Fire Retardant Coatings

[BayPointArchitect]

I have a client who applied a fire retardant coating to all wood surfaces within a barn per the Fire Marshal's requirement. The barn is being converted to a place of assembly (A3) and therefor the interior surfaces need to be class A with a flame spread index of 25 or less and a smoke development index of 450 or less. Reference: 2012 IBC Table 803.9.
After applying this product to the interior of the assembly space, she now wants to put a finishing layer of water-based poly. Nothing in the ICC evaluation report would suggest that this is either okay or prohibited. And the manufacturer will not return my phone calls.

Anyone have an opinion as to whether-or-not covering the fire retardant coating with something else is acceptable?

Thank you,

ICC Certified Plan Reviewer
NFPA Certified Fire Plan Examiner

 

[cda]

Get a piece of the same wood

Apply both finishes

Take a bbq bic lighter to it

See if it burns

I would not have allowed the first stuff

If I did I would have took the bic lighter to it, to see if it burns

Have had to many failures !!!!


Oh and ask the city/ fire marshal if they will accept the second finish

 

[mark handler]

You do not want to piss her off but ask her to justify why.
Sounds like she is trying to protect the coating.

 

[mark handler]

Most coating manufacturers have instruction about "other coatings" on under or over their product. May not be in the report but in other literature.

 

[ADAguy]

The fire retardant is typically intumescent when exposed to flame. If covered over the surface material would have to burn off first.

 

[steveray]

We have done field tests on unknown plastics, but I would need alot more info on the first coating to accept the second one over it...

Get a piece of the same wood

Apply both finishes

Take a bbq bic lighter to it

See if it burns

I would not have allowed the first stuff

If I did I would have took the bic lighter to it, to see if it burns

Have had to many failures !!!!


Oh and ask the city/ fire marshal if they will accept the second finish

 

[cda]

We have done field tests on unknown plastics, but I would need alot more info on the first coating to accept the second one over it...

Thats why I said I wold have done a field test the first go around.

 

[BayPointArchitect]

Follow up:
The product manufacturer sent me an e-mail to say that his product still works if applied to bare, dry wood and the product is allowed to soak into the wood. After that, he believes that any additional coating of paint or varnish will have no affect. So I told the building owner to print that out and keep it handy for future reference.

thanks everyone!

 

[ADAguy]

Sounds like it is not intumescent if it soaks into the wood.