Yes, we see them in commercial and residential applications, including single family homes. We recently had a situation where small diameter (6') fans were suspended below an overhang at an exterior lunch and gathering space attached to a large office building. The local fire authority required that the clearances be observed just as they are prescribed in the manufacturer's installation data and NFPA 13. Maintaining the clearance from blades to the deflectors vertically required that these fans be installed at 8' above finished floor and the lid was at 11'.
We protested that it wasn't the intent in such an application but the ahj would not budge. I ended up contacting Big Ass Fans directly and asked them if they could draft a letter or in some way help us clarify the intent, which I was sure was not to require conformance to such a deep clearance. To my unpleasant surprise they would not touch it, stating that they had done all the research that they intended to do for the time being and the installation guidelines say what they say. They did recommend that I looked at the test reports that were used by the NFPA 13 committee to draft the current language in the standard. I read both FM test reports and also the UL narrative that are available on this subject. If you bore into the FM test data, there are some thermal images that show that the spinning fan actually throws heat away from the center of its shadow and by diverting it that way creates a hot red ring around the outside of the blade circle. It's reasonable to infer that, if sprinklers are positioned outside that circle, this phenomenon would actually enhance their operation but our local building department wouldn't concur unless we had our own fire test data to support such a conclusion. All of this makes installation of these fans in a sprinklered environment other than high bay storage potentially a very undesirable scenario because the fans will be hanging way down below the ceilings if enforcing agencies know the rules. Steve Leyton (Sent from my phone; please excuse typos and voice text corruptions.) -------- Original message -------- From: Matt Grise via Sprinklerforum <[email protected]> Date: 2/12/20 12:32 PM (GMT-07:00) To: [email protected] Cc: Matt Grise <[email protected]> Subject: HVLS fans in non-storage hazard Has anyone seen or heard any info on HVLS fans in non-storage hazard applications? We are seeing them frequently in fitness centers and apartment clubhouses, even in some larger loft apartments. It seems like the study that led to the guidelines in NFPA 13 11.1.7 (2016 ed) was based on storage applications. Does anyone know of any information or studies done in other hazard types? As far as I can tell, NFPA 13 does not differentiate between hazard types for the HVLS rules, but I was curious how they affect residential and light hazard systems, or if there is a minimum HVLS size or well defined criteria. Some of the new ‘industrial look’ residential fans have straight airfoil blades, but I don’t know if they qualify. Any info would be appreciated! Thanks, Matt
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