I understand your reference, but when you say "put any covering over a base material..." I don´t follow the logic.
For instance, we would not allow bare polystyrene to be put on the walls (even if it were an refrigeration unit). Such an application, I doubt would increase the FRR of the assembly. We would apply another layer over the polystyrene that was noncombustible, or worse yet, we would attempt to solve the problem with fire resistance chemicals (the worse being polybrominated diphenol ethers). I remember a fire in a New York city burrough staircase. Oil based paint had accumulated on the walls from years of painting. It was precisely this paint, albeit only mils thick, that ended up seriously injuring or killing someone with an open door at the top of the stairs. Although my application is a sprinklered corridor without the vertical flame spread a stair tower leverages, I still want to be careful what goes on the walls and ceilings in the exit access, as I know you do as well. Incidentally, neither American Gypsum or National Gypsum have responded to my inquiries to their desk and mobile telephones. I am still pursuing an formal interpretation. This application in question--Vinyl---contain chlorides but it is still double the heat content of paper. And the paper still lays behind the vinyl. Am I really worried? No. Am I curious as to what the formal interpretation is? Yes. scot deal excelsior fire On 3/10/08, Larrimer, Peter A <[EMAIL PROTECTED]> wrote: > Scott, > > This brings back a lesson at the University of Maryland. Harmathy's Rules > of fire resistance would indicate that you can put any covering over a base > material that has a rating and the rating will only go up. The interior > finish rating will be different and possibly a concern, but the fire > resistance rating of your Type X gypsum assembly will not decrease. Check > out the following for a discussion on Harmathy's rules and specifically Rule > 2. I don't think that it is restricted to wood, but it may be. > http://www.fpl.fs.fed.us/documnts/pdf1988/white88a.pdf > > Pete > _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field)
