Check out this super detailed guide on UL flame retardant ratingsCSA fire rating:FT1: Vertical burning test (no requirement for drops);FT2: Horizontal burning test;FT3: Vertical burning incendiary drop test (cannot ignite newsprint);FT4: Vertical combustion test in a closed combustion chamber (similar to a closed building) heat energy 70,000 btu/h;FT5: Flame resistance test, usually used in underground work portable CABLE.UL fire rating:A: Horizontal fire test;B: VW-1: Vertical fire test, drops