Pipe Materialscheckbox
☐ 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
6.1.2 The pipe material, size, slope, and invert elevations for each reach shall be as indicated on the storm drainage plan and profile.
NOTE 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. (6.1.3)
6.1.4 The Contractor shall not change pipe material within a reach between two structures.
6.1.5 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.
NOTE 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. (6.1.6)

6.2 Reinforced Concrete Pipe

6.2.1 Requirements in this article apply where reinforced concrete pipe is permitted in the datasheet.
6.2.2 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.
NOTE 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. (6.2.3)
6.2.4 The strength class of reinforced concrete pipe for each reach shall be as indicated in the datasheet.
Reinforced Concrete Pipe Strength Classselect
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
Per drawings — the storm drainage pipe schedule (deferred by default)
6.2.5 The Contractor shall not substitute a lower strength class than the class indicated for a reach.
6.2.6 The installation type for reinforced concrete pipe shall be as indicated in the datasheet.
Concrete Pipe Installation Typeselect
Type 1 per ASTM C1479
Type 2 per ASTM C1479
Type 3 per ASTM C1479
Type 4 per ASTM C1479
Concrete cradle
Concrete encasement
Per drawings — the storm drainage trench and bedding details (deferred by default)
NOTE 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. (6.2.7)
6.2.8 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.
6.2.9 The Contractor shall verify that the gasket is seated in its groove around the full circumference before the spigot is stabbed.
6.2.10 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.
6.2.11 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.

6.3 Corrugated Thermoplastic Pipe

6.3.1 Requirements in this article apply where corrugated polyethylene or corrugated polypropylene pipe is permitted in the datasheet.
6.3.2 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.
6.3.3 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.
NOTE 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. (6.3.4)
6.3.5 The minimum pipe stiffness for corrugated thermoplastic pipe shall be as indicated in the datasheet.
Corrugated Thermoplastic Pipe Minimum Pipe Stiffnesstext
Enter value...
psi at 5% deflection
Derived — the nominal pipe diameter and the minimum pipe stiffness tabulated for that diameter in the governing product standard (by default)
NOTE 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. (6.3.6)
6.3.7 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.
6.3.8 The gasket shall be factory-installed on the spigot or in the bell.
6.3.9 Split couplers, snap-together bands, and external wrap-only couplings shall not be used where the joint performance class is watertight.
6.3.10 Corrugated thermoplastic pipe shall be installed in accordance with ASTM D2321.

6.4 Solid-Wall and Profile-Wall PVC Pipe

6.4.1 Requirements in this article apply where solid-wall or profile-wall PVC sewer pipe is permitted in the datasheet.
6.4.2 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.
6.4.3 Profile-wall PVC sewer pipe shall conform to ASTM F949 or ASTM F794 for the size supplied.
6.4.4 The dimension ratio of solid-wall PVC sewer pipe shall be as indicated in the datasheet.
Solid-Wall PVC Sewer Pipe Dimension Ratioselect
SDR 35
SDR 26
SDR 23.5
SDR 21
NOTE 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. (6.4.5)
6.4.6 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.
6.4.7 Solvent-cement joints shall not be used on buried storm sewer.
NOTE 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. (6.4.8)
6.4.9 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.
6.4.10 PVC sewer pipe shall be installed in accordance with ASTM D2321.

6.5 Corrugated Metal Pipe

6.5.1 Requirements in this article apply where corrugated steel or corrugated aluminum pipe is permitted in the datasheet.
6.5.2 Corrugated steel pipe shall conform to AASHTO M36 or ASTM A760, and corrugated aluminum pipe shall conform to AASHTO M196 or ASTM B745.
6.5.3 The metallic coating on corrugated steel pipe shall be as indicated in the datasheet.
Corrugated Steel Pipe Metallic Coatingselect
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
NOTE 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. (6.5.4)
6.5.5 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.
6.5.6 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.
6.5.7 Where the joint performance class is watertight, coupling bands shall include a gasket or sleeve qualified for that class by the band manufacturer.
6.5.8 Field-cut ends, damaged coating, and bolt holes shall be repaired with a coating compatible with the base metal before backfill.
6.5.9 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.

