Safety regulations for manual gas welding (gas cutting)


1. Strictly follow the general safety rules for the operation of the welder and the rules for the safe use of calcium carbide, acetylene generators, diluted acetylene cylinders, water seal safety devices, rubber hoses, oxygen cylinders and welding (cutting) torches.

2. The acetylene station must be serviced by a special person and follow the rules for the safe operation of the acetylene station.

3. All equipment must be checked before operation or when the acetylene station is stopped for a long time before starting work. Connections, valves and fasteners of the acetylene generator, oxidation bottle and rubber hose must be firmly fixed, play, damage and air leakage are not allowed. Oxygen cylinders and their accessories, rubber hoses and instruments must be free of grease and dirt.

4. Use only soapy water when checking equipment, accessories and piping for leaks. During the test it is forbidden to use open fire and smoke. It is strictly forbidden to use fire to test for air leakage.

5. The distance between oxygen cylinders, acetylene generators (or acetylene cylinders) and open flames must be more than 10 meters. If conditions limit, it is not allowed to be less than 5 meters, and isolation measures must be taken.

6. Do not use non-sparking tools to open the oxygen or acetylene gas valve.

7. When the piping of the gas cylinder equipment is frozen, it is strictly forbidden to use fire to roast or hit the frozen block with tools. Oxygen valves or piping should be melted with warm water at 40°C. Acetylene generators, backfire prevention devices, and piping can be thawed with hot water or steam, or thawed with a hot aqueous solution of 23% to 30% sodium chloride and kept warm.

8. The place of welding work must be equipped with appropriate fire-fighting equipment. Avoid direct sunlight on the oxygen cylinder or acetylene generator when working outdoors.

9. Pressure vessels, pressure gauges and safety valves should be regularly sent for calibration and testing in accordance with regulations. To check and adjust pressure devices and safety devices, remove the calcium carbide basket and take measures to remove residual gas.

10. At the end of work or leaving the workplace, screw on the safety cap of the gas cylinder, clean the site, and put the gas cylinder and acetylene generator in the designated place. When leaving work, release the pressure, drain the water and remove the calcium carbide basket.

Calcium carbide

1. The storage location must be dry andwell ventilated. The calcium carbide bucket must be sealed, and the words "calcium carbide bucket" and "do not use water for firefighting" must be written on the bucket. Fireworks, storage or laying of water pipes and ditches is prohibited indoors. allowed to be stored indoors. Acetylene and calcium carbide cylinders should not be stored in the same room.< /p>

2. The calcium carbide barrel must be handled with care and must not be thrown to prevent sparks and explosions. It is forbidden to wear in the rain on rainy days.

3. When loading and crushing calcium carbide, the operator must wear gloves, a mask and goggles to prevent broken calcium carbide from getting into the eyes.

4. For calcium carbide fires, dry sand or carbon dioxide fire extinguishers should be used. Do not extinguish fire with foam, carbon tetrachloride or water. Calcium carbide powder can only be destroyed in the open air.

Acetylene generator

1. The words "Danger!" must be written on the outside of the body of the acetylene generator. and "Acetylene Generator!".

2. Mobile small-sized acetylene generators must be transported on rubber wheels or trolleys equipped with spring devices. When manipulating, the pressure must be relieved first.

3. Parts (especially the inner wall) of the acetylene generator should not be made of pure copper (that is, red copper) to avoid the formation of acetylene copper and the occurrence of explosions. Copper alloys with a copper content of less than 70% can be used. The explosion-proof membrane (sheet) must not be replaced by a copper or iron sheet. The rupture disk should be replaced at least once a year.

4. Closed-type acetylene generators must be equipped with accurate and sensitive pressure gauges and safety valves. Before inserting calcium carbide, first check whether the water feeder and the air outlet pipe in the gas chamber are blocked, and then insert calcium carbide after heating. The size of calcium carbide must be appropriate, and it is forbidden to use calcium carbide powder. When the calcium carbide block is small, it is necessary to use a hollow calcium carbide basket to avoid excessive temperature rise. The position of the calcium carbide basket must comply with the regulations.

5. The pressure of the acetylene generator must be maintained, the water must be kept clean, and the solution decomposed by calcium carbide must be washed off with water in a timely manner. The temperature of the gas chamber of the acetylene generator should not exceed 80°C, and that of the water supply generator, the temperature of the cooling water should not exceed 50°C. Stop operation when the temperature exceeds the specified limit. And spray cooling with cold water and add low temperature cooling water.

