Promote the use of compressed air foam fire engines, largely for urban residential building fire fighting played a good role. His main features are good fire extinguishing and less water damage. At present, all grass-roots brigades of the Jiaxing fire brigade are equipped with compressed air foam vehicles. Fires in urban residential buildings are generally used as main vehicles. In combination with the actual use of the Haining Municipal Fire Brigade where I was located , I believe that it is necessary to systematically study the performance characteristics and fire extinguishing capacity of the compressed air foam fire truck . This will give the fire commanders and drivers better understanding of the equipment and equipment. Therefore, it is of great practical significance to better improve the effectiveness of fire fighting on the fire. First, the performance characteristics of compressed air foam fire engines (1) Good coverage, high fire extinguishing efficiency and safety. Compressed air is used compressed air foam fire, high strength spray was concentrated off and the foam fire-extinguishing liquid and water triple, heat sink attached to the large area of water film on the foam, strong heat absorption, while the foam also has cut off the air The role of special foam liquid can prevent chemical chain reaction , fire extinguishing effect is much better than the traditional foam, water tank fire engines. Foaming agent can significantly reduce the tension between the water molecules , so that the foam liquid has a strong permeability , can penetrate into the combustion of the internal , greatly reducing the time of the fire. Due to rapid cooling, can reduce the risk of flashover and the resurgence of reducing smog formation, therefore, no combatants burden of high temperature, can greatly reduce the risk of combatants. (II) Less water used for fire protection and effective reduction of water loss. With urbanization, the construction of the fire hydrant system in major cities far behind the development of buildings and population, low fire hydrant water supply capacity, most of the water supply area of no more than 25L / S, resulting in widespread equipped with on-board artillery fire ( 40L / S ~ 50L / S) can not be continuous ejection, often can not support more than four gun fire extinguishing and cooling for the simultaneous protection. For large and medium-sized fire sites , it is often necessary to mobilize multiple fire trucks to remotely transport water for extinguishing purposes. CAFS directly extinguish Class A fires with water only 1/3 or less of the conventional water, water for cooling the dry foam protection only 1/10 ~ 1/20 of the conventional water. CAFS fire applications that have the ability to achieve fire brigade vehicle in artillery fire hydrant existing city water supply a continuous jet of fire, but also includes the use of 8 ~ 10 in the nosepiece while a cooling and fire fighting protection area Combat capabilities. Promote the use of CAFS fire engines, fire hydrant water supply capacity constraints will make the city the grim situation of firefighting force combat capability has been significantly improved. (3) Good environmental protection effect. The highly efficient compressed air foam concentrate is extracted from vegetable protein and contains aromatic odors . It can be decomposed spontaneously within 24 h under natural conditions . It does not produce any harmful residues and does not produce odors . It has no adverse effects on animals , plants and groundwater . US Environmental Protection Agency has been made in the Ministry of Forestry and the Department of Energy approval, to overcome the ordinary foam after the fire toxicity and odor. (4) The use of water and foam is small and the cost of use is low. Because all the water adheres to the surface of the foam , all play an endothermic role , reducing the loss of water , overcoming the weaknesses of the conventional water tank fire engines with large water consumption , and in the same fire-fighting conditions , with traditional tank fire engines. Compared to more than 80% water saving , it is particularly suitable for use in urban and rural areas where there is a lack of water. Compressed air foam is a high-expansion foam with a high foaming rate . Usually, the formula ratio is only 0.2% to 0.5%, while the formula ratio of ordinary foam is 3% to 6%, and the amount of compressed air foam concentrate is only 1/1 of the ordinary foam liquid. 10 . (five) strong mobility, vertical security more secure. When water and other foams are used to extinguish a fire, the hose is heavy, the water gun (foam gun) has a large recoil, and the combatants' physical exertion is heavy. The position of the transfer gun is inflexible and it is inconvenient to fight in high altitude and small environments. The use of foam to extinguish the fire, the water-filled foam belt is light, and it is very convenient to transfer the water gun positions. The combat personnel consume less energy, and it is easier to extinguish the fire in high altitude and small environments. At the same time, it is safer to vertically fix the water belt. II. Analysis of fire extinguishing capacity of compressed air foam fire trucks (A) The level of fire extinguishing ability. When conventional fire hose long-distance water supply, as friction with the water laying long-distance water flow and pressure loss must have, which resulted in the lack of pressure in the scene of the fire, fire effect is greatly discounted. In order to maintain the injection pressure and flow requirements of long-distance fire-fighting fire hoses , conventional fire trucks must operate under high load conditions. Even so , its ability to supply water from a distance is limited. 