Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
---
title: Sump and Sewage Pumps
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## Pumped drainage exists because not every fixture or drain can reach the sewer by gravity. {note}
−## A basement restroom below the building drain invert, a below-grade mechanical room with floor drains, an elevator pit, a foundation underdrain, and a storm sump all share the same problem: liquid collects below the gravity drain and must be lifted to it, and the pump that does the lifting is the single point of failure for everything that drains to that basin. {note}
+## A basement restroom below the building drain invert, a below-grade mechanical room with floor drains, an elevator pit, a foundation underdrain, and a storm sump all share the same problem: liquid collects below the gravity drain and must be lifted to it, and the pump that does the lifting is the single point of failure for everything that drains to that basin.
## A failed sump pump floods a basement; a failed sewage ejector backs raw sewage into occupied space and releases sewer gas; this standard is written to close the gap between a code-minimum installation and one that runs reliably, fails safely, and can be serviced without entering the basin. {note}
−## The service and the solids the pump must pass govern almost every other decision in this standard, so the pump type and service are established first and the remaining requirements follow from it. {note}
+## The service and the solids the pump must pass govern almost every other decision in this standard, so the pump type and service are established first and the remaining requirements follow from it.
## Coordinate basin locations, inlet inverts, and discharge points with [[drawing: the plumbing floor plans and the plumbing equipment schedule]], and coordinate the gravity discharge piping and its connection point with [[sync/sanitary-waste-and-vent-piping]].
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# Service Conditions {toc}
−## The pump, basin, controls, and all wetted and exposed materials shall be suitable for the temperature, corrosivity, and atmosphere of the service and the space in which the basin is installed. {note}
+## The pump, basin, controls, and all wetted and exposed materials shall be suitable for the temperature, corrosivity, and atmosphere of the service and the space in which the basin is installed.
```datasheet
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# Pump Type and Service {toc}
−## The pump type shall be selected for the liquid pumped and the solids it must pass; the four service categories below cover the large majority of building applications. {note}
−## Selecting a sump pump for a sewage application, or an ejector where a grinder is required, is the most common and most consequential error in this scope, and it produces clogging, motor failure, and sewage backup. {note}
+## The pump type shall be selected for the liquid pumped and the solids it must pass; the four service categories below cover the large majority of building applications.
```datasheet
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default: "Sewage ejector pump — solids-handling sanitary (spherical solids up to 2 in)"
```
+## Selecting a sump pump for a sewage application, or an ejector where a grinder is required, is the most common and most consequential error in this scope, and it produces clogging, motor failure, and sewage backup. {note}
## Sump Pumps {toc}
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# Capacity and Performance {toc}
−## Each pump shall be selected from its certified performance curve to deliver the design flow at the design total dynamic head, with the operating point on the stable portion of the curve. {note}
+## Each pump shall be selected from its certified performance curve to deliver the design flow at the design total dynamic head, with the operating point on the stable portion of the curve.
```datasheet
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### Each pump shall deliver the design flow shown on the plumbing equipment schedule at the design total dynamic head, established from the static lift plus the friction and fitting losses of the discharge piping.
### The pump operating point shall fall on the stable portion of the certified curve, away from the shut-off head and away from the runout end of the curve.
−### The total dynamic head shall be calculated from the actual installed discharge routing, not assumed; an underestimated head produces a pump that delivers less flow than required and a basin that fills faster than it empties. {note}
+### The total dynamic head shall be calculated from the actual installed discharge routing, not assumed; an underestimated head produces a pump that delivers less flow than required and a basin that fills faster than it empties.
### Sewage ejector and grinder pump discharge velocity shall be sufficient to keep solids in suspension in the discharge piping, generally not less than 2 feet per second.
### The Contractor shall verify that the selected pump capacity equals or exceeds the design inflow to the basin so the pump can keep up with the maximum rate of drainage delivered to the sump.
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## A pumped drainage system has no gravity bypass, so the consequence of a single pump failure is determined entirely by whether a second pump is provided. {note}
+### The pump configuration shall be as indicated on the contract documents.
+
```datasheet
label: Pump Configuration
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default: "Duplex — two pumps with automatic alternator (sewage and critical service)"
```
−
−### The pump configuration shall be as indicated on the contract documents.
### Sewage ejector and grinder pump systems serving fixtures that cannot tolerate an outage, and any pumping system serving more than a single fixture group or designated as critical, shall be duplex with two pumps each sized for the full design flow.
### A duplex system shall include an automatic alternator that alternates the lead and lag pump on successive cycles so the pumps wear evenly and each pump is exercised regularly.
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### Duplex sewage basins shall be sized to house both pumps, the guide rails, and the level controls without interference, generally not less than 30 inches in diameter.
