Utility Manholes and Handholes
Remake batch 25 and its neighbor re-points, batch 24 where missing, and the adopted-electrical-code parameter: brought in line with the authoring repository
Showing changes from Rev 5
to Rev 6
in Utility Manholes and Handholes.
---
title: Utility Manholes and Handholes
category: Electrical
−toc_depth: 3
description: >
− When to use: Selecting and specifying below-grade access structures for underground electrical and low-voltage systems — precast concrete manholes (personnel-entry), precast concrete handholes/vaults, and polymer-concrete or composite handholes serving medium-voltage feeders, low-voltage distribution, lighting circuits, and communications/data ductbanks. Covers ductbank pull points, cable splice and termination locations, inspection access, cover and frame assemblies, load/tier ratings, cover markings, sumps and drainage, grounding/bonding attachments, pulling irons, and cable rack inserts.
− Not intended for: Underground conduit/ductbank routing, trench design, and concrete encasement (see [[sync/underground-ductbank]]); conduit and raceway material, fittings, and methods (see [[sync/raceways-and-conduit]]); shielded conductors above 1000 V and their joints (see [[sync/medium-voltage-cables]]), low-voltage conductors and cables (see [[sync/conductors-and-cables]]), and cable tray (see [[sync/cable-tray]]); broader storm/sanitary/water/gas main coordination (see [[sync/site-utilities]]); above-grade pull, junction, and outlet boxes; AASHTO bridge-loaded roadway manholes; and wet-well or sump-pump drainage structures.
+ When to use: The below-grade access structures of an underground electrical or communications duct system on a campus, a plant, or a building site: precast concrete manholes and vaults that a person enters to pull, splice, and rack cable, and the handholes of precast concrete, polymer concrete, fiberglass, or composite that are worked from grade. Covers the choice between a manhole and a handhole, the load rating of each structure, the precast concrete sections and their joints, the handhole enclosure and its cover, the duct windows and terminators at the wall, frames, covers, legends, locking and grade adjustment, the access opening, steps and ladders, cable racks and arms, pulling irons, sumps and drainage, the ground rod sleeve and bonding provisions, the structure's own excavation, base, and backfill, field checks, warranty, and spares.
+ Not intended for: the duct bank, its conduit, its spacers, its encasement, its slope, its end bells, and the proving of its ducts ([[sync/underground-ductbank]]); above-grade conduit, pull boxes, and junction boxes ([[sync/raceways-and-conduit]]) and cable tray ([[sync/cable-tray]]); the shielded cable above 1000 V, its splices, its arc-proofing, its tags, and how it is trained on the rack arms ([[sync/medium-voltage-cables]]); building wire and power cable rated 1000 V and below ([[sync/conductors-and-cables]]); the grounding electrode, the ground bar as a product, and the bonding of the racks, irons, covers, and conduits ([[sync/grounding-and-bonding]]); a chamber built in place by the concrete trade where a plant-cast unit does not fit ([[sync/site-concrete-structures]]); storm and sanitary sewer access chambers and their castings ([[sync/storm-drainage]], [[sync/sanitary-sewer-systems]]); mass excavation, dewatering, and fill beyond the structure's own backfill zone ([[sync/earthwork]], [[sync/excavation-support-and-dewatering]]); and the pavement restored over the structure ([[sync/asphalt-paving]], [[sync/concrete-paving]]).
---
# Scope {toc}
−## This standard covers the design, selection, and specification of below-grade access structures for underground electrical power distribution and telecommunications/low-voltage systems on commercial, institutional, industrial, and site-utility projects. {note}
+## This standard governs the below-grade structures that give access to an underground electrical or communications duct system: the manhole or vault a person climbs into to pull, splice, and rack cable, and the handhole that is reached from grade with the cover off. It covers the structure as a product and as set in the ground, from the decision between a manhole and a handhole, through the load rating, the precast sections and the enclosure, the openings in the walls, the frame and cover, the hardware cast or set inside, the drainage, and the grounding provisions, to the excavation and backfill that belong to the structure alone, the field checks, the warranty, and the spares. {note}
−## The structure types addressed are personnel-entry precast concrete manholes, hand-access precast concrete handholes and vaults, and polymer-concrete or fiberglass composite handholes, together with their cover and frame assemblies, sump and drainage provisions, grounding and bonding attachments, pulling irons, and cable rack inserts. {note}
+## The structure is the one part of a duct system that is opened again and again for the life of the site, and it is the part that is wrong most often: a handhole rated for a lawn that ends up in a drive aisle, a manhole with no pulling iron opposite the duct that matters, a sump with nowhere to drain, a cover with no legend over a telecommunications vault, a rack insert that was never cast in. Each of those is decided here, before the structure is cast, so that the cable trade finds the structure ready when the pull begins. {note}
−## These structures serve as ductbank pull points, cable splicing and termination locations, and inspection access points for medium-voltage feeders, low-voltage distribution, lighting circuits, and communications/data systems, including mixed-use underground duct systems. {note}
+## A manhole and a handhole differ in what a person does with them, not in their size alone. A manhole is entered, which makes it a confined space with the work space, the headroom, the access opening, and the entry procedures that NFPA 70 Article 110 Part V and the OSHA confined-space rules require. A handhole is never entered; its depth is the depth a person can reach from grade, and its floor is often open to the soil. The choice between them follows the cable: a splice in medium-voltage cable, a large conductor count, or a change of direction in a heavy feeder needs a manhole, and a pull point in a lighting or communications run needs a handhole. {note}
−## The distinction between a manhole and a handhole is access, not merely size. {note}
+## The following are governed elsewhere and are outside this standard: {note}
−## A manhole is sized and rated for personnel to physically enter and work inside it; this makes it a permit-required confined space and triggers working-clearance, ventilation, and access requirements. A handhole (also called a vault when of larger plan dimension) permits hand access from grade for pulling and splicing but is never entered by personnel. The selection between the two is driven by cable volume, the need for in-structure splicing or terminations, and maintenance frequency. {note}
+- the duct bank, its conduit, its spacers, its encasement, its slope toward the structure, the end bells it enters the wall with, the identification of its ducts, and the proving of the ducts, under [[sync/underground-ductbank]]
+- above-grade conduit, pull boxes, and junction boxes, under [[sync/raceways-and-conduit]], and cable tray, under [[sync/cable-tray]]
+- the shielded cable above 1000 V, its splices, its arc-proofing, its identification tags, the slack loop left in the structure, and how it is trained and racked on the arms, under [[sync/medium-voltage-cables]]
+- building wire and power cable rated 1000 V and below, under [[sync/conductors-and-cables]], and the communications cable pulled through the structure, under [[sync/structured-cabling]] for the building cabling plant it continues
+- the grounding electrode and the rod driven through the sleeve, the ground bar as a product, the bonding conductor, and the bonding of the racks, pulling irons, covers, frames, and conduits in the structure, under [[sync/grounding-and-bonding]]; the sleeve, the inserts, and the bonding provisions the structure is built with are furnished here
+- a chamber built in place by the concrete trade where a plant-cast unit does not fit the configuration or the site, under [[sync/site-concrete-structures]], which carries the same list of cast-in items for that case
+- the access chambers of the storm and sanitary sewers and their castings, under [[sync/storm-drainage]] and [[sync/sanitary-sewer-systems]]
+- mass excavation, construction dewatering, excavation support, and fill beyond the backfill zone of the structure, under [[sync/earthwork]] and [[sync/excavation-support-and-dewatering]]
+- the pavement, curb, and landscape restored over and around the structure, under [[sync/asphalt-paving]] and [[sync/concrete-paving]]
+- the equipment installed inside a vault and the clearances its own standard requires around it
+- a pull box on a public right-of-way that the state department of transportation requires to be built to its standard drawing, which that department's standard specifications govern
−## The following are outside the scope of this standard. {note}
+## The governing standard for a structure the serving utility will own shall be as indicated in the datasheet.
−- Underground conduit and ductbank routing, trench design, and concrete encasement — see [[sync/underground-ductbank]].
−- Conduit and raceway material selection, fittings, and installation methods — see [[sync/raceways-and-conduit]].
−- Medium-voltage cable and its splices — see [[sync/medium-voltage-cables]]; low-voltage conductors and cables — see [[sync/conductors-and-cables]]; cable tray — see [[sync/cable-tray]].
−- Broader site utility coordination for storm, sanitary, water, and gas mains — see [[sync/site-utilities]].
−- Above-grade pull boxes, junction boxes, and outlet boxes mounted on walls or in ceilings, which are governed by NEC Article 314 but are not the subject of this standard.
−- Traffic-signal or roadway manholes with structural bridge-loading requirements beyond H-20, which fall under AASHTO/civil scope.
−- Wet-well or sump-pump structures for drainage systems, which are mechanical/plumbing scope.
+```datasheet
+label: Governing Standard for Structures the Serving Utility Will Own
+type: select
+options:
+ - "The serving utility's construction standard"
+ - "This standard, as accepted by the serving utility"
+default: "The serving utility's construction standard"
+```
−# Referenced Standards {toc}
+## A utility that will own and maintain a structure on its side of the service point builds it to its own drawings, inspects it against them, and refuses one it did not approve, so its standard governs those structures whatever this standard says; an Owner-owned structure on the Owner's side of the service point is built to this standard, and the serving utility reviews it only where the utility's cable will pass through it. {note}
−## Equipment, materials, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
+## The location, the designation, the rim and invert elevations, and the system occupying each structure shall be as indicated on [[drawing: the structure schedule on the site electrical plans]].
−## Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
+## The Contractor shall confirm the duct entry locations, the window sizes, and the invert elevations of every duct bank arriving at a structure against [[sync/underground-ductbank]] before the shop drawings for that structure are submitted.
−## ANSI/SCTE 77 tier nomenclature (Tier 8, Tier 15, Tier 22) is the dominant load-rating language for polymer-concrete and composite handholes in the US market; for precast concrete structures, AASHTO H-10/H-20/HS-20 loading is the equivalent reference. Both rating systems are cross-referenced in this standard to avoid confusion. {note}
+# Referenced Standards {toc}
+## Structures, hardware, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
+
+## Where the contract documents, the manufacturer's published instructions, the Authority Having Jurisdiction, or two referenced standards impose conflicting requirements, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
+
| Standard | Title |
|----------|-------|
−| NFPA 70 (NEC) Article 314 | Outlet, Device, Pull, and Junction Boxes; Conduit Bodies; Fittings; and Handhole Enclosures |
−| NFPA 70 (NEC) Article 110.26 | Spaces About Electrical Equipment (working clearances) |
−| NFPA 70 (NEC) Article 110.31 / 110.34 | Enclosures for Electrical Installations and Working Space (Over 1000 V) |
−| NFPA 70 (NEC) Article 250 | Grounding and Bonding |
−| NFPA 70 (NEC) Article 300.3 | Conductors (general installation and segregation) |
+| NFPA 70 | National Electrical Code (Article 110 Part V, 250, 314.30, 805.47) |
| ASTM C478/C478M | Circular Precast Reinforced Concrete Manhole Sections |
| ASTM C857 | Minimum Structural Design Loading for Underground Precast Concrete Utility Structures |
| ASTM C858 | Underground Precast Concrete Utility Structures |
−| AASHTO M199 | Precast Reinforced Concrete Manhole Sections |
−| ANSI/SCTE 77 | Specification for Underground Enclosure Integrity |
−| NEMA 250 | Enclosures for Electrical Equipment (1000 Volts Maximum) |
−| ASTM A48 | Gray Iron Castings |
+| ASTM C891 | Installation of Underground Precast Concrete Utility Structures |
+| ASTM C990 | Joints for Concrete Pipe, Manholes, and Precast Box Sections Using Preformed Flexible Joint Sealants |
+| ASTM C443 | Joints for Concrete Pipe and Manholes, Using Rubber Gaskets |
+| ASTM C1244 | Concrete Sewer Manholes by the Negative Air Pressure (Vacuum) Test Prior to Backfill |
+| ASTM C1107 | Packaged Dry, Hydraulic-Cement Grout (Nonshrink) |
+| ASTM A48/A48M | Gray Iron Castings |
| ASTM A536 | Ductile Iron Castings |
−| IEEE 80 | Guide for Safety in AC Substation Grounding |
+| ASTM A123/A123M | Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products |
+| ASTM A153/A153M | Zinc Coating (Hot-Dip) on Iron and Steel Hardware |
+| ANSI/SCTE 77 | Specification for Underground Enclosure Integrity |
+| AASHTO M 306 | Drainage, Sewer, Utility, and Related Castings |
+| AASHTO LRFD Bridge Design Specifications | Vehicular live load HL-93 and the HS20-44 design truck |
+| ACI 318 | Building Code Requirements for Structural Concrete (exposure categories) |
+| NPCA Quality Control Manual for Precast Concrete Plants | Plant certification program of the National Precast Concrete Association |
| OSHA 29 CFR 1910.146 | Permit-Required Confined Spaces |
+| OSHA 29 CFR 1926 Subpart AA | Confined Spaces in Construction |
# Submittals {toc}
## Action Submittals {toc}
−### The Contractor shall submit the following action submittals for review and approval before fabrication or delivery:
+### The Contractor shall submit the following for the Engineer of Record's review and acceptance before any structure is cast or any enclosure is ordered:
−- Product data for each manhole, handhole, and vault type, including dimensions, wall thickness, weight, and load/tier rating.
