Grease Duct-NFPA code requirements

There is an NFPA Forum on this site that has a large number of AHJ and code officials.

I find their interpretations quite useful.

Google "Flamebar." They coat duct work with 2 hr fire rated material. HOWEVER, I seem to recall clearance requirements in NFPA, although I could be wrong... Check NFPA 96.

CB

Two points here. Zero Clearance to combustibles can be achieved with 1.5" of FireMaster FastWrap+ per the UL 1978 Test which is accepted by NFPA96 and the IMC 2003 or earlier. Google FireMaster FastWrap+ to find out more. They have local representation.

NFPA allows products listed for reducing clearance to combustibles to be used. They have to be tested to a nationally recognized standard.

Once the 2006 IMC becomes law the FireWrap products will be installed in two layers.

The Flambar product mentioned earlier has ONLY been tested for air ducts to an European standard. If it is to be used for grease ducts it also needs to have mineral wool added to the outside and is thicker than the the above mentioned wrap and also gets expensive. The grease duct test is different from the 2Hr shaft alternative listing (inside vs outside fire threat).

A funny thing, last week a rep stopped by the office and showed us their zero clearance product for grease duct.
Selkirk metalbestos makes the product, round duct, easy to clean etc.

Used this product in all of our grease exhaust design:
"Zero Clearance to combustibles can be achieved with 1.5" of FireMaster FastWrap+ per the UL 1978 Test which is accepted by NFPA96 and the IMC 2003 or earlier."

Great product and approved for use in Los Angeles.

The Selkirk product is zero clearance. The original email for this string addressed a "wrap" question. The Selkirk product is prefabricated and preengineered per job. It looks nice but is EXPENSIVE compaired to a field fabricated duct and wrap. Lead times can also be an issue. If there is a change of scope during the project this system if ordered does not lend itself to modification. It can be damaged during shipment so check for dents upon arrival. Since it is round it takes up more vertical height than a welded rectangular duct. Also some contractors who are not familiar with this system have misinstalled it or vowed to never install another. Its a nice job when done properly and looks good in an exposed area. If the area is conceiled the wraps typically are used. The economics making the decision.

Just to add a little more grease to the fire, do these prefab ducts/flues require chase enclosures?

JMartinH (Specifier/Regul) 11 Jun 07 12:53
(Just to add a little more grease to the fire, do these prefab ducts/flues require chase enclosures?)

I read, the above thread, as a "B" vent application.

The literature I've read states something about being an "alternative" to fire rated enclosures, but the UL 1978 states "intended to be installed in a fire restive enclosure when required by NFPA 96 of the IMC". Assuming no fire rated chase is required, is there a UL listed through penetration floor assembly for one of these flues/ducts? I have found nothing in my UL Directory for concentric flues.

On the selkirk website under installation instructions there is a through penetration fire stop assembly. (UL System C-AJ-7101)

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