To avoid sprinklers in the cavity, can you use fire-retardant blown-in cellulose?

[Ryan Schultz]

You know the NFPA exception if you fill a floor cavity with non-combustible insulation, you can avoid sprinklers in the cavity?
Can you use blown-in cellulose insulation in this condition? From my understanding it's typically made fire-retardant through chemical additives.
I couldn't find much research on the internet, however, where the direction one way or the other, was obvious.

 

[mtlogcabin]

Non-combustible and fire retardant are two different things.
My first response to fire retardant cellulose insulation would be no way.

 

[mtlogcabin]

NONCOMBUSTIBLE MATERIALS. Materials that, when tested in accordance with ASTM E 136, have not fewer than three of four specimens tested meeting all of the following criteria:

1. The recorded temperature of the surface and interior thermocouples shall not at any time during the test rise more than 54ºF (30ºC) above the furnace temperature at the beginning of the test.

2. There shall not be flaming from the specimen after the first 30 seconds.

3. If the weight loss of the specimen during testing exceeds 50 percent, the recorded temperature of the surface and interior thermocouples shall not at any time during the test rise above the furnace air temperature at the beginning of the test, and there shall not be flaming of the specimen.

 

[TheCommish]

NFPA 13 2007 edition
8.15.1.2.7 Concealed spaces entirely filled with noncombustible insulation shall not require
sprinkler protection.
In some cases, filling an unsprinklered combustible concealed space with noncombustible
insulation, as indicated by 8.15.1.2.7, might be more economically advantageous than installing
sprinklers.
8.15.1.2.8 Concealed spaces within wood joist construction and composite wood joist construction
having noncombustible insulation filling the space from the ceiling up to the bottom
edge of the joist of the roof or floor deck, provided that in composite wood joist construction
the joist channels are firestopped into volumes each not exceeding 160 ft3 (4.53 m3) to the
full depth of the joist with material equivalent to the web construction, shall not require
sprinkler protection.

seems to align with NFPA 13. 2022 section 9.2.1.7

 

[steveray]

Side question...Does that cover open web trusses or just "joists"?

 

[TheCommish]

Steveray, have to get back to the office and have some time, NFPA 13 gets specific.

what is the proposed construction of open web trusses wood or steel?

 

[steveray]

Steveray, have to get back to the office and have some time, NFPA 13 gets specific.

what is the proposed construction of open web trusses wood or steel?

Not a big deal, I know where to find it next time I need it....I struggled with it once on an assisted living/ apartments (I-joists) and ultimately it was a $400,000+ change order to the owner for the designers miss on the plans (long story).....But that may have been a 2000ish NFPA 13....And agree it is very specific on terminology and recommend a thorough reading for anyone dealing with it...