−- Product data for each cover and frame assembly, including casting material, clear opening, weight, locking provisions, and cast legend.
−- Shop drawings showing plan and section views, knockout/duct-entry locations and sizes, sump and drain details, and grade-adjustment provisions.
−- Shop drawings showing the location, type, and rated capacity of all pulling irons, pulling eyes, and cast-in inserts.
−- Shop drawings showing cable rack standoff insert locations, spacing, and the rack and arm system to be furnished.
−- Structural design calculations sealed by a professional engineer, demonstrating compliance with the specified load/tier rating per ASTM C857 or ANSI/SCTE 77.
−- A grounding and bonding plan showing the bonding of metallic covers, frames, pulling irons, and cable racks and the connection to the system grounding electrode.
+- Product data for each precast structure type, identifying the producer, the governing product standard, the inside dimensions, the wall and slab thicknesses, the concrete strength, the reinforcement, the joint type, and the shipping weight of each section
+- Product data for each handhole enclosure and cover, identifying the material, the inside dimensions, the ANSI/SCTE 77 tier or the AASHTO load rating, the cover securing hardware, the legend, and the bottom configuration
+- Shop drawings for each structure, in plan and section, showing every duct window or terminator with its size, wall, and invert, the access opening, the pulling irons, the rack inserts, the ground rod sleeve, the sump, the steps or ladder, the lifting inserts, and the structure designation
+- Structural calculations for each precast structure, sealed by a professional engineer licensed in the state of the project, showing the design to ASTM C857 for the load class of the structure, the earth and groundwater loads at its depth, and the resistance to flotation where the structure stands in groundwater
+- Product data for the frames and covers, identifying the casting alloy and grade or the composite material, the clear opening, the weight, the legend, the securing hardware, and the AASHTO M 306 or ANSI/SCTE 77 listing
+- Product data for the cable racks, arms, insulators, inserts, pulling irons, steps or ladders, sump gratings, and grade rings
+- Product data for the joint sealant, the exterior joint wrap and coating where selected, the duct window closure grout or seal, and the frame-seat mortar
```datasheet
label: Action Submittals
type: checkbox
options:
− - Structure product data (dimensions, weight, rating)
− - Cover and frame product data (material, opening, legend)
− - Shop drawings (plan/section, duct entries, sump)
− - Pulling iron/eye locations and capacities
− - Cable rack insert layout and rack system
− - Sealed structural design calculations
− - Grounding and bonding plan
+ - "Precast structure product data"
+ - "Handhole enclosure and cover product data"
+ - "Structure shop drawings with openings, hardware, and designation"
+ - "Sealed structural calculations to ASTM C857"
+ - "Frame and cover product data with listing and legend"
+ - "Rack, iron, insert, step, grating, and grade ring product data"
+ - "Sealant, wrap, coating, grout, and mortar product data"
default:
− - Structure product data (dimensions, weight, rating)
− - Cover and frame product data (material, opening, legend)
− - Shop drawings (plan/section, duct entries, sump)
− - Sealed structural design calculations
− - Grounding and bonding plan
+ - "Precast structure product data"
+ - "Handhole enclosure and cover product data"
+ - "Structure shop drawings with openings, hardware, and designation"
+ - "Sealed structural calculations to ASTM C857"
+ - "Frame and cover product data with listing and legend"
+ - "Rack, iron, insert, step, grating, and grade ring product data"
+ - "Sealant, wrap, coating, grout, and mortar product data"
+constraint: all_of
```
+### The shop drawing is where a manhole is either right or expensive. A duct window on the wrong wall, a pulling iron off the line of the duct it serves, or a rack insert missing from a wall that will carry three circuits is cast into eight tons of concrete before anyone on the site sees it, and the remedy is a core drill or a new structure. The drawing is reviewed against the duct bank drawings and the cable schedule together, not alone. {note}
+
## Informational Submittals {toc}
−### The Contractor shall submit the following informational submittals:
+### The Contractor shall submit the following for the record, before the structures they concern are delivered:
−- Certified proof-load test reports for composite and polymer-concrete enclosures and covers per ANSI/SCTE 77.
−- Certified concrete compressive-strength test reports for precast concrete structures.
−- Manufacturer's confined-space and rigging/lifting instructions for personnel-entry manholes.
−- Source quality-control certifications showing compliance with ASTM C478, ASTM C858, or AASHTO M199 as applicable.
+- The precast plant's certification or approval under the program indicated in the datasheet
+- Concrete compressive strength test reports for the sections delivered, identified to the structures they belong to
+- The ANSI/SCTE 77 test report of an independent laboratory for each non-concrete enclosure and cover model, at the tier furnished
+- The producer's installation instructions and the lifting and rigging plan for each precast structure, including the crane position, the lifting inserts, and the sequence of setting the sections
+- The Contractor's confined-space entry program for the installation work in each manhole, under 29 CFR 1926 Subpart AA
```datasheet
label: Informational Submittals
type: checkbox
options:
− - ANSI/SCTE 77 proof-load test reports
− - Concrete compressive-strength test reports
− - Confined-space and rigging instructions
− - Source QC / material certifications
+ - "Precast plant certification"
+ - "Concrete strength test reports by structure"
+ - "ANSI/SCTE 77 laboratory test reports by enclosure model"
+ - "Installation instructions and lifting and rigging plan"
+ - "Confined-space entry program for installation"
default:
− - ANSI/SCTE 77 proof-load test reports
− - Concrete compressive-strength test reports
− - Source QC / material certifications
+ - "Precast plant certification"
+ - "Concrete strength test reports by structure"
+ - "ANSI/SCTE 77 laboratory test reports by enclosure model"
+ - "Installation instructions and lifting and rigging plan"
+ - "Confined-space entry program for installation"
+constraint: all_of
```
## Closeout Submittals {toc}
−### The Contractor shall submit the following closeout submittals before final acceptance:
+### The Contractor shall submit the following before the structures are accepted:
−- Record drawings showing the as-built location, structure designation, invert elevations, and rim elevation of each installed structure.
−- A structure schedule listing each structure's identification number, type, rating, and the circuits or systems routed through it.
−- Operation and maintenance data, including drainage, grounding test results, and cover-hardware torque values.
+- Record drawings showing the surveyed location of each structure, its designation, its rim elevation, the invert of every duct entering it, and the wall each duct enters
+- The structure schedule as built, listing for each structure its type, its inside dimensions, its load class, its cover legend, and the circuits and ducts occupying it
+- The infiltration observation report and, for a sealed structure, the vacuum test report
+- The manufacturers' warranties for the structures, the enclosures, and the castings, assigned to the Owner
+- The signed receipt for the spare parts and the special tools
```datasheet
label: Closeout Submittals
type: checkbox
options:
− - As-built record drawings (locations, inverts, rim)
− - Structure schedule (ID, type, rating, circuits)
− - O&M data and grounding test results
+ - "Record drawings with surveyed locations, rims, and duct inverts"
+ - "As-built structure schedule"
+ - "Infiltration observation and vacuum test reports"
+ - "Assigned manufacturers' warranties"
+ - "Spare parts and special tool receipt"
default:
− - As-built record drawings (locations, inverts, rim)
− - Structure schedule (ID, type, rating, circuits)
− - O&M data and grounding test results
+ - "Record drawings with surveyed locations, rims, and duct inverts"
+ - "As-built structure schedule"
+ - "Infiltration observation and vacuum test reports"
+ - "Assigned manufacturers' warranties"
+ - "Spare parts and special tool receipt"
+constraint: all_of
```
# Quality Assurance {toc}
−## Precast concrete manhole sections shall be produced in a plant certified for the production of precast concrete utility structures.
+## Precast structures shall be produced in a plant certified or approved under one of the programs indicated in the datasheet.
−## Composite and polymer-concrete enclosures shall be proof-load tested to the specified ANSI/SCTE 77 tier before shipment, and certified test reports shall be furnished.
+```datasheet
+label: Precast Plant Certification
+type: checkbox
+options:
+ - "NPCA Plant Certification"
+ - "ACPA QCast Plant Certification"
+ - "State department of transportation precast plant approval"
+ - "Plant quality control program reviewed and accepted by the Engineer of Record"
+default:
+ - "NPCA Plant Certification"
+ - "State department of transportation precast plant approval"
+constraint: any_of
+```
−## The structural designer of each personnel-entry manhole shall be a professional engineer licensed in the jurisdiction of the project.
+## The plant programs audit the same things, mixture control, reinforcement placement, curing, and the record that ties a section to its strength test, and differ in who audits them: the NPCA program is the one most utility-structure producers hold, the ACPA program is the pipe and circular-manhole producers' program, a state DOT approval is what a producer serving public-works jobs holds and is sometimes the only one it holds, and a plant program accepted by the Engineer of Record is the route for a regional producer with none of the three, at the cost of the Engineer's own audit. {note}
−## A single manufacturer shall furnish each structure complete with its matching cover and frame assembly so that load ratings are coordinated as a system.
+## Each non-concrete enclosure and cover shall be of a model that an independent laboratory has tested to ANSI/SCTE 77 at the tier furnished, and the enclosure and the cover shall be the pair tested together.
−## Mixing a third-party cover or frame onto a structure body can defeat the certified tier rating, because the rating is established for the body and lid as a tested assembly. Furnishing matched components from one source preserves the certified rating and assigns single-source responsibility for fit and performance. {note}
+## A tier rating belongs to the tested assembly of a body and its cover, and a cover from another maker or another product line on a tested body carries no rating; the matched pair is what the test report certifies and what the structure schedule relies on. {note}
−## Personnel-entry manholes are permit-required confined spaces and shall comply with OSHA 29 CFR 1910.146.
+## The structural design of each precast structure shall be the responsibility of a professional engineer licensed in the state of the project, retained by the producer or the Contractor.
−## Confined-space provisions — ventilation access, fixed or portable ladder access, and rescue retrieval — shall be coordinated among the electrical, structural, and safety disciplines and reflected in the structure design.
+## Each manhole shall be treated as a permit-required confined space, and the Contractor shall enter it during construction only under a confined-space entry program conforming to 29 CFR 1926 Subpart AA.
+## The Contractor shall deliver to the Owner, with the closeout submittals, the information the Owner's permit-required confined-space program under 29 CFR 1910.146 needs for each manhole: its designation, its access opening size, its depth, and its ventilation openings where any.
+
+## Where the Owner, the Contractor, and the producer disagree whether a crack, a spall, a leaking joint, or a cover that rocks in its frame is a defect, the Engineer of Record shall make the initial determination, with the structure left accessible for examination.
+
# Environmental and Service Conditions {toc}
−## Below-grade structures are continuously exposed to a wet, corrosive, and load-bearing environment, and the design basis must state the conditions the structure is built to withstand. {note}
+## A manhole spends its life in the ground, wet for part of every year, loaded by the soil on its walls and by whatever crosses the surface above it, and frozen through its upper sections in a cold climate. Those four conditions, the surface load, the groundwater, the soil chemistry, and the frost, set the load class, the drainage approach and the joint treatment, the concrete exposure class, and the base and backfill of the structure, and each is decided in its own article below against the fact that drives it. {note}
−## The governing service conditions are the surface load above the structure, the groundwater regime (high water table, periodic flooding, or dry), soil corrosivity and chemistry, and frost depth. Each of these drives a distinct design decision: load determines the tier/structural rating, groundwater determines the drainage and watertightness approach, corrosivity determines material selection, and frost depth determines minimum cover and grade-ring detailing. {note}
+## Each structure shall be designed for the earth pressure at its depth, for the groundwater pressure with the water at [[parameter: seasonal-high-groundwater-elevation]], and for the surface load of its load class, in accordance with ASTM C857.
