Small-scale fire test

It was decided to take some of the thirteen materials through three small-scale fire tests and measure the emission of smoke and gases. 

The small scale fire tests were, the Scandinavian "box test", Nordtest NT-FIRE 004, the DIN 53436-test and a cone calorimeter test. The study covered six different wall lining materials. 

The thirteen materials used in the over all study are presented in Table I. From the materials in Table I, numbers 2, 3, 12, 11, 6 and 8 were chosen for the study in the small scale fire tests. 

For the small scale fire test methods it was possible to determine the mass of the sample burnt. In the full scale fire test this could not be done. To make gas emissions comparable between the fire models, the emissions of gases in the small scale fire tests have been reduced by the amount of material burnt in each case. 

Results small scale fire tests. Initially we had in mind to make a comparison between NT-FIRE 025 and NT-FIRE 004 "box test" since most lining materials had been classified using that method. It turned out that the gases generated by the method NT-FIRE 004 needed a very high dilution before they could be fed into our direct reading instruments. Instrumentation used for smoke stack sampling. EMP-797, turned out to be suitable for our purpose. 

A comparison of results for fire effluents from full scale and small scale fire tests has to be done in steps. A full scale fire is a developing event where temperature and major constitutions changes continously. A small scale fire test either take one instant of that developing stage and try model that or try to model the development in a smaller scale. On a priority one level rate of heat release, temperature, oxygen concentrations and the ratio of C02/C0 concentrations have to be similar for a comparison. The full scale fire experiments reaches a temperature of 900 C at the moment of flashover, while the small scale fire tests are reaching temperatures just above 400 °C for NT-FIRE 004 and the cone experiments. For the DIN 53436-method the temperature was set to 400 °C. 

As an alternative to Equation 20.17, a solid material s HRR (or mass loss rate) after ignition is sometimes related directly to transient measurements obtained from small-scale fire tests. This is expressed in Equation 20.18 ... 

Batt, A.M. Appleyard, P. The mechanism and performance of combustion modified flexible foams in small scale fire tests. J. Fire Sci. 1989, 7, 338-363. 

Khan, M.M., Bill, R.G. Jr., and Alpert, R.L., Screening of plenum cables using a small-scale fire test protocol, Fire Mater., 2006, 30, 65-76. 

As discussed in Section 2.4, there are four basic methods for assessing the fire hazard of commodities for warehouse storage. This includes small-scale fire tests, subjective physical comparison, intermediate or full-scale fire tests, and fire tests based upon calorimetry. The most accurate assessment of the fire hazard of a commodity will be obtained with intermediate or full-scale fire tests and with some commodities, fire tests based upon calorimetry. 

In small-scale fire tests, as in many laboratory screening tests, several stages are involved. At relatively low temperatures, as from 80 to 100°C (175 to 212 F)> slow oxidation occurs. This feature, which is also characteristic of aging, is often enhanced as temperatures increase. As the temperature is raised closer to 100 C (212°F), the process is accelerated. When the temperature becomes high enough, from 200 to 300 C (390 to 570°F), the process becomes exothermic in the presence of air (oxygen), which is to say... 

There are little data available other than for flame spread (UL 94, limiting oxygen index). So the assistance of the resin suppliers must be sought at the start of the design. The tests described in Chapter 8 are only small-scale fire tests and would be suitable to monitor quality control of materials and components. Large-scale tests would be required to check... 

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