Electrical Room Fire Rated Construction
- Thread starter twada
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ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Electrical Room Fire Rated Construction
No, unless the building is type "A" construction.
No, unless the building is type "A" construction.
sandsnow
Senior Member
- Location
- Southern California
Re: Electrical Room Fire Rated Construction
What is Type A? We're still on the '97 UBC.
Re: Electrical Room Fire Rated Construction
Any dry transformer that is enclosed except for ventilating openings does not need a fire rated room or vault unless these conditions apply:
1. The building is of a contruction type where fire rated electrical rooms are required. Unfortunately, the NEC ( NFPA ) building type does not correspond to BOCA yada yada.
2. The transformer needs to be cut off from flammable vapors, flammable dusts, dusts that would plug up the transformer ventilation yada yada.
3. The dry transformer is over 35,000 volts phase to phase. Dry transformer technology goes all the way up to 46,000 volts and fully hardened against lightning.
I have also put 4x4 wooden sleepers underneath a 27 KVA transformer both to keep it from being pushed too close to the wall and to double the lower front ventilation opening. Maybe somebody would want fire treated wood or steel sleepers but my interpretation of NEC is that the transformer is listed for direct mounting on a wooden floor. If the ventilation is great enough then any heat that radiates down through the ventilation openings would be overwhelmed by the air going up.
Any dry transformer that is enclosed except for ventilating openings does not need a fire rated room or vault unless these conditions apply:
1. The building is of a contruction type where fire rated electrical rooms are required. Unfortunately, the NEC ( NFPA ) building type does not correspond to BOCA yada yada.
2. The transformer needs to be cut off from flammable vapors, flammable dusts, dusts that would plug up the transformer ventilation yada yada.
3. The dry transformer is over 35,000 volts phase to phase. Dry transformer technology goes all the way up to 46,000 volts and fully hardened against lightning.
I have also put 4x4 wooden sleepers underneath a 27 KVA transformer both to keep it from being pushed too close to the wall and to double the lower front ventilation opening. Maybe somebody would want fire treated wood or steel sleepers but my interpretation of NEC is that the transformer is listed for direct mounting on a wooden floor. If the ventilation is great enough then any heat that radiates down through the ventilation openings would be overwhelmed by the air going up.
- Location
- Massachusetts
Re: Electrical Room Fire Rated Construction
You should really look things up and stop shooting from the hip, of course that is just my opinion.
[ May 20, 2005, 03:58 AM: Message edited by: iwire ]
MC5W do you own a code book?
You should really look things up and stop shooting from the hip, of course that is just my opinion.
There are some exceptions for Class 155 or higher insulation systems.
Thats is fine for the NEC, however don't do that in a building type that is of resistant construction.
[ May 20, 2005, 03:58 AM: Message edited by: iwire ]
Re: Electrical Room Fire Rated Construction
The transformer with wooden sleepers underneath was in a factory with concrete floors, concrete block walls, and a SPRINKLER SYSTEM.
I have never seen a dry transformer over 112.5 KVA that had less than 220 degree Celsius insulation.
Iwire, you did not quote the exceptions that I listed below my statement about dry ventilated trnasformers.
According to General Electric's installation instructions a dry ventilated transformer that is at full load will have a surface temperature of 90 degrees Celsius. That is more than hot enough to cause 2nd degree burns. Fortunately, many people only use 1/4 to 1/2 of their electrical system. If it was the kind of place where they really do use 3/4 or more of their electrical system the transformer needs to be behind a fence or better.
The only instances I know of where a dry transformer caught on fire wer over at International Exposition Center when running the indoor amusement park. The amusement park outfit thinks that 240 volts is somehow safer that 480 volts which is pure B.S. according to people who have died from contacting 120 volts. In this case the 480 volt primary taps of 120Y208 volt transformers were set to produce a secondary voltage of about 230 volts. That pushed too much magnetism through the core causing the core to overheat.
Interestingly enough, British coal mines have not had an electrocution since 1964 and they have 1,100 volt and 3,300 volt extension cords. So, if 3,300 volts is a safe voltage, how come 480 volts is not a safe voltage?
[ May 26, 2005, 04:25 AM: Message edited by: mc5w ]
The transformer with wooden sleepers underneath was in a factory with concrete floors, concrete block walls, and a SPRINKLER SYSTEM.
I have never seen a dry transformer over 112.5 KVA that had less than 220 degree Celsius insulation.
Iwire, you did not quote the exceptions that I listed below my statement about dry ventilated trnasformers.
According to General Electric's installation instructions a dry ventilated transformer that is at full load will have a surface temperature of 90 degrees Celsius. That is more than hot enough to cause 2nd degree burns. Fortunately, many people only use 1/4 to 1/2 of their electrical system. If it was the kind of place where they really do use 3/4 or more of their electrical system the transformer needs to be behind a fence or better.
The only instances I know of where a dry transformer caught on fire wer over at International Exposition Center when running the indoor amusement park. The amusement park outfit thinks that 240 volts is somehow safer that 480 volts which is pure B.S. according to people who have died from contacting 120 volts. In this case the 480 volt primary taps of 120Y208 volt transformers were set to produce a secondary voltage of about 230 volts. That pushed too much magnetism through the core causing the core to overheat.
Interestingly enough, British coal mines have not had an electrocution since 1964 and they have 1,100 volt and 3,300 volt extension cords. So, if 3,300 volts is a safe voltage, how come 480 volts is not a safe voltage?
[ May 26, 2005, 04:25 AM: Message edited by: mc5w ]
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