Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
---
title: Sanitary Sewer Systems (Site)
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## Materials, design, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited or the authority having jurisdiction adopts a different edition. {note}
−## Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing. {note}
+## Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
| Standard | Title |
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## ASTM F679 has been withdrawn; its scope for large-diameter PVC gravity sewer pipe was consolidated into ASTM D3034, which now covers 3 in. through 60 in. {note}
−## Any reference, submittal, or product data citing F679 for sewer pipe shall be updated to D3034. Citing the withdrawn standard creates submittal-review confusion and a potential non-compliance finding by the reviewing utility. {note}
+## Any reference, submittal, or product data citing F679 for sewer pipe shall be updated to D3034. Citing the withdrawn standard creates submittal-review confusion and a potential non-compliance finding by the reviewing utility.
## The Ten States Standards are a state-adopted design-criteria floor, not an ASTM or ASCE numbered product standard. {note}
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## Action Submittals {toc}
−### The Contractor shall submit the following action submittals for review and approval before any sanitary sewer material is ordered or installed: {note}
+### The Contractor shall submit the following action submittals for review and approval before any sanitary sewer material is ordered or installed:
- Product data for all gravity pipe, fittings, and joints, including material, stiffness class or DR, and NSF/ANSI 14 certification.
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## Closeout Submittals {toc}
−### The Contractor shall submit the following closeout submittals before final acceptance of the sanitary sewer system: {note}
+### The Contractor shall submit the following closeout submittals before final acceptance of the sanitary sewer system:
- Record drawings showing as-built horizontal alignment, invert elevations at each structure, and lateral tie-in stations and depths.
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# Quality Assurance {toc}
−## The Contractor shall employ installers experienced in the placement, jointing, and testing of buried gravity and pressure sewer pipe of the materials and sizes specified. {note}
+## The Contractor shall employ installers experienced in the placement, jointing, and testing of buried gravity and pressure sewer pipe of the materials and sizes specified.
### Pipe and fittings of a given material shall be supplied by a single manufacturer for the project unless the Engineer approves an alternate in writing.
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## Material selection {toc}
−### The gravity sewer pipe material shall be selected for the burial depth, soil and groundwater conditions, and utility-conflict clearances of the run. {note}
+### The gravity sewer pipe material shall be selected for the burial depth, soil and groundwater conditions, and utility-conflict clearances of the run.
−### PVC gasketed sewer pipe is the default gravity material for the great majority of site sanitary runs at normal depth. HDPE is selected where fusion-welded leak-free joints, long deflected pulls, or directional drilling are advantageous. Ductile iron is reserved for shallow-cover crossings, restrained-joint conditions, and the rigid segment at the building connection where loading or proximity to other utilities requires it. {note}
−
```datasheet
label: Gravity sewer pipe material
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```
+### PVC gasketed sewer pipe is the default gravity material for the great majority of site sanitary runs at normal depth. HDPE is selected where fusion-welded leak-free joints, long deflected pulls, or directional drilling are advantageous. Ductile iron is reserved for shallow-cover crossings, restrained-joint conditions, and the rigid segment at the building connection where loading or proximity to other utilities requires it. {note}
+
### PVC gravity sewer pipe and fittings shall conform to ASTM D3034 with integral bell-and-spigot gasketed joints meeting ASTM D3212 and elastomeric gaskets meeting ASTM F477.
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## Hydraulic design {toc}
−### The gravity sewer shall be designed to maintain a self-cleansing velocity of at least 2.0 ft/s when flowing full or half-full at the design peak flow. {note}
+### The gravity sewer shall be designed to maintain a self-cleansing velocity of at least 2.0 ft/s when flowing full or half-full at the design peak flow.
