(Tianjin Fire Research Institute, Ministry of public security, Tianjin 300381), five factors, such as time, foam thickness, foam retention time and heat radiation intensity, affect the insulation performance of compressed air foam. Based on the analysis of the experiment factors of compressed air foam insulation protection mechanism and its main influence, at the same time for the fire troops to use compressed air foam system and puts forward the corresponding suggestions for thermal protection: fire extinguishing agent; compressed air foam system; thermal protection: X913, TQ569 Code: A compressed air foam system because of water saving, high efficiency and both thermal protection performance advantages, has been widely used in North America and europe. The purpose of the compressed air bubbles are generally used for forest fire, fire and chemical city building fire to heat insulation protection, can be a barrier to the compressed air bubble compared to the traditional low multiples generated in the bubble system generated bubble formation in buildings or adjacent buildings, with smaller density and larger particle size and good uniformity of bubble of researchers have speculated that small, dense compressed air bubbles are arranged together, which depend on the thermal conductivity of the lower air containing insulation protective role play. However, due to the lack of previous test methods and other factors, the research on the heat insulation protection mechanism of compressed air bubble is not deep enough, and the main factors that affect the thermal insulation performance of compressed air bubble are not known. Therefore, the author studied the thermal protective performance of the compressed air, the factors of the protective performance of heat insulation is discussed, in order to improve the understanding of the compressed air bubble protective performance of heat insulation, compressed air compressed air foam system thermal protection performance test device is mainly composed of a radiation plate, a sample plate and acquisition system composed of global protection performance test heat insulation device and test including scientific guidance for fire and rescue combat work 1 test instrument and test method 1.1 test instrument test instrument, as shown in. In order to ensure the radiation distribution, using two electric radiation plate (600mnK 500mm) V display (each radiation board power is 48kW) thermal protection test platform is composed of a bracket, foam sample plate (600mmX 250mm) and used for cement plate positioning guide plate with 6mm thickness of samples composed of foam, metal retainer can be installed around the different height in order to get the different thickness of the bubble in the cement board the central position of a hole, insert the thermocouple from the back, used to measure the temperature rise of the global sample plate. The electric radiant plate is placed vertically with the ground, and the bubble sample plate is close to the ground (with a small angle to prevent the bubble fall during the test). From a distance of /cm radiant heat radiation intensity curve test with compressed air foam system should be provided with controllable and repeatable compressed air bubbles because the compressed air used for actual combat equipment agent flow is too large for a fire test of basic research, produce far beyond the amount required by the test of the bubble; on the other on the one hand can flexibly control the number and state of global, accurate repeatability test can not be carried out, so it cannot be used for experimental study and test for compressed air foam system can solve the above problems, the installation diagram as shown in the 1.2 thermal protection performance test samples and test variable test to select a total of two the compressed air foam samples, referred to as FoamA and FoamB; choose a certain representative and operational project of Zhong "11th Five-Year" technology support project "class a foam protection And fire extinguishing performance evaluation and application technology research "(2006BAK06B05-4- set up a heat insulation baffle (see), and put the foam sample stage on the guide way, and push it to the location where the test needs thermal radiation. Then remove the heat shield and start the time. Collect foam plate center thermocouple temperature, until it reached the desired temperature test value of 3 results and discussion 3.1 effect of heat radiation intensity with time under the condition of 5min, the effects of different heat radiation intensity on the protective properties of foam insulation, as shown in Table 2 Table 2 thermal radiation effects on global protection performance the 10. valve insulation foam solution with compressed air foam system installation diagram according to the domestic and foreign research data and the previous 11. pipe liquid flowmeter 13. pressure tank 17. intake pipe test, the author chooses 25% foaming rate, drainage time, foam thickness, foam retention time (from cast bubble to bubble in the acceptance of thermal radiation between the time in front of the plate) and radiation heat radiation intensity of five factors as test variables, the sample plate temperature lag on the protective properties of foam insulation effect effect were investigated respectively. Time to measure, namely the compressed air foam insulation protection ability mainly in the sample plate reached 50 ~ C and 100 ~ C lag time said at the same time the author of a blank sample plate (i.e. without water or foam sample plate) in the thermal radiation intensity of 13.978.36 and 5.38kW/m2 under the temperature curve for calibration, parameters such as in three blank contrast test, as shown in Table 1 the thermal radiation intensity of /kW/m2 foam drainage time multiples of 25% /s up to 50 C in /s to 100C in the table 2 shows that sample FoamA protection heat insulation heat radiation intensity decreases with the increase of. Table 1 test parameters in contrast can be seen, the bubble has a certain effect applied lag sample FoamB also increased with the increase of heat insulation protection ability of heat radiation and low down f I guess the compressed air foam has a thermal protection function is mainly because of the large number of air bubble containing is a poor conductor of heat for temperature rise in temperature at the early stage, has the heat insulation effect on the sample plate. As time goes on, the temperature rises further, and the foam gradually ruptures until it disappears. Then, the cooling effect changes from foam to water. Water also plays a role in the temperature rise lag of the sample plate.
2 Foam