−## Each structure shall be rated for the surface loading imposed at its final installed location, accounting for the finished paving and traffic plan and not the interim site condition.
+## Where any part of a structure lies below [[parameter: seasonal-high-groundwater-elevation]], the structure as backfilled shall resist flotation when empty, with the water at that elevation, with a factor of safety of not less than 1.1 by its own mass, by the backfill on an extended base, or by anchors, as the structural calculations show.
−## The design shall account for the maximum groundwater elevation anticipated at each structure location.
+## A sealed manhole is a boat: a 6 ft by 8 ft by 7 ft chamber displaces more than 20,000 lb of water, and a structure with a tight floor, sealed joints, and sealed duct windows in a high water table lifts out of its excavation, taking the duct bank with it, unless its own weight and the soil on its base hold it down. An open-bottom handhole and a manhole with weep openings fill instead of floating, which is why the flotation check and the drainage decision are made together. {note}
−## Where the soil or groundwater is corrosive, composite, fiberglass, or polymer-concrete structures should be selected in preference to metallic enclosures, and ferrous hardware should be galvanized or stainless.
+## The freeze-thaw exposure class of the concrete in each precast structure shall be as indicated in the datasheet.
```datasheet
−label: Maximum Groundwater Elevation Relative to Structure
+label: Freeze-Thaw Exposure Class
type: select
+derived: "[[parameter: climate-zone]] and whether the structure stands in water at [[parameter: seasonal-high-groundwater-elevation]]"
options:
− - Below structure floor (dry)
− - At or near floor (seasonal)
− - Above floor (submerged / high water table)
−default: At or near floor (seasonal)
+ - "F0"
+ - "F1"
+ - "F2"
+ - "F3"
+default: derived
```
−```datasheet
−label: Frost Depth (Minimum Cover to Top of Structure)
−type: range
−unit: in
−min: 0
−max: 60
−step: 6
−default: 36
−drawing_ref: true
−```
+## The sulfate exposure class of the concrete in each precast structure shall be as indicated in the datasheet.
```datasheet
−label: Soil/Groundwater Corrosivity
+label: Sulfate Exposure Class
type: select
+drawing_ref: "the geotechnical report"
options:
− - Non-corrosive
− - Moderately corrosive
− - Severely corrosive (chlorides/sulfates)
−default: Non-corrosive
+ - "S0"
+ - "S1"
+ - "S2"
+ - "S3"
+default: deferred
```
−# Structure Type and Load Rating {toc}
+## The ACI 318 exposure classes are the language a producer's mixture is qualified in. A structure in a climate where its concrete never freezes while wet is F0; one that freezes with only rain wetting it is F1; one that freezes saturated, which is the upper part of any structure standing in groundwater in a cold climate, is F2; and F3 adds deicing salt, which reaches the top slab and the upper joint of a manhole in a salted pavement. The sulfate class is read from the soil and groundwater chemistry in the geotechnical report, and it changes the cement type and the water-cementitious ratio of the mixture rather than the structure. {note}
−## Structure type and load rating are the two decisions that drive every downstream selection, and they must be made together because the available type/rating combinations are not unlimited. {note}
+## Where the soil or the groundwater is reported as corrosive to steel, every ferrous item exposed inside or outside the structure shall be hot-dip galvanized after fabrication in accordance with ASTM A123/A123M or ASTM A153/A153M, or shall be stainless steel or nonmetallic, as the hardware articles of this standard allow.
−## A polymer-concrete or composite handhole is light, fast to set, and ideal for low-voltage and telecommunications pull points, but it is not a personnel-entry structure and the highest readily available composite tier is Tier 22. A precast concrete manhole is the choice wherever personnel must enter to splice or terminate medium-voltage cable, and it is also the structure that most readily achieves AASHTO HS-20 heavy-traffic ratings. The decision flow is: determine whether personnel entry is required, then determine the surface load, then select the type that satisfies both. {note}
+# Structure Types and Selection {toc}
−## Structure Type Selection {toc}
+## A manhole shall be provided wherever a splice in cable rated above 1000 V is made, wherever a person must enter to pull, train, or rack the cable, and wherever the cable count or the conductor size exceeds what can be pulled and trained from grade through a handhole, at the locations indicated on the structure schedule.
−### The structure type shall be selected based on whether personnel entry is required, the cable volume, and the need for in-structure splicing or terminations.
+## A handhole shall be provided where the structure is a pull point, a splice point for cable rated 1000 V and below or for communications cable, or a change of direction that the cable can be trained through from grade, at the locations indicated on the structure schedule.
−### A personnel-entry precast concrete manhole shall be provided wherever medium-voltage cable splicing, terminations, or equipment requiring working clearances are located within the structure.
+## The inside dimensions of each manhole shall be as indicated in the datasheet.
−### Personnel-entry manholes containing medium-voltage conductors or equipment shall provide the working clearances and access required by NEC Article 110.31 and 110.34.
+```datasheet
+label: Manhole Inside Dimensions
+type: text
+drawing_ref: "the structure schedule"
+default: deferred
+```
−### A hand-access handhole or vault may be provided where the structure functions only as a pull point or low-voltage splice location and no personnel entry is required.
+## The inside dimensions of each handhole shall be as indicated in the datasheet.
```datasheet
−label: Structure Type
−type: select
−options:
− - Precast concrete manhole (personnel-entry)
− - Precast concrete handhole/vault (hand-access)
− - Polymer-concrete composite handhole
− - Fiberglass (FRP) handhole
−default: Polymer-concrete composite handhole
+label: Handhole Inside Dimensions
+type: text
+drawing_ref: "the structure schedule"
+default: deferred
```
+## The inside dimensions of each structure shall be not less than those required by NFPA 70 314.28 and 314.30 for the largest raceway and conductor entering it, and shall provide the training radius of the largest cable through the structure, the splice length where a splice is made, and the rack arms and slack loop the cable standard requires, verified against the cable schedule before the shop drawings are submitted.
+
+## The inside clear height of each manhole from the floor to the underside of the roof shall be not less than the value indicated in the datasheet, and not less than the headroom NFPA 70 110.72 requires in the cabling work space.
+
```datasheet
−label: Precast Manhole Inside Diameter
−type: select
+label: Manhole Inside Clear Height
+type: range
unit: in
options:
− - "48"
− - "60"
− - "72"
− - "96"
−default: "60"
+ min: 72
+ max: 120
+ setpoints: [72, 78, 84, 90, 96, 108, 120]
+constraint: min
```
+## The work space in each manhole shall meet NFPA 70 110.72 for the walls on which cable is racked, with the width measured from the face of the rack arms, not from the wall.
+
+## Six feet of headroom is the code floor and leaves a splicer stooped under the roof with a rack of cable at eye level; 7 ft is the height most utility manholes are built to, and it is the height at which four arms of medium-voltage cable and a splice stack on one wall with room for the splicer between them; a taller chamber buys more arms per wall and room for a sheave at a deep duct, at the cost of a deeper excavation, a heavier section, and more water to pump. A manhole that is also the low point of a long duct run gains from the extra depth, because the sump is then below the lowest duct by a useful margin. {note}
+
+## The occupancy of each structure by power and by communications systems shall be as indicated in the datasheet.
+
```datasheet
−label: Handhole/Vault Plan Size (W x L)
+label: Power and Communications Occupancy
type: select
−unit: ft
options:
− - 2 x 2
− - 2 x 3
− - 3 x 3
− - 3 x 5
− - 4 x 4
− - 4 x 6
−default: 3 x 5
−drawing_ref: true
+ - "Separate structures for power and for communications"
+ - "Shared structure with a barrier partition between the systems"
+default: "Separate structures for power and for communications"
```
+## Where a structure is shared, the communications cable shall be separated from the power conductors by a concrete, brick, or tile partition or by a barrier in accordance with NFPA 70 805.47(A), with the partition shown on the shop drawings and each compartment given its own access opening where a person must enter.
+
+## Separate structures cost a second excavation and a second casting at every access point and keep the communications contractor out of a chamber with energized power cable, and they are what most serving utilities and campus communications departments require; a shared structure saves the second structure where the site is tight and is lawful only with the partition the code requires, which turns one chamber into two narrower ones and costs most of the saving in a small structure. {note}
+
+## A chamber whose configuration or site no plant-cast unit fits shall be built in place under [[sync/site-concrete-structures]], with the openings, the hardware, and the provisions this standard requires carried into that structure's cast-in item list.
+
+# Load Rating {toc}
+
+## The load class of each structure shall be as indicated in the datasheet.
+
```datasheet
−label: Handhole/Vault Depth
−type: range
−unit: in
−min: 12
−max: 48
−step: 6
−default: 24
−drawing_ref: true
+label: Structure Load Class
+type: select
+drawing_ref: "the structure schedule"
+options:
+ - "Pedestrian and landscape area with no vehicle access"
+ - "Sidewalk and turf crossed by maintenance and light service vehicles"
+ - "Parking area, service drive, and fire lane"
+ - "Roadway and loading area under highway loading"
+ - "Industrial yard and airport apron under a stated wheel load"
+default: deferred
```
−## Load and Tier Rating {toc}
+## A precast concrete structure shall be designed to ASTM C857 for the loading that corresponds to its load class: the pedestrian loading of ASTM C857 for the pedestrian class, the 8,000 lb wheel for the light service vehicle class, the 12,000 lb wheel for the parking and service drive class, the 16,000 lb HS20-44 wheel with impact for the highway class, and the wheel load and contact area stated on the structure schedule for the industrial and airport class.
−### The single most common and costly error in handhole specification is a tier rating inconsistent with the final paving plan. {note}
+## A non-concrete handhole shall carry an ANSI/SCTE 77 tier not less than Tier 8 in the pedestrian class, Tier 15 in the light service vehicle class, and Tier 22 in the parking and service drive class.
−### Handholes set in areas called "non-traffic" during early design routinely end up in driveways or parking lots after a site redesign. Because the tier rating is established by proof-load testing, an under-rated cover in a traffic area is a failure waiting to happen and a field replacement at minimum. Where the traffic routing over a structure is uncertain at design time, specify one tier higher than the apparent minimum. {note}
+## In the highway class and the industrial and airport class, a handhole shall be either a precast concrete structure designed to ASTM C857 or a non-concrete enclosure that its manufacturer has tested to the AASHTO wheel load of that class and so certifies in the product data.
−### Each structure and its cover shall be rated for the surface loading at its final installed location.
+## Each cover and frame on a concrete structure in a vehicular class shall be listed to AASHTO M 306, and each cover on a non-concrete enclosure shall be of the tier the enclosure carries.
−### Where the traffic routing over a structure is uncertain at design time, the structure shall be specified one tier above the apparent minimum.
+## Each structure shall be rated for the surface over it at finished grade, as the grading and paving plans show it, and not for the condition of the site on the day it is set.
−### Polymer-concrete and composite enclosures and covers shall carry an ANSI/SCTE 77 tier rating not less than that scheduled for the structure.
+## The tiers of ANSI/SCTE 77 are written for enclosures off the roadway that meet occasional, non-deliberate vehicle loading, each tier naming a design load that a test load one and one-half times greater proves on the assembled body and cover; the ASTM C857 loadings are highway-derived wheel loads for a buried concrete structure. The two systems describe the same surface in different words, and the load class in the datasheet is written in the words of the surface so that either product can be matched to it. A handhole in a lawn 3 ft from a drive aisle is in the drive aisle the first time a delivery truck cuts the corner, which is why the class is read from the paving plan at the final condition and, where the use of the surface is uncertain, from the heavier of the two surfaces that could end up over it. {note}
−### Precast concrete structures in vehicular areas shall be designed for AASHTO H-20 or HS-20 wheel loading per ASTM C857.