6.6 Ductile Iron Pipe

6.6.1 Requirements in this article apply where ductile iron pipe is permitted in the datasheet.
6.6.2 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.
NOTE 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. (6.6.3)
6.6.4 The interior lining of ductile iron storm pipe shall be as indicated in the datasheet.
Ductile Iron Pipe Interior Liningselect
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
6.6.5 The bedding, embedment, joint assembly, structure connection, and testing requirements of this standard apply to ductile iron pipe.

6.7 Fittings and Manufactured Branches

6.7.1 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.
6.7.2 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.
NOTE 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. (6.7.3)

7 Drainage Structures

7.1 Manholes and Junction Structures

7.1.1 Structure locations, types, rim elevations, and pipe invert elevations shall be as indicated on the storm structure schedule.
7.1.2 The construction of storm drainage manholes and junction structures shall be as indicated in the datasheet.
Manhole and Junction Structure Constructionselect
Precast circular reinforced concrete sections per ASTM C478
Precast rectangular reinforced concrete box sections per ASTM C1433
Cast-in-place reinforced concrete
7.1.3 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.
7.1.4 The base configuration of precast structures shall be as indicated in the datasheet.
Precast Structure Baseselect
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
7.1.5 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
7.1.6 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.
NOTE 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. (7.1.7)
7.1.8 The Contractor shall verify structure size against the pipe sizes and angles converging at that structure before precast components are ordered.

7.2 Structure Top and Access

7.2.1 The top configuration of precast structures shall be as indicated in the datasheet.
Precast Structure Top Configurationselect
Eccentric cone
Concentric cone
Flat reinforced top slab
Derived — the structure depth, the barrel diameter, and the clearance required above the largest pipe crown (by default)
NOTE 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. (7.2.2)
7.2.3 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.
7.2.4 The access provision within manholes and junction structures shall be as indicated in the datasheet.
Manhole Access Provisionselect
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
NOTE 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. (7.2.5)
7.2.6 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.
7.2.7 Where a fixed ladder is provided, its design shall be submitted to the Engineer of Record for acceptance before fabrication.
7.2.8 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.

7.3 Pipe Connections to Structures

7.3.1 The connection of each pipe entering or leaving a structure shall be as indicated in the datasheet.
Pipe-to-Structure Connectionselect
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
7.3.2 Where the joint performance class is watertight, the grouted rigid connection shall not be used.
NOTE 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. (7.3.3)
7.3.4 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.
7.3.5 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.
7.3.6 The annular space at every pipe connection shall be sealed on both the interior and exterior faces of the structure wall.

7.4 Structure Joints

7.4.1 The joint between precast structure sections shall be as indicated in the datasheet.
Precast Structure Section Jointselect
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
7.4.2 Where the joint performance class is watertight, the cement mortar joint shall not be used.
7.4.3 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.
7.4.4 The Contractor shall confirm that the upper section is fully seated before the lifting load is released.
7.4.5 Excess butyl sealant extruded into the interior of the structure shall be trimmed flush.

7.5 Bench and Channel

7.5.1 The bench and flow channel within each manhole and junction structure shall be as indicated in the datasheet.
Manhole Bench and Channel Constructionselect
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
7.5.2 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.
7.5.3 Channel inverts shall match the pipe inverts shown for that structure.
NOTE 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. (7.5.4)
7.5.5 The bench shall slope from the channel edge to the structure wall at not less than 1 in. per foot.
7.5.6 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.

7.6 Drop Connections

7.6.1 Where an inflow pipe invert is more than 24 in. above the outlet pipe invert, a drop connection shall be provided.
7.6.2 The drop connection configuration shall be as indicated in the datasheet.
Drop Connection Configurationselect
External drop outside the structure barrel
Internal drop inside the structure barrel
Prefabricated drop assembly furnished with the structure
NOTE 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. (7.6.3)
7.6.4 Flow shall be conveyed from the inflow pipe to the structure invert without discharging onto the bench.

