I suspect if it's gotten hot enough to activate the fire sealing material, you were saying goodbye to the cable anyway - insulation often melts in the 100 - 200 degree Celsius sorts of numbers, an extended overload is enough to melt it remember...
Rat Hole Fire Safety
- Thread starterbobgaggle
- Start date
I suspect if it's gotten hot enough to activate the fire sealing material, you were saying goodbye to the cable anyway - insulation often melts in the 100 - 200 degree Celsius sorts of numbers, an extended overload is enough to melt it remember...
BillConnerFASTC
Well-Known Member
Fire prevention begins long before there is flame. Protection of occupants from the effects of fire does include compartmentalization to prevent the movement of smoke, a primary cause of death and injuries from fire, and of course heat sufficient to ignight combustible materials, to adjacent compartments. These fire and smoke barriers are not intended to be air tight but simply robust enough to withstand fire for a period of time and resist the passage of smoke. Fire sprinklers and ventilation play a role in this as well.
As far as a cable pass, generally they are expected to prevent the spre
of fire and smoke but consider that a fire door is permitted to up to a 3/4" gap or undercut. On a 36" door that is 27 sq inches, equal to just under a 6" diameter hole. However the elevation above the floor, in relation to the neutral pressure plane ultimately, is significant. But the fact that in a fire, just about every barrier will permit some passage of air and smoke. And frankly, on a stage, I think that allowing air from the audience enter the stage and vent through the roof is a good thing.
I've always been told what Bill said. When I worked as a young pup in the telco industry we often would encounter ceilings that used the entire space above the grid (office grid) as a plenum for air return. In such instances we'd be required to use plenum rated cable and zip ties as well (at $1 per tie!). I asked a building inspector once about it because my 16 year old mind couldn't wrap itself around the fact that each one of these bits of plastic cost as much as a taco and we were slinging them by the hundreds into the overhead. He explained it the same way. The building can burn itself to the ground for all they care, fire code buys time to get people out. People will die (or become incapacitated) from smoke inhalation long before they'd burn to death in many cases, toxic plastic fumes don't help.
In that situation it would be pulling vacuum on the house and the smoke wouldn't penetrate. It's why your house doesn't fill with smoke when the fireplace is cooking. What I've always wondered is what if the fire began in the house/lobby/vom areas? I think I read on here before that there haven't ever been documented cases of fires starting anywhere but on stages. Is that fact? We don't have sprinklers over those areas and I've always wondered about that.
In that situation it would be pulling vacuum on the house and the smoke wouldn't penetrate. It's why your house doesn't fill with smoke when the fireplace is cooking. What I've always wondered is what if the fire began in the house/lobby/vom areas? I think I read on here before that there haven't ever been documented cases of fires starting anywhere but on stages. Is that fact? We don't have sprinklers over those areas and I've always wondered about that.
In current codes, if any part of a building is sprinklered, it all must be sprinklered. I'm guessing your facility was built with a deluge system but wasn't required to sprinkler the building (I highly doubt that would be allowed in new construction today). The greatest risk with theaters of course is all that combustible material hanging in the fly space next to hot lights. A fire that started in the house or lobby wouldn't be as likely to grow as quickly as one that starts on stage which would provide a little more opportunity for the audience to escape.
Interesting. No deluge system, just a fire curtain. The only areas with sprinkler coverage is the stage, shop, annex, and dressing rooms. The building was built in 1995.
BillConnerFASTC
Well-Known Member
There are a number of instances in the national model codes where partial sprinkler systems are acceptable, but to get many of the credits for sprinklers, the building must be fully sprinkle red.
BillConnerFASTC
Well-Known Member
When I researched fires in theaters in the late 1989s, the majority were not on stages, mostly trash can and popcorn machine fires in cinemas.
Your concern is interested but I'm much more concerned by theaters with lobbies considered atriums and atrium exhaust system. Fire over stage, less than perfect controls, and now the really big exhaust fans in the atrium pull smoke from the stage through the house and into lobby. Just a disaster in waiting. Because codes are reactionary, nithingvwilk be done untik it happens.