+# Precast Concrete Manholes and Vaults {toc}
−### The ANSI/SCTE 77 tier and the AASHTO loading class shall both be shown on the structure schedule so the rating intent is unambiguous regardless of the structure material furnished.
+## The form of each precast manhole shall be as indicated in the datasheet.
```datasheet
−label: ANSI/SCTE 77 Tier Rating (Composite/Polymer Handholes)
+label: Manhole Form
type: select
options:
− - Pedestrian/non-traffic (no tier)
− - Tier 8 (~18,000 lb proof load)
− - Tier 15 (~33,750 lb light vehicular)
− - Tier 22 (~49,500 lb heavy vehicular / H-20)
−default: Tier 15 (~33,750 lb light vehicular)
+ - "Rectangular precast sections to ASTM C858"
+ - "Circular precast sections to ASTM C478"
+default: "Rectangular precast sections to ASTM C858"
```
+## The top of each precast manhole shall be as indicated in the datasheet.
+
```datasheet
−label: AASHTO Loading Class (Precast Concrete Structures)
+label: Manhole Top
type: select
options:
− - Non-traffic / pedestrian
− - H-10
− - H-20
− - HS-20
−default: H-20
+ - "Separate precast top slab"
+ - "Monolithic top cast with the upper section"
+ - "Eccentric cone riser on circular sections"
+default: "Separate precast top slab"
```
−# Concrete Construction {toc}
+## A rectangular chamber gives flat walls to rack cable on, square corners for the duct windows, and a floor plan the duct bank drawings can be laid out against, and it is what nearly every electrical and communications manhole is; a circular chamber is the sewer trade's product, stocked by every pipe producer in 48 in. to 96 in. diameters, cheaper where a producer of rectangular vaults is far away, and awkward to rack and window because every wall is curved. A separate top slab lets the base and walls be set and backfilled while the slab is on the truck and is removed later to lower a long splice or a reel of cable into the chamber; a monolithic top saves the perimeter joint and the slab's lifting operation at the cost of that access; a cone on a circular chamber brings the opening to the frame without a slab and needs the vertical room above the highest duct to develop its taper. {note}
−## Precast concrete is the default for personnel-entry manholes and heavy-traffic vaults because its mass, reinforcement, and proven structural standards give it the durability and load capacity those duties demand. {note}
+## Circular precast sections shall conform to ASTM C478/C478M, and rectangular and other non-circular precast structures shall conform to ASTM C858, each designed for the loading of ASTM C857 at the load class of the structure.
−## Cylindrical manhole sections are governed by ASTM C478/C478M (AASHTO M199 is the equivalent commonly cited on DOT and public-works work), while rectangular and non-circular vaults are governed by ASTM C858, with design loads taken from ASTM C857. Cast-in-place construction is reserved for non-standard geometries or congested duct entries that no stock precast unit accommodates, because field-formed concrete is slower and harder to quality-control than plant-cast units. {note}
+## The concrete of each precast structure shall have a 28-day compressive strength of not less than the value indicated in the datasheet, and the mixture shall be qualified for the freeze-thaw and sulfate exposure classes indicated above.
−## Precast circular manhole sections, risers, and bases shall conform to ASTM C478/C478M or AASHTO M199.
+```datasheet
+label: Concrete Compressive Strength
+type: range
+unit: psi
+options:
+ min: 4000
+ max: 7000
+ setpoints: [4000, 4500, 5000, 6000, 7000]
+default: 4000
+constraint: min
+```
−## Precast rectangular and non-circular utility structures shall conform to ASTM C858.
+## Four thousand psi is the strength the product standards require and the strength the producers' mixtures are qualified to, and a structure designed to ASTM C857 at that strength carries its load class without a higher figure; a 5,000 psi or 6,000 psi mixture is specified where the exposure class F2 or F3 or the sulfate class S2 or S3 drives the water-cementitious ratio down and the strength follows, and where the structural design of a deep or a wide-span structure asks for it. {note}
−## Concrete structural design loading shall be determined in accordance with ASTM C857.
+## Reinforcement shall be placed with the cover the product standard requires for the exposure of each face, and the reinforcement around each duct window, each access opening, and each lifting insert shall be as shown on the structural calculations.
−## Concrete shall attain a minimum 28-day compressive strength of 4,000 psi unless a higher strength is required by the structural design.
+## Section Joints and Watertightness {toc}
−## Cast-in-place structures shall be used only where standard precast units cannot accommodate the required geometry or duct-entry arrangement, and shall meet the same load rating as the equivalent precast structure.
+### Each horizontal joint between precast sections shall be sealed as indicated in the datasheet.
−## Joints between precast sections shall be sealed with a preformed butyl or mastic sealant to limit groundwater infiltration.
−
```datasheet
−label: Concrete Compressive Strength (28-day)
−type: range
−unit: psi
−min: 3000
−max: 6000
−step: 500
−default: 4000
+label: Section Joint Seal
+type: select
+options:
+ - "Preformed butyl sealant to ASTM C990"
+ - "Rubber gasket to ASTM C443"
+ - "Cement mortar"
+default: "Preformed butyl sealant to ASTM C990"
```
+### A butyl sealant is laid on the lower section and compressed by the weight of the upper one, forgives a joint face that is not perfectly clean, and seals as long as the sections are brought together within its compression window, which is why it is the joint on most utility structures; a confined rubber gasket in a machined joint profile gives the tightest joint and is the sewer trade's joint, available on circular sections from every pipe producer and on rectangular sections from few; a mortared joint is the cheapest, is sound in a dry site above the water table, and opens with the first settlement or frost movement, after which it leaks. {note}
+
+### The exterior of the section joints shall be wrapped as indicated in the datasheet.
+
```datasheet
−label: Manhole Construction Method
+label: Exterior Joint Wrap
type: select
options:
− - Precast (plant-cast sections)
− - Cast-in-place
−default: Precast (plant-cast sections)
+ - "None"
+ - "Every section joint"
+ - "Section joints below the seasonal high groundwater elevation"
+default: "None"
```
+### Where an exterior joint wrap is indicated, it shall be a self-adhering butyl rubber wrap not less than 6 in. wide, centered on the joint, applied to a clean, dry, primed surface before backfill, and lapped not less than 6 in. at its ends.
+
+### A wrap over a sealed joint is a second barrier that stops the fine seepage a compressed sealant can still pass under a head of water, and it costs a day of access to the outside of the structure before backfill; a wrap on every joint buys that barrier where the structure must stay dry and is pumped by the Owner, a wrap below the groundwater elevation puts it only where there is a head to resist, and no wrap is the usual condition of a structure whose sump drains and whose cable is rated for immersion. {note}
+
+### The exterior surfaces of each precast structure shall be waterproofed as indicated in the datasheet.
+
```datasheet
−label: Base / Floor Type
+label: Exterior Waterproofing
type: select
options:
− - Standard precast base section
− - Flat slab base
− - Open / no base (drainage to soil)
−default: Standard precast base section
+ - "None"
+ - "Cold-applied bituminous coating"
+ - "Cementitious crystalline coating"
+ - "Elastomeric membrane"
```
−# A box sized by catalog convenience rather than by the cables it must serve generates RFIs at cable installation, when the installer discovers the bend radius or fill cannot be achieved.
+### A dense precast wall is its own water barrier, and most utility structures are backfilled bare; a bituminous coating is the traditional dampproofing of a utility manhole, cheap, applied at the plant, and worth its cost where the groundwater carries sulfate or chloride that would otherwise work on the concrete; a crystalline coating closes the pores of the concrete itself and does not depend on a film that backfill can tear; a membrane is the tightest and the most expensive, and it is specified for a structure that must stay dry in a high water table and whose joints are also wrapped, because a membrane over an unwrapped joint ends at the joint. {note}
−# NEC Article 314 establishes minimum dimensions for pull and junction boxes and handhole enclosures based on the largest raceway entering and the conductor bend radius, not on round-number catalog sizes. The plan dimensions and depth must be verified against the actual cable schedule for the largest conductors that will be pulled, with a service factor for future pulls, before a structure size is committed. {note}
+### Lifting inserts, form tie holes, and every penetration not used shall be filled flush with a non-shrink grout conforming to ASTM C1107 or with the producer's plugging compound before the structure is backfilled.
−# Plan dimensions and depth shall satisfy the minimum sizing required by NEC Article 314 for the largest raceway and conductor entering the structure.
+# Handhole Enclosures {toc}
−# Structure dimensions shall be verified against the project cable schedule for conductor bend radius and fill before a size is committed.
+## The material of each handhole enclosure shall be as indicated in the datasheet.
−# Each structure shall include a service factor of spare interior space for future cable pulls.
+```datasheet
+label: Handhole Enclosure Material
+type: select
+options:
+ - "Polymer concrete"
+ - "Fiberglass-reinforced polymer"
+ - "Precast concrete"
+ - "Polyethylene or structural plastic"
+default: "Polymer concrete"
+```
−# The number, size, and location of duct entries (knockouts or cast-in terminators) shall be coordinated with the ductbank design per [[sync/underground-ductbank]] and shown on the shop drawings.
+## Polymer concrete, a resin-bound aggregate with a fiberglass reinforcement, is light enough to set by hand in the smaller sizes, does not corrode, reaches Tier 22 in every catalog, and is the enclosure most site electrical and communications handholes are; fiberglass-reinforced polymer is lighter still, is the enclosure of the telephone and cable plant, and flexes under load, which the tier test allows within a limit; precast concrete is heavy, needs a machine to set, carries highway loading with an iron cover, and costs the least per cubic foot in the larger sizes; a polyethylene or structural plastic box is the lightest and cheapest, tops out at Tier 8 or a stated light-duty rating, and is the enclosure of landscape lighting and irrigation controls rather than of a duct system. {note}
+## The bottom of each handhole shall be as indicated in the datasheet.
+
```datasheet
−label: Spare Capacity / Service Factor for Future Pulls
−type: range
−unit: '%'
−min: 0
−max: 50
−step: 10
−default: 30
+label: Handhole Bottom
+type: select
+options:
+ - "Open bottom on a crushed-stone base"
+ - "Closed bottom with a drain opening"
+ - "Closed bottom, sealed"
+default: "Open bottom on a crushed-stone base"
```
−# Cover and Frame Assemblies {toc}
+## An open bottom lets the water that enters a handhole drain into the stone beneath it, lets a ground rod be driven inside the box, and is how nearly every polymer concrete and fiberglass handhole is furnished; a closed bottom with a drain opening keeps soil and rodents out of a box in a sandy or an organic soil and still drains; a sealed bottom is a box that holds water, chosen where the box sits in a contaminated soil or where the Owner will pump it, and it is the one configuration that puts a splice under water in a high water table. {note}
−## The cover and frame are the only part of the structure the public ever sees or touches, so material, load match, marking, and security all converge here. {note}
+## The cover of each handhole shall be as indicated in the datasheet.
−## Frames and covers are cast from gray iron (ASTM A48, Class 35B minimum) for general duty, ductile iron (ASTM A536, Grade 65-45-12) for heavy-traffic duty, or molded from polymer-concrete or composite for handholes. The casting must match the structure's load/tier rating, carry the correct discipline legend, and be secured against unauthorized or accidental opening in any area accessible to the public. {note}
+```datasheet
+label: Handhole Cover
+type: select
+options:
+ - "Matching cover of the enclosure material"
+ - "Iron frame and cover"
+ - "Steel checker-plate cover"
+ - "Concrete cover slab with lifting slots"
+default: "Matching cover of the enclosure material"
+```
−## Cover and Frame Material {toc}
+## The matching cover is the one the enclosure was tested with, carries the tier with the body, and is the cover on nearly every non-concrete handhole; an iron frame and cover on a precast concrete handhole carries highway loading and takes the same legend and grade adjustment as a manhole casting; a steel checker-plate cover is light, is lifted by one person, rusts unless galvanized or stainless, and is the cover of an indoor or a canopy-covered box more than of one in the open; a concrete slab with lifting slots is the cheapest cover on a precast box in turf and needs a bar and two people to lift. {note}
−### Gray iron frames and covers shall conform to ASTM A48, Class 35B minimum.
+## A handhole enclosure and its cover shall each bear the manufacturer's name, the model, the tier or load rating, and the date of manufacture, molded or cast where they can be read with the cover removed.
−### Ductile iron frames and covers shall conform to ASTM A536, Grade 65-45-12, and shall be used for heavy-traffic and HS-20 applications.