### The basin volume between the pump-on and pump-off levels shall be sufficient that the pump does not start more frequently than the motor's permitted starts per hour at the design inflow.
−### Short-cycling — a basin too small for the pump, so the pump starts and stops rapidly — overheats and destroys the motor and is the most common cause of premature pump failure; the basin working volume and the pump capacity shall be coordinated. {note}
+### Short-cycling — a basin too small for the pump, so the pump starts and stops rapidly — overheats and destroys the motor and is the most common cause of premature pump failure; the basin working volume and the pump capacity shall be coordinated.
### The basin shall be provided with anti-flotation provisions — a ballast collar, anti-flotation flange, or concrete anchorage — where it is installed below the groundwater table so that an empty basin cannot float.
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# Valves and Piping Connections {toc}
−## Each pump in a basin shall discharge through its own check valve and its own isolation (full-open) valve so that either pump can be isolated and removed while the other remains in service. {note}
+## Each pump in a basin shall discharge through its own check valve and its own isolation (full-open) valve so that either pump can be isolated and removed while the other remains in service.
```datasheet
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## Each pump motor shall be served and protected in accordance with NEC Article 430, and the pump controls and alarm shall be powered so that the alarm remains functional when the normal power or a pump control fails. {note}
+### Each pump motor shall be provided with branch-circuit protection, a disconnecting means, and motor overload protection in accordance with NEC Article 430.
+### A means of disconnecting each pump shall be provided within sight of the pump location or capable of being locked open, as required by the NEC.
+### The high-water alarm for a sewage ejector or grinder system, and the pumps serving an essential facility, shall be connected to the emergency or legally required standby power system where the building is provided with one, so that a normal power outage does not disable the alarm or the critical pumps.
+
```datasheet
label: Power Source for Sewage Pump and Alarm
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default: "Normal power for pumps; alarm on emergency or standby power (critical sewage)"
```
+### The control panel enclosure shall be rated for the environment in which it is installed; a NEMA 4X enclosure shall be used where the panel is exposed to washdown, humidity, or corrosive sewer atmosphere near the basin.
```datasheet
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default: "NEMA 4X (washdown, corrosion, near basin)"
```
−
−### Each pump motor shall be provided with branch-circuit protection, a disconnecting means, and motor overload protection in accordance with NEC Article 430.
−### A means of disconnecting each pump shall be provided within sight of the pump location or capable of being locked open, as required by the NEC.
−### The high-water alarm for a sewage ejector or grinder system, and the pumps serving an essential facility, shall be connected to the emergency or legally required standby power system where the building is provided with one, so that a normal power outage does not disable the alarm or the critical pumps.
−### The control panel enclosure shall be rated for the environment in which it is installed; a NEMA 4X enclosure shall be used where the panel is exposed to washdown, humidity, or corrosive sewer atmosphere near the basin.
### Wiring within and into the basin shall be suitable for the wet, corrosive environment, and cord and cable penetrations through a gas-tight cover shall be sealed to maintain the cover's integrity.
−### A sewage alarm on the same circuit as the pump it watches goes dark exactly when the pump loses power, defeating its purpose; the alarm shall not depend solely on the same supply as the pump. {note}
+### A sewage alarm on the same circuit as the pump it watches goes dark exactly when the pump loses power, defeating its purpose; the alarm shall not depend solely on the same supply as the pump.
# Installation {toc}
−## General {toc}
+## The Contractor shall install each basin plumb and at the elevation required so that all drainage served by the basin flows into it by gravity.
+## In other than existing structures, the sump shall not receive drainage from any piping within the building that is capable of being discharged by gravity to the building sewer.
+## The basin shall be set on a stable, level bearing surface, bedded and backfilled per the basin manufacturer's instructions, and anchored against flotation where groundwater is present.
+## The inlet shall enter the basin above the high-water alarm level where possible, and the inlet connection shall be sealed to the basin.
−### The Contractor shall install each basin plumb and at the elevation required so that all drainage served by the basin flows into it by gravity.
−### In other than existing structures, the sump shall not receive drainage from any piping within the building that is capable of being discharged by gravity to the building sewer.
−### The basin shall be set on a stable, level bearing surface, bedded and backfilled per the basin manufacturer's instructions, and anchored against flotation where groundwater is present.
−### The inlet shall enter the basin above the high-water alarm level where possible, and the inlet connection shall be sealed to the basin.
−
## Pump Setting and Discharge {toc}
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## For critical duplex sewage and grinder systems, the Owner may require a complete spare pump matching the installed model so a failed pump can be replaced without procurement lead time.
## The spare parts list and the recommended replacement interval for wear items shall be included in the operation and maintenance manual.