Q: Does a roof top air handler require sprinkler heads if it is unoccupied? We have large walk-in style air handlers on the roof of our hospital and they are not protected with automatic sprinklers.
A: Well… section 18.104.22.168 of the 2012 Life Safety Code requires buildings containing health care facilities to be protected throughout with automatic sprinklers. Initially, one could make the case that mechanical equipment sitting outside the building (although on top of the building) is not part of the building and therefore is not included in this requirement. Taking a look at NFPA 13 (2010 edition), I see sprinklers are required in elevator equipment rooms, and sprinklers are required in electrical rooms (with some exceptions). But these rooms are actually inside the building and would be required to be protected with sprinklers according to section 22.214.171.124 of the 2012 LSC.
So it depends: Is the roof-top air handler room considered outside the building, or is it considered part of the building? That’s going to be the deciding factor, and who makes this decision? The authority having jurisdiction (AHJ) does. Even though accreditation organizations like The Joint Commission, HFAP and DNV are AHJs, they typically leave the construction interpretations to the local and state AHJs. So, if your state or local AHJ has made the determination that the air handler on top of the hospital roof does not require sprinklers, that may be enough to convince the accreditation organizations.
Or it may not. You never know if the accreditation organizations will make a different interpretation while a surveyor is onsite. If you do not want to install sprinklers, then I suggest you get it in writing from your state and local AHJs that sprinklers are not required in the air handler, and keep that document on file. If an accreditation surveyor thinks you should have sprinklers, pull that document out and see if that stops them from writing a citation. However, if you start storing combustible items in the air handler (like cardboard boxes of clean filters) then that will likely prompt the surveyor to write a finding.