Fire prevention of painting operation in the hotte

2022-08-08
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Fire prevention of paint work in shipbuilding (repair) industry

the paint (coating) work of ships can not only protect the ships with steel structures from corrosion and prolong the service life of ships, but also make the ships look new after painting. However, due to the great fire risk during painting, once an explosion fire accident occurs, it will cause casualties and heavy economic losses. However, the living space of the individual recycling army has been greatly compressed. In recent years, only Taizhou City, Jiangsu Province, has experienced deflagration, explosion and fire accidents during the use of paint in the shipbuilding (repair) industry, which must be paid great attention to by relevant parties. At 8:45 on September 25th, 2002, a barge in Xiaoqi shipyard, Duotian Town, Xinghua City was deflagration during maintenance. The air wave caused by deflagration knocked a painter down from a 4-meter-high ship and hurt him, and burned an electric welder at the same time. According to the investigation, when the accident occurred, the painter painted in the bunker and the welder welded in another connected bunker. According to the preliminary analysis, the cause of the accident was that a large amount of paint vapor produced by the paint operation encountered the welding sparks produced by the welding operation, resulting in deflagration. According to the city's fire department, dozens of fire and explosion accidents caused by improper use of paint have occurred in the city in recent years. On January 23 this year, the 27000 ton bulk carrier No. 4 under construction in Jingjiang shipyard deflagration occurred during the welding of the emergency fire pump compartment, causing two deaths. Coincidentally, on October 10, 1999, when two workers in the prefabricated hatch cover of Jingjiang shipyard were painting, an explosion suddenly occurred, causing the two people to be killed on the spot. On March 24 of the same year, a new cargo ship being painted in Taizhou Xincheng Steel Shipyard suddenly exploded due to illegal operations, resulting in serious injuries to 8 workers present, and 2 workers died after ineffective rescue. It is understood that paint was being painted in the cabin at that time, and a large amount of paint vapor volatilized in the warehouse and could not be emitted. The concentration reached the explosion limit and exploded instantly when encountering fire

an accident was shocking, but the reasons were basically the same. They were all in the process of painting, and the accident occurred due to improper use. Why does paint explode? Relevant experts from the fire department pointed out that because the paint used contains banana water, Sina water, paint, diluent, etc., these are flammable liquids, which are easy to burn when the concentration reaches 50%. If the concentration exceeds 50%, its danger is second only to gasoline. If you mix paint with gasoline, it will be even more dangerous. The paint is easy to volatilize, and the volatile gas is mixed with air to form an explosive gas mixture, with an explosion limit of 1.%. Within this range, it will explode in case of open fire. Therefore, during the use of paint, attention should be paid to the following matters: no open fire, no smoking, maintaining indoor ventilation, etc

in order to explain the fire risk of paint, we first look at the finished paint. Although the finished paint contains resin pigments, it can be thought that the thinner accounts for about half of the finished paint. Therefore, what is the distinguishing principle between the fire risk of paint and the "significant improvement in the measurement of thinner"? The station of the General Administration of quality supervision, inspection and Quarantine of the people's Republic of China gave a instructive reply: they thought it was similar. For example, banana water is widely used as diluent in nitro paint materials. Banana water is composed of acetate lipids and ketones as solvents, ethanol and butanol as auxiliary solvents, benzene, toluene, xylene and light petroleum solvents as diluents. The flash point of these solvents is mostly below 28 ℃, and some are even below minus 46 ℃. Because these flammable liquids have low flash point, low boiling point and are volatile, their vapor and air form an explosive gas mixture, which can burn or explode when encountering Mars

because the ship is huge and difficult to move, the paint operation can only be carried out on site. Because the paint (coating) contains a variety of flammable liquids, the mixed explosive gas formed by the combustible gas volatilized by the ship when painting in the factory and Wharf (including on water) and the air is prone to fire and explosion when encountering open flames such as blowtorch, welding and cutting. Therefore, great attention should be paid to the fire prevention and explosion-proof safety of ship paint to ensure safety. Its fire prevention safety measures mainly include the following aspects:

