Increasing the hazard of an occupancy arbitrarily - allowed or not?
Increasing the hazard of an occupancy arbitrarily - allowed or not?
(OP)
Let's say you have a typical light hazard occupancy which requires quick response sprinklers, and lets say for whatever reason I don't want to use quick response sprinklers, or can't because of other project considerations.
Is it possible to just arbitrarily increase the hazard to ordinary 1, revise the density accordingly, etc?
Is it possible to just arbitrarily increase the hazard to ordinary 1, revise the density accordingly, etc?





RE: Increasing the hazard of an occupancy arbitrarily - allowed or not?
However, if you consider water sprinkler system and changed your hazard classification from light to ordinary 1 for whatever reason,
1. Water required will be higher (0.15 GPM/sqft instead of 0.10 GPM/sqft)
2. Coverage per sprinkler will be less (130 sqft/sprinkler instead of 225 sqft/sprinkler)
So basically, there's additional cost for piping, fittings, sprinklers, and pump capacity.
But whatever your reason is, we won't understand unless you tell us.
RE: Increasing the hazard of an occupancy arbitrarily - allowed or not?
I'm aware that it is more costly - however, certain construction features would not be possible if you could not do this. For example, light hazard beneath drop-out ceiling tiles. NFPA 13 says you can't install quick response sprinklers above drop-out ceiling tiles. It also says quick response sprinklers must be installed in light hazard occupancies.
A designer may tell an architect "it can't be done" but the truth may be that the designer simply didn't consider the option of increasing the light hazard occupancy to ordinary 1 to make it work. Yes, it's more costly, as many architectural features end up being, but it's possible. This would not be true if you can't arbitrarily increase the hazard like this. Hence the question.
RE: Increasing the hazard of an occupancy arbitrarily - allowed or not?
I take a lesson from Lincoln when asked this very question.
"If you call a dog's tail a leg, then how many legs does the dog now have?"
The answer is 4. Simply calling it a leg does not make it one.
The QR is there for a reason. Getting the water out fast is far more important than getting a lot more out at a later time.
And remember, the sprinkler system is just one part of the fire protection picture.
Bottom line is it will be far more expensive up front, and possibly exponentially so if you have to defend after a fire as to why you did not meet code minimum...
R/
Matt
RE: Increasing the hazard of an occupancy arbitrarily - allowed or not?
I have a question about that myself.
WHY isn't QR allowed above? The ceiling will bank the heat and take the first hit. Since QR is so effective, why do we not want them above?
R/
Matt
RE: Increasing the hazard of an occupancy arbitrarily - allowed or not?
Actually this is done in some restaurants where the dining area is light hazard and kitchen is ordinary hazard. Also, in a building where most part is ordinary hazard and little part is light hazard. So it is better going for higher hazard in case of worst case scenarios.
RE: Increasing the hazard of an occupancy arbitrarily - allowed or not?
But what you're saying seems to be that light hazard materials require faster water discharge?
RE: Increasing the hazard of an occupancy arbitrarily - allowed or not?
Light hazard fires have less to burn. Therefore there are lower rates of heat release. This is where the R.T.I. of 55( I think) or less is important.
Ordinary occupancies put off more heat. Read the base definitions in chapter 3 again using this thought process.
R/
Matt
RE: Increasing the hazard of an occupancy arbitrarily - allowed or not?
What's in a name? An office by any other name is still just an office. Yeah, that was my bad attempt at paraphrasing Shakespeare to make a point.
I believe I know the question that brought this up. In that situation, the builder wanted to use drop out tiles to save putting pendent sprinklers in the ceiling since the shell space was already protected. However, as in most cases, when non-experienced individuals try their hand at fire protection work, they often miss many of the nuances of our industry.
Travis Mack
MFP Design, LLC
www.mfpdesign.com
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RE: Increasing the hazard of an occupancy arbitrarily - allowed or not?