Designing Commercial Sewage Lift Stations Part 7: Elevator Pits

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By Chris Edmondson

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Sump pumps aren’t just for plumbing applications.  Did you know that most elevator pits also require sump pumps?  ASME 17.1 – 2007 states that any elevator that is provided with Firefighters’ Emergency Operation must include a pump or drain that is capable of removing 50 GPM per shaft.  While local jurisdictions may vary slightly in their adoption or enforcement of this requirement, more often than not, a sump pump will be required to meet Elevator Code. Image courtesy of Salvatore Vuono / FreeDigitalPhotos.net

Why is this the case?  There are several reasons, including the obvious, which is the fact that water in an elevator pit could endanger the lives of firefighters or building occupants if a building’s fire safety/sprinkler system activates.  Elevator pits represent a low point in any building so virtually any liquid, including hydraulic fluids, could conceivably collect there, creating a safety hazard.  Other sources might include building water leaks or even ground water seepage.

Engineers designing such systems would be well advised to check with the local inspector on the requirement and the sizing of such a pump, but most states typically require the pump capacity to be 3,000 GPH (50 GPM) at 15 or 20 feet of head. 

Safety and Environmental Precautions

Certain safeguards must also be in place to prevent hydraulic oil from being pumped into the public sewer system in the event of a leak.  Not having the proper protection is a major code violation and carries a hefty fine if somehow oil from the elevator pit contaminates sewer water.  We suggest that a sensing device be applied that differentiates between oil and water and allows water to be pumped from the elevators sumps without the danger of pumping oil into sewers or waterways.  We recommend the CentriPro Oil Smart Switch and Alarm Kit, which has two sensing points, Pump On and Pump Off, to reduce the risk of pumping oil or other hydrocarbons into the environment.

Finally, be sure to take the proper ground-faulting protection per Section 620.85 of the NEC.  This code requires that each 125-volt, single-phase, 15- and 20-ampere receptacle installed in elevator pits be of a ground-fault circuit-interrupter type.

For more information, check out JMP’s webinar on designing sump and sewage systems.