Smoke density chamber, National Bureau

The traditional way in which smoke obscuration has been measured is by determining the maximum smoke density (or the specific maximum smoke density) by means of a smoke density chamber developed by the National Bureau of Standards (NBS smoke chamber, ASTM E662). This instrument measures the obscuration inside a static 500 L chamber, after a sample has been exposed, vertically, to a 2.5 W/cm2 radiant source. 

Lee, T.G., "The Smoke Density Chamber Method for Evaluating the Potential Smoke Generation of Building Materials," 1973, National Bureau of Standards (National Institute of Standards and Technology), Gaithersburg, MD, Technical Note, 757, ASTM E-662). 

Chapter 6 Smoke test. The test is based on the National Bureau of Standards (NBS, now NIST, National Institute of Standards and Technology) smoke density chamber, which has also been standardized as ASTM E 66239 (see also Section 4.1.1). The test exposes a vertical test specimen ca. 75 mm x 75 mm (3 in. x 3 in.) to an incident radiant heat flux of 25kW/m2, from a radiant heat burner for 4 min, in the presence of an open-flame pilot burner. The test applies to the same materials as the heat release rate test. The acceptance criterion is an average maximum specific optical density of smoke that does not exceed 200 (no units). 

The National Bureau of Standards smoke density chamber (Figure 7) is a more recent technique used to evaluate smoke. This chamber can be used to measure adequately the smoke produced from untreated and fire-retardant-treated wood (27, 28). This method has three advantages over the tunnel method (1) application to a variety of room situations, burning areas, and light-path lengths, (2)... 

One particularly widely used test is the National Bureau of Standards (NBS) smoke chamber test. This provides a measure of the obscuration of visible light by smoke in units of specific optical density. The NBS smoke test can be run in either of two modes ... 

The XP-2 chamber was further developed by the US National Bureau of Standard (NBS). This NBS chamber as standardized in ASTM E 662-1979 has become the most wide-spread test apparatus in the United States. In this method, the light transmittance is again measured for calculating the specific optical density of the smoke generated on the following theoretical basis ... 

Until recently, one of the main tests was the National Bureau of Standards (NBS) smoke chamber (ASTM E662) [13]. In this test, a vertical sample is decomposed under radiant heat in a sealed cabinet and the build up of optical density is monitored. The test can be run under both smouldering and flaming conditions, depending on whether a pilot ignition flame is present. 

Smoke emission is measured in an air colunrn above a burning specimen in a National Institute of Standards Technology (previously the National Bureau of Standards) smoke chamber (see Fig. 4-28). In the NIST test a specified area of plastic is exposed to heat under flaming conditions, with smoke measurements being reported as specific optical density. This is dimensionless value represents the optical density measured over a unit of path length within a chamber of unit volume that is produced from a test specimen of... 

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