ASTM E662-14 Specific Optical Density of Smoke

Scope:

This ASTM E662-14 test method is only useful for research and development purposes, not for regulatory rating purposes. Under the specified exposure conditions, it can determine the optical density of smoke generated by solid material specimens and assemblies.

Procedure:

In this test procedure, an electrically heated radiant energy source is installed within an insulated ceramic tube and positioned to produce irradiance. The specimen is mounted within the holder. Flaming and non-flaming combustion is provided to the test specimens. Smoke accumulation is measured by a photometric system having a vertical light path. The optical density is then calculated by using the light transmittance measurements.

Specimen Size:

The specimen should be conditioned at an ambient temperature of 73 ± 5 °F (23 ± 3 °C) and a relative humidity of 50 ± 5%

Data

Specific optical density, Ds, at any given time, is calculated as follows:

                        D_s = G [log₁₀ (100/T)+F]

Where,

G = V/AL,

V = volume of the closed chamber, ft³ (or m³),

A = exposed area of the specimen, ft² (or m²),

L = length of the light path through the smoke, ft. (or m),

T = percent light transmittance as read from the light-sensing instrument,