Smoke Detectors in Raised Floor

[Low Voltage Primadona]

I am doing a project that has 18" raised flooring, I knew I saw a spec requiring smoke detectors above a certain height. Can anyone help me with a code section that references this requirement? Wiring for all low voltage in this area is plenum, this could be ahuge change order for me.

 

[nhfire77]

I am doing a project that has 18" raised flooring, I knew I saw a spec requiring smoke detectors above a certain height. Can anyone help me with a code section that references this requirement? Wiring for all low voltage in this area is plenum, this could be ahuge change order for me.

Is there environmental air circulating under the floor?

Read article 645 to see if you need detection, and other issues such as smoke dampers, suppression systems.