UL 790 Standard Test Methods for Fire Tests of Roof Coverings

1 Scope

1.1 These requirements cover the fire resistance performance of roof coverings exposed to simulated fire sources originating from outside a building on which the coverings are installed. They are applicable to
roof coverings intended for installation on either combustible or noncombustible decks (see 1.7) when the roof coverings are applied as intended.

1.2 Three classes of fire exposure are described.

1.3 Class A roof coverings are effective against severe fire test exposures. Under such exposures, roof
coverings of this class afford a high degree of fire protection to the roof deck, do not slip from position,
and are not expected to produce flying brands.

1.4 Class B roof coverings are effective against moderate fire test exposures. Under such exposures, roof
coverings of this class afford a moderate degree of fire protection to the roof deck, do not slip from
position, and are not expected to produce flying brands.

1.5 Class C roof coverings are effective against light fire test exposures. Under such exposures, roof
coverings of this class afford a light degree of fire protection to the roof deck, do not slip from position,
and are not expected to produce flying brands.

1.6 Tests conducted in accordance with these requirements are intended to demonstrate the
performance of roof coverings during the types and periods of fire exposure involved, but are not intended
to determine the acceptability of roof coverings for use after exposure to fire. These fire test methods do
not provide a basis to compare expected performance under all actual fire conditions but they do provide
a basis for comparison of the response of roof coverings when subjected to fire sources that are described
herein.

1.7 A combustible deck is formed of wood (sheathing boards or plywood). A noncombustible deck is
formed of metal, concrete, or poured gypsum.

2 Units of Measurement

2.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory or
approximate information.