IBC Sprinkler Height
IBC Sprinkler Height
(OP)
Hello,
I know this is an NFPA forum, but maybe some of you have the expertise in IBC as well.
IBC 2015 mentions in Section 404.3 that sprinklers are not required where the ceiling of atrium is above 55 ft height. In the "IBC Code and Commentary" they explain that sprinkler systems are no longer effective at 55 ft and that installing them provides little benefits.
Does anyone know what they’re basing this explanation on? Is there any paper/criteria that allow us to know whether sprinklers are effective or not if they’re on a certain height? If performance based design is the answer, what criteria should be considered in making our study?
Thanks for your help.
I know this is an NFPA forum, but maybe some of you have the expertise in IBC as well.
IBC 2015 mentions in Section 404.3 that sprinklers are not required where the ceiling of atrium is above 55 ft height. In the "IBC Code and Commentary" they explain that sprinkler systems are no longer effective at 55 ft and that installing them provides little benefits.
Does anyone know what they’re basing this explanation on? Is there any paper/criteria that allow us to know whether sprinklers are effective or not if they’re on a certain height? If performance based design is the answer, what criteria should be considered in making our study?
Thanks for your help.





RE: IBC Sprinkler Height
RE: IBC Sprinkler Height
As to the basis of the 55 foot number, I seem to remember it was based on a literature search of European FP Engineering research, but I'm getting older so my answer is questionable.
RE: IBC Sprinkler Height
RE: IBC Sprinkler Height
This same concept applies for the heat movement towards the ceiling. As the heat rises it will cool, the amount it cools is based on the fire heat release rate, fire area, and ambient temperature. With tall spaces this cooling effect becomes more significant and generally results in sprinklers not activating...it's hard to hold 165F at the sprinkler location for sufficient time to operate because of this cooling effect. I've discussed with AHJs the omission of ceiling sprinklers in these situations and the addition of added detection or notification, it's usually met with positive results.
As mentioned previously, FM has performed testing and agree that sprinklers aren't nearly as effective in opening at these heights. You can also consult NFPA 92 for some discussion on heat layers and calculation methods.