+## A handhole cover shall carry its legend and shall be secured as the Frames and Covers article requires, and a metal cover shall be bonded under [[sync/grounding-and-bonding]] as NFPA 70 314.30(D) requires for the conductors in the enclosure.
−### Composite and polymer-concrete covers shall carry the same ANSI/SCTE 77 tier rating as the structure they serve.
+## The walls of a handhole shall accept the duct entries at the locations and inverts on the structure shop drawings, through knockouts, cored openings, or the open bottom as the enclosure manufacturer's instructions allow, without cutting a wall rib or a corner the tier rating depends on.
−### Metallic handhole enclosures used in submersible or continuously wet locations shall be rated NEMA 250 Type 6P.
+# Duct Entries {toc}
+## The duct entries through the walls of each precast structure shall be provided as indicated in the datasheet, at the walls, sizes, and inverts on the structure shop drawings.
+
```datasheet
−label: Cover/Frame Material
+label: Duct Entry Provision
type: select
options:
− - Gray iron (ASTM A48 Class 35B)
− - Ductile iron (ASTM A536 65-45-12)
− - Polymer-concrete composite
− - Fiberglass (FRP)
−default: Ductile iron (ASTM A536 65-45-12)
+ - "Cast-in duct terminators"
+ - "Precast knockout windows closed at the site"
+ - "Field-cored openings"
```
+## A cast-in terminator is a bell end or a terminator fitting set in the form at the plant, one per duct, in the array the duct bank drawings show, so that the duct bank is formed to the wall and no grouting is left for the site; it is the tightest entry and it commits the duct layout at the plant, which is its cost when the duct bank changes. A knockout window is a thinned panel in the wall, the size of the whole duct array, broken out at the site, with the ducts and their end bells entering through it and the window grouted around them; it tolerates a late change in the array and depends on the grout for its seal. A field-cored opening serves a future duct or a duct that the shop drawings missed, one duct at a time, and cuts whatever reinforcement is in its path. {note}
+
+## Each duct window shall be closed around the ducts as indicated in the datasheet, after the duct bank has been connected and before the structure is backfilled.
+
```datasheet
−label: Cylindrical Manhole Clear Opening
+label: Duct Window Closure
type: select
−unit: in
options:
− - "24"
− - "30"
− - "36"
−default: "30"
+ - "Non-shrink grout"
+ - "Hydraulic cement with a waterstop ring"
+ - "Mechanical modular seal on each duct"
+default: "Non-shrink grout"
```
+## Non-shrink grout to ASTM C1107 fills a window around a duct array completely and is the closure of nearly every window; a hydraulic cement with a waterstop ring around each duct holds against a head of water and is specified on a structure below the groundwater elevation that the Owner wants dry; a modular mechanical seal is a bolted rubber link assembly around each duct in a cored opening, the tightest closure and the one that is removable, and it fits a single cored duct rather than a grouted array. {note}
+
+## The grout or cement of a window closure shall be placed from both faces of the wall, shall fill the window from the ducts to the edge of the opening, and shall be finished flush with the inside face of the wall.
+
+## Windows for future ducts shall be provided where indicated on [[drawing: the structure schedule]], and each future window shall be left intact or closed with a thinned panel that a hammer breaks out without a core drill.
+
+## The end bell or terminator at the mouth of each duct, the sealing of the duct itself after the cable is in, and the slope of the duct bank toward the structure are furnished under [[sync/underground-ductbank]], and the window, its reinforcement, and its closure around the ducts are furnished here. {note}
+
+## The lowest duct entering a manhole shall enter above the top of the sump, and the floor of the structure shall be set so that every duct drains into the structure and no duct invert lies below the floor.
+
+# Frames and Covers {toc}
+
+## Manhole Cover and Frame {toc}
+
+### The material of each manhole cover and frame shall be as indicated in the datasheet.
+
```datasheet
−label: Cover Profile
+label: Manhole Cover and Frame Material
type: select
options:
− - Non-recessed (flush, solid)
− - Recessed (paving infill)
−default: Non-recessed (flush, solid)
+ - "Gray iron"
+ - "Ductile iron"
+ - "Polymer concrete or fiberglass composite"
+ - "Aluminum or galvanized steel hatch"
```
−## Cover Markings {toc}
+### Gray iron frames and covers shall conform to ASTM A48/A48M Class 35B or stronger, and ductile iron frames and covers shall conform to ASTM A536 grade 65-45-12 or stronger.
−### NEC 314.30 requires that a handhole cover be marked to identify it, but it does not specify the legend text — the owner standard must define it, or the contractor will install blank or wrong-discipline covers. {note}
+### A composite manhole cover and its frame shall be tested as an assembly to ANSI/SCTE 77 at the tier of the structure or to the AASHTO wheel load of its load class, and the test report shall be in the product data.
−### A cover that reads ELECTRIC over a telecommunications structure, or carries no legend at all, invites a wrong-discipline excavation and is a safety and maintenance liability. The discipline legend, and any owner asset-numbering provision, must be specified explicitly rather than left to the installer. {note}
+### A hatch cover shall be of aluminum or of hot-dip galvanized steel, with a frame cast or anchored into the top slab, a hinged and spring-assisted door that locks open, and a load rating for the load class of the structure stated in the product data.
−### Each cover shall be cast with a legend identifying the system it serves.
+### Gray iron is the casting of nearly every manhole in a pavement, stiff, heavy enough to stay seated by its own weight, and cheap; ductile iron carries impact and tension that would crack gray iron and is chosen under a wheel load above highway loading, under repeated heavy impact, and where a lighter cover of the same rating is wanted; a composite cover is lighter than iron, does not conduct, and has no scrap value where theft of iron covers is a recurring loss, at a lower impact rating and a higher price; a hatch gives a rectangular opening large enough to lower a splice case or a reel through, suits a vault serviced from above and a chamber in turf or a plaza, and is a trip edge and a snow-plow casualty in a pavement. {note}
−### Where the owner requires asset identification, each structure shall be furnished with a cast-in or attached identification marker bearing the structure designation.
+### A round access opening shall have the clear diameter indicated in the datasheet, and not less than the diameter NFPA 70 110.75(B) requires.
```datasheet
+label: Round Access Opening Clear Diameter
+type: range
+unit: in
+options:
+ min: 26
+ max: 48
+ setpoints: [26, 27, 30, 32, 36, 42, 48]
+constraint: min
+```
+
+### A rectangular access opening shall have clear dimensions not less than NFPA 70 110.75(B) requires, and not less than the opening needed to lower the largest splice assembly, reel, or piece of equipment the structure will receive.
+
+### Twenty-six inches is the code minimum for a person in a harness; 30 in. and 32 in. are the openings most utilities standardize on, large enough for a person with a tool bag and a retrieval tripod over the hole; a 36 in. opening passes a cable reel stand and a splice tent frame and is the opening of a vault where equipment is lowered through the roof; the larger the opening, the heavier the cover and the larger the frame seat the top slab has to carry. {note}
+
+### The cover shall seat on a machined or ground bearing surface, shall not rock under a wheel load, and shall sit flush with the top of the frame within 1/8 in.
+
+## Cover Legend {toc}
+
+### Each cover shall carry a legend cast or molded into its top surface in letters not less than 1 in. high, as indicated in the datasheet.
+
+```datasheet
label: Cover Legend
type: select
+derived: "the system that occupies the structure, as the structure schedule lists it"
options:
− - ELECTRIC
− - HIGH VOLTAGE
− - TELEPHONE
− - FIBER
− - COMMUNICATIONS
− - SIGNAL
−default: ELECTRIC
+ - "ELECTRIC"
+ - "HIGH VOLTAGE"
+ - "COMMUNICATIONS"
+ - "TELEPHONE"
+ - "FIBER OPTIC"
+ - "SIGNAL"
+ - "TRAFFIC SIGNAL"
+ - "LIGHTING"
+ - "CATV"
+default: derived
```
−## Cover Security and Locking {toc}
+### Where a shared structure has a compartment for each system, each compartment's cover shall carry the legend of the system in that compartment.
−### NEC 314.30 permits a handhole cover to be secured either by requiring a tool to open it or by weighing more than 100 lb, but in a public area a lightweight unlocked cover is a security and safety liability and the locking requirement must be made explicit. {note}
+### The legend is read by a locator with a one-call ticket, by a maintainer looking for the right structure in a row of three, and by the next contractor deciding whether to lift it; ELECTRIC and HIGH VOLTAGE tell the person at the cover what is energized under it, the communications legends tell them it is not, and an Owner with its own convention names the system in its own words, cast at no extra cost when the pattern is ordered. NFPA 70 314.30(D) requires a handhole cover to identify its function, and this standard applies the same rule to every cover. {note}
−### Where a structure is in a publicly accessible area, the design intent for cover security cannot be left to the 100 lb default. A pentagonal-bolt, hex-bolt, or proprietary locking cover should be required so that the cover cannot be casually removed, exposing energized equipment or an open hole. {note}
+## Cover Securing {toc}
−### Covers in publicly accessible areas shall be secured by a locking mechanism and shall not rely on weight alone.
+### Each manhole cover shall be secured as indicated in the datasheet.
−### Covers over medium-voltage manholes shall be locked or otherwise secured against unauthorized entry per NEC 110.34.
+```datasheet
+label: Manhole Cover Securing
+type: select
+options:
+ - "Unbolted, held by its weight"
+ - "Pentagon-head bolts"
+ - "Hex-head bolts"
+ - "Cam or bar lock operated by a special tool"
+default: "Unbolted, held by its weight"
+```
−### Locking hardware shall be corrosion-resistant and shall be operable with standard maintenance tools.
+### Each handhole cover shall be secured as indicated in the datasheet.
```datasheet
−label: Cover Security Method
+label: Handhole Cover Securing
type: select
options:
− - Weight only (>100 lb, non-traffic)
− - Pentagonal-bolt locking
− - Hex-bolt locking
− - Proprietary locking
−default: Pentagonal-bolt locking
+ - "Hex-head bolts"
+ - "Pentagon-head bolts"
+ - "Unbolted, held by its weight"
+ - "Hidden-bolt or special-tool lock"
+default: "Hex-head bolts"
```
−# Drainage and Sump {toc}
+### A cover that is not bolted shall weigh more than 100 lb, and a cover that weighs 100 lb or less shall be bolted or locked so that a tool is needed to open it, in accordance with NFPA 70 314.30(D) for a handhole and as this standard requires for a manhole.
−## A structure built without a deliberate water-management decision will either fill with water (if sealed in a high water table) or flood from surface inflow (if unsealed in a low-lying area); the specification must state which approach applies.
+### A cover over a structure that contains conductors rated above 1000 V shall be bolted or locked whatever its weight, so that the structure is accessible only to a qualified person with the tool.
−## There is no universally correct drainage scheme. Where the water table is below the structure floor and a daylight or storm connection is available, a gravity drain is simplest. Where no gravity outlet exists, a perforated sump pit in the floor lets water percolate into the soil. Where the structure must remain dry or the authority prohibits discharge, a sealed watertight structure is required and water is removed by maintenance pumping. The choice depends on the water table and the local authority, and it must be coordinated with [[sync/site-utilities]]. {note}
+### A cover in a sealed structure shall be bolted and gasketed, with a gasket in a groove in the frame seat and bolts at not more than 12 in. on center around the opening.
−## The drainage approach for each structure shall be specified as gravity drain, perforated sump, or sealed watertight.
+### An iron manhole cover of 150 lb to 300 lb is secured by its own weight, is lifted with a hook, and needs no bolt in a pavement where a vehicle on it is the only load it sees; pentagon-head bolts need a socket that is not sold at a hardware store and are the utility industry's deterrent to the casual lifter; hex-head bolts hold a light cover down against a wheel passing over its edge and against frost, and are opened by anyone with a wrench; a cam or bar lock under a hidden bolt is the securing of a structure in a public place where a lifted cover is an open shaft, and it costs a special tool that the Owner has to keep track of. On a handhole, where the cover weighs 40 lb to 90 lb and the code requires a tool, bolts are the usual means and the choice is between the hex head anyone can open and the pentagon head that only the Owner's crew can. {note}
−## Structures with a gravity drain shall drain to daylight or to a storm system approved by the authority having jurisdiction.