80 to fire using fire hose lining type as the water main line 65 for two gun type (flow rate of 15L / S), for example, at 500m Sheung with resistance from 0.845M Pa, at 0.35MPa gun to maintain the rated pressure injection pump supply pressure must be reached for a conventional fire 1.2M Pa, the above distance has reached its limit water conditions. Compressed air foam fire trucks transport compressed air bubbles over long distances in a fire hose . This type of wear makes the wear and tear on the journey very insignificant. The test results of the Israeli army, the fire hose conveyed the CAFS when 600 m, the injection pressure and the gun system pressure almost equal distance. As a result, if there is a need for a large flow of water at the fire site and there is no adequate water supply at the side of the fire, the use of this advanced equipment for long-distance water supply will be very effective. Compared with conventional firefighting, the compressed air foam fire-fighting vehicle has obvious advantages, and also reflects the practicality of the advanced equipment equipped with fire-fighting force for compressed air foam fire engines. The compressed air foam fire truck can also increase the level of water supply for the main battle fire truck. At present , the main fire-fighting vehicles equipped with fire fighting units in our country are equipped with a 40 L /S water pump and can supply 1 mobile fire monitor (32 type foam monitor or 40 type monitor ) or 5 types of 65 type fire sprinklers simultaneously. (7.5L/S) . Large-scale fire scenes often require more fire hoses and guns for direct fire extinguishing and cooling protection of surrounding targets . In this case, more main fire engines are required to provide water at the same time. (b) Vertical supply of fire extinguishing agents. High-rise buildings themselves generally have high fire-resistance grades, but due to high building height, complex structures, various functions, personnel concentration, dense equipment, and large interior combustible loads, it poses great difficulties for fire suppression and evacuation. In the event of a fire, it will easily result in a large number of casualties, major economic losses and serious social impacts. The characteristics of high-rise building fires are determined by its basic characteristics and equipment characteristics. High-rise buildings have high altitude, many layers, complicated functions, numerous equipments, and many vertical pipe wells. Therefore, it is often encountered in fighting such fires. Many problems, such as the laying of water hoses, water supply problems, and especially the issue of fire-fighting water supply, are particularly acute. In the fire fighting of high-rise building fires, traditional fire trucks have been difficult to adapt to the needs of fire extinguishing. The main reason is that it is impossible to transport water to the fire site. One reason is that the water pressure is usually insufficient , and another reason is that the water belt breaks and blocks water flow. , while CAFS fire truck just can overcome these difficulties, it meets the three essential elements to the high-rise building water supply: ( 1 ) Pump water supply pressure: The application of the CAFS fire truck will significantly change the load on the fire truck water supply. Under normal circumstances , when the water is injected in the form of foam, the water supply of the pump does not exceed 20L /S, and the water supply pressure does not exceed 1.0MPa. At this time, the pump speed does not exceed 2500 r/min, and the engine speed does not exceed 1800r/min ( conventional is 2150r/ Around min ), the fire engine runs under low-load operating conditions , which obviously increases the reliability and lifespan. When using water jets to inject compressed air bubbles , the fire hose is a gas - mixture two-phase fluid . When the wet foam is used, the inlet pressure of the water gun does not exceed 0.15 MPa, and when the dry foam is used, the inlet pressure of the water gun does not exceed 0.02 MPa . The pressure on the fire hose is so low that the compressibility of the compressed air also avoids the water hammer impact on the fire hose when the pressure suddenly changes , ensuring the reliability of the water supply. ( 2 ) Resistance along the waterline: When water is supplied to high-rise buildings , the water pressure of the fire engine must meet the requirements of the sum of the jet pressure, the level difference, and the resistance along the way. In addition to the above-mentioned reduction in resistance along the way , since the proportion of compressed air foam in the hose is only 1/2 or less of the water, 80% of the hose is air, reducing the friction with the hose, and the weight is light. The gravitational potential energy is small, the pressure loss of the water belt is small, and the water ribbon is also discharged at two or three places . Unlike the traditional foam system , when the water hose is discounted , the front water gun cannot water , and each time the soldier holding the airbrush adjusts. position, at least need help carry water with a soldier to move water along with the other soldiers still need a place to adjust all discounts, in order to facilitate the water. The test results of the Israeli army, the fire hose conveyed the CAFS when 600 m, the injection pressure and the gun system pressure almost equal distance. ( 3 ) Vertical water supply distance: When water is supplied to a high-rise building, the air foam injected by the compressed air foam fire truck is compared with the fire extinguishing agent sprayed by a conventional fire engine. The air foam obviously has obvious advantages over ordinary fire extinguishing agents. The vertical water supply distance for conventional fire engines in China is 50 meters . If 80mm water is used for vertical water supply, the foam foam for fire-fighting foam can reach a distance of at least 100 meters ; if a 65mm water supply is used