Safety knowledge of welding in special environment
The welding of general industrial enterprises in formal workshops is very common, but a lot of welding is done outside these places. For example, the welding in places such as high-altitude operation inside the container or in the field belongs to the welding in special environment. In addition to following general safety techniques, some special regulations safety knowledge must be followed when welding in these places.
Safety knowledge of Welding in Vessel
In addition to complying with the general welding operation regulations, the safety technology of welding operation in the container should also pay attention to the following points:
- When welding and cutting in airtight containers, tanks, barrels and cabins, the holes and holes of the welding work should be opened to allow the internal air to circulate to prevent the welder from being poisoned and scalded. When the work is completed or suspended, the welding tools, cables, etc. should be brought out with the person, and should not be placed in the work place.
- Special protective measures must be taken when welding in narrow and poorly ventilated containers, pipe sections, tunnels, inspection wells, semi-closed sections, etc. Ensure welders are insulated from live objects by rubber pads, insulating shoes, and insulating gloves, and have good ventilation and lighting.
- 12V lamps and lanterns must be used for operation in the window, and the light bulb must be protected by a metal mesh cover. Welding should not be performed when the window is wet.
- If necessary, workers in the container should wear life-saving equipment such as respirators.
- Before welding and repairing chemical containers, it is necessary to use a strong inert medium (such as nitrogen, carbon dioxide, water vapor or water) to completely discharge the original combustible or toxic substances in the container, and then carry out welding repair, that is, replacement welding repair. After the inner and outer walls of the container are thoroughly cleaned and replaced, the content of combustible substances in the window should be lower than 1/3 of the lower explosive limit of the substance.
- When the chemical container is not replaced by welding and repairing with pressure, the oxygen content (mass fraction) of the combustible gas in the container should be controlled below 1%; the welding and repairing container must maintain a certain continuous and stable positive pressure. The positive pressure value can be controlled at 1.5-5 kPa according to the actual situation. When it exceeds, the operation should be stopped immediately.
- If a violent fire erupts during the welding repair operation under pressure without replacement, take immediate measures to extinguish the fire. Before the flame is extinguished, the gas source in the container must not be cut off, and sufficient stable pressure must be maintained in the system to prevent an explosion accident caused by inhaling air in the container to form a mixture.
- For replacement welding with pressure or without replacement welding, it is necessary to go through the approval procedures for hot work, and the welding operation can only be carried out after the on-site safety measures are formulated and the supervision responsibility system is implemented.
Safety knowledge of Welding at heights
- When working at heights, the welder must first fasten the safety belt with snap hooks and attach himself to the frame. In order to protect the people below from being burned by falling molten droplets and slag, or being injured by accidental falling metal objects, a platform should be set up below the work place, and the platform should be covered with iron sheets or asbestos sheets. Scaffolding and the decking of the suspended platform above 1.5 mm above the ground must be surrounded by a fence with a height of not less than 1 m.
- When the upper layer is constructed, a protective grille must be installed below to prevent sparks, tools, parts and welding rods from falling and hurting people. Shavings, flax and other combustible materials within 5 m of the welding site must be removed.
- Welders working at heights must be equipped with intact welding tongs, helmet-type masks with a full set of spare lenses, sharp chisels and hand hammers, and shield masks shall not be used instead of helmet-type masks. The welding cable should be tightly tied to the fixed place, and it is strictly forbidden to wrap it around the body or work on the back.
- The working platform for welding should ensure that the welder can flexibly and conveniently weld welds in various spatial positions. When installing the welding equipment, the installation location should make the radius of the welding equipment function as large as possible. When using a movable electric welding machine to perform electrode arc welding at a high place, a power cord with a rubber hose must be used; the movable electric welding machine should be placed stably and have a good grounding device.
- When welding at high places, do not use high-frequency arc starter to prevent electric shock, slipping and falling. When working at heights, there should be a guardian, and pay close attention to the safety dynamics of the welder. The power switch should be located near the guardian, and the power supply should be cut off immediately in case of emergency. Welders working at heights must wear safety helmets when carrying out installation and disassembly work.
- When encountering rain, fog, snow, cold weather and dry cold, the welding work should be carried out in accordance with special specifications, and the welding work place should be protected from bad weather.
- In addition to mastering general operating safety techniques, welders who work at heights must undergo special physical examinations and pass the examination on safety technical rules for working at heights before they can take up their posts.
Safety knowledge of welding in open air or field work
- When working in the open air in summer, a weatherproof shelter or temporary pergola must be available.
- When working in the open air, pay attention to the wind direction, and be careful not to let the blown molten iron and slag hurt people.
- Open-air welding is not allowed in rainy, snowy or foggy weather. When working in wet areas, the welder should stand on a place covered with insulating materials and wear insulating shoes.
- A simple shield should be installed to block the arc light so as not to hurt the eyes of nearby workers or pedestrians.
- When welding in the open weather in summer, it is necessary to prevent the oxygen cylinder and acetylene cylinder from being directly exposed to the sun, so as to avoid gas expansion and explosion. If the bottle valve or pressure reducer freezes in winter, use hot water to freeze, and fire is strictly prohibited.