+### Cover bolts, washers, and the inserts they thread into shall be of one of the materials indicated in the datasheet, with the bolt and the insert of the same material or of materials that do not corrode in contact.
−## Structures relying on a perforated sump shall include a sump pit recessed in the floor to collect and percolate water.
+```datasheet
+label: Cover Bolt Material
+type: checkbox
+options:
+ - "Type 304 stainless steel"
+ - "Type 316 stainless steel"
+ - "Hot-dip galvanized steel"
+ - "Silicon bronze"
+default:
+ - "Type 304 stainless steel"
+ - "Type 316 stainless steel"
+constraint: any_of
+```
−## Sealed watertight structures shall use gasketed or mastic-sealed joints and sealed duct entries to exclude groundwater.
+### Bolt threads shall be coated with an anti-seize compound at installation, and the cover shall be removed and reseated once after the pavement is complete to prove that every bolt turns.
−## Ductbank invert elevations shall be coordinated so that conduits drain toward the structure and do not trap water, per [[sync/underground-ductbank]].
+## Grade Adjustment {toc}
−## Many owners require ductbanks to slope toward manholes at a minimum of 1/8 in. per ft so that water drains out of the conduit and into the structure. If the manhole invert is set level with the incoming conduit, gravity drainage fails and water is trapped in the duct, which can freeze and damage cable. The structure invert must be set below the incoming conduit inverts so the slope is real. {note}
+### The frame of each manhole shall be brought to finished grade by the method indicated in the datasheet.
−## The structure invert shall be set below the invert of every incoming conduit so that ductbank drainage toward the structure is achieved.
−
```datasheet
−label: Drainage Approach
+label: Grade Adjustment Method
type: select
options:
− - Gravity drain to daylight/storm
− - Perforated sump pit (percolation)
− - Sealed watertight (pump-out)
−default: Perforated sump pit (percolation)
+ - "Precast concrete grade rings set in mortar"
+ - "Polyethylene or recycled rubber grade rings"
+ - "Mortared brick courses"
+ - "Cast-in-place concrete collar"
+ - "Frame set directly on the top slab"
+default: "Precast concrete grade rings set in mortar"
```
+### The height of the grade adjustment between the top slab and the frame shall not exceed the value indicated in the datasheet.
+
```datasheet
−label: Sump Pit Provided
+label: Grade Adjustment Stack Height
+type: range
+unit: in
+options:
+ min: 0
+ max: 24
+ setpoints: [0, 4, 6, 8, 12, 16, 24]
+default: 12
+constraint: max
+```
+
+### Where the adjustment required at a structure exceeds the maximum stack height, a taller precast riser section or a deeper structure shall be furnished rather than more rings.
+
+### Precast concrete rings are stocked in 2 in. to 8 in. heights, carry a wheel load through a mortar bed, and are the adjustment on nearly every manhole in a pavement; polyethylene and rubber rings are light, are set without mortar, and are the adjustment where the frame will be reset every time the pavement is milled, at the cost of a ring that a heavy wheel load can distort; brick courses are the oldest method, are permitted by many jurisdictions and prohibited by others, and depend entirely on the mason; a cast collar fits an odd elevation or an off-center frame and ties the frame to the slab in one piece; a frame set directly on the slab is the stiffest and is possible only where the slab elevation was set to the final grade when the structure was ordered. Every ring adds two joints, and each joint is a hinge under traffic; a tall stack works loose, admits water behind the frame, and settles, taking the pavement with it, which is why the stack has a ceiling and a riser section takes over above it. {note}
+
+### The frame shall be set on a full mortar bed on the top ring or the slab, with its inside face flush with the inside face of the opening, no mortar projecting into the structure, and the rings and the frame sealed to each other on the outside with the joint sealant of the structure or with an external frame seal.
+
+### The top of the frame shall be set flush with the finished pavement within 1/4 in., and in turf shall be set 1 in. above finished grade unless the Engineer of Record directs a different elevation for mowing or drainage.
+
+### A handhole set in a pavement shall have its cover flush with the pavement within 1/4 in., and a handhole in turf shall have its cover 1 in. above finished grade, with the enclosure set on its base to that elevation rather than raised on a stack of material the manufacturer does not supply.
+
+# Access and Work Space {toc}
+
+## The means of entry into each manhole shall be as indicated in the datasheet.
+
+```datasheet
+label: Manhole Entry Means
type: select
options:
− - "Yes"
− - "No"
−default: "Yes"
+ - "Polypropylene-encased steel steps cast in the wall"
+ - "Fixed fiberglass ladder"
+ - "Fixed aluminum ladder"
+ - "Portable ladder furnished by the entrant, no fixed means"
```
−# Grounding and Bonding {toc}
+## Cast-in steps shall be copolymer polypropylene encased steel steps conforming to ASTM C478/C478M, set at the spacing the product standard allows, in a single line from the access opening to within 16 in. of the floor, on a wall that carries no cable rack in the line of the steps.
−## "Per NEC" is not a grounding specification; NEC Article 250 mandates bonding but does not dictate electrode placement or ground-ring continuity, and omitting the method produces inconsistent installations and coordination RFIs. {note}
+## A fixed ladder shall be corrosion resistant in accordance with NFPA 70 110.79, anchored to the wall at its top and its bottom with stainless steel anchors, and shall extend from the floor to the underside of the access opening, with its rungs clear of every rack arm.
−## NEC 250.92 and 250.96 require that metallic covers, frames, pulling irons, cable racks, and other metallic components within a manhole or handhole be bonded to the grounding system. What the code does not decide is how: a driven ground rod at each structure, a continuous bare-copper ground conductor carried through the ductbank and bonded at each structure, or both. The owner must choose one scheme so the installation is consistent and so the method is coordinated with the grounding requirements in [[sync/conductors-and-cables]]. For manholes associated with medium-voltage distribution, step-and-touch potential should be evaluated per IEEE 80. {note}
+## Where no fixed means is furnished, the structure shall have no step or ladder insert, and the inside face of the wall under the opening shall be clear of hardware for the width of a portable ladder.
−## All metallic covers, frames, pulling irons, cable racks, and metallic components within each structure shall be bonded together and to the grounding system per NEC 250.92 and 250.96.
+## Steps cast in the wall are always there, cost little, and are what the sewer trade and many municipal electric utilities require; they also corrode at the wall where the encapsulation is cut, they take a wall that could carry cable, and a step that fails under a person who trusted it is the injury most utilities that prohibit them are remembering. A fiberglass ladder does not corrode and does not conduct, which matters in a chamber with energized cable; an aluminum ladder is lighter and cheaper and corrodes in a wet structure with concrete in contact. A portable ladder set by the entrant under the confined-space program is the practice of most electric utilities and of every Owner whose entrants bring a tripod and a retrieval line anyway, and it leaves all four walls for cable. {note}
−## The grounding scheme for each structure shall be specified as a driven ground rod at the structure, a continuous bonded ground conductor in the ductbank, or both.
+## The access opening of a manhole shall be located in the roof so that a person descending through it lands on a clear floor area and not on a rack, a splice, or the sump, and so that the duct windows and the pulling irons can be reached from the floor below it.
−## Bonding jumpers and grounding conductors shall be copper, sized per NEC Article 250.
+## The floor of each manhole below the access opening shall be clear of racks and hardware over an area not less than 30 in. by 30 in. for the landing and for the retrieval equipment.
−## For manholes associated with medium-voltage distribution, step-and-touch potential shall be evaluated in accordance with IEEE 80.
+# Cable Racks and Pulling Irons {toc}
−## Bonding connections shall be made with listed irreversible (exothermic or compression) connectors suitable for direct burial and wet locations.
+## Cable Racks and Arms {toc}
+### Cable racks and arms shall be furnished for every wall of each manhole that the structure schedule shows carrying cable, of the material indicated in the datasheet.
+
```datasheet
−label: Grounding Scheme
+label: Cable Rack and Arm Material
type: select
options:
− - Driven ground rod at each structure
− - Continuous bonded ground conductor in ductbank
− - Both (rod plus continuous conductor)
−default: Continuous bonded ground conductor in ductbank
+ - "Glass-reinforced nylon or fiberglass"
+ - "Hot-dip galvanized steel"
+ - "Stainless steel"
+ - "Aluminum"
```
+### A nonmetallic rack of glass-reinforced nylon or fiberglass does not corrode, does not conduct, needs no bonding, and carries the arm loads of medium-voltage cable in every catalog, at a higher price per stanchion and a lower load rating per arm than steel; a hot-dip galvanized steel rack is the traditional rack, the strongest, and the cheapest, and it rusts at the arm sockets in a wet structure within the life of the cable and has to be bonded; a stainless rack is the steel rack without the rust at several times the price; an aluminum rack is light and corrosion resistant in a dry structure and pits where it stands in water against concrete. {note}
+
+### Each rack stanchion shall be anchored to the wall as indicated in the datasheet, at the top and the bottom and at not more than 24 in. between.
+
```datasheet
−label: Ground Rod Length (where used)
+label: Rack Anchorage
type: select
−unit: ft
options:
− - "8"
− - "10"
−default: "10"
+ - "Cast-in threaded inserts"
+ - "Cast-in channel"
+ - "Post-installed anchors"
+default: "Cast-in threaded inserts"
```
−# Cable Support Hardware {toc}
+### A threaded insert cast into the wall at the plant is set to the shop drawing, cuts no reinforcement, and is what the rack maker's stanchion is punched for; a continuous channel cast into the wall takes a stanchion anywhere along it and suits a structure whose rack layout is not settled when it is cast; a post-installed anchor is drilled into the wall at the site, finds reinforcement by chance, and is the fastening of a rack added to an existing structure or of an insert the plant missed. {note}
−## The cable racks, pulling irons, and cast-in inserts are what make a structure usable for pulling and for the orderly long-term support of cable, and they must be specified and located on the shop drawings rather than improvised in the field. {note}
+### Rack stanchions shall be spaced along each wall at not more than the value indicated in the datasheet, with a stanchion within 12 in. of each side of every duct window and of every corner.
−## If pulling iron capacity and insert locations are left out of the shop drawing requirements, installers discover inadequate pulling points during the cable pull and resort to field core-drilling of the precast walls, which weakens the structure and delays the work. Cable racks carry the cables off the floor and away from standing water; their material is selected for the corrosion environment, and their inserts must be cast into the walls at the correct spacing before the structure leaves the plant. {note}
+```datasheet
+label: Cable Rack Spacing
+type: range
+unit: in
+options:
+ min: 18
+ max: 48
+ setpoints: [18, 24, 30, 36, 48]
+default: 36
+constraint: max
+```
−## Cable Racks {toc}
+### Three feet is the spacing most utilities rack medium-voltage cable at, and it supports a 1,000 kcmil cable with a splice case between two arms without sag; a closer spacing carries a heavier splice and a tighter training radius, and a 4 ft spacing is the limit at which a large cable still clears the floor between arms. The stanchion at each side of a window carries the cable as it leaves the duct, which is where the training radius starts. {note}
−### Cable racks, arms, and standoff inserts shall be furnished and their locations cast into the structure walls at the spacing shown on the shop drawings.
+### Each stanchion shall extend from not more than 18 in. above the floor to within 12 in. of the underside of the roof, with arm slots along its full length.
−### Cable rack material shall be selected for the corrosion environment from epoxy-coated steel, aluminum, or fiberglass.
+### The number of arms on each stanchion and the length of each arm shall be as indicated in the datasheet.
−### Cable racks shall support cables off the structure floor and clear of any sump or standing water.
−
```datasheet
−label: Cable Rack Material
−type: select
+label: Rack Arms per Stanchion
+type: range
+unit: each
options:
− - Epoxy-coated steel
− - Aluminum
− - Fiberglass
−default: Fiberglass
+ min: 2
+ max: 8
+ setpoints: [2, 3, 4, 5, 6, 8]
+drawing_ref: "the structure details"
+default: deferred
+constraint: min
```
+### Each stanchion shall carry, beyond the arms the installed cable occupies, not less than one vacant arm position for a future circuit.
+
+### The cable support on each rack arm shall be as indicated in the datasheet.