### Self-cleansing velocity keeps solids in suspension so the pipe scours itself rather than accumulating a sediment bed that reduces capacity and generates odor. The minimum slope that achieves 2.0 ft/s depends on pipe diameter and the Manning roughness coefficient; smaller pipe needs a steeper slope. A single flat minimum slope applied across all diameters is wrong in both directions: it is non-conservative for 8 in. pipe and grossly over-steep for 6 in. laterals. Compute the minimum slope per diameter. {note}
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step: 0.001
setpoints:
+ - 0.011
- 0.013
+ - 0.015
```
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step: 0.1
setpoints:
+ - 2
- 2.5
+ - 4
```
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step: 25
setpoints:
+ - 300
- 400
+ - 500
```
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step: 0.5
setpoints:
− - 3.0
+ - 3
+ - 5
```
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## Service laterals {toc}
−### Each building service lateral shall connect to the main through a factory-molded wye or tee fitting, or an approved manufactured saddle wye where a field connection to an existing main is required. {note}
+### Each building service lateral shall connect to the main through a factory-molded wye or tee fitting, or an approved manufactured saddle wye where a field connection to an existing main is required.
### Field-cored connections made without a proper manufactured saddle fitting are a leading source of I/I and of structural failure at the connection: a hand-cut hole with a mortared-in pipe stub cracks and admits groundwater. Specify a factory wye on new mains and an approved saddle wye fitting only where tying into an existing main. {note}
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# Bedding and Backfill {toc}
−## The pipe bedding and trench backfill class shall be selected to support the pipe, protect the joints, and transfer surface loads without overstressing the pipe wall. {note}
+## The pipe bedding and trench backfill class shall be selected to support the pipe, protect the joints, and transfer surface loads without overstressing the pipe wall.
## Bedding is the engineered material placed under and around the pipe up to the spring line or pipe crown; it controls pipe deflection and joint integrity far more than the native backfill above it. "Granular fill" with no gradation or AASHTO limit is an open invitation for the contractor to use angular crushed concrete or oversized stone that point-loads and cracks PVC bell joints. Specify the bedding class and the gradation limits explicitly. {note}
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step: 0.125
setpoints:
+ - 0.375
- 0.75
+ - 1
```
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# Manholes {toc}
−## Manhole type and material shall be selected for groundwater, hydrogen sulfide exposure, and traffic loading. {note}
+## Manhole type and material shall be selected for groundwater, hydrogen sulfide exposure, and traffic loading.
## Precast reinforced concrete manholes per ASTM C478 are the dominant and default type. Fiberglass manholes per ASTM D3753 are selected where high groundwater, corrosive soil, or sustained hydrogen sulfide (H2S) exposure would attack concrete. H2S generation is most severe downstream of force main discharges and in low-velocity reaches; in those locations a corrosion-resistant manhole or a protective lining is warranted. Traffic loading determines the barrel diameter, base thickness, and frame-and-cover load rating. {note}
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# Lift Stations {toc}
−## A lift (pump) station shall be provided only where gravity flow to the public main or on-site treatment is not feasible at the design depth and slope. {note}
+## A lift (pump) station shall be provided only where gravity flow to the public main or on-site treatment is not feasible at the design depth and slope.
## A lift station introduces ongoing energy cost, mechanical maintenance, and a wet-weather failure mode that gravity sewers do not have, so it is an option of last resort. Confirm during early design whether the site can reach the public main by gravity at acceptable cover and slope; if it cannot, the lift station must be sized and located before the collection-system layout is finalized, because the station footprint, electrical service, and force main routing constrain the whole site. The decision threshold is governed by the tap invert elevation, site grades, and the resulting required excavation depth. {note}
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step: 0.5
setpoints:
− - 3.0
+ - 2.5
+ - 3
+ - 4
```
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## Wet well {toc}
−### The wet well material and effective volume shall be selected to limit pump cycling and to provide emergency storage. {note}
+### The wet well material and effective volume shall be selected to limit pump cycling and to provide emergency storage.
### Wet well storage volume sets the pump cycle time. Too small a volume causes the pump to start and stop rapidly; frequent starts overheat the motor, accelerate wear, and void the pump warranty. The active volume between the pump-on and pump-off levels must be large enough to hold cycle time within the motor manufacturer's maximum starts-per-hour limit at the design flow. The wet well must also provide reserve storage above the high-level alarm to ride through a short power or pump outage without an overflow. {note}
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step: 1
setpoints:
+ - 6
- 10
+ - 15
```
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## Valve vault and force main {toc}
−### A valve vault separate from the wet well shall house the discharge check valves, isolation valves, and force main connection. {note}
+### A valve vault separate from the wet well shall house the discharge check valves, isolation valves, and force main connection.
