Flooring & Sub Flooring Question

[QUIKSVT]

After reading numerous threads, I was wondering why everyone installs fir strips under wood flooring (laminate flooring or the like). I understand if it's for insulating purposes or if it provides a space for insulation, but can't I simply lay the laminate flooring over the top of the existing fireproofing coating that exists on top of the plywood & metal floorpan? This is in a 1997 Mini Bird P-Chassis bus that I'm converting to a tailgating machine. Thanks in advance for any help!

[chev49]

if you have a plywood floor, in my estimation, you can.. my last bus had a plywood floor, and i did just that.
its best to use the underlay first, though
in my current bus, i just removed all the metal center strips, reglued the rubber center strip upside down and added pergo flooring directly on top of that with glue... its been that way a year, and it works fine. no movement, just stays put.. but, i plan on never going to a cold climate, being only between oregon and alabama, so am not worried about insualting the floor..
did double insualte the sides and the roof, though, for the heat.. even with the main entrance door open, it is still pretty cool when the temp gets over 80 outside...