Welding and Oxy-fuel Safety Tips
October 1, 2007
Welding, whether arc welding or oxy-fuel, carries with it the potential for serious accidents. Although we will discuss some basic safety tips to lessen that potential, nothing can take the place of thoroughly reading your particular equipment's operator manual and following all of the safety, operation and maintenance instructions it contains.
Welding, whether arc welding or oxy-fuel, carries with it the potential for serious accidents. Although we will discuss some basic safety tips to lessen that potential, nothing can take the place of thoroughly reading your particular equipment’s operator manual and following all of the safety, operation and maintenance instructions it contains.
The welding process emits sparks, which can present a fire hazard. Make sure your welding area is well ventilated and free of flammable gases, vapors or liquids. Welding also heats the workpiece and can lead to severe burns if proper equipment is not worn, so welding gloves should always be used. Clothing should be flame resistant, and collars, cuffs and pockets should be buttoned to prevent them from catching sparks. Tennis shoes and cloth shoes are inadequate foot protection when welding. Instead, high top leather shoes offer the best protection.
In addition to protective clothing, a welding helmet with an appropriate filter shade should always be worn when welding or watching someone weld. Arc welding produces intense visible and invisible rays than can burn eyes and skin. Also, be mindful of the possibility of a passerby being subjected to the arc flash, and put up a welding screen if necessary. Remember, even a quick tack weld requires the use of welding helmet and appropriate apparel. Oxy-fuel welding also requires the appropriate filtered eyewear.
Avoid working in wet conditions, since water is an electrical conductor, and insulate yourself from the work and the ground by standing on a dry rubber mat or similar non-flammable material. Connect the workpiece to a proper earth ground and connect the frames of all electrically powered machines to a properly grounded disconnect switch, receptacle or other appropriate ground. Always double-check the installation and verify proper grounding. Never use chains, wire ropes, cranes, hoists and elevators as grounding connectors.
When using gas cylinders, chain them securely to a stationary, upright support or cart at all times. When moving or storing a cylinder, fasten the threaded protector cap to the top of the cylinder. Doing so shields the valve system from impact damage.
Immediately remove a faulty regulator from service for repair by a manufacturer’s designated repair center. Do not attempt to repair it yourself.
Use only recommended ferrules or clamps designed to connect hoses to fittings—never use ordinary wire or other substitutes. Always suspend hoses off the ground to keep them from being run over, stepped on or otherwise damaged and coil up excess hose to prevent kinks and tangles. Examine hoses regularly for leaks, wear and loose connections. To check for leaks, immerse pressured hoses in water (bubbles will indicate leaks.) Repair a leaky or worn hose by cutting out damaged area and splicing. Do NOT use tape.
Gas cylinders require special care in oxy-fuel welding. The acetylene cylinder is hollow and contains a porous material saturated with liquid acetone, which keeps the gases stable under pressure. For this reason, always store the cylinder in the vertical upright position and secure it. If the cylinder is tipped, acetone may leak into the valve area and could release acetone into the system. If an acetylene cylinder is tipped, place it upright for twice as long as it had been lying down before using it. Also, be certain a cap covers the valve when the cylinders are not secured. If the cap is not present and the cylinder falls, the valve could break and propel the cylinder, causing injury to you or other workers.
Pressurized gases for the welding industry are available in different cylinder sizes and there is no industry standard for color-coding the cylinders. To ensure you are using the correct gas, always check the label and testing date prior to using any cylinder.
Remember to take precautions when storing fuel and oxygen cylinders. The improper handling of oxygen cylinders (not fuel cylinders) is responsible for the majority of accidents with this type of equipment. Store oxygen tanks at least 20 feet away from fuel cylinders or behind a properly designed firewall to minimize the risk of an explosion or fire.
Inspect the cylinder valve for damage and/or the presence of contaminants such as oil, grease or dust before using. Briefly open the oxygen cylinder valve to clear dirt and debris from the connections prior to attaching the regulator. The short burst of oxygen will clear the valve of dirt and debris.
If the valve is damaged, do not use the cylinder. Visually inspect all hoses, O-rings (for nicks), safety devices, flashback arrestors, and torch and regulator connections for signs of damage or excessive wear.
Make sure the torch valves and regulator adjusting screws are in the off position before opening the cylinders. Position the cylinder valve between you and the regulator and pressurize the system by slowly opening the oxygen valve. Continue to turn the oxygen double seating valve until it is fully opened. Turn the adjusting screw on the oxygen regulator to 10 psi.
Next, place the acetylene cylinder between you and the regulator and turn the valve one-half to three-quarters of the way open. Doing so allows for sufficient gas flow to begin the pressurization process and also ensures that the fuel valve can be quickly shut off in the event of a fire. If the cylinder requires the use of a special tool key, keep the key easily within reach. Adjust the regulator adjusting screw on the acetylene regulator to 10 psi.
After turning on the regulator, perform a leak test. Apply a Leak Detection Solution (or oil-free soap and water) to the valve, regulator, hose and torch connections and look for bubbles. If bubbles appear, it indicates a leak and you should check the connections for a tight fit. If tightening does not stop the leak, immediately take the equipment out of service for repair.
Make sure you set the regulator adjusting screws to the correct outlet pressure for the type of tip you are using to ensure the proper gas pressures and flow. Operating the torch with insufficient gas flow can cause gas starvation, resulting in overheating of the tip and may cause a backfire and/or flashback to occur.
Before lighting the torch, purge the system of mixed gas that might remain in the hoses by opening the fuel valve and allow it to run for approximately three seconds for every 25-feet of hose length, then close the valve on the torch. Purge the oxygen hose using the same process. Once you have purged the system, you are ready to light the torch.
Use a friction style striker to ignite the torch. Never use matches or a cigarette lighter as the intense heat from the torch can quickly ignite the lighter and cause severe injury.
Remember, these are safety tips to keep in mind, but are not intended to be a comprehensive lesson in safety. Consult your equipment’s owner’s manual for complete safety guidelines.
Mike Pankratz is from Miller Electric Mfg. Co., and Bruce Buhler is a product manager for Smith Equipment. Additional safety information for arc welding can be found at MillerWelds.com and information on oxy-fuel safety can be found at smithequipment.com.