Heat pump systems do not have a thermal cutoff switch like electric or natural gas heat systems that turn the system off on high heat. It is actually quite possible that a heat pump system designed to produce a 40 F delta T will do exactly that when 100 F return air gets back to the system. The discharge air will be 140 F. The manufacturers and some HVAC engineers will say this condition would not occur, but that is not the case because installations can have enough mistakes in them to produce the high heat condition. Just ask them to show you the high heat safety control elements in the system circuit. It will not be there because the safety requirement comes from fire safety and not from sprinklers too close.
Allan Seidel St. Louis, MO > On May 31, 2017, at 3:29 PM, Zachary Siegrist <[email protected]> > wrote: > > Thank you Roland for your response and some background on the topic. > > Zach > > On Wed, May 31, 2017 at 10:37 AM, Roland Huggins <[email protected] > <mailto:[email protected]>> wrote: > Both. WE submitted this after trying to convince an AHJ that with a heat > pump (aka low temp air), there was no need for separation. It was initiated > by the discharge diffuser but the duct itself will not be radiating a higher > temperature so the allowance applies overall. > > Apply the NFPA caveat required for committee members when writing their own > opinions, not a formal interpretation of the NFPA or any of its technical > committees. > > Roland > > > Roland Huggins, PE - Senior VP Engineering > American Fire Sprinkler Assn. > Dallas, TX > http://www.firesprinkler.org <http://www.firesprinkler.org/> > > Fire Sprinklers Saves Lives > > > > >> On May 31, 2017, at 5:27 AM, Zachary Siegrist <[email protected] >> <mailto:[email protected]>> wrote: >> >> I have a job where the heads ( ordinary temp) are less than 1 ft 0 in from >> the edge of a downward discharge diffuser throughout the space. The >> contractor has supplied me letter from the HVAC company stating that the air >> discharged out of the diffusers are less than 100F and therefore the heads >> do not need to be switched out or relocated to meet the specified distances >> in Table 8.3.2.5(a). I believe he is trying to use Item 9 under 8.3.2.5 >> stating “ordinary temperature sprinklers located adjacent to a heating duct >> that discharges air that is less than 100F are not required to be separated >> in accordance with Table 8.3.2.5(a).” >> >> My question is this: a diffuser is listed under the heating duct category >> in the ‘type of heat condition’ column in Table 8.3.2.5 (a). Are diffusers >> viewed differently than the ductwork itself? Any thoughts as to if the >> previously referenced section applies to sprinklers located adjacent to >> diffusers or just sprinklers located adjacent to heating ducts? Typically >> heads are just switched out to intermediate temperature sprinklers but this >> is the first time someone has taken this approach. >> >> Zach >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> <mailto:[email protected]> >> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org >> <http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org> > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > <mailto:[email protected]> > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > <http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org> > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
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