7.7 Inlets and Catch Basins

NOTE 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. (7.7.1)
7.7.2 The inlet type, throat or grate dimensions, and pipe connection elevations at each location shall be as indicated on the inlet schedule and inlet details.
7.7.3 The Contractor shall not substitute one inlet type for another.
NOTE Inlet capacity is computed for the gutter flow produced by Design Storm FrequencyDesign Storm FrequencyParameterEach project supplies its own value.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. (7.7.4)
7.7.5 The construction of inlets and catch basins shall be as indicated in the datasheet.
Inlet and Catch Basin Constructionselect
Precast reinforced concrete per ASTM C913
Precast reinforced concrete box sections per ASTM C1433
Cast-in-place reinforced concrete
Precast polymer concrete
7.7.6 The sediment sump depth below the outlet pipe invert shall be as indicated in the datasheet.
Sediment Sump Depth Below Outlet Invertrange
in
036
NOTE 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. (7.7.7)
7.7.8 Inlets in vehicular areas shall be provided with castings of the load rating required for that area by this standard.

8 Castings

8.1 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.
8.2 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.
8.3 Castings shall not be installed in a vehicular area unless they bear the AASHTO M306 mark.

8.4 Casting Alloy

8.4.1 The casting alloy shall be as indicated in the datasheet.
Casting Alloyselect
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
NOTE 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. (8.4.2)
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. (8.4.3)

8.5 Casting Load Rating

8.5.1 The minimum casting load rating in vehicular areas shall be as indicated in the datasheet.
Minimum Casting Load Rating in Vehicular Areasselect
H-10 light vehicular loading
H-20 or HS-20 highway loading
H-25 or HS-25 highway loading
Aircraft or container-handling loading
8.5.2 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.
8.5.3 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.
NOTE 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. (8.5.4)

8.6 Covers, Grates, and Restraint

8.6.1 The restraint and sealing of manhole covers shall be as indicated in the datasheet.
Manhole Cover Restraintselect
Standard seated cover without restraint
Gasketed self-sealing cover
Bolted cover with stainless steel fasteners
Locking or pick-resistant cover
8.6.2 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.
8.6.3 Bolted covers shall use stainless steel or hot-dip galvanized fasteners.
NOTE 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. (8.6.4)
8.6.5 The legend cast into storm drainage covers shall be as indicated in the datasheet.
Storm Drainage Cover Legendselect
STORM
STORM SEWER
STORM DRAIN
DRAIN
8.6.6 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.
8.6.7 Grates in bicycle and pedestrian routes shall have bar openings oriented and spaced so that a bicycle tire cannot enter the opening.
8.6.8 Grates in accessible routes shall comply with the adopted accessibility standard for opening width and orientation.

8.7 Adjustment to Grade

8.7.1 The method of adjusting the casting to finished grade shall be as indicated in the datasheet.
Casting Grade Adjustment Methodselect
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
8.7.2 The maximum height of the grade adjustment stack shall be as indicated in the datasheet.
Maximum Grade Adjustment Stack Heightrange
in
68121624
8.7.3 Where the adjustment required at a structure exceeds the maximum stack height, a custom-height riser section shall be furnished rather than additional rings.
NOTE 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. (8.7.4)
8.7.5 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.

9 Outfalls and End Treatments

9.1 The end treatment at each outfall shall be as indicated in the datasheet.
Outfall End Treatmentselect
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
Per drawings — the outfall details (deferred by default)
NOTE 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. (9.2)
9.3 Riprap gradation, apron dimensions, and bedding or filter fabric beneath the apron shall be as indicated on the outfall scour protection details.
9.4 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.
9.5 Cast-in-place headwall and wingwall footings shall bear below Frost DepthFrost DepthParameterEach project supplies its own value.frost-depth and on undisturbed or engineered fill approved by the geotechnical engineer of record.
9.6 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.
9.7 The provision of a safety grate or trash rack at outfalls shall be as indicated in the datasheet.
Outfall Safety Grate or Trash Rackselect
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
NOTE 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. (9.8)
9.9 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.

