Sidewall Sprinklers Installation with Beams
“We propose installing sidewall sprinklers in a 21-ft ceiling height room with beams. Figure 8.7.5.1.3 has been used during design to avoid obstructions to sidewall spray pattern. Engineer of record states this cannot be done per Section 8.7.5.1.3 as the beams are not considered "light fixtures or similar obstructions.? We disagree. In the Handbook, the commentary at Section 8.7.5.1 specifically calls out lights and beams in the same sentence and equates one to another. Our question is: If following the obstruction rules guidelines of Table 8.7.5.1.3 and Figure 8.7.5.1.3, are sidewalls allowed to protect a room with beams?” In response to your question, we have reviewed NFPA 13, 2016 edition that you indicated as the applicable standard. Our informal interpretation is sidewall sprinkler cannot be installed. Unfortunately, you’ve found one of the rare occurrences where the Handbook is wrong. AS identified in section 8.4.2 (1) sidewall sprinklers are limited to smooth, flat ceilings (a subset of unobstructed). The annex material (A.3.7.2(3) identifies examples of smooth ceilings. It does include beam construction when spaced more than 7-1/2 ft apart. The tricky part here is that it applies to the INDIVIDUAL bay such that a sidewall sprinkler can be use when the spray is parallel to the beams. You cannot spray perpendicular or across the beams. This is a common misunderstanding because the figure looks just like the beam rule in section 8.6 (SSU/P sprinklers). You’ll notice that 8.6.5.1.2(1) makes no reference to the type of obstruction because it can be used for any and all types that are tight to the ceiling. That is why 8.7.5.1.3 explicitly identifies lights and similar obstructions since it cannot be applied to anything other than smooth ceilings. On a related note, make sure you review the article on sidewall sprinklers and obstructions closer than 4 ft for standard spray and 8 ft for extended coverage sprinklers (2016 Sprinkler Age-Sept issue). It can be accessed on our webpage if you don’t have a copy. ------------ Technical Update is prepared by the Technical Services Dept. of the AFSA: Roland Huggins, a PE registered in fire protection engineering, Vice President of Engineering and Technical Services; and Tom Wellen, a PE registered in fire protection engineering and Tom Noble E.T., a Technical Programs Specialist. This is provided with the understanding that the AFSA assumes no liability for this opinion or actions taken on it and they are not to be considered the official position of the NFPA or its technical committees. Copyright 2017, American Fire Sprinkler Association. All Rights Reserved. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.firesprinkler.org/private.cgi/sprinklernotes-firesprinkler.org/attachments/20170116/13fb678c/attachment.htm>
