scope:

This test method is intended to provide a means for assessing the lethal toxic potency of combustion products produced from a material or product ignited when exposed to a radiant flux.

This test method has been designed to generate toxic potency data on materials and products (including composites) for use in fire hazard analysis. It is also permitted to be used to assist in the research and development of materials and products.

Purpose.

This test method is intended to provide data for the mathematical modeling of fire hazard as a means for the evaluation of materials and products.

This test method shall be used to predict, and subsequently confirm, the lethal toxic potency of smoke produced upon exposure of a material or product to specific fire test conditions. Confirmation determines whether certain major gaseous toxicants account for the observed toxic effects as well as the lethal toxic potency. If a predicted lethal toxic potency value is not adequately confirmed, indicating the potential for unusual or unexplained toxicity due to other components, the lethal toxic potency shall be investigated using other methodology, such as conducting an experimental determination of the LC₅₀ using the apparatus described. (See B.3.1 and B.3.2.)

This test method produces lethal toxic potency data that shall be considered appropriate for use in modeling the hazard of both preflashover and postflashover fires. Most fire deaths due to smoke inhalation in the United States occur in areas other than the room of fire origin and are caused by fires that have proceeded beyond the room of fire origin. It is assumed that these fires typically are flashover fires. Therefore, the principal emphasis is placed on evaluating toxic hazard under these conditions. In postflashover fires, large concentrations of carbon monoxide result from a reduced air supply to the fire plume. Because bench-scale tests do not have the capability to simulate this phenomenon, the lethal toxic potencies determined in this test method shall require adjustment for use in modeling the hazard from postflashover conditions (see 11.2.3). For preflashover conditions, the LC₅₀ values derived from this method shall be permitted to be used as toxic potency data without adjustment.

Lethal toxic potency values determined in this test method exhibit a degree of uncertainty where used to predict real-scale toxic potencies. (See B.4.2.)

Tests shall be conducted on small-sized specimens representative of the materials, products, or composites in their intended end use.

This test method does not attempt to address the toxicological significance of changes in particulate or aerosol size, smoke transport, distribution, or deposition or of changes in the concentration of any smoke constituent as a function of time that occurs in an actual fire.

The propensity for smoke from any material, when tested for its effects on a rat, to have the same effects on a human in fire situations shall be inferred only to the extent that a rat can be correlated with a human biologically. (See B.2.5.)

This test method shall not be used to assess incapacitation. Incapacitation shall be inferred from lethal toxic potency values.

The effects of sensory irritation are not addressed by this test method.