### Keeping valves out of the wet well keeps maintenance staff out of the hazardous, gas-laden wet well for routine valve work and keeps the valves above the sewage. Each pump discharge needs a check valve to prevent backflow when it stops and an isolation valve to allow servicing one pump while the other runs. {note}
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step: 0.5
setpoints:
− - 5.0
+ - 2
+ - 5
+ - 8
```
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## Odor control {toc}
−### Odor control shall be evaluated for any lift station or force main discharge in proximity to occupied buildings, building entries, or parking areas. {note}
+### Odor control shall be evaluated for any lift station or force main discharge in proximity to occupied buildings, building entries, or parking areas.
### Hydrogen sulfide released at the wet well vent or at the force main discharge manhole produces odor complaints and corrosion. A station that vents next to a building entry or a parking area is a post-occupancy liability. Passive venting (a carbon-media canister or a tall vent stack) suffices for low-strength or remote stations; an active carbon or chemical scrubber may be warranted where the station is close to occupied space or the wastewater is septic. {note}
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# Testing {toc}
−## All gravity sewer testing shall be completed and accepted before final backfill compaction and surface restoration over the tested segment. {note}
+## All gravity sewer testing shall be completed and accepted before final backfill compaction and surface restoration over the tested segment.
## Test sequencing is a requirement, not a convenience. A low-pressure air test or deflection test run after the trench is fully backfilled and paved makes any failure expensive to find and destructive to repair. The acceptance tests must be scheduled into the construction sequence so they occur on the open or lightly-backfilled trench, with the spec stating the order explicitly so the test is not skipped. {note}
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step: 10
setpoints:
+ - 50
- 100
+ - 200
```
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step: 0.5
setpoints:
− - 5.0
+ - 5
+ - 7.5
```
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# Installation {toc}
−## Pipe shall be installed to line and grade on a continuously supported, properly bedded trench bottom, with bell ends laid facing upstream. {note}
+## Pipe shall be installed to line and grade on a continuously supported, properly bedded trench bottom, with bell ends laid facing upstream.
## Sewer pipe is laid uphill against the flow with the bell facing upstream so the spigot of each joint points downstream into the bell, which keeps the joint from being pried open by flow and bedding movement. Line and grade are non-negotiable on a gravity sewer; small grade errors that create bellies (low spots) trap solids and defeat the self-cleansing design. {note}
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# Delivery, Storage, and Handling {toc}
−## Plastic pipe shall be protected from prolonged ultraviolet exposure and supported to prevent deformation during storage. {note}
+## Plastic pipe shall be protected from prolonged ultraviolet exposure and supported to prevent deformation during storage.
## PVC and HDPE pipe degrade and lose impact strength under sustained sunlight, and they take a permanent set if stored unsupported in tall stacks or over point supports. Gaskets and elastomeric connectors must be kept clean and out of the sun. Castings, pumps, and control panels must be kept dry and undamaged until installation. {note}
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# Warranty {toc}
−## The Contractor shall warrant the installed sanitary sewer system against defects in materials and workmanship for the project warranty period. {note}
+## The Contractor shall warrant the installed sanitary sewer system against defects in materials and workmanship for the project warranty period.
### The Contractor shall warrant the complete installed system, including pipe, structures, and the lift station, against defects in materials and workmanship for a minimum of one year from final acceptance.
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# Spare Parts {toc}
−## The Contractor shall furnish the spare parts and special tools needed to keep the lift station in service after acceptance. {note}
+## The Contractor shall furnish the spare parts and special tools needed to keep the lift station in service after acceptance.
### The Contractor shall furnish one spare submersible pump of each type and size installed, or the spare-pump quantity required by the AHJ, for the lift station.
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- Pump removal tools, lifting chain, and guide-rail components
```