Elevator Sump Pumps
Code Tidbit - December, 2011 By: Douglas A. Page, PE, MPA, LEED AP, CEM, CPD
You may (or may not) recall several years ago I wrote an article for Plumbing Engineering on elevator sump pumps. The purpose of the article was to discuss the requirements for draining an elevator shaft. The whole gig was the Building Code and Elevator Code did not provide guidance for sizing the sump pump. The intent is to drain the elevator shaft in order to minimize water in the shaft when a sprinkler head went off. That way, the elevator could be used for Fire Service during a fire event.
As an 'update', let's start with the Building Code:
"§3004.4 Plumbing and mechanical systems. Plumbing and mechanical systems shall not be located in an elevator shaft.
Exception: Floor drains, sumps and sump pumps shall be permitted at the base of the shaft provided they are indirectly connected to the plumbing system."
Keep the stuff not serving the elevator out of the elevator shaft! The drainage at the bottom of the shaft needs to discharge as indirect waste. Not yet sure what they really mean by the "Plumbing System." The Plumbing Code states:
"§P802.1.8 Elevator pit drain or sump pump. All elevator pits for elevators that have Firefighters' Emergency Operation shall have a drain or sump pump in accordance with ASME A17.1 Section 188.8.131.52. The drain or sump pump discharge shall be into the sanitary or storm drainage system through an indirect waste connection. The elevator pit discharge system is not required to include an oil separator, except as required by §P1003.4."
Yak. So we have to put a drain or sump in an elevator pit. It has to be indirectly connected to the storm or sanitary. Given the elevator pit is the lowest place in the building 999 times out of 1000, we're probably putting in a sump pump. We need an oil separator, where required by section 1003.4. Well, OK - 1003.4 states:
"P1003.4 Oil separators required. At repair garages, car-washing facilities, at factories where oily and flammable liquid wastes are produced and in hydraulic elevator pits, separators shall be installed into which all oil-bearing, grease-bearing or flammable wastes shall be discharged before emptying into the building drainage system or other point of disposal.
Exception: An oil separator is not required in hydraulic elevator pits where an approved alarm system is installed and an indirect waste connection in accordance with §P802.1.8."
Now we need the oil separator unless "an approved alarm system is installed" As you probably know by now, "Approved" means whatever the Code Enforcement Official" (CEO) says is acceptable. It's not as arbitrary as it sounds. He or she needs to be able to justify it too. Historically, the "alarm" is a hydrocarbon sensor that shut down the pump and sounds an alarm if hydrocarbons are present. So all we need is a sump pump that discharges indirectly to the storm or sanitary, with an oil sensor.
Over the years, I heard stories of CEOs (like maybe in Rochester, NY) that were requiring oil separators in elevator shaft drainage. This is, well, silly. I've also had 'chats' with CEO's insisting the drainage go to sanitary. The reasons I've heard were garbage and leaking oil from hydraulic elevator equipment ends up in the bottom of these shafts. My position on this is if there is garbage and oil at the bottom of the elevator shaft, the owner is NOT doing their due diligence, and the CEO is not enforcing the Property Maintenance Code. This is just one man's opinion…
Driving this home, a (NYS DOS) Technical Bulletin states:
"Elevator Pit Drain:
Section 184.108.40.206 of the ASME A17.1 requires that a drain or sump pump be provided in all elevator pits for elevators that have Firefighters' Emergency Operation. FEO is required in all new elevators that penetrate a floor as per BCNYS Section 3003.2 and ASME A17.1. MCNYS Section M802.2 requires the drain or sump pump to discharge into the sanitary or storm drainage system through an indirect connection. The drain or sump pump is not required to include an oil separator."
But WAIT! There's more! Remember that §P802.1.8 requires elevator pits to have a drain or sump pump in accordance with ASME A17.1 Section 220.127.116.11. So what's ASME 18.104.22.168 say?
"In elevators provided with Firefighters' Emergency Operation, a drain or sump pump shall be provided. The sump pump/drain shall have the capacity to remove a minimum of 11.4 M3/h (3,000 gal/h) per elevator."
3,000 gal/h is 50 gallons/minute. 50 gallons per minute PER ELEVATOR? If we had a bank of, say, three elevators, we would need three pumps with a minimum capacity of 50 gpm each. This is 150 gpm. Do you suppose we are discharging 150 gpm to a mop sink as indirect waste? How about a nice 4" hub drain? Don't like hub drains because they evaporate, how about a trap primer on the hub drain? YAK.
What do you suppose the basis of this stellar decision making process was for 50 gpm? Remember the sprinkler head requirement for sizing the sump pump noted above? So, if
Pressure = (Flow / K-factor)^2 We could solve for GPM knowing the sprinkler listing and needed coverage. I had a chat with a well known sprinkler head manufacturer who agreed 20 - 35 gpm are reasonable flow rates for most heads. For argument's sake, let's just call it 25 gpm.
From another Technical Bulletin:
"Sprinkler Protection of Hoistways and Machine Rooms:
The referenced standard for sprinkler systems is NFPA 13, Installation of Sprinkler Systems, 2002 edition. For sprinkler protected buildings, Section 8-14.5 of this standard requires a sprinkler head at the bottom of the hoistway (not more than 2 ft. above the pit floor) for equipment using a combustible hydraulic fluid or where the hoistway is combustible. A sprinkler head is also required at the top of combustible hoistways and freight elevator hoistways. Section 8-14.5 also requires sprinkler protection for all machine rooms in sprinkler protected buildings…"
One head at the top, one head at the bottom, and everyone assumes both heads go off. 2 x 25 gpm = 50 gpm, the required flow rate of the sump pump. I could of course be giving the Elevator Code Committee too much credit, but there you have it.
FOR EXTRA CREDIT! NFPA 13 has exceptions. For example:
"22.214.171.124 The sprinkler required at the bottom of the elevator hoistway by 126.96.36.199 shall not be required for enclosed, noncombustible elevator shafts that do not contain combustible hydraulic fluids."
"188.8.131.52 The sprinkler required at the top of the elevator hoistway by 184.108.40.206 shall not be required where the hoistway for passenger elevators is noncombustible and the car enclosure materials meet the requirements of ASME A17.1, Safety Code for Elevators and Escalators."
So, if we had an elevator shaft with no heads, could we get rid of the sump pump? Hint: Where did we say the lowest part of the building was? Are there heads outside the shaft in a fully sprinklered building?
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