Elevator Emergency Power

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spsnyder

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I have a project where a high rise has two banks of elevators with no emergency power. Each bank has its own machine room and panel. There is not adequate emergency power to provide power to all elevators. The controls for the elevators make it possible to power only one elevator from the generator at a time. The scenario would be as follows. The generator kicks on and all elevators stop except for one in each bank. These elevators drop down to the ground floor, open and turn off. The next elevator in the sequence turns on and so on... The last elevator in each bank remains on, powered by the generator. My long winded question is this. Does the NEC explicately allow the emergency feeders to be sized for the load associated with one elevator? The following is from the NEC...

430.26 Feeder Demand Factor
Where reduced heating of the conductors results from motors operating on duty-cycle, intermittently, or from all motors not operating at one time, the authority having jurisdiction may grant permission for feeder conductors to have an ampacity less than specified in 430.24, provided the conductors have sufficient ampacity for the maximum load determined in accordance with the sizes and number of motors supplied and the character of their loads and duties.


Thanks.
 
The sections you want are 220.21 and 701.6. Loads not to be operated all at the same time.

Elevators are a Legally Required Standby Load. You can use the same power source but not the same transfer switch as Emergency Loads.

The 2006 IBC section 3003 allows for at least one elevator to be operable and the power transferable to all elevators in a bank.

I don't have the IBC in front of me being at home now. I'm pretty sure that if you have two banks that you need power for at least two elevators (one from each bank) at the same time.

You didn't say if this was retrofit or new. If it is retrofit you need to consult the AHJ.

also check section 403 to see if building qualifies as a high rise. Typically 75' above finish grade to highest occupied floor unless locally amended like ours is. We're at 55' above finished grade.
 
Larry,

Thank you very much. That's exactly what I was looking for. (220.21 is now 220.60 in the 2005)

To answer your questions...

This is a retrofit. Right now the power goes out and the elevators come to a complete stop. Doors don't open, doesn't go to next floor etc. According to the elevator people.

This is a high rise as well. The Building Code of NYS (ICC based) requires one elevator in each bank to have stand-by power if the capacity does not exist to power all elevators.

Thanks again.
 
sandsnow said:
The sections you want are 220.21 and 701.6. Loads not to be operated all at the same time.

Elevators are a Legally Required Standby Load. You can use the same power source but not the same transfer switch as Emergency Loads.
Click to expand...

Elevators are listed under 700, Emergency Loads, not 701 Legally Required Standby Loads
 
who will coordinate alt floor recall and shunt trips?

who will coordinate alt floor recall and shunt trips?

The elevator recall, Alternate floor recall, and shunt trips for the breakers all need to be coordinated with the fire alarm contractor and approved by the fire marshal in my counties.
Fire service swithches for which the fireman can overide the elevator controls and put all of the fans into a smoke purge mode with positive pressurisation fans to pressurize the stairwells so they cant fill up with smoke.
You wouldnt want the elevator recall to recall the elevator right into the fire in the lobby.
The fines for performing this kind of work without the proper permits in place and an an approved stamped drawing from the fire marshal are extremely high.
As they should be.
I do realize that this is a retrofit so it may or may not be required in your areas as preexisting nonconforming but these are the features I am installing on newer installs making it more and more complicated each year
 
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Dave_PE said:
Elevators are listed under 700, Emergency Loads, not 701 Legally Required Standby Loads
Click to expand...

Are you talking about the FPN? Please remember that is not a Code requirement.

The scope in 700.1 spells out how you determine an Emergency Load.

Elevators could be a Emergency Load, but you have to have a code or regulation that requires it. Our Building Code (UBC 97 and soon 2006 IBC) does not classify elevators as an Emergency Load, but as a Standby Load which translates into a Legally Required standby Load in the NEC.

The only loads that are required by 700 to be Emergency are in the sources of power section. Fuel Transfer Pumps and Dampers. 700.12(B)(2) and (B)(4)
 
Dave, In NYS (IBC) Section 403.10.1 (High Rise Buildings) requires Standby Power for Elevators.

quogueelectric. Thank you for the info on the fire alarm coordination. Definately makes a lot of sense.

Sandstone, "Elevators are a Legally Required Standby Load. You can use the same power source but not the same transfer switch as Emergency Loads." - Due to the layout I am going to have to have separate transfer switches but I hadn't realized that 701.7(A) [2005] required it. I

Thanks to all.
 
Larry, you are correct...I was actually making reference to the FPN....although not a code requirement, it can be taken as a pretty strong recommendation by some Fire Marshalls and it depends what the AHJ thinks that day. See below, this is local ordinance.......is it standby or emergency?

"All high-rise buildings shall have a standby emergency generator of sufficient size to provide power supply to the emergency lighting, fire pump, fire alarm system, communication system, a minimum of one (1) elevator, mechanical smoke removal equipment and any other required or optional emergency equipment. This emergency power system shall be inspected and accepted by the fire marshal"
 
Dave_PE said:
.......is it standby or emergency?

"All high-rise buildings shall have a standby emergency generator of sufficient size to provide power supply to the emergency lighting, fire pump, fire alarm system, communication system, a minimum of one (1) elevator, mechanical smoke removal equipment and any other required or optional emergency equipment. This emergency power system shall be inspected and accepted by the fire marshal"
Click to expand...

It looks as though they are defining the capacity of the power source and then stop short of defining how it is distributed. What is optional emergency equipment?
 
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