6. It is strictly forbidden to use acetylene generators with a floating barrel.

7. The mobile acetylene generator and oxygen cylinder cannot be placed together, and the distance between them must be more than 3 meters.

8. Each acetylene generator must be equipped with a watertight backfire fuse. Clean water should be added before work to keep the water level at a certain height. Each ignition arrester can only work for one torch. Acetylene generators supplying more than two burners must have a common flame arrester.

9.Before operating the acetylene generator, check the explosion-proof and anti-release safety devices such as the explosion-proof disc (diaphragm), explosion-proof needle and the release guard. After replacing the calcium carbide, the acetylene gas containing air in the container must be released before welding and cutting can be allowed.

Waterproof protective device

1. Before using the water seal safety device, check the water level once with the water level control valve (check again after quenching) and check for air leakage.

2. The water seal safety device must be placed vertically so as not to affect the backfire prevention function, and its working pressure must be compatible with the working pressure of the acetylene generator.

3. Each welding and cutting torch must have an anti-return device. If more than one welding torch is operating at the same time, a full water seal safety device must be installed on the acetylene generator, and one must be installed at each welding. (torch) burner Independent backfire arrester.

4. The water seal safety device should be disassembled and cleaned once a month, and overhauled regularly.

5. To check for air leakage and defrost, follow the relevant requirements of the General Regulations.

Rubber hose

1. The rubber hose must be pressure tested. The test pressure of the oxygen hose is 2 MPa, the test pressure of the acetylene hose is 0.5 MPa. Do not use substitutes that have not passed the pressure test, as well as worn, aged, brittle, leaking and grease-contaminated hoses.

2. The length of the hose is usually 10 to 20 meters. Do not use too short or too long hoses. The joints must be tightly clamped with special clamps or annealed wire.

3. The oxygen hose is black and the acetylene hose is red. Do not confuse when connecting to the welding torch.

4. If the acetylene hose falls, breaks or catches fire during operation, first extinguish the flame of the welding torch or torch, and then turn off the gas supply. When the oxygen hose is lit, the oxygen cylinder valve must be quickly closed toYou stop the oxygen supply. The bending method for extinguishing an oxygen hose fire is not allowed. When an acetylene hose ignites, the front bending method can be used to extinguish a fire.

5. Do not put rubber hoses on high-temperature pipes and wires or press on the hoses with heavy or hot objects, and do not run hoses and electric welding wires together. Avoid cutting when using. If the hose passes through a roadway, a sheath or sheath should be added.

Oxygen tank

1. Each gas cylinder must be used for a period of regular inspection (three years), the color code is obvious, and the cylinder cap is intact. Oxygen cylinders should be stored separately from other cylinders containing flammable gas, lubricants, and other flammable items, and should not be transported in the same vehicle. Bottle caps are required for transport and storage when using gas cylinders. Do not lift oxygen cylinders while driving or using a crane.

2. The oxygen cylinder accessories are faulty or defective and the valve screw must be stopped when it slips. Oxygen cylinders should be placed vertically on a fixed support to avoid accidents caused by falling.

3. Do not use oxygen cylinders without pressure reducers.

4. The oxygen in the oxygen cylinder must not be completely used up, the residual pressure in the cylinder must be at least 0.05 MPa, and the valve must be tightened, and the “empty cylinder” mark must be written on it.

5. When opening the oxygen valve, use special tools and move slowly. Do not face the decompression gauge, but make sure that the gauge pointer is flexible and normal.

6. When the oxygen cylinder is in the same place as welding, the bottom of the cylinder must be covered with insulators to prevent it from entering the secondary circuit of the welding machine.

7. Oxygen cylinders should avoid heat and impact and should be placed as vertical as possible when in use, and a one-way valve should be installed on the main confluence outlet pipe used in parallel.

Acetylene bottle

1. During operation, transportation and storage, the acetylene cylinder must be fixed vertically, it is strictly forbidden to lay it down or drop it, avoid strong vibrations and collisions, use a special trolley during transportation, and do not use a crane. pick it up; at ambient temperatures above 40°C, cooling measures must be taken.

2. When using an acetylene cylinder, the welding torch and torch are equipped with a backflash safety device and a pressure reducer.

3. The operator must stand behind the valve port and carefully open it. Loosening the cylinder valve must not exceed1.5 turns.

