Maintaining Fire Rating of Fume Hood Exhaust Duct Shaft Penetration

[belz]

I have a lab project in which FRP duct will be used for fume hood exhaust. The duct penetrates a 2hr shaft. Per NFPA 91 2004 4.1.12 The duct must be wrapped or encased with a listed or approved material equal to the fire rating of the fire barrier on each side for 10 feet. I would like to use a fire wrap type product in lieu of a drywall enclosure. Does anyone know of a UL product for use with FRP? My understanding is that they have only been rated for metal duct.

 

[ChasBean1]

I don't see why it coudn't cover FRP. I saw some call for duct gauge of least 26.

See "FyreWrap 0.5" about a third of the way down the page on this link:

http://www.fyrewrap.com/#Fyrewrap-Plenum-Insulation-Wrap-05

Says it's made for plastic piping, why not duct? Probably better to confirm with manufacturer however...

 

[DrRTU]

Fyrewrap or Firemaster should be an acceptable product but you will be limited to a dimension of less than 24” due to the material needed to be held in place with bands.