Safety preparation and operation principle of weld

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Safety preparation and operation principle of welding operation

welding and cutting are common production means in industrial enterprises, belonging to special types of work. During the operation, if the operator is paralyzed, lacks necessary knowledge or violates the safety regulations of hot work, it will lead to fire and explosion accidents

on December 25, 2000, a major fire accident occurred in Dongdu commercial building in Luoyang. The cause was that four electric welders working without certificates carried out electric welding operation against regulations on the first floor underground, and the welding slag splashed on the second floor, igniting combustibles such as sponge mattresses, resulting in a major fire, and 309 lives became enemies in an instant. On the afternoon of November 15, 2010, a fire broke out in the teacher's apartment on the 28th floor, 718 Jiaozhou Road, Shanghai. The fire caused by the non-standard operation of unlicensed welders killed 53 people and injured more than 70 people. The illegal operation of welders who lack safety operation knowledge has brought a heavy lesson to the safety production of enterprises

safety preparation before welding operation

regardless of the size of the welding and cutting operation, preparations must be made before operation:

safety inspection on the welding and cutting operation site should be done well to remove all kinds of combustibles and prevent fire accidents caused by welding and cutting sparks. In particular, the temporarily determined welding and cutting site shall be thoroughly inspected, the welding and cutting operation area shall be delimited, and the safety rope shall be pulled at the operation site if necessary. The safe distance between combustible materials and welding and cutting operation shall generally not be less than 10m, but the specific conditions shall be treated specifically, such as the size of wind force, different wind directions, operation parts, welding, R & D breakthrough 1 batch as soon as possible, engineering utilization 1 batch, industrialized mass production 1 batch is cutting, etc

welding and cutting shall be carried out in a safe area. For welding and cutting parts that cannot be disassembled, the welding and cutting parts shall be closely separated from other inflammables and explosives. When welding and cutting containers and pipes of combustible gases, the residual combustible gases in them must be replaced with carbon dioxide, nitrogen, etc. The equipment and pipelines storing flammable liquids shall be cleaned with water and steam to remove dirt. Before operation, the inspection method of "one question, two observation rules, subject to the fracture in the section in the middle of the gauge length, three sniffing and four explosion measurement" shall be adopted, and blind operation shall not be allowed. Dangerous goods on site shall be removed. For the equipment to be welded and cut, the pressure must be relieved and all manholes and valves must be opened before operation. When working in flammable and explosive places, ventilation shall be carried out, and welding and cutting shall be carried out after the flammable gas is discharged. During operation, the humidity should be increased and various cooling should be carried out. At the same time, fire extinguishing equipment and necessary technical measurement should be prepared

acetylene generator, oxygen cylinder or arc welding equipment shall be placed in appropriate positions in the temporarily determined welding and cutting places. These equipment shall be kept at a certain safe distance from the welding and cutting operation site. Obvious signs such as "fire is not accessible" and "prevent electric contact" shall be set beside the acetylene generator and electric welding machine, and safety ropes shall be blocked to prevent irrelevant personnel from accessing these equipment. The wire for arc welding shall be laid on the channel without combustible substances. Workers engaged in welding and cutting operations must wear work clothes. In winter, the cotton padded clothes for keeping out the cold must be sewn well, and the cotton wadding cannot be exposed to prevent smoldering and fire in case of sparks. For temporary welding and cutting sites with large welding and cutting projects and complex environment, work with relevant departments to formulate safe operation implementation plans, so as to determine personnel, fixed points, fixed measures and implement the safety post system

ventilation and fire prevention standard for welding operation

ventilation and fire prevention shall also be paid attention to in welding operation. The standards are as follows:

ventilation for welding operation shall take different ventilation and smoke exhaust measures or adopt various air supply masks according to the welding operation environment, welding workload, type of welding rod (agent) and dispersion degree of operation, so as to ensure that the air quality at the welder's operation point complies with relevant regulations. Avoid the welding smoke air flow passing through the welder's breathing belt. When the height of the welder's working room is less than 3.5 ~ 4m or the working space of each welder is less than 200m3, and the internal structure of the working room affects the air flow, so that the concentration of smoke and harmful gas at the welding working point exceeds the relevant regulations, comprehensive ventilation shall be adopted

the concentration of harmful smoke and dust generated during welding and cutting shall meet the maximum allowable concentration in the workshop. Ventilation methods such as local ventilation or small ventilation units shall be adopted, and the air volume and wind speed of the hood shall be calculated according to the control distance and control wind speed from the hood to the welding operation point. The control wind speed of the cover shall be greater than 0.5m/s, and the cover shall be as close to the operation point as possible. When using a fixed cover, the control wind speed shall not be less than 1 ~ 2m/s. The form of the cover shall be selected in combination with the characteristics of the welding operation point. When welding and cutting in narrow and local space, local ventilation shall be adopted. Harmful or asphyxiating gas shall be prevented from accumulating in the welding space, and a special person shall be responsible for monitoring. For welding, cutting and other work, if dust and harmful flue gas are encountered and local servo system ventilation measures cannot be adopted, air supply respirator shall be adopted. Low noise ventilation and dust removal facilities shall be selected to ensure that the environmental mechanical noise value of the workplace does not exceed the sound pressure of 85dB

welders shall strictly abide by the fire safety management system stipulated by the enterprise during welding and cutting. According to the environmental conditions of the welding site, the following measures shall be taken: welding is not allowed in the no fire zone specified by the enterprise. When welding is required, the work must be moved to the designated hot work area or carried out in the safety area; The distance between combustible and flammable materials in welding operation and the ignition source of welding operation shall not be less than 10m. During welding and cutting operations, if holes, holes and gaps are left on the nearby wall and ground, and holes are left at the connecting orifice of the transport belt, sealing or shielding measures shall be taken

the "ten no welding and cutting" principle of welding operation

the "ten no welding and cutting" principle that welders should abide by. In daily operation, the welder has the right to refuse welding and cutting under any of the following circumstances, and the enterprise shall support it and shall not force the workers to operate against regulations

first, the welder cannot carry out welding and cutting operation without operation certificate and formal welder's technical guidance on site; Second, welding and cutting within the scope of class I, class II and class III hot work shall not be carried out without going through the hot work approval procedures; Third, welders do not understand the situation around the welding and cutting site and cannot weld and cut blindly; Fourth, welders cannot weld and cut when they do not know whether the interior of welding and cutting parts is safe; Fifth, all kinds of containers containing combustible gases, flammable liquids and toxic substances before thorough cleaning; Large oil tanks and gas tanks cannot be welded and cut if gas explosion measurement is not carried out after cleaning, or if there is an interval of more than 2 hours after explosion measurement; Sixth, combustible materials (such as plastic, cork, FRP, polypropylene film, straw, asphalt, etc.) shall be used for heat preservation, cooling, sound insulation and heat insulation. Where sparks can splash, they cannot be welded and cut without taking practical and reliable safety measures; Seventh, vessels and pipes with pressure or sealing shall not be welded and cut; Eighth, there are inflammables and explosives piled near the welding and cutting parts, which cannot be welded and cut without thorough cleaning or effective safety measures; 9. The parts in contact with external units shall not be welded and cut until they are clear about the impact of external units, or they are aware of the danger and have not taken practical and effective safety measures; X. when the welding and cutting site conflicts with other nearby types of work, welding and cutting shall not be allowed


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