+
```datasheet
−label: Cable Rack Spacing (on center)
−type: range
−unit: in
−min: 12
−max: 48
−step: 6
−default: 36
+label: Rack Arm Cable Supports
+type: select
+options:
+ - "Glazed porcelain insulators"
+ - "Polymer saddles"
+ - "None, cable tied to the arm"
```
−## Pulling Irons and Inserts {toc}
+### A porcelain insulator on each arm supports a medium-voltage cable on a rounded, non-conducting saddle that does not cut the jacket and does not carry a fault current into the rack, and it is the support most utilities put under every medium-voltage cable; a polymer saddle does the same at a lower price and a lower crushing load, and it is the support of a communications structure and of a nonmetallic rack whose arms are already non-conducting; a bare arm with a cable tie is the support of a light cable in a handhole-sized vault and of a communications cable, and it is the arm a heavy cable wears its jacket against. {note}
−### Pulling irons or pulling eyes shall be cast into the structure opposite each duct entry to provide a pulling point in line with the duct.
+### Arms, insulators, and saddles shall be rated by their manufacturer for the load of the cable and splices they carry, with the rating in the product data, and an arm shall not be loaded beyond that rating in the racking arrangement the cable standard requires.
−### Each pulling iron shall be rated for the maximum pulling tension of the largest cable to be installed, with the rated capacity shown on the shop drawings.
+### The arrangement of the cable on the arms, one circuit per arm, power opposite communications, the splice supported on an arm at each side, and the slack loop, is governed by [[sync/medium-voltage-cables]] and the standard of each other cable in the structure; the racks, arms, and supports they are arranged on are furnished here. {note}
−### The location and rated capacity of every pulling iron, pulling eye, and cast-in insert shall be shown on the shop drawings and shall be cast in at the plant, not field-drilled.
+## Pulling Irons {toc}
+### A pulling iron shall be cast into the wall opposite each duct window, centered on the window and at the elevation of the center of the duct array, and a pulling iron shall be cast into the floor below the access opening.
+
+### The rated working load of each pulling iron shall be not less than the value indicated in the datasheet, and not less than twice the maximum calculated pulling tension of any cable pulled against it.
+
```datasheet
label: Pulling Iron Rated Capacity
type: range
unit: lb
−min: 5000
−max: 30000
−step: 5000
−default: 15000
+options:
+ min: 5000
+ max: 30000
+ setpoints: [5000, 7500, 10000, 15000, 20000, 25000, 30000]
+derived: "the maximum calculated pulling tension through the structure under the cable standard, with the factor of two of this standard"
+default: derived
+constraint: min
```
−# Grade Adjustment {toc}
+### The pulling tension of a cable is calculated under its own standard from the conductor size, the route, and the lubricant, and the iron that anchors the sheave or the puller sees that tension and the shock of a stuck cable breaking free; the factor of two covers the shock and the angle of the pulling line, and an iron rated below it is the one that pulls out of the wall with the puller at full load, which is the accident this article exists for. {note}
−## Final cover elevation must match finished grade, and if the design does not specify adjustable grade rings the contractor field-improvises and the cover ends up proud of or below the pavement.
+### Pulling irons shall be of the material indicated in the datasheet, with the anchorage into the wall or the floor shown on the structural calculations.
−## The top of the structure is set during installation but the finished grade is established later by paving or landscaping. Concrete adjustment rings or HDPE/cast-iron grade rings let the installer bring the frame and cover to the exact final elevation. The allowable range of adjustment and the ring material must be specified so the contractor does not improvise with shims or excess mortar. {note}
+```datasheet
+label: Pulling Iron Material
+type: select
+options:
+ - "Hot-dip galvanized steel"
+ - "Stainless steel"
+ - "Polymer-coated steel"
+default: "Hot-dip galvanized steel"
+```
−## The structure shall be furnished with adjustable grade rings or adjustment rings to set the cover flush with finished grade.
+### A hot-dip galvanized steel iron is the iron in nearly every structure, strong, cheap, and good for decades in a chamber that drains; a stainless iron is chosen where the structure stands in brackish or corrosive water and the iron will be relied on for the life of the structure; a polymer-coated iron adds a barrier over the zinc and is damaged by the first pulling line that saws across it. {note}
−## The final cover elevation shall match the finished grade at the structure within the tolerance specified by the authority having jurisdiction.
+### The irons, inserts, sleeves, and other items cast into each manhole at the plant shall be as indicated in the datasheet, and none of them shall be drilled into the structure at the site where the datasheet calls for them cast in.
−## Grade-ring material shall be specified as concrete adjustment rings, HDPE rings, or cast-iron rings.
+```datasheet
+label: Items Cast Into Each Manhole
+type: checkbox
+options:
+ - "Pulling iron opposite each duct window"
+ - "Pulling iron in the floor below the access opening"
+ - "Cable rack inserts or channel on each racked wall"
+ - "Ground rod sleeve through the floor"
+ - "Ground bar inserts near the access opening"
+ - "Sump pit with a grating frame"
+ - "Step or ladder inserts"
+ - "Lifting inserts in each section"
+ - "Circuit schedule holder insert"
+default:
+ - "Pulling iron opposite each duct window"
+ - "Pulling iron in the floor below the access opening"
+ - "Cable rack inserts or channel on each racked wall"
+ - "Ground rod sleeve through the floor"
+ - "Ground bar inserts near the access opening"
+ - "Sump pit with a grating frame"
+ - "Lifting inserts in each section"
+constraint: all_of
+```
+# Sumps and Drainage {toc}
+
+## Each manhole shall be provided with the drainage provision indicated in the datasheet.
+
```datasheet
−label: Grade Ring Material
+label: Sump and Drainage Provision
type: select
options:
− - Concrete adjustment rings
− - HDPE rings
− - Cast-iron rings
−default: Concrete adjustment rings
+ - "Sump pit with a cover grating at the low point of the floor"
+ - "Floor drain piped to a gravity outlet"
+ - "Weep openings through the floor to the stone base"
+ - "Sealed floor without a sump"
+default: "Sump pit with a cover grating at the low point of the floor"
```
+## A sump pit collects the water the duct bank drains into the chamber at one place a pump can reach, keeps the floor dry between storms, and is the drainage of nearly every electrical manhole, pumped by the Owner's crew before an entry; a floor drain to a gravity outlet keeps the chamber dry without a pump and exists only where a storm sewer or a slope to daylight lies below the floor and the authority permits the connection; weep openings let water pass down into the stone base and up again when the water table rises, and they drain a structure above the groundwater elevation in a free-draining soil for nothing; a sealed floor is the choice where the soil is contaminated, where the structure must not discharge, or where the floor is below groundwater and every opening would be an inlet, and it is the floor that fills from above and is pumped. {note}
+
+## The sump shall be not less than 12 in. across and 12 in. deep, cast into the floor at its low point away from the access landing, with a removable grating flush with the floor.
+
+## The floor of each manhole shall be formed to drain to the sump or the drain from every wall, with no pocket that holds standing water away from the sump.
+
+## Where a floor drain to a gravity outlet is indicated, the drain shall be trapped or fitted with a backwater valve where the outlet is a storm sewer, and the outlet and its connection shall be furnished under [[sync/storm-drainage]].
+
+## Weep openings shall not be used in a structure whose floor lies below [[parameter: seasonal-high-groundwater-elevation]].
+
+## A sump pump is not furnished under this standard; where the Owner will keep a manhole dry by a permanent pump, the pump, its power, and its discharge are a project-specific design and the structure under this standard carries only the sump the pump sits in and the sleeve its discharge leaves through. {note}
+
+## Each handhole shall drain through its open bottom or its drain opening into the stone base beneath it, and a sealed handhole shall be set with its floor sloped to one corner so that it can be pumped.
+
+# Grounding Provisions {toc}
+
+## Each manhole shall be furnished with the ground rod provision indicated in the datasheet.
+
```datasheet
−label: Grade Adjustment Range Provided
−type: range
−unit: in
−min: 2
−max: 12
−step: 1
−default: 6
+label: Ground Rod Provision
+type: select
+options:
+ - "Cast-in sleeve through the floor"
+ - "Rod driven through the open bottom"
+ - "None in the structure"
```
−# Mixed-Discipline Structures {toc}
+## A sleeve cast through the floor of a manhole lets a rod be driven inside the chamber after the structure is set and keeps the rod and its connection where a person can test them, which is the arrangement in nearly every electrical manhole; a rod driven through the open bottom is the handhole's version of the same thing; a structure with no rod of its own is bonded through the duct bank to the electrode at the next structure or at the equipment, which the grounding standard allows where the run is short, and it saves a rod in a structure that carries only communications cable or low-voltage lighting circuits. {note}
−## Placing power and telecommunications cable in the same structure without segregation violates utility owner rules and the spirit of NEC 300.3, and it must be resolved at design, not in the field. {note}
+## The ground rod sleeve shall be a nonmetallic pipe not less than 3 in. in diameter cast through the floor near a wall and clear of the sump, the access landing, and the pulling irons, with its top flush with the floor and sealed around the rod after the rod is driven.
−## Where a single structure must carry both power and communications cable, the two systems must be physically segregated — typically on cable racks on opposite walls with a minimum clearance between them — so that induced voltage, heat, and maintenance access do not create a conflict. Many utility owners flatly prohibit shared structures; where they are permitted, the segregation arrangement must be shown on the shop drawings. {note}
+## Inserts for a ground bar shall be cast into the wall of each manhole adjacent to the access opening, at a height a person standing on the floor reaches, where the datasheet of cast-in items calls for them.
−## Power and communications cable shall not share a structure unless the design explicitly provides for it and the serving utility permits it.
+## The rod, the ground bar, the bonding conductor, and the bonding of the racks, pulling irons, frame, cover, steps or ladder, and metallic conduits in the structure are furnished under [[sync/grounding-and-bonding]], which connects to the sleeve and the inserts furnished here; a handhole's metal cover is bonded there as NFPA 70 314.30(D) requires. {note}
−## Where a shared structure is permitted, power and communications cable shall be segregated on opposite walls with the minimum clearance required by the serving utility and NEC 300.3.
+## A metallic rack, ladder, or pulling iron shall be furnished with a bonding lug or a drilled and tapped hole for the bonding conductor, and a nonmetallic rack shall be furnished with none.
−## The segregation arrangement for any shared structure shall be shown on the shop drawings.
+# Identification {toc}
+## Each structure shall carry its designation from the structure schedule as indicated in the datasheet.
+
```datasheet
−label: Structure Discipline
+label: Structure Identification Marker
type: select
options:
− - Power only
− - Communications only
− - Shared (segregated power + communications)
−default: Power only
+ - "Engraved tag inside at the access opening"
+ - "Number cast or stamped into the cover"
+ - "Painted stencil on the inside wall"
```
−# Installation {toc}
+## An engraved stainless or laminated plastic tag inside the opening is read by the person who lifts the cover and survives a repaving that replaces the cover; a number cast or stamped in the cover is read without lifting it and is lost when the cover is swapped with the next one down the street; a stencil is the cheapest, is read from the opening, and is repainted every decade or two. The marker is what ties the structure to the record drawings, the circuit schedule, and the confined-space inventory, and a structure without one is identified by counting from the corner. {note}
−## A structure is only as good as its bedding, its duct connections, and its final grade, and these execution items are where field practice most often departs from the design intent. {note}
+## Each manhole shall carry on its wall adjacent to the access opening a weatherproof holder for a circuit schedule, and the Contractor shall place in it before acceptance a laminated schedule of the circuits racked in the structure, the duct each occupies, and the wall each enters.
−## The excavation must be over-dug and a compacted granular base provided so the structure bears uniformly and does not settle. Duct entries must be made up watertight so the structure does not become the low point that collects every conduit's groundwater. The cover must be brought to the exact finished grade. Each of these is an obligation the installer must meet, and each is a common source of callbacks when skipped. {note}
+## The identification of the ducts themselves at the wall, including the spare ducts, is furnished under [[sync/underground-ductbank]], and the tags on the cable are furnished under the standard of that cable. {note}
−## The structure shall be set on a compacted granular base of the depth required by the structural design and the bearing soil.
+# Testing {toc}
−## Backfill shall be placed and compacted in lifts around the structure to the density required by the project geotechnical requirements.
+## The Contractor shall perform the field checks indicated in the datasheet on each structure, in the presence of the Owner's representative where the Owner requests it, and shall record the result against the structure designation.
−## Duct entries shall be sealed watertight at the structure wall after cables are installed.
