Welding and Cutting Safety Overview
Always read the safety information and the Material Safety Data Sheet (MSDS) supplied by the manufacturers of gases, materials and equipment used in welding operations. This information will recommend safe practices that will protect you from health hazards, such as fumes, gases and arc burns. Recommendations concerning ventilation and protective devices should be carefully followed.
To weld and cut safely, you must have a thorough knowledge of the welding process and equipment you will be using, and all of the hazards involved.
Fumes and Gases Can Harm Your Health
Keep your head out of the fumes. Do not breathe fumes and gases caused by the arc. Use enough ventilation. The type and amount of fumes and gases depend on the equipment and supplies used. Air samples can be used to find out what respiratory protection is needed.
Provide enough ventilation wherever welding and cutting are performed. Proper ventilation can protect the operator from the evolving fumes and gases. The degree and type of ventilation needed will depend on the specific welding and cutting operation. It varies with the size of the work area, on the number of operators, and on the types of materials to be welded or cut. Potentially hazardous materials may exist in certain fluxes, coatings, and filler metals. They can be released into the atmosphere during welding and cutting. In some cases, general natural draft ventilation may be adequate.
Other operations may require forced draft ventilation, local exhaust hoods or booths, or personal filter respirators or air-supplied masks. Welding inside tanks, boilers, or other confined spaces requires special procedures, such as the use of an air-supplied hood or hose mask.
Sample the welding atmosphere and check the ventilation system if workers develop unusual symptoms or complaints. Measurements may be needed to determine whether adequate ventilation is being provided. A qualified person, such as an industrial hygienist, should survey the welding operations and surrounding environment.
Do not weld on plate contaminated with unknown material. The fumes and gases which are formed could be hazardous to your health. Remove all paint and other coatings before welding.
More complete information on health protection and ventilation recommendations for general welding and cutting can be found in the American National Standard Z49.1, Safety in Welding and Cutting. This document is available from the American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126.
Electric Shock Can Kill You
Do not touch live electrical parts. To avoid electric shock, follow the recommended practices listed below. Faulty installation, improper grounding, and incorrect operation and maintenance of electrical equipment can be sources of danger.
- Ground all electrical equipment and the work piece. Prevent accidental electrical shocks. Connect power supply, control cabinets and work piece. to an approved electrical ground. The work lead is not a ground lead. It is used to complete the welding circuit. A separate connection is required to ground the work, or the work lead terminal on the power supply may be connected to ground. Do not mistake the work lead for a ground connection.
- Use the correct cable size. Sustained over-loading will cause cable failure and result in possible electrical shock or fire hazard. Work cable should be the same rating as the torch cable.
- Make sure all electrical connections are tight, clean and dry. Poor electrical connections can become over heated and even melt. They can also cause poor welds and produce dangerous arcs and sparks. Do not allow water, grease or dirt to accumulate on plugs, sockets or electrical units.
- Moisture and water can conduct electricity. To prevent shock, it is advisable to keep work areas, equipment and clothing dry at all times. Fix water leaks immediately. Make sure that you are well insulated. Wear dry gloves, rubber-soled shoes, or stand on a dry board or platform.
- Keep cables and connectors in good condition. Improper or worn electrical connections can cause short circuits and can increase the chance of an electrical shock. Do not use worn, damaged or bare cables.
- Avoid open-circuit voltage. Open circuit voltage can cause electric shock. When several welders are working with arcs of different polarities or when using multiple alternating current machines, the open-circuit voltages can be additive. The added voltages increase the severity of the shock hazard.
- Wear insulated gloves when adjusting equipment. Power should be shut off and insulated gloves should be worn when making any equipment adjustment to assure shock protection.
- Follow recognized safety standards. Follow the recommendations in American National Standard Z49.1, Safety in Welding and Cutting, available from the American Welding Society, 550 N. W. LeJeune Road, Miami, FL 33126, and also the National Electrical Code, NFPA No. 70, which is available from the National Fire Protection Association, Batterymarch Park, Quincy, MA 02269.
- Cylinders must be kept out of the welding circuit to prevent arc burns on the cylinder.
Tips to Avoid ARC Radiation and Burns
Warning – Arc rays and spatter can injure eyes and burn skin. Wear correct eye, ear and body protection.
Electric arc radiation can burn eyes and skin the same way as strong sunlight. Electric arcs emit both ultraviolet and infrared rays. Operators, and particularly those people susceptible to sunburn , may receive eye and skin burns after brief exposure to arc rays. Reddening of the skin by ultraviolet rays becomes apparent seven or eight hours later. Long exposures may cause a severe skin burn. Eyes may be severely burned by both ultraviolet and infrared rays. Hot welding spatter can cause painful skin burns and permanent eye damage.
Be sure you are fully protected from arc radiation and spatter. Cover all skin surfaces and wear appropriate eye and face protection from arc burns and burns from sparks or spatter.
- Keep sleeves rolled down. Wear gloves and a helmet. Use correct lens shade to prevent eye injury. Choose the correct shade from the table below. Observers should also use proper protection.
Filter Recommendations
(Adapted from ANSI Safety Standard Z49.1)Application Lens Shade Number* MIG (Gas Metal and Flux Cored Arc) 60 to 160 amps 11 160 to 250 amps 12 250 to 500 amps 14
* As a rule of thumb, start with a shade that is too dark to see the arc zone, then go to a lighter shade which gives sufficient view of the arc zone without exerting a strain on your eyes. - Protect against arc flashes, mechanical injury or other mishaps. Wear spectacles or safety glasses with No. 2 shade filter lens and side shields inside the welding helmet or hand shield. Helpers and observers should wear similar protection.
- Wear protective clothing such as heat and fire-resistant jackets, aprons, and leggings. Exposure to prolonged or intense arc radiation can cause injury. Thin cotton clothing is inadequate protection. Cotton deteriorates with this type of radiation.