Scientific approaches to extinguishing hazardous chemicals

Thread Content

In the event of a fire in a hazardous chemicals warehouse, it is necessary to select the appropriate extinguishing agents based on the different properties of the hazardous chemicals, and to take targeted fire-fighting measures. 1. Proper selection of extinguishing agents ①Most fires involving flammable and combustible liquids can be extinguished using foam. For water-soluble organic solvents, flame-retardant foam should be used to extinguish fires, such as those involving alcohols and ethers. ②Flames involving combustible gases can be extinguished using extinguishing agents such as carbon dioxide and dry powder. ③Toxic gases and acidic or alkaline liquids can be diluted using spraying, jet streams, or by creating a water curtain. ④For fires involving water-reactive materials such as alkali metals and alkaline earth metals, water and carbon dioxide cannot be used to extinguish the fire; instead, dry powder, dry sand, or cement powder should be used to cover and put out the fire. ⑤Substances that react with water, such as ethanethiol and acetyl chloride, can react when in contact with water or water vapor, producing toxic or flammable gases. Therefore, such fires cannot be extinguished with water; instead, carbon dioxide, dry powder, cement powder, dry sand, and the like should be used for suppression. ⑥Powdery substances such as sulfur powder and powdered pesticides should not be exposed to strong water jets; instead, mist water should be used to extinguish them, in order to prevent dust explosions from occurring and causing the situation to worsen. 2. Fire-fighting measures for different objects (1) Fires in warehouse buildings: ① When there are no items that catch fire when exposed to water or other water-sensitive items in the warehouse, water gun positions should be quickly established to use straight water jets to extinguish the fire in the building, thereby eliminating the threat posed by the fire to the items stored there. Use a spray or flowering jet simultaneously to protect the items inside the warehouse. ②When there are a small amount of water-sensitive items or other items that cannot be exposed to water in the warehouse, personnel should be organized to evacuate these items first, before using water to extinguish the fire in the warehouse building. ③When there are many water-sensitive items or other items that should not be exposed to water in the warehouse, it is necessary to first check whether the barrels and containers holding such items are damaged. If the containers are not damaged, efforts should be made promptly to use straight water flow to extinguish the fire in the warehouse building and eliminate the threat posed by the fire to those containers; if the containers are leaking, appropriate fire extinguishing agents should be used to control the fire, after which the leaking containers should be moved outside to create the conditions necessary for using water to put out the fire in the warehouse building. (2) Fires involving hazardous chemicals in warehouses: ① When the hazardous chemicals on fire in the warehouse can be extinguished using water or foam, immediate action should be taken to use water or foam to put out the fire and protect other nearby hazardous chemicals. At the same time, deploy sufficient forces to cool and protect the warehouse structure, thereby eliminating the threat posed by the fire to the warehouse. In the event of a fire involving liquid substances in barrels or gaseous substances in bottles, water should be sprayed to cool the barrels or bottles that are at risk of explosion. While deploying additional forces to extinguish the fire, a certain number of forces should also be assigned to evacuate items at risk from the flames, in order to reduce fire-related losses. ②When hazardous chemicals on fire in a warehouse cannot be extinguished using water or foam, appropriate fire extinguishing agents should be used instead. In the case of fires involving alkali metals and alkaline earth metals, or when materials that burn when exposed to water are on fire, dry sand, asbestos cloth, cement, etc., should be used to cover and extinguish the fire. If it is not possible to obtain the appropriate extinguishing agent in a short time, forces should be deployed to protect adjacent warehouses and evacuate the items stored there, in order to prevent the fire from spreading. Once the extinguishing agent is available, efforts should then be made to put out the fire. (3) When both the warehouse building and the items stored inside catch fire: ① Mobilize resources to establish defensive positions in order to prevent the fire from spreading to adjacent warehouses. ②Based on the identification of the characteristics of the items present, fire extinguishing agents are used selectively to carry out the firefighting.