Safety Operating Procedures for Gas Cutting and Welding Equipment
1. Hazard Analysis
1.1 Fire and Explosion: There is a risk of fire or explosion during the operation due to unsafe conditions in the surrounding environment or improper use of equipment.
1.2 Burns and Scalds: There is a risk of burns or scalds during the operation due to improper handling or inadequate personal protective measures.
1.3 Mechanical Injuries: There is a risk of mechanical injuries such as cuts and punctures during the operation due to inadequate protection of tools and materials or improper handling.
2. Applicability and Requirements
2.1 This operating procedure applies to the safe technical operation of gas cutting and welding equipment for operators.
2.2 Operators must participate in professional safety skills training organized by relevant departments, pass the assessment, and obtain a safety operation permit before being allowed to work.
3. Safety Operating Procedures
3.1 Preparations for Gas Cutting and Welding
3.1.1 Check that rubber hose connections, oxygen gauges, pressure regulators, etc., are securely fastened and free from leaks. It is strictly prohibited to have grease or dirt on gas welding tools and oxygen cylinders.
3.1.2 Oxygen cylinders and acetylene generators must not be placed near heat sources and electrical switchboards. They should not be placed below high-voltage lines or any other electrical wires. Avoid exposure to direct sunlight. They should be placed upwind from the operator's position to prevent explosions. Fences should be installed around the area with "No Smoking" signs displayed. The distance between oxygen cylinders, acetylene cylinders, and welding or cutting torches should be at least 10 meters. In special circumstances, isolation and protective measures should be taken, and the distance should not be less than 5 meters. If there are two or more acetylene generators in the same location, the distance between them should not be less than 10 meters.
3.1.3 Oxygen cylinders should be stored in a designated area. Smoking and open flames are prohibited, and the use of oxygen cylinders without pressure regulators is prohibited.
3.1.4 Oxygen cylinders should be equipped with safety caps and two shock-absorbing rubber rings. When moving, the safety cap should be tightened, and dragging, rolling, or hoisting of oxygen cylinders is prohibited. Gloves with grease should not be used for transporting oxygen cylinders. Dedicated carts should be used for transportation, ensuring secure fixation and avoiding collisions.
3.1.5 Oxygen cylinders should be stored upright with stable supports to prevent tipping. If placed horizontally, the cylinder neck should be elevated.
3.1.6 Before using acetylene cylinders, check the explosion-proof and flashback arrestor safety devices.
3.1.7 Select the appropriate welding torch and nozzle based on the thickness of the workpiece, and ensure that the nozzle is tightly screwed on without any gas leakage.
3.1.8 Differentiate between hoses for welding and cutting torches, and they should not be used interchangeably. Red hoses are used for oxygen, while green or black hoses are used for acetylene. When using a new hose, remove any impurities or dust inside to ensure unobstructed flow.
3.1.9 Rubber hoses should not be placed on hot pipes or wires, and heavy objects or hot items should not be placed on the hoses. Furthermore, rubber hoses should not be laid together with welding wires.
3.1.10 When installing a pressure regulator, check that there is no grease on the oxygen cylinder valve connection. Slightly open the outlet of the oxygen cylinder valve. When closing the oxygen cylinder valve, loosen the adjustment screw of the pressure regulator (do not close it tightly).
3.1.11 To check the suction performance of the welding or cutting torch, connect the oxygen hose first. After disconnecting the acetylene hose and the welding or cutting torch, open the acetylene valve and the oxygen valve. Lightly press the acetylene inlet on the torch with a finger. If there is a suction sensation and normal airflow, reconnect the acetylene hose. If oxygen flows back from the acetylene connection, repair it immediately and prohibit further use.
3.1.12 When checking for gas leaks in equipment, torches, pipelines, and connections, apply soapy water and observe the presence of bubbles. Do not use an open flame for leak testing.
3.1.13 If the welding or cutting nozzle is blocked, it can be cleared using a cleaning needle. Using wire to clear the nozzle is prohibited.
3.2 Precautions during Gas Cutting and Welding
3.2.1 When opening the oxygen cylinder valve, do not strike it with iron tools. Use dedicated tools and perform the action slowly, avoiding facing the pressure regulator.
3.2.2 Before ignition, open the valve of the welding or cutting torch quickly and blow air with oxygen to check the nozzle outlet. It is not allowed to use it when there is no wind, and when testing, avoid directing it towards the face.
3.2.3 During ignition, slightly open the oxygen regulator valve first, then open the acetylene regulator valve. Adjust the flame size and shape after ignition. The ignited torch should not be released from the hand. First, close the acetylene valve, then the oxygen valve, and place the torch down only after the flame is extinguished. It is prohibited to place the torch on the ground, and lighting it with a cigarette butt is strictly forbidden.
3.2.4 When welding inside a container, both ignition and extinguishing should be done outside the container.
3.2.5 When welding or cutting storage containers that have contained oil, fully open the holes on the container cover. Clean the inner wall of the container with alkaline water and then blow it dry with compressed air. Take adequate safety precautions.
