sprinklernotes
Temperature Ratings
The following information was provided: We have installed 200°F dry HSW to
protect the exterior breezeways of an apartment building and the inspector has
stated the sprinklers need to be 155°F.
You asked the following question: What temperature rating will be appropriate
for the breezeway?
In response to your question(s), we have reviewed NFPA 13R, Standard for the
Installation of Sprinkler Systems in Low-Rise Residential Occupancies, 2010
edition.
Our informal interpretation: Ordinary or intermediate temperature sprinklers
should be permitted to be installed.
When sprinklers are exposed to outside temperatures, 100°F can be reached in
most places in the United States. Per NFPA 13R:
6.2.3.1* Sprinklers installed where maximum ambient ceiling temperatures do not
exceed 100°F (38°C) shall be ordinary temperature-rated sprinklers unless
modified by 6.2.3.3.
Although the 2010 edition of NFPA 13R requires sprinklers to be ordinary
temperature unless the maximum ambient temperature exceeds 100°F, the industry
standard and accepted practice allows sprinklers of either ordinary or
intermediate temperature ratings to be utilized throughout an NFPA 13R system.
The difference in activation times between ordinary and intermediate
temperature-rated sprinklers is negligible.
Over the years, NFPA 13R has been modified to account for this issue and the
current language in the 2019 edition of NFPA 13R supports the use of
intermediate temperature-rated sprinklers:
6.2.3.1* Sprinklers installed where maximum ambient ceiling temperatures do not
exceed 100°F (38°C) shall be ordinary temperature-rated sprinklers or
intermediate temperature-rated unless modified by 6.2.3.3.
