Smoke measurement

National Research Council. (1986b). "Environmental Tobacco Smoke Measuring Exposures and Assessing Health Effects." National Academy Press, Washington, DC. 

Figure 12.33 shows the velocity distribution down through the full length of the exhibition hall. It is quite obvious that the flow is a stratified flow with the highest velocity in the occupied zone. Smoke measurements show that the cold air from the cooling device accelerates down into the occupied zone, due to gravity, and moves horizontally as a stratified flow along the floor in the restaurant and exhibition section. 

All of the TOP and standard smoke measurements are made at low altitude, where atm constituents available for reaction with the primary smoke particles are plentiful. The importance of atm constituents is illustrated in Table 3 where the number of grams of smoke formed per gram of smoke agent used is tabulated... 

Results from the NBS Cone Calorimeter have been shown to correlate with those from real fires. Moreover, it measures properties very relevant to fire hazard, in particular heat release, the most important of them. The OSU Calorimeter will measure many of the same properties. Furthermore, the results generated by both instruments have similar significance because of the good correlation between them. Smoke measurements are only relevant to fire... 

Figure 5. Mass Optical Density of Smoke Measured in the NBS Smoke Chamber for the Fiber Reinforced Composite Materials...

Jarvis MJ. 1989. Application of biochemical intake markers to passive smoking measurement and risk estimation. Mutat Res 222 101-110. 

Gleason, J.F., N. Christina Hsu and O. Torres (1998) Biomass burning smoke measured using backscattered ultraviolet radiation SCAR-B and Brazilian smoke interannual variability. Journal of Geophysical Research (in press). 

The standard Cone Calorimeter (Section 14.3.3.2.1) described in ASTM E 1354 includes a smoke photometer to measure light extinction in the exhaust duct. The system is based on a laser light source. The same system is also standardized internationally, although it is described in a separate document from the main Cone Calorimeter standard (ISO 5660-2). Smoke measurements are reported in terms of the average specific extinction area (ASTM E 1354 and ISO 5660-2) and the smoke production rate and total smoke production for the period prior to ignition and the flaming period (ISO 5660-2). 

Babrauskas, V., Applications of predictive smoke measurements, J. Fire Flamm., 12, 51 (1981). 

Quintiere, J.G., Smoke measurements An assessment of correlations between laboratory and full-scale experiments, Fire Mater., 6, 145 (1982). 

The time to ignition remains unchanged for the PE-ZCHS-5 but is reduced for PE-ZCHS-10. The THR is observed to be reduced by approximately 13%, a smaller change than observed when copper-containing additives catalyze cross-linking and thus enhance char formation (5). The amount of smoke measured from cone calorimetry as ASEA increases with the additive fraction. Combining the TGA and cone data, the 5% loading provides the best combination of thermal stability and fire properties. 

Aircr t Gas Turbine Engine Exhaust Smoke Measurement, Aerospace... 

Kleindienst TE, Shepson PB, Edney EO, et al. 1986. Wood smoke Measurement of the mutagenic activities of its gas and particulate-phase photooxidation products. Environ Sci Technol 20 493-501. 

NRC. 1986. National Research Council. Environmental tobacco smoke Measuring exposures and assessing health effects. Washington, DC National Academy Press. 

In the same 25-ft tunnel test the so-called smoke development index (SDI) can also be determined. The smoke measurement is based on the percentage of retardation of light passing through the tunnel exhaust stream and detected by a photocell, and then data obtained are converted to the SDI, with red oak flooring set at 100. AC 174 does not specify any particular SDI as the code requirement, but the industry generally considers SDI above 450 as hazardous and not acceptable, particularly for interior flnish. 

BS 6401 [103] and ASTM E662 [104] are based on the NBS smoke test and are essentially the same test although some differences occur see Fig. 18. A 75 mm square specimen of up to 25 mm thick is combusted in a vertical orientation at 25 kW m incident heat flux. Tests are carried out with and without a scries of pilot flames along the lower edge of the specimen. The smoke is contained in a cabinet of 0.51 m and measured using a vertical photomultiplier lamp system. The results are typically expressed as specific optical density, which relates the optical density of the smoke to the volume of the cabinet, the length of the smoke-measuring path, and the area of the specimen exposed in the test. Other methods have been used in which specific optical density is related to the mass of the specimen combusted and/or to time. 

Part 3 of this standard refers to a draft method in which smoke is measured dynamically. The equipment is similar to that of Part 2. except that a small hood is mounted over the radiator and test specimen. The hood is connected to a duct that passes through the roof of the test cabinet. A smoke measuring system and extraction fan are attached to this duct and the test operated with the chamber cabinet open. 

Figure 25 Schematic diagram of room calorimeter test (ISO 7905). 1. Room. 2. Gas burner ignition source. 3. Room exit door. 4. Hood. 5. Fire gas mixing baffles. 6. Gas sampling, temperatures, and velocity probes, smoke measuring sensors. 7. Exhaust fan. Note Furniture calorimeter is similar but without room. Test. specimen is burned directly under hood (NT Fire 032).

Optical methods are favored for measuring smoke density because they provide information relevant to visibility through smoke. Other methods involve weighing particulates and calculating the weight loss on combustion relative to the weight loss ofthe combustible. This method correlates with smoke measurements by optical methods [26-28]. 

Today, smoke measurements are more and more being obtained by cone calorimetry as described in Section 6.3.5. 

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... 

At present there are more than fifteen widely used different test methods to evaluate smoke, each employing its own unique set of heating conditions, sample size and orientation, gas flow and means of smoke measurement. The most frequently used tests are those based on optical methods, i.e. attentuation of a light beam due to the sample formulations burning. There are also mechanical methods, those based on separation of liquid and solid aerosol particles from the smoke gases, the Arapahoe method and electrical methods (generation of electrical charges in an ionization chamber). 

The smoke and combustion gases are drawn to a sampling point, where the smoke measurement is made with a low intensity helium-neon laser beam projected across the diameter of the duct. The smoke data are reported as the specific extinction area. This is defined as the area (m ) of the smoke generated per mass (kg) of specimen decomposed thus the units are m /kg. Specimens used as 100 mm x 100 mm and up to 50 mm thick. The heat flux can be varied from 1 to lOOkW/m, with horizontal or vertical specimen orientation. 

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