Rectangle Ductile
gratings are made of ductile iron; we make cast iron gratings on BS EN124 2015.
The products are A15, B125, C250 and D400, They are used in Green belt,
Pavement, Auxiliary road, Main road and Express way. We make Ductile Gratings
all by producing line, the quality cast iron gratings is very good, and we
warmly welcome customers all over the world to do business with us.
Gratings, Ductile Gratings, Ductile iron gratings, cast iron gratings Runchun Casting (Zhoushan) Co., Ltd. , https://www.en124casting.com
Preliminary study on prevention and disposal of liquid ammonia leakage accident
Liquid ammonia is widely used in the refrigeration and ice-making industries due to its cost-effectiveness. For example, in Qidong City, Jiangsu Province, more than 200 ice-making and refrigeration companies operating in six coastal and Yangtze River fishing ports rely on ammonia-based refrigeration systems. However, liquid ammonia is highly hazardous. Its flammable and toxic nature makes it essential for local fire brigades to be well-prepared in preventing and responding to ammonia leaks. Based on recent investigations and practical experiences of multiple ammonia leakage and explosion incidents, this article outlines key prevention and response strategies.
First, understanding the fire risks associated with liquid ammonia is crucial. Ammonia is a colorless, toxic gas with a sharp, pungent odor. It dissolves easily in water, forming an alkaline solution. Liquid ammonia is commonly used as a refrigerant, but direct contact can cause severe frostbite. The explosive concentration range of ammonia is between 15.7% and 27.4%, meaning that when mixed with air or oxygen, it can form a highly explosive mixture. Additionally, heating the storage container may lead to explosions. Exposure to ammonia can irritate the skin, eyes, and respiratory system, causing coughing, bronchospasm, acute pulmonary edema, and even blindness or suffocation.
Second, effective prevention measures are vital to avoid ammonia leaks. As a Class B flammable gas, ammonia is stored under pressure in steel cylinders or tanks. To ensure safety, these containers must be regularly inspected and stored in cool, well-ventilated areas, away from heat sources, sunlight, and incompatible substances like fluorine, chlorine, and acids. During handling, care should be taken to avoid damaging the cylinder or valve. When transporting, the tank should not be overfilled and should avoid high temperatures. Protective equipment such as valves and level gauges should be in place. In refrigeration systems, the ammonia compressor room must meet strict fire protection standards, including being classified as a Class B fire hazard, using buildings with at least second-class fire resistance, and incorporating features like emergency pressure relief devices, water mist fire hydrants, and appropriate personal protective equipment like gas masks and breathing apparatuses.
Third, in the event of a leak, immediate and proper action is essential. First, establish a warning zone based on the situation, and park vehicles and personnel upwind and on higher ground. Second, all responders must wear appropriate PPE, including chemical-resistant suits and self-contained breathing apparatuses. If in direct contact with liquid ammonia, cold protection gear should be worn. In emergencies, cotton trousers and a wet mask can provide temporary protection. Third, eliminate all ignition sources and flammable materials in the area, and improve ventilation. If a cylinder is leaking, use non-sparking tools and try to keep the leak opening upward to limit the spread of the liquid. If the leak cannot be sealed, consider submerging the cylinder in water or a dilute acid solution, or moving it to an open area for decontamination. Fourth, use mist or spray water to disperse the ammonia vapor and prevent it from entering sewers or restricted zones. Finally, if a fire occurs, apply water mist, foam, sand, or CO2 to suppress the flames, and cool the container walls with large amounts of water. If possible, move any movable objects out of the fire area. If signs of danger appear, such as a loud venting sound or discoloration of the container, retreat immediately.
By following these preventive and responsive measures, the risks associated with liquid ammonia can be significantly reduced, ensuring safer operations in industrial environments.