10 Trench Excavation and Foundation

10.1 Trench Dimensions

10.1.1 Trench excavation, sloping, benching, shoring, and worker protection shall conform to EarthworkEarthworkResolves to the current adopted revision.sync/earthwork and Excavation Support And DewateringExcavation Support and DewateringResolves to the current adopted revision.sync/excavation-support-and-dewatering, and to 29 CFR 1926 Subpart P.
10.1.2 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.
10.1.3 Trench width at the pipe springline shall not exceed the maximum trench width used in the design of the pipe for that reach.
NOTE 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. (10.1.4)
10.1.5 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.
10.1.6 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.

10.2 Trench Foundation

10.2.1 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.
10.2.2 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.
10.2.3 Where the trench bottom is unsuitable, the foundation shall be stabilized as indicated in the datasheet before bedding is placed.
Trench Foundation Stabilization Where the Bottom Is Unsuitableselect
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
10.2.4 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.
NOTE 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. (10.2.5)
10.2.6 Where crushed stone is placed against a fine-grained trench bottom or fine-grained trench walls, a separation geotextile shall be placed between them.
NOTE 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. (10.2.7)

10.3 Groundwater and Flotation

10.3.1 Trenches whose bottom lies below Seasonal High Groundwater ElevationSeasonal High Groundwater ElevationParameterEach project supplies its own value.seasonal-high-groundwater-elevation shall be dewatered continuously, in accordance with Excavation Support And DewateringExcavation Support and DewateringResolves to the current adopted revision.sync/excavation-support-and-dewatering, from before excavation of the pipe zone until sufficient backfill is in place to resist flotation.
10.3.2 The groundwater level shall be maintained not less than 12 in. below the trench bottom throughout pipe laying, embedment placement, and embedment compaction.
10.3.3 Dewatering discharge shall be conducted through the sediment controls required by Erosion And Sediment ControlErosion and Sediment ControlResolves to the current adopted revision.sync/erosion-and-sediment-control and shall comply with the project's NPDES permit.
10.3.4 Dewatering discharge shall not be routed into the newly installed storm system until that system has been tested and accepted.
NOTE 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. (10.3.5)
10.3.6 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.

11 Pipe Embedment and Backfill

11.1 Embedment Material

11.1.1 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.
Flexible Pipe Embedment Material Classselect
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
NOTE 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. (11.1.2)
11.1.3 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.
11.1.4 The bedding course thickness below the pipe shall be as indicated in the datasheet.
Bedding Course Thickness Below the Piperange
in
34691218
11.1.5 The bedding course thickness shall be not less than 6 in. where the trench bottom is rock, cemented material, or a stabilized foundation course.
11.1.6 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.
11.1.7 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.

11.2 Placement and Compaction

11.2.1 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.
11.2.2 Embedment shall be placed in lifts not exceeding 8 in. of loose thickness up to the top of the pipe zone.
NOTE The pipe zone extends from the top of the bedding to a plane 12 in. above the crown of the pipe. (11.2.3)
11.2.4 The minimum compaction of Class II and Class III embedment materials shall be as indicated in the datasheet.
Minimum Embedment Compaction for Class II and Class III Materialsrange
% of maximum standard Proctor dry density
859095100
11.2.5 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.
NOTE 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. (11.2.6)
11.2.7 Compaction equipment shall not be operated directly over the pipe until at least 12 in. of compacted cover is in place above the crown.
11.2.8 Hand-operated plate compactors or rammers shall be used within the pipe zone.
NOTE 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. (11.2.9)

11.3 Cover Limits

11.3.1 The minimum cover over the crown of the pipe shall be as indicated in the datasheet.
Minimum Cover Over the Pipe Crowntext
Enter value...
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 (by default)
11.3.2 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.
11.3.3 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.
11.3.4 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.
NOTE 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. (11.3.5)

11.4 Final Backfill

11.4.1 Trench backfill above the pipe zone shall conform to the requirements of EarthworkEarthworkResolves to the current adopted revision.sync/earthwork for the area in which the trench falls, and this standard does not restate those requirements.
11.4.2 Trench backfill compaction shall be tested at the frequency required by EarthworkEarthworkResolves to the current adopted revision.sync/earthwork, and material failing that test shall be removed or scarified and recompacted at the Contractor's expense.
NOTE 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. (11.4.3)