1. Painters participating in ship repair and construction must undergo on-the-job training, master painting operation technology and safety knowledge such as fire prevention and explosion prevention, and take emergency measures and common sense of fire fighting before taking up their posts

2. Combustible materials should be used as little as possible on the ship, and attention should be paid to fire separation. The main structure, superstructure and deck house of the hull shall be separated into several main vertical areas by non combustible materials. Even if there is a fire in one of the main vertical areas, the fire can be controlled in the central and local areas within a certain period of time. The bulkheads of paint storage rooms and paint mixing rooms shall be separated by steel or materials with the same fire resistance as steel. The cabin (room) shall be ventilated and dry, cool and insulated

3. Paint and spray paint containers should be covered and sealed at any time. And we should master a small amount of frequent withdrawal, and the leftover should be returned to the warehouse immediately. It is also not allowed to stay on the site overnight or dump casually

4. Open fire and smoking are strictly prohibited, and it is not allowed to use blowtorch to bake and shovel paint. Electrical equipment should be explosion-proof. Open fire is forbidden for painting, and open fire is also used for gas cutting. These are two conflicting processes. Therefore, the two processes cannot be carried out at the same time, nor can hot work be carried out near the ship part that has just been painted. This is because the combustible gas emitted by the paint has not yet completely escaped, especially in the cabin, due to poor ventilation conditions, it takes a long time. If the task is urgent and the fire must be carried out in time, the three-level fire management system must be strictly implemented, and the fire fighting preparation must be made. The method of mechanical strong ventilation can be adopted to accelerate the escape of combustible gases. But at this time, it should be noted that non explosion-proof motors should not be placed directly in the diffusion area of combustible gas to avoid accidents caused by electric sparks. The air compressor should be placed outdoors. The painting machine parts shall be temporarily grounded to conduct and remove static electricity

5. After painting or painting the cabin (room), open fire is also prohibited, and ventilation should be strengthened to eliminate combustible gases. When hot work is required, it is best to use an explosion detector to detect it first. If the concentration of combustible gas is below 10% of the lower explosion limit, hot work can be carried out. If there is no instrument, it can also be judged by smell. Generally, hot work can be carried out as long as the human nose does not feel the pungent smell. After the explosion detection and inspection of hot work, the hot work can be carried out only after the approval procedures are handled according to the requirements of hot work regulations

6. When painting is carried out in the driver's cab, radar telegraph room, engine room, oil tank, ship power station and other first-class hot work places, or in the cold storage, cabin (room), the ship under repair should be present, the factory should be on duty to monitor, and be prepared for fire fighting

7. Paint, spray paint and other chemical flammable coatings and adhesives of nitrocellulose raw materials shall not be used in all parts of passenger ships, living quarters of dry cargo ships and oil cargo ships, as well as engine rooms and engine rooms

8. Generally, blowtorch should not be used on the ship, and it is not allowed to use blowtorch to bake and shovel paint on the ship. Because there are combustibles near and on the back of the ship's iron plate, it is easy to cause a fire by baking with a blowtorch before removal

9. When painting the cabin (room), a no fire area should be marked out. After painting, it must be ventilated frequently to disperse combustible gases. Other hot work can be carried out only after there is no danger of explosion

10. Do not stack a large number of flammable But Ray Gibbs explained: "The improvement of material processing has begun to pay off. Combustible materials. The operation site should be cleaned frequently to remove dirt and residual combustibles. Cotton yarn and rags stained with paint should be removed from the special metal box every day. Oil stained work clothes should be hung in the designated place, and it is not allowed to pile up to prevent spontaneous combustion. Sufficient foam, dry powder fire extinguishers, dry sand, wet gunny bags, asbestos blankets and other fire-fighting equipment should be equipped. This series of models are mainly used for fire fighting It is suitable for non-metallic material test water with test load less than 5kn, just in case

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