ELECTRICAL ROOMS - FIRE RATING
I'm looking for required fire ratings of Elec Rms in office bldgs, as well as other bldg types. What is the best manual to research: NFPA 101, NFPA 75, or other?
What is the maximum voltage inside the room?
What is the maximum kVA rating of any transformer inside the room?
There is not a basic answer. For an electric room, no rating is identified that I know of. However if it is against a corridor or other room with a rating, the walls are rated. NEC 450.21(B) requires a 1 hour rating for transformers over 112.5kva with two exceptions. The exception that applies in most cases is for class 155 or higher insulation and completely enclosed except for vents. The 'class' is the insulation rating which for general purpose transformers is 220C with 150C rise or for 15kVA can be 180C with 115C rise. If you have emergency equipment, NFPA 110, 126.96.36.199 for 'EPS' lists a separate 2 hour room and has further discussions of level 1 and level 2. It also mentions flooding including sewers. NFPA 13 for sprinklers, 9.2.10 states in electric rooms, sprinklers are not required, however, in A9.2.6 it states that they are allowed as long as not over dedicated space and has information in the appendex.
Hello James Hines,
Thank you for your reply to my Elec Rms - Fire Rat'g inquiry. It was very detailed. Using your's and Nick Sasso's replies as a guide, I did more research and found the following:
1. NFPA 70 - NEC, 450.21 (A) (B) and (C): The Elec Rm I'm dealing with has large transformers well over the 112.5 kva limit, but also well under the 35,000 volt limit in (C). Exceptions for the insl class and 115 C rise will not be taken.
2. NFPA 70 - NEC, 450.42 & 450.43, Walls, Roofs, Flrs, & Drs: If you also look at these sections, they call for a 3 - hr fire rating. However, exceptions are offered for a 1 - hr rating w/ sprinklering. In my case the Elec Rm is sprinklered, so the 1 - hr rating is good in any event for the sections mentioned.
3. NFPA 110, 188.8.131.52, Emergency Power Systems: My Elec Rm does have emergency eqpmt, so by NFPA 110, the Elec Rm would need to be 2 - hr rated. I did not see any exceptions, including any exception for sprinklering.
Another QUESTION: In your opinion, does NFPA 110, 184.108.40.206 stand alone w/o exceptions?
Please note that 2019 NFPA 13: 9.2.10 does NOT state that in electric rooms, sprinklers are not required. NFPA 13 9.2.10 applies to equipment enclosures, NOT electrical rooms.
9.2.10 Equipment Enclosures. Sprinklers shall not be required to be installed within electrical equipment, mechanical equipment, or air handling units not intended for occupancy.
NFPA 13: 9.2.6, on the other hand, applies to electrical equipment rooms. NFPA 13: 9.2.6 states
9.2.6 Sprinklers shall not be required in electrical equipment rooms where all of the following conditions are met:(1) The room is dedicated to electrical equipment only.(2) Only dry-type or liquid-type with listed K-class fluid electrical equipment is used.(3) Equipment is installed in a 2-hour-rated enclosure including protection for penetrations.(4) Storage is not permitted in the room.
9.2.6 Sprinklers shall not be required in electrical equipment rooms where all of the following conditions are met:
(1) The room is dedicated to electrical equipment only.
(2) Only dry-type or liquid-type with listed K-class fluid electrical equipment is used.
(3) Equipment is installed in a 2-hour-rated enclosure including protection for penetrations.
(4) Storage is not permitted in the room.
NFPA 13: 9.2.6 states that sprinklers are not required in electrical equipment rooms as long as 9.2.6 conditions (1) through (4) are met. Good luck with number (4). I haven't come across an electrical room yet that has not been used for storage.
Thanks again for your reply, but sprinklering was not my concern. Sprinklering is not reqd, but it was installed in the Elec Rm I'm dealing with. It may turn out that a 2 - hr rating will be reqd anyway due to the emergency eqpmt in the rm, as noted in my response to Nick Sasso. Hope that all bases are covered now.
Double check the applicable codes to confirm whether or not a separate electrical equipment room is required for the emergency (or standby) equipment.
Jeanne C. Schmager Tebera, PE, CFPS
Henry Adams, LLC<http://www.henryadams.com/> |Baltimore, MD & Washington, DC
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Yes, but we still need to start with NFPA-70 and know the following information up front:
Hell Nick Sasso,
Thank you for your reply. The questions were well put. Please see my 10-29-19 response to James Hines. Your questions were answered, and I also asked another question to verify whether or not NFPA 110, 220.127.116.11 had any exceptions.
Hello James Soyejima,
You still haven't told me the maximum voltage inside of the room. If you don't tell me, then I can't help you. Don't assume that you have answered it. You need to first study NFPA-70, Article 110, Part III, "Over 1000 Volts."
If there is anything that is Over 1000-volts, then see 110.31(A)(1), (2), (3), etc. Note: Stud and wallboard construction is NOT permitted.
That is the starting point. Hope this helps.
PS - I'm answering based on the 2017 NEC and any forthcoming answers for all posts will be based on 2017 NEC until further notice.
I thought I gave the volts, but see that you are right. The highest voltage for 1 - transformer (not combined voltages of multiple transformers) is over 13,000 volts. That's why I went to section 450.42 & 450.43. No stud wall construction is understood. I think my bases are covered regarding transformers.
My main inquiry now is focused on emergency eqpmt in the Elec Rm. As mentioned in my response to J. Hines, unless there are any exceptions, it looks like the Elec Rm fire rating will be upped from 1 to 2 hrs.
Thanks for the correction,
The answer(s) to this question also depend on the the codes that have been adopted and that are being enforced in the jurisdiction where the building is located. If the building is being constructed in accordance with the International Building Code, and the building has a smoke control system, then IBC 909.11.1 requires a one-hour rated room for the standby electrical equipment.
The construction is built to multiple code reqmts, including NFPA and IBC as the base code. The building is smoke controlled and is Not a problem.
Agree. It's much to broad of a question. And - we still don't know the maximum voltage in the room.
NFPA 70 can help you a lot , if needed in Spain we do also have some ratings from the Electrical Distribution companies, I assume that our recomendations can be applied at USA (at least with normal non-extreme Weather).
As an Architect, I have found that the applicable Building Code typically provides the requirements for fire rating between spaces or of a space. Many states have adopted the International Building Codes.
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