12 Pipe Installation

12.1 Laying and Alignment

12.1.1 Pipe shall be laid beginning at the downstream end of each reach and progressing upstream, with bells facing upstream.
NOTE 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. (12.1.2)
12.1.3 The method of verifying pipe alignment and grade shall be as indicated in the datasheet.
Pipe Alignment and Grade Verification Methodselect
Pipe laser set to the design invert and slope
Robotic total station
Transit and offset grade stakes
String line and batter boards
12.1.4 Each pipe section shall be brought to the design line and grade before the joint is closed.
NOTE Once a gasketed joint is home, correcting alignment requires disassembling the joint, so the check belongs before the joint is made rather than after. (12.1.5)
12.1.6 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.
12.1.7 Joint deflection shall not exceed the deflection published by the joint manufacturer for that pipe size and joint type.
12.1.8 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.
12.1.9 The completed reach between structures shall hold a uniform grade with no sag.
NOTE 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. (12.1.10)

12.2 Joint Assembly

12.2.1 The bell and gasket seat of each pipe shall be cleaned of soil and debris immediately before the joint is assembled.
12.2.2 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.
12.2.3 Petroleum-based lubricants, grease, and detergents shall not be applied to elastomeric gaskets.
NOTE 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. (12.2.4)
12.2.5 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.
NOTE Over-insertion rolls or pinches the gasket out of its seat, which produces a leak path that no external sealing can reliably close. (12.2.6)
12.2.7 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.

12.3 Cutting Pipe

12.3.1 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.
12.3.2 Reinforced concrete pipe shall be cut with a diamond saw, and shall not be cut by flame, impact, or percussion methods.
12.3.3 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.
12.3.4 Corrugated metal pipe field cuts shall be recoated in accordance with the coating manufacturer's instructions before backfill.
12.3.5 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.

12.4 Transitions and Couplings

12.4.1 The method of joining dissimilar pipe materials, field cut-ins, and connections to existing pipe shall be as indicated in the datasheet.
Joining Method at Material Transitionsselect
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
12.4.2 Transition couplings shall be sized to the actual outside diameters of both pipes.
NOTE 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. (12.4.3)
12.4.4 Where the joint performance class is watertight, the coupling shall be qualified to that class for both materials being joined.

12.5 Locating and Identification

12.5.1 The provision for locating buried nonmetallic storm sewer shall be as indicated in the datasheet.
Locating Provision Over Nonmetallic Pipeselect
Detectable marking tape above the pipe zone
Tracer wire attached along the pipe
Detectable marking tape and tracer wire
No locating provision
12.5.2 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.
12.5.3 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.

12.6 Connections to Existing Systems

12.6.1 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.
12.6.2 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.
12.6.3 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.
12.6.4 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.
12.6.5 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.
12.6.6 The point of connection to the public storm system shall be as indicated on the civil utility plan.

13 Structure Installation

13.1 Foundation and Base

13.1.1 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.
13.1.2 The base elevation shall be verified and released before any pipe is connected to the structure.
NOTE 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. (13.1.3)
13.1.4 Structure foundations shall bear below Frost DepthFrost DepthParameterEach project supplies its own value.frost-depth where the structure is set in frost-susceptible soil.
13.1.5 Cast-in-place bases shall be placed on the granular foundation course with reinforcement and pipe opening formwork in place, in accordance with Cast In Place ConcreteCast-in-Place ConcreteResolves to the current adopted revision.sync/cast-in-place-concrete and Concrete ReinforcementConcrete ReinforcementResolves to the current adopted revision.sync/concrete-reinforcement.

13.2 Setting Sections and Frames

13.2.1 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.
13.2.2 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.
13.2.3 Exterior backfill against structures shall meet the compaction required by EarthworkEarthworkResolves to the current adopted revision.sync/earthwork for the area, and shall not be placed until the structure has been tested where testing is required before backfill.
13.2.4 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.
13.2.5 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.
NOTE 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. (13.2.6)
13.2.7 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.