+```datasheet
+label: Field Checks
+type: checkbox
+options:
+ - "Inspection for cracks, spalls, honeycomb, and exposed reinforcement before backfill"
+ - "Inspection of every section joint and window closure for leakage after the first wet period or after the water table rises"
+ - "Vacuum test of each sealed structure to ASTM C1244 before backfill"
+ - "Verification of the tier or load rating marking on each delivered enclosure and cover against its load class"
+ - "Cover seating, flushness, and bolt operation after the pavement is complete"
+ - "Sump, drain, and weep flow by filling the floor with water"
+ - "Duct inverts and structure rim surveyed and compared with the record drawings"
+default:
+ - "Inspection for cracks, spalls, honeycomb, and exposed reinforcement before backfill"
+ - "Inspection of every section joint and window closure for leakage after the first wet period or after the water table rises"
+ - "Verification of the tier or load rating marking on each delivered enclosure and cover against its load class"
+ - "Cover seating, flushness, and bolt operation after the pavement is complete"
+ - "Duct inverts and structure rim surveyed and compared with the record drawings"
+constraint: all_of
+```
−## The structure shall be set plumb and to the invert elevations shown on the drawings.
+## A structure that shows a crack through a wall, a spall that exposes reinforcement, a joint that leaks a running stream, a window closure that leaks around a duct, or a cover that rocks shall be repaired or replaced by the Contractor at no cost to the Owner, and a repair shall be made by a method the producer recommends in writing and the Engineer of Record accepts.
−## The cover and frame shall be set flush with finished grade using the specified adjustment rings.
+## Where a sealed structure fails its vacuum test, the Contractor shall locate and seal the leak and shall repeat the test at no cost to the Owner until the structure passes.
−## Personnel-entry manholes shall not be entered for installation work until confined-space entry procedures per OSHA 29 CFR 1910.146 are in place.
+## Damp walls and a seep at a joint that does not run are the condition of most structures in the ground and are not a defect; a stream through a joint, a window that pours when the water table is up, and a floor that does not drain are, because each puts the splice under water and the entrant in it. The vacuum test is for the structure the Owner has decided to keep dry and has paid for the sealed joints and windows of; applied to a structure with weep openings it proves nothing. {note}
−# Testing {toc}
+## The continuity of the bonding and the resistance of the electrode at each structure are tested under [[sync/grounding-and-bonding]], and the duct proving is performed under [[sync/underground-ductbank]]. {note}
−## Each structure shall be visually inspected after setting for cracks, spalls, and joint or duct-entry leakage.
+# Installation {toc}
−## The continuity of all bonding connections shall be verified, and the grounding electrode resistance shall be measured and recorded where a ground rod is installed.
+## Excavation and Base {toc}
−## Sealed watertight structures shall be tested for water-tightness by visual inspection for infiltration after a high-groundwater or wet-weather period, or by a vacuum/exfiltration test where required by the authority having jurisdiction.
+### Each precast structure shall be installed in accordance with ASTM C891 and the producer's instructions, and each non-concrete enclosure in accordance with its manufacturer's instructions.
−## Composite and polymer-concrete enclosure proof-load certification shall be confirmed against the delivered product's markings.
+### The excavation for a structure shall extend not less than 12 in. beyond the outside face of the structure on every side for the placement and compaction of the backfill, with the excavation support, the dewatering, and the protection of adjacent utilities under [[sync/earthwork]] and [[sync/excavation-support-and-dewatering]].
+### Each structure shall be set on a base course of compacted crushed stone of the thickness indicated in the datasheet, placed on a subgrade that the geotechnical engineer of record has accepted and leveled so that the structure bears uniformly over its whole base.
+
```datasheet
−label: Field Tests
−type: checkbox
+label: Base Course Thickness
+type: range
+unit: in
options:
− - Visual inspection (cracks, spalls, leakage)
− - Bonding continuity verification
− - Ground electrode resistance measurement
− - Watertightness inspection/test (sealed structures)
−default:
− - Visual inspection (cracks, spalls, leakage)
− - Bonding continuity verification
− - Ground electrode resistance measurement
+ min: 6
+ max: 24
+ setpoints: [6, 8, 12, 18, 24]
+constraint: min
```
−# Delivery, Storage, and Handling {toc}
+### Six inches of stone levels a firm subgrade and is the bed under most handholes and under a manhole on a sand or gravel; 12 in. bridges a soft or wet clay subgrade and gives a manhole that stands in groundwater a drained bed to sit on; a thicker bed replaces an unsuitable subgrade or a frost-susceptible soil below a shallow structure, and above 24 in. the geotechnical engineer is designing a foundation rather than a bed. {note}
−## Precast structures shall be lifted only at the cast-in lifting points using the manufacturer's rigging instructions.
+### Where the base of a handhole lies above [[parameter: frost-depth]], the handhole shall be set on a free-draining crushed-stone base and backfilled at its sides with the same material so that no frost-susceptible soil bears on the enclosure.
−## Structures shall be stored on level, well-drained ground and protected from impact and from the intrusion of debris into duct openings.
+### A soft, wet, or organic subgrade under a structure shall be removed and replaced with compacted crushed stone to the depth the geotechnical engineer of record directs, and the Contractor shall notify the Engineer of Record before setting a structure on a subgrade that pumps under a loaded truck.
−## Covers and frames shall be stored to prevent damage to machined seating surfaces and locking hardware.
+## Setting and Backfill {toc}
−## Composite and polymer-concrete enclosures shall be protected from point loading and from prolonged direct sunlight during storage where the manufacturer so requires.
+### Each precast section shall be lifted only by the cast-in lifting inserts, with the rigging in the lifting plan, and shall be set level and plumb, with the base at the elevation that puts the floor at the invert the structure schedule gives and the top slab at the elevation the grade adjustment allows.
−# Warranty {toc}
+### The sections shall be set with the joint sealant in place and the joint fully closed under the weight of the upper section, and a joint that does not close shall be lifted, cleaned, resealed, and reset.
−## The manufacturer shall warrant each structure, cover, and frame against defects in materials and workmanship for the period specified below from the date of substantial completion.
+### Each manhole shall be set so that its access opening falls where the structure schedule and the paving plan locate it, and not under a curb, a wheel stop, a planter, or a parking stall line.
−## The warranty shall cover failure to meet the certified load or tier rating under the rated service conditions.
+### Backfill around each structure shall be of the material indicated in the datasheet, placed in lifts and compacted as [[sync/earthwork]] requires for backfill against a buried structure, brought up evenly on all sides so that the difference in fill height across the structure never exceeds 2 ft.
```datasheet
−label: Warranty Period
+label: Structure Backfill Material
type: select
−unit: years
options:
− - "1"
− - "2"
− - "5"
−default: "1"
+ - "Excavated soil free of debris and of stones over 3 in."
+ - "Granular structural fill under the earthwork standard"
+ - "Crushed stone"
+ - "Controlled low-strength material"
```
−# Spare Parts {toc}
+### Excavated soil put back around a structure costs nothing and settles unless it is compacted in lifts, and it is the backfill of a structure in turf; granular fill compacts to the density a pavement over it needs and drains; crushed stone drains fastest, needs little compaction, and is what the makers of polymer concrete handholes require around their enclosures; a flowable fill needs no compaction at all in a trench too narrow for a compactor, locks the structure in, and floats a light enclosure if it is poured too fast. {note}
−## The Contractor shall furnish spare covers and frames for each structure type and size installed, in the quantity specified below.
+### No backfill shall be placed against a structure until the duct banks entering it have been connected and their windows closed, the exterior joint wrap and coating where indicated have been applied and inspected, and the pre-backfill checks under Testing have been made.
−## The Contractor shall furnish spare locking hardware sets matching the installed locking covers.
+### A compactor heavier than a hand-operated plate shall not operate within 24 in. of a structure wall, and the backfill within that distance shall be compacted by hand-operated equipment in lifts not exceeding 6 in.
+### Where a structure is set below the groundwater level, the dewatering shall continue until the backfill has reached the height at which the structure resists flotation, as the structural calculations show.
+
+### The frame and cover, or the enclosure cover, shall be set to finished grade as the Grade Adjustment article requires after the final course of pavement or the finished turf is in place, and a structure whose grade is set before the pavement shall be protected and reset at the Contractor's cost if the pavement comes to a different elevation.
+
+### Each manhole shall be pumped dry, swept, and left with its cover seated and secured at the end of each day's work in it, and the Contractor shall not leave an open structure unattended.
+
+# Delivery, Storage, and Handling {toc}
+
+## Precast sections shall be delivered on dunnage, lifted only at the lifting inserts, and stored on level ground on dunnage so that no section bears on a joint face.
+
+## Joint faces shall be protected from damage and from mud during storage, and a section with a chipped or broken joint face that the sealant cannot bridge shall be rejected.
+
+## Non-concrete enclosures shall be stored on a flat surface, out of direct sunlight where the manufacturer requires it, with their covers on, and shall not be stacked beyond the height the manufacturer allows.
+
+## Frames, covers, and hardware shall be stored off the ground, with machined seats protected and with the locking hardware and the special tools kept together with the covers they fit.
+
+## Joint sealant, wrap, grout, and coating shall be stored within the temperature range their manufacturers publish and shall not be used after their shelf life.
+
+# Warranty {toc}
+
+## The producer of the precast structures, the manufacturer of the enclosures, and the manufacturer of the frames and covers shall each warrant their products against defects in materials and workmanship, including a crack, a spall, a failed joint face, a cover that fails below its rating, and an enclosure that fails below its tier, for the period indicated in the datasheet.
+
```datasheet
−label: Spare Covers/Frames per Type and Size
+label: Manufacturer's Warranty Period
type: range
−unit: each
−min: 0
−max: 5
−step: 1
−default: 1
+unit: years
+options:
+ min: 1
+ max: 10
+ setpoints: [1, 2, 3, 5, 10]
+constraint: min
```
+## Where a warranty period is not selected in the datasheet, the manufacturer's standard warranty shall apply, and its term shall be stated in the product data.
+
+## The Contractor shall warrant the installation, including the setting, the joints, the window closures, the backfill, and the grade adjustment, against settlement, leakage through a joint or a window, a frame that works loose, and a cover that fails to seat, for the project warranty period from the date of substantial completion, and shall repair the defect at no cost to the Owner.
+
+## A structure, section, enclosure, or cover replaced under warranty shall be warranted for the remainder of the original period or for one year from the date of the replacement, whichever ends later.
+
+## Warranty corrective work shall include the excavation, the pavement, the turf, the dewatering, the pumping of the structure, and the protection of the cable in it that the repair disturbs, and their restoration, at the expense of the party whose warranty covers the failure.
+
+## Where the Owner, the Contractor, and the manufacturer disagree whether a warranty-period failure is a product defect, an installation defect, or damage from a cause outside both warranties, the Engineer of Record shall make the initial determination, with the structure left accessible for examination.
+
+# Spare Parts {toc}
+
+## The Contractor shall deliver the spare parts indicated in the datasheet to the Owner before the structures are accepted, and shall obtain a signed receipt for them.
+
```datasheet
−label: Spare Locking Hardware Sets
−type: range
−unit: each
−min: 0
−max: 10
−step: 1
−default: 2
+label: Spare Parts to Be Furnished
+type: checkbox
+options:
+ - "One spare cover and frame of each manhole casting type and size installed"
+ - "One spare cover of each handhole enclosure model installed"
+ - "Two complete sets of cover bolts and washers of each type installed"
+ - "Two special tools for each locking cover type installed"
+ - "One rack stanchion and four arms, with their supports, of each rack type installed"
+ - "One sump grating of each size installed"
+default:
+ - "Two complete sets of cover bolts and washers of each type installed"
+ - "Two special tools for each locking cover type installed"
+constraint: all_of
```
+
+## Spare covers and hardware shall be identical to and interchangeable with the installed items, shall be labeled with the structure type and the legend they fit, and shall be delivered to the location the Owner designates.
+
+## A handhole cover cracked by a truck and a manhole cover lost to a snowplow or a scrap thief are replaced in a day only if the Owner has one of the same pattern on the shelf, because a cover with the Owner's legend and the right tier is not a stocked item at a supply house; the special tool for a locking cover is the one spare that is needed on the first night call and is missing most often. {note}