AHU smoke dampers
AHU smoke dampers
(OP)
I'm installing and AHU to serve 3 floors of production area.
There is a smoke damper on the inlet and discharge side of the AHU, to shut down in fire mode. The inlet of the AHU takes air from a fresh air plenum in another fire compartment. The consultant reckons we need these dampers to shut in fire mode, which is fair enough, but he wants to put a smoke detector at the inlet and another one at the outlet. I think this is a waste, and one would do at the outlet. He reckons because of the presence of filters including a HEPA filter smoke at one end would not reach the other, which I think is incorrect. What do you think/ The consultant keeps on refering to NFPA 90 too. Is he correct?
There is a smoke damper on the inlet and discharge side of the AHU, to shut down in fire mode. The inlet of the AHU takes air from a fresh air plenum in another fire compartment. The consultant reckons we need these dampers to shut in fire mode, which is fair enough, but he wants to put a smoke detector at the inlet and another one at the outlet. I think this is a waste, and one would do at the outlet. He reckons because of the presence of filters including a HEPA filter smoke at one end would not reach the other, which I think is incorrect. What do you think/ The consultant keeps on refering to NFPA 90 too. Is he correct?





RE: AHU smoke dampers
Unless you are using HEPA filters I cant see snoke being filtered out.
Friar Tuck of Sherwood
RE: AHU smoke dampers
Regards,
RE: AHU smoke dampers
Maybe I'm missing something, but if your AHU is more than 15000 CFM (I'm assuming it is, since you say it covers three floors), doesn't the Mechanical Code require smokes in both supply and return?
The one at the discharge is to detect components of the AHU which may be afire.
Just my take on it...
Old Dave
RE: AHU smoke dampers
HEPA filtration as we all know, is defined by 99.97% removal of 3 micron particles and bigger. smoke is in the order of 0.01-1 microns. so your HEPA will not stop them getting to detector. But you do need to stop AHU produced smoke (i.e. That fan that blows), so HP side protection is definately required. So in short I have to agree with the Consultant
Justin and the consultants
RE: AHU smoke dampers
But thats my arguement, the consultant want smoke detection upstram and down stram of the HEPA filters because he thinks the filters will filter out the smoke. so why do you agree with that since you admit that the smoke particles are to small to be captured by the HEPA filters.
Does HP side mean High pressure side?
RE: AHU smoke dampers