Building materials, flammability, ASTM

In the ASTM E84 25-foot tunnel furnace test (34) for measuring flame spread of building materials, an igniting pilot flame is applied to the underside of a horizontally mounted specimen. The flame heats the combustible material to pyrolysis, and the flammable gases given off are ignited by the pilot flame. 

During the initial stages of a fire, fire-retardant-treated wood contributes less heat than does untreated wood, especially from the flammable volatiles (8,26). This means that the spread of fire to nearby combustibles is slow. The fire tends to be confined to the primary source. In the ASTM E84 test for building materials, treated specimens produce about 75 percent less heat than untreated red oak. In a total combustion test, however, such as the National Bureau of Standards potential heat method (54), both treated and untreated wood release about the same total heat. 

ASTM E 84 Standard Test Method for Surface Burning Characteristics of Building Materials ASTM E 108 Standard Test Methods for Fire Tests of Roof Coverings ASTM E 119 Standard Test Methods for Fire Tests of Building Construction and Materials ASTM E 136 Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750°C ASTM E 162 Standard Test Method for Surface Flammability of Materials Using a Radiant Heat Energy Source... 

Flame Resistance. Traditionally, small-scale laboratory flammability tests have been used to initially characterize foams (38). However, these do not reflect the performance of such materials in bulk form. Fire characteristics of thermal insulations for building applications are generally reported in the form of qualitative or semiquantitative results from ASTM E84 or similar tunnel tests (39). Similar laiger scale tests are used for aircraft and marine applications. 

This ASTM test will be briefly described here. The test is not intended for use as a basis of rating for building code purposes, as, for example, ASTM E 84. The purpose of the test is to determine the relative surface flammability performance of various materials under specific test conditions under a radiant heat source. 

---