for vertical water supply, the compressed air foam fire engine can provide foam. The distance can reach at least 150 meters . Compressed air foam fire trucks generally use 40mm hose, which means that its vertical foam supply distance will be higher. (c) Cooling capacity. In the process of fire suppression , the cooling and heat insulation protection of the buildings around the fire source is to reduce the fire damage. Especially in the process of cooling and heat insulation of large and medium-sized fires , the amount of water consumed is greater than the amount of water required for direct fire extinguishing. Conventional cooling heat protection, with a spray gun is continuously (or monitor) the target to be protected, but the effective utilization rate of the process water is very low, most of the water jet flow to the target surface to the rear surface However, it is not possible to participate in the above endothermic process , and only 5% to 10% of the total cooling water spray is involved in the endothermic cooling . The dry foam formed by CAFS has a higher foam ratio and stability. In the process of fighting a tank fire, the cooling is very important, mainly to prevent the explosion of the tank and the spread of the fire to bring about unnecessary losses to the fire fighting. Take the tank fire as an example to illustrate the cooling capacity of a compressed air foam fire truck. When using a wet foam to cool the full length of the flask during cooling, the temperature of the tank is relatively high due to the heat radiation of the tank. If the water is used for cooling, most of the water cannot be used effectively and is lost because of the fast flow of water. Whereas the cupping was cooled with a wet foam, the foam itself has an ability to reduce the surface tension of water, compressed air foam containing approximately 30% water and 70% air, moisture attached on the foam at the time of the fire by the rapid, large section to achieve endothermic cooling off with water while the rest is dependent on the bubble, as the adhesion properties of foam material, and then slowly release the solution, continue to play its role in absorbing cool fire, greatly reducing Loss of water wasted. Cooling of the tank adjacent the semi-circumference of dry foam was cooled, compressed air foam fire dry foam adhesion may be formed form a stable foam layer in the tank adjacent the surface to be protected, and can be hung on a vertical wall of the tank stays in A stable foam layer is formed on the surface of the adjacent oil tank to be protected , and can be hung vertically on the tank wall for a certain period of time, which can effectively play a role in flame-retardant protection. After the foam is sprayed on the can, the spray can be stopped until the foam is vaporized and then ejected. This greatly saves water resources. Due to the good insulating capacity of the air in the foam, compared to a single water significantly improves the thermal cooling effect. And the dry foam can cover the breather valve at the top of the tank to prevent the fire source from coming into contact with the flammable gas that evaporates out of the oil to cause a greater fire. When a certain effect is achieved on the cooling of the cupping tank and the adjacent tank, the dry foam can be used to extinguish the cupping tank when performing the fire fighting total attack. Because the system provides large impulse foam , a blanket is formed on the fuel surface through the flame , thereby reducing the feedback of the flame heat to the fuel surface and reducing the damage to the foam. The foam is evenly distributed and can effectively cover the surface of the fuel. And to achieve the purpose of fire fighting. The cooling method of the compressed air foam fire truck is totally different from that of the conventional fire truck. The conventional fire truck is completely water cooled, and the compressed air foam fire truck is completely cooled by compressed air foam. Although the former is very cheap in terms of cost, the latter is more expensive than water with foam, but considering the overall situation of fire fighting, that is, the increased fire extinguishing efficiency greatly reduces the water-staining loss. Third, the conclusion The compressed air foam fire truck is a new type of equipment equipped by the current firefighting force. It has the characteristics of good environmental protection, high fire extinguishing efficiency, and less water for fire fighting. Firstly, this paper introduces the application, performance characteristics and working principle of the compressed air foam fire truck, and then analyzes the fire extinguishing ability of the vehicle in combating various types of fires and the traditional fire truck, which fully highlights the vehicle's Many highlights and practicalities in all types of fires. Through the description of this article, the specific features of the compressed air foam fire truck and its advantages in fire extinguishing are introduced. This provides a feasible basis for the basic commander and driver of the military to better understand the performance of the new equipment and equipment of the fire fighting force. To provide theoretical guidance for better formation of troops in the fire fighting of fire fighting units, and to truly implement the tenacious battle style of “fighting and winning†by our fire fighting forces . The information in this article comes from the Internet and was reorganized and edited by China Rescue Equipment Network. A linear pendant lamp is a type of lighting fixture that is designed to hang from the ceiling and provide illumination in a linear or rectangular shape. It typically consists of a long, narrow fixture with multiple light sources, such as LED bulbs or fluorescent tubes, arranged in a linear pattern. 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