4. The gas in the cylinder cannot be used up and a certain residual pressure must be left. At an ambient temperature of less than 0°C, the residual pressure is 0.05 MPa, at an ambient temperature of 0-15°C, the residual pressure is 0.1 MPa, at an ambient temperature of 15-2 At 5°C, the residual pressure is 0.2 MPa , and at an ambient temperature of 25-40°C, the residual pressure is 0.3 MPa.

5. The fleet of acetylene cylinders for welding should not exceed 5 pcs. If it exceeds, the workshop should have a separate pantry. If there are more than 20, they should be placed in the acetylene cylinder library.

6. It is strictly forbidden to store acetylene cylinders together with cylinders containing chlorine, oxygen, calcium carbide and other flammable and explosive items. The working point, oxygen cylinders and open fire must be at least 10 meters apart.

Working with a flashlight

1. Copper wire or bamboo stick must be used for the transparent welding tip, and iron wire is prohibited.

2. Before use, check the injection and suction power of the welding torch or torch. The method is as follows: first connect the oxygen tube, open the acetylene valve and the oxygen valve (the acetylene tube must be disconnected from the welding torch and torch at this time), and lightly touch the acetylene inlet on the welding torch with your fingers. If there is suction, then good suction capacity. When connecting the acetylene gas line, first make sure that the flow of acetylene gas is normal, and then connect it. If there is no suction, or even oxygen flows from the acetylene joint, it must be repaired, otherwise it is strictly forbidden to use it.

3. Depending on the thickness of the workpiece, select the appropriate welding torch, cutter, welding nozzle, and cutting nozzle. Avoid using the welding torch for cutting thick metal, and use a small cutting nozzle for cutting thick metal.

4. After the welding and injection test of the torch is normal, the connection should be firmly connected with the oxygen rubber tube, and the acetylene inlet connection and the acetylene rubber tube should not be connected too tight, so as to prevent air leakage and easy insertion is appropriate. It is not allowed to use a leather tube that has been fired during aging and hardening.

5. There must be enough clean water in the work area to cool the welding tip. When the welding torch (or torch) makes a “pop” due to excessive heat, the acetylene gas supply valve should be closed immediately and the welding torch (or torch) should be placed in water to cool. Please note that it is better not to close the oxygen valve.

6.When resting for a short time, the welding torch valve (or pboat) must be tightly closed, and the welding torch must not be placed on the ground. When resting for a long time or leaving the workplace, it is necessary to extinguish the flare, close the ball valve of the gas cylinder, relieve the pressure of the pressure reducer, release the residual gas in the pipe, shut off the water supply, and then pack the hose and tools.

7. Operating rules for ignition of a welding torch or torch

(1) Before igniting, quickly open the valve of the welding torch (or torch) and purge it with oxygen to check the nozzle outlet, but do not aim at the face to check the wind. Do not use when there is no wind;

(2) When welding in a container, ignition and extinguishing must be carried out outside the container;

(3) For a jet-suction welding torch (or torch), the acetylene valve on the welding torch (or torch) should be slightly ajar when ignited, and then directed towards the wick or match to ignite. , turn on the oxygen flywheel immediately to adjust the flame. If it is found that the welding and cutting torch is defective, after igniting and supplying oxygen, the oxygen must be immediately turned off to prevent the explosion of fire or the explosion phenomenon during ignition;

(4) When using the acetylene cutting machine, acetylene gas should be released first, and then oxygen should be released to start the fire;

(5) When using a hydrogen cutting machine, hydrogen must be released first, and then oxygen must be released to start a fire.

8. When the flame goes out, the burner must first close the acetylene valve and then close the oxygen valve. The torch must first shut off the cutting oxygen, and then shut off the acetylene and oxygen preheat valves. When a backfire occurs, if there is a fire on the rubber hose or the backfire prevention device, the oxygen valve and acetylene valve on the burner must be quickly closed, and then the primary oxygen valve and acetylene valve must be closed, and then fire extinguishing measures. should be accepted.

9. When oxygen and hydrogen are used together, acetylene gas is released first, then hydrogen gas, and finally oxygen gas, and then ignites. When it goes out, turn off the oxygen first, then the hydrogen, and finally the acetylene.

10. When working with the welding torch and torch, the rubber hose must not be worn on the back. Do not use a welding torch (or torch) flame to ignite.

11. During use, if gas leakage is found in the gas passage or valve, stop operation immediately. Continue to use after the air leak has been repaired.

12. When the air source pipeline passes through the pedestrian crossing, it must be closed and keep a safe distance from the electrical circuit.

13. The place of gas welding (cutting) should be well ventilated, and when welding (cutting) in a container,mechanical ventilation.