This isn't a strictly electrical question, but as fire alarm systems use electricity, somehow I'm supposed to know all of the answers. 
I need to add return grilles in a hard ceiling, which is serving as a fire and smoke barrier. Above the ceiling is a return air plenum. There are existing return grilles that have fire and smoke dampers installed immediately above them. The smoke detectors that close the existing smoke dampers are within the return air plenum.
It seems to me that having the smoke detectors "downstream" of the smoke dampers is not a very effective design, but I'm not sure it's a code violation. Can someone share their knowledge on this one?
If it's code-compliant, I can add the new dampers (just connecting them to the existing damper circuit) without having to add more smoke detectors and drive up the fire alarm costs.
I need to add return grilles in a hard ceiling, which is serving as a fire and smoke barrier. Above the ceiling is a return air plenum. There are existing return grilles that have fire and smoke dampers installed immediately above them. The smoke detectors that close the existing smoke dampers are within the return air plenum.
It seems to me that having the smoke detectors "downstream" of the smoke dampers is not a very effective design, but I'm not sure it's a code violation. Can someone share their knowledge on this one?
If it's code-compliant, I can add the new dampers (just connecting them to the existing damper circuit) without having to add more smoke detectors and drive up the fire alarm costs.