Life safety vs standby transfer swtiches. 2

[BJC]

I have a situation where I am being told I should power elevators and stairwell pressurization fans from the ememgency power system.
The person telling me this says the functions are safety the same as lighting. I am reading the NEC and the IBC to say I need two switches, safety and leaglly required standby.
The building is a 14 story condo with two elevators. The fire pump has it's own xfr switch.
Has anyone elxe hear fo the stairwell pressurizaton and elevators being on the emergency power system. Ther may be a difference in terms Emergency and standby as used by the NEC and the IBC
thanks

 

[Senselessticker]

There is a very big difference in emergency vs. standby power. Powering the elevator with "emergency" power should not fall under the requirements of NFPA-101. However, if the elevator is required to be on a standby system, I don't believe there is a problem with powering the elevator from the same source as the emergency (i.e. the same generator), so long as the you are able to manually switch over from emergency to "standby" power. I'm saying this without really checking into NEC 700/701, so please correct me if I'm wrong. I will be dealing with a similar situation soon, so I'm curious for input from others. I'll read up on Art. 700/701 and correct myself if I'm mistaken.

 

[davidbeach]

Egress lighting and a few other things would be NEC 700 emergency system. Pressurization fans would be NEC 701 legally required standby. Elevators themselves might be NEC 701, or would more likely be NEC 702 optional standby. A strict, literal, reading of the NEC would provide for separate transfer switches for 700, 701, and 702 systems. On the other hand, there are many AHJs that will accept single transfer switches for multiple systems if there are other means (excess capacity for example) to prevent the loss of higher priority loads should there be problems with the system.

 

[jrhaus]

Elevators are used for fire fighter service in high rise buildings, thus the requirement for them to be on life safety. The International Mechanical code requires smoke evac and stair pressurization to be treated as as life safety system and also requires emergency feeders to be separated (2hr fire rating) from normal feeders in some cases. Two transfer switches are required for most installations as there is typically some load connected to the generator that falls into the NEC 702 category.

 

[stookeyfpe]

Whoever is telling you this has apparently not read the 2003 International Building Code. IBC section 403.10.2 requires the following loads to be on standby power in a high riser building:
-- power and lighting for the fire command room
-- electric powered fire pumps
-- ventilation and fire detection for smokeproof enclosures
-- elevators in accordance with Chapter 30

Emergency power is required for:
-- Exit signs and illumination
-- Elevator car lighting
-- Emergency voice/alarm systems
-- Fire alarm systems

 

[BJC]

stookeyfpe
Thats exactly the way I read it. There are several local projects where they (AHJs) are letting people use one trasfer switch.
I know a AHJ can do what they want. I was asking to see how many others had seen it and if there was some rational behind it.

 

[stookeyfpe]

BJC:

No they can't. The AHJs responsibility is to verify compliance with the adopted standard. If you as the design professional can meet the requirement of the code using one transfer switch and the AHJ wants two, have them provide you with the specific code section that specifies this. If not, kindly tell them that it is not a requirement and ask to appeal the decision. This usually causes the AHJ to rethink the decision. You can also them that they are pulling something out of their a__ but usually that may preturb them.

 

[rbulsara]

Not having read latest IBC, but the NEC and other codes permit a common ATS and even a generator that can serve both emergency and standby loads as long as they are rated to carry the total load. There is no specific requirement for separatino of ATSs except for Health Care facitlities. But that is a separate issue. In fact if a conditon arises to shed the load, standby loads can be shed rather than loosing the emergency loads.

There is no requirement to have separate generators for emergency and standby loads either along the same logic.

 

[BJC]

rbulsara Have you got chapter and verse?
There well hidden in my copies.

 

[rbulsara]

BJC:

IN fact I am asking for the chapter and verse requiring separation of ATSs or sources besides healthcare facilities..

 

[stookeyfpe]

2002 NEC, section 700.5 (A) and NFPA 110, Chapter 6.

 

[rbulsara]

stookeyfpe:

OK. It's not NEC 700.5(A) but 700.5(D) which says a emergency transfer switch shall only supply emergency load.

So I stand corrected for that. I am not sure how this item was there in the Code, if so it is very loosely enforce. But that is beside the point.

Thanks

 

[davidbeach]

NEC 700.5 deals with capacity and has an (A) and a (B) and stops there. I think you are probably referring to 700.6 Transfer Equipment.

 

[rbulsara]

davidbeach:

Yes, 700.6 (D). Thanks again.
The original question is if two sepratate (transfer)switches are required for (life) safety and standby loads.

 

[rbulsara]

Plus of course what constitutes "emeergency" and standby loads, but that has been answered by stookeyfpe.

 

[stookeyfpe]

A red star to rubulsara and david deach for improving my knowledge of the NEC. I can't wait to upset some electrical plans examiners with this thread.

And in my own humble opinion, the 2003 IBC clearly stipulates the loads and I promise you as an AHJ I will not pull some requirement from a posterior orifice and impose it upon you.

This website is a wonderful tool.

 

[tommom]

I pointed out this paragraph to our local large municipality, and they are now enforcing it after some time of NOT enforcing it - that is, they will require emergency (ie life safety) loads to be separated from standby. In many cases, what we do in smaller buildings is use battery packs and only supply one transfer switch for standby loads such as elevators.

 

[BJC]

I was away for a while. my belated thanks to all that replied.
StookeyPE - thanks again. When all is said and done even if you have a note or an OK from the AHJ it won't hold up when things get to a courtroom. Laws and codes are our responsibility to follow, not to evade with exceptions from AHJ.
If one wants to read why stairwells are pressurized the book
"102 Minutes: The Untold Story of the Fight to Survive Inside the Twin Towers
by Jim Dwyer, Kevin Flynn"
is pretty interesting.

 

[tommom]

BJC,

I always say, AHJ are neither our quality control agency nor our excuse for not following code.