duct smokes

[Paulgordon2]

What size RTU are you required to install a duct. smoke?
cfm?, tonage? kw?
feed or return?

 

[Jps1006]

'round these parts (Chicago suburb) 2000 CFM or larger

 

[jtester]

We also have to install them in AC units that serve the egress path regardless of cfm rating.

Jim T

 

[barbeer]

5 ton units here!

in the supply.

 

[DHkorn]

NFPA, National fire code

NFPA, National fire code

Over 2000 CFM on the supply. Over 15,000 CFM on the supply and the return.

Local inspectors vary on if the want the signal to be an alarm or a supervisory. DD are prone to false alarm a liitle more than average.

 

[DHkorn]

My last answer didn't look clear after I read it.
On units with a CFM rating of 2,000 or more. One duct detector on the supply duct. On units greater than 15,000 cfm, duct detectors are required on both the supply and the return.
Local inspectors often modify this requirement. The most common is weather they want the device to report as an alarm or as a supervisory. Supervisory signals are usually local. Thats because DD's are prone to false alarm more than usual.

 

[Dean83169]

Here its 2000 and under on the supply over 2000 on supply and return

 

[lowryder88h]

Hvac

Hvac

Here in Mass its as DHKorn has replied to your inquery.

 

[ron]

Requirements depend on which national code or local code the jurisdiction follows. I think the NFPA 90 and IMC differ in their requirements. One like return ducts and the other both supply and return at CFM's >2000