On an Internet Forum, was being discussed insulation and condensation control of pole buildings.
“Dave” posted: “If you spray foam the interior, for insulation and moisture barrier, there is a polyurethane foam that is rated for fire retardant qualities… and it stops air infiltration….”
Dave sent me the link to a supplier, and it turns out this is a case of something sounding really good.
The supplier you mentioned in the post has on their website, “We are the ONLY supplier offering E-84 Fire Rating STANDARD in our surface spray product line.”
Flame Spread is based on: ASTM E-84/UL 723/NFPA 255: “Test for Surface Burning Characteristics of Building Materials.”
Flame-spread is used to describe the surface burning characteristics of building materials. The most widely recognized laboratory test of such fire characteristics is defined in several tests:
Method of Test of Surface Burning Characteristics of Building Materials
NFPA Standard No. 255
Standard ASTM E-84 and
No. 723 of Underwriters Laboratories, Inc.
These are commonly known as the tunnel test or “Method of Test of Surface Burning Characteristics of Building Materials. (NFPA No. 255, ASTM E 84, UL No. 723).
The flame spread is a number, calculated from the results of a test, which indicates the relative rate at which flame will spread over the surface of the material as compared with flame spread on asbestos-cement board, which is rated 0, and on red oak, which is rated 100.
Note this rating is not the rate at which the flame actually spreads along the surface and is not at all an indication of the fire resistance of the material.
The product supplier is not giving the results of the flame spread test, they are just saying the product has been tested!!
If one really digs through the Technical Information on their website, it turns out a two inch thickness has a flame spread rating of 20. This is a low enough rating to get it into Class I, but is not near what is offered by gypsum wallboard (10-15).
Building codes require that spray foam needs to be protected (covered) for fire safety with a 15-minute thermal barrier.
In summary – if using spray foam, plan upon covering it.