3.2.6 The pressure gauge on the oxygen cylinder should be sensitive and functioning properly. The oxygen in the cylinder should not be completely used up, and a residual pressure of at least 0.1-0.2Mpa must be reserved. The valve should be tightened, and no grease should be allowed on the valve. The cylinder should be marked as "empty." The same applies to acetylene cylinders as per regulations.
3.2.7 During welding or cutting operations, it is prohibited to wear the rubber hose on the back and to use the flame of the welding or cutting torch for illumination. When the oxygen and acetylene hoses need to cross roads or tracks, they should pass underneath or be suspended to avoid being damaged by the wheels.
3.2.8 The welding or cutting nozzle cover should have good sealing. In case of overheating, the acetylene valve should be closed first, followed by the oxygen valve. It should then be cooled by immersion in water.
3.2.9 In the event of flashback, the acetylene regulator valve on the welding or cutting torch should be quickly closed, followed by the closure of the oxygen regulator valve. This will extinguish the flashback quickly. In case of an emergency (if it still does not extinguish), the acetylene hose can be disconnected, and the primary oxygen valve and acetylene valve should be closed, followed by taking appropriate fire-fighting measures. After a short wait, the oxygen regulator valve can be opened to blow out any residual flames and carbon particles inside the welding or cutting torch before resuming welding or cutting operations.
3.2.10 If an explosion sound or vibration is detected from the welding torch, the acetylene valve and oxygen valve should be quickly closed. After cooling, work can be resumed.
3.2.11 When performing welding or cutting operations at heights, safety belts should be used. It is strictly prohibited to stand or work beneath the area where high-altitude operations are being conducted to prevent injuries from falling objects.
3.3 Post-Operation Considerations for Gas Cutting and Welding
3.3.1 Close the safety cap on the cylinder valve and place the cylinder in the designated area.
3.3.2 Regularly test and inspect pressure vessels, pressure gauges, and other safety accessories for periodic and mandatory checks.
3.3.3 When temporarily stopping gas cutting or welding, close the valve on the welding or cutting torch. Before leaving the work area, the torch must be extinguished, the valve closed, and the residual gas in the hose released by venting the pressure from the pressure regulator.
3.3.4 In the event of the acetylene hose becoming detached, ruptured, or catching fire during use, immediately extinguish the flame of the welding or cutting torch and stop the gas supply. If necessary, the hose can be bent to extinguish the fire.
3.3.5 In the event of the oxygen hose catching fire, quickly close the valve on the oxygen cylinder to stop the oxygen supply. However, the method of bending the hose should not be used to extinguish the fire.
3.3.6 When extinguishing the flame of a welding torch, the acetylene valve should be closed first, followed by the closure of the oxygen valve. For extinguishing the flame of a cutting torch, the cutting oxygen valve should be closed first, followed by the closure of the acetylene and preheating oxygen valves. Then, the adjustment screw of the pressure regulator should be loosened.
3.3.7 During incomplete welding or cutting operations inside large containers, it is strictly prohibited to place the welding or cutting torch inside the container to prevent gas leakage from the torch valves and hose connections. Storing a large amount of acetylene and oxygen inside the container can lead to ignition, resulting in combustion and explosion.
4. On-site Emergency Measures
4.1 Principles of on-site emergencies: Rescue first, then handle the situation. When an accident or injury occurs, appropriate measures must be taken to rescue the personnel first. Simultaneously, the incident should be reported to the unit leaders and the office. If there are injured individuals, they should be promptly transported to the nearest hospital for treatment. During the handling process, attention should be given to protecting the accident scene.
4.2 Corresponding measures:
4.2.1 In the event of a fire accident, nearby personnel should immediately use water or fire extinguishers to extinguish the fire. The team leader should organize the rescue efforts. Meanwhile, personnel should be assigned to immediately report to unit leaders and safety administrators. Upon receiving the report, the unit leaders and safety administrators should promptly arrive at the fire location, coordinate and organize the rescue operations, and implement emergency response measures based on the fire situation. If the fire is significant or cannot be extinguished on-site and there is a tendency for the fire to spread, the evacuation plan should be immediately activated, and the emergency hotline 119 should be called to request professional firefighting teams for rescue.
4.2.2 In the event of scald or burn injuries, the injured individuals should be immediately taken to a safe location. Cold compresses or rinsing with cold water should be used to alleviate the pain. Burn ointment should be applied or medical treatment should be sought for dressing and treatment.
4.2.3 In the event of mechanical injuries, effective measures should be taken to stop bleeding and dress the wound based on the nature of the injury. If there are fractures, joint injuries, limb compression injuries, or significant soft tissue injuries, immobilization should be applied, and the injured individuals should not be moved arbitrarily. Prompt transportation to the hospital for treatment should be arranged.
