Define each ISO building class 1 through 6?

Answer 1

ISO 1 - Frame Construction (Wood walls & Roof, foundation construction does not matter) Masonry Veneer or accents still count as ISO 1. ISO 2 - Joisted Masonry - Free standing Masonry shell with wood floors and joists, flammable roof. (If structure burns, masonry walls remain) ISO 3 - Light noncombustible - Structure does not add to fire (fuel) load of building, but does not resist fire well. Light steel construction. ISO 4 - Masonry Noncombustible - Free standing masonry walls with noncombustible floors and roof. ISO 5 - Modified Fire resistive - Walls between fire devisions in structure have 1 hour fire rating. Noncombustible structure. ISO 6 - Fire Resistive - Walls between fire devisions have 2 hour fire rating, otherwise noncombustible structure.