The suggested use for each type is not absolute, and overlapping of fields of use may occur between adjoining types, depending upon the kind and occupancy of the building involved; the kind of roof employed; the presence, absence, or thickness of any insulation; the specific material and construction used in the roofing membrane itself; and the temperatures and other climatic conditions to which the roofing may be subjected in service.

Type I - Suitable for use on roofs with inclines up to 1 inch per foot. Type II - Suitable for use on roofs with inclines from ½ up to 3 inches per foot. Type III - Suitable for use on inclines from ½ to 6 inches per foot. Type IV - Suitable for use on roofs with relatively steep slopes and generally in areas with relatively high temperatures. Type V - Suitable for use below ground level moderate temperature conditions both during the process of installation and service. Type VI - Suitable for use above ground level where not exposed to temperatures exceeding 125°F. (52°C.) Type VII - Suitable for use above ground level, where exposed on vertical surfaces in direct sunlight or at a temperature above 125°F. (52°C.).