14 Testing and Acceptance

14.1 Pipe Leakage Testing

14.1.1 The pipe leakage test method shall be as indicated in the datasheet.
Pipe Leakage Test Methodselect
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
14.1.2 Leakage testing shall be performed after embedment is complete and before final backfill closes the trench above the pipe zone.
14.1.3 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.
NOTE 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. (14.1.4)
14.1.5 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 Seasonal High Groundwater ElevationSeasonal High Groundwater ElevationParameterEach project supplies its own value.seasonal-high-groundwater-elevation.
14.1.6 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.
14.1.7 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.
14.1.8 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.
14.1.9 The Contractor shall identify and correct the cause of a failure before retesting, and shall record both the failure and the passing retest.

14.2 Structure Leakage Testing

14.2.1 The structure leakage test method shall be as indicated in the datasheet.
Structure Leakage Test Methodselect
Negative air pressure vacuum test per ASTM C1244
Hydrostatic exfiltration test
Visual inspection for infiltration only
No structure leakage test
14.2.2 The vacuum test shall be performed after the structure is complete and before exterior backfill is placed, in accordance with ASTM C1244.
14.2.3 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.
NOTE 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. (14.2.4)
14.2.5 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.
14.2.6 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.

14.3 Deflection Testing

14.3.1 The maximum allowable installed deflection of flexible pipe shall be as indicated in the datasheet.
Maximum Allowable Installed Pipe Deflectionrange
%
357.5
14.3.2 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.
NOTE 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. (14.3.3)
14.3.4 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.
14.3.5 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.
14.3.6 The Contractor shall not modify a mandrel, substitute a smaller mandrel, or ream the pipe to pass a reach.
14.3.7 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.
NOTE 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. (14.3.8)

14.4 Video Inspection

14.4.1 The extent of post-installation video inspection shall be as indicated in the datasheet.
Post-Installation Video Inspection Extentselect
All storm sewer mains and laterals
All storm sewer mains
Reaches selected by the Engineer of Record
No video inspection
14.4.2 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.
14.4.3 The video record shall be continuously referenced to distance from the starting structure and shall identify each structure, joint, service connection, and defect observed.
NOTE 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. (14.4.4)
14.4.5 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.

14.5 Test Records

14.5.1 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.
14.5.2 Test reports shall be submitted within five working days of the test.
14.5.3 The Contractor shall not remove or replace a failing test report with the report of a subsequent passing test.

14.6 Final Acceptance

14.6.1 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.
14.6.2 Acceptance shall not waive the Contractor's warranty obligations or the Contractor's liability for latent defects.
NOTE 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. (14.6.3)

15 Cleaning and Turnover

15.1 The completed system shall be cleaned of sediment, debris, mortar droppings, and construction materials after all testing is complete and before turnover.
15.2 The final cleaning method shall be as indicated in the datasheet.
Final System Cleaning Methodselect
Hydraulic jet flushing with vacuum recovery of debris
Mechanical bucket cleaning
Manual removal from structures
15.3 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.
15.4 Sediment removed during cleaning shall be disposed of off site or at a location approved by the Owner in writing.
15.5 Inlet sumps, structure benches, and structure inverts shall be flushed and left free of standing sediment.
15.6 Grates and covers shall be cleaned of construction debris and shall be verified to seat in their frames without rocking.
15.7 Temporary inlet protection, sediment bags, and construction sediment traps within the storm system shall be removed at turnover.
NOTE 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. (15.8)
15.9 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.

16 Delivery, Storage, and Handling

16.1 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.
16.2 Pipe shall be stored on level ground, blocked against rolling, and stacked no higher than the pipe manufacturer's published stacking limit.
16.3 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.
NOTE 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. (16.4)
16.5 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.
16.6 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.
16.7 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.
NOTE 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. (16.8)

17 Warranty

17.1 The warranty period for the storm drainage system shall be as indicated in the datasheet.
Storm Drainage System Warranty Periodrange
years
1235
17.2 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.
17.3 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.
17.4 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.
17.5 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.
17.6 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.
17.7 Where the parties disagree whether settlement is attributable to trench backfill, the Engineer of Record shall make the initial determination.
NOTE 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. (17.8)
17.9 Manufacturer warranties for castings, precast structures, and manufactured end treatments shall be assigned to the Owner at closeout.
17.10 The warranty period shall not limit the Contractor's liability for non-conforming work discovered after it expires.
NOTE 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. (17.11)

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