We have a condition of an existing roof truss adjacent to new construction that requires 1 hour rated fireproofing. The truss is unable to support the additional load of gypsum board fireproofing, and spray-on cementitious is not appropriate since it is over a gymnasium. We are considering intumescent paint, similar to products manufactured by Albi. Does anybody have good or bad experience with this type fireproofing?
Albi is good, but you may also want to check out products by Carboline/AD Firefilm
Since this is an interior application, look at water-based products such as AD/Firefilm III
NOTE: In either case, these should be specified as Intumescent Fireproofing and not intumescent paint.
Contact your local rep on these for prep/priming of existing steel and color overcoat if required.
Good catch on the “paint” vs. “fireproofing,” Richard.
I’ve used intumescent fireproofing before, and the finished appearance of field-applied coatings could be disappointing. However, since the truss is over a gymnasium, I assume it is high enough that some imperfections in the appearance won’t be much of an issue.
Thanks for the information. Sorry, “paint” was merely shorthand.
Our work is almost all in healthcare and usually comes with very strict code compliance requirements.
From my experience, you will need to carefully review each product to verify that there is a listed assembly for your truss member sizes.
I have used intumescent fireproofing for chemical industry fireproofing; very high heat or chemical atmospheres with excellent success. Unfortunately I have found it cost prohibitive for any extensive architectural purposes; like 8 times the cost of non-intumescent.
Smooth finishes by troweling are possible but again very costly.
Only 8 times? About 6 to 7 years ago it priced out at about $50 a linear foot for a 6-inch pipe column. Needless to say, gyp board wrapped column became very attractive.
Check out the special inspection provisions in IBC Section 1704.