One common problem we hear about with our residential projects is the location of sidewall sprinklers and the allowable distance away from heat vents or hot air diffusers.
NFPA 13, 2016 edition (and prior) provides guidance for this situation in Table 18.104.22.168(c). (NFPA 13R Table 22.214.171.124.3 has the same values)
In most cases, whether the design is based on NFPA 13 or NFPA 13R, space along the wall is limited due to door frames, adjacent walls or other space constraints. Finding 24” worth of space can often be difficult but in most of the cases – the simple solution is to use intermediate temperature rated sprinklers throughout the system.
NFPA 13, Section 126.96.36.199 states, “unless the requirements of 188.8.131.52, 184.108.40.206, 220.127.116.11, or 18.104.22.168 are met, ordinary- and intermediate-temperature sprinklers shall be used throughout buildings.” Clearly, the use of intermediate temperature sprinklers is permitted and there is no difference in the cost between the two sprinkler devices and we can be 12” closer to the hot air diffuser. In terms of fire and life safety, the time of activation between these two sprinklers under test and actual fire conditions is minuscule, so the only real difference is that one is red and the other is yellow.
A word of caution however, because section 22.214.171.124 (Temperature Ratings) states, “unless the requirements of 126.96.36.199.2, 188.8.131.52.3, or 184.108.40.206.4 are met, sprinkler temperature ratings shall be the same as those indicated in Table 220.127.116.11(a) and Table 18.104.22.168(b) or those used in large-scale fire testing to determine the protection requirements for the hazard involved” it is wise to ensure your AHJ is aboard prior to installation and perhaps even tell the project architect what and why we’re using yellow colored bulb sprinklers. They may not care but it beats having the argument after installation.
NFPA 13R provides similar language:
- 22.214.171.124* Sprinklers installed where maximum ambient ceiling temperatures do not exceed 100°F shall be ordinary
Temperature rated sprinklers or intermediate temperature rated unless modified by 126.96.36.199.
- 188.8.131.52* Sprinklers installed where maximum ambient ceiling temperatures are between 101°F and 150°F shall be intermediate temperature rated sprinklers unless modified by 184.108.40.206.
- 220.127.116.11* The practices of 18.104.22.168.1 through 22.214.171.124.3 shall be observed when installing residential sprinklers unless higher expected ambient temperatures require a higher temperature rating.
For additional information about this or any technical questions, please feel free to contact me (via email) firstname.lastname@example.org or my cell phone: (602) 568-7392
Bob Caputo, Technical Support & Training