Thomas Industrial Library

Safety

What precautions in handling oxygen and fuel gas cylinders and related equipment apply to OFC?

All precautions listed in the Safety section of Oxyacetylene Welding, Chapter 1 must be followed.

What are the main hazards of OFC and what safety equipment can prevent these injuries?

• External eye injuries from cutting sparks prevented by safety glasses, or safety shields.

• Internal eye (retinal) damage from viewing hot metal and the radiation coming off it prevented by using a number 5 tinted lens while cutting or oxyfuel welding.

• Burns from weld sparks and hot metal prevented by leather gloves, non-flammable clothing, leather skins when working overhead, cuffless pants, pocketless shirts, a welding cap, and high-top shoes.

• Fires from the welding process are prevented by moving flammables away from the weld zone and having water or fire extinguishers close at hand.

• Fumes from paint or plating vaporized by the cutting process prevented by good ventilation and keeping out of the cutting plume.

What fire safety consideration are important in OFC?

• When cutting near materials that will burn, make sure that flame, sparks, hot slag, and hot metal do not reach them. Cutting creates more sparks than OAW.

• If the work to be cut can be moved, bring it to a safe location before cutting it.

• When flammable materials cannot be moved, use sheet metal shields or guards to keep the sparks away from burnables.

• Prevent sparks from falling into holes or cracks in wooden buildings.

• Do not use tarps or fabric covers to protect other materials from sparks as they will catch fire.

• If cutting on a wooden floor, first sweep it clean, then wet it down before starting cutting.

• Avoid using excessive oxygen pressure while cutting as this will propel sparks farther and make more of them.

• Plan ahead where hot metal will fall when cut; be especially careful to avoid your legs, feet, gas hoses, cylinders, and regulators.

• Have fire extinguishers, buckets of sand, or water on hand should a fire start.

• Make sure jacketed or hollow parts are vented before beginning cutting operations.

What is best way to cut into a sealed tank or container?

Never cut into a sealed container regardless of its size. Even if the container is clean and empty, penetration of the shell could release hot gases or send the cutting flame back toward the weldor. If the container is empty and contains no residual vapors, vent it to atmosphere by opening a valve, hatch, bung or drilling a hole, then proceed to cut or weld. See Figure 2-27.

Figure 2–27. How to cut into a clean container.

How can cutting or welding be done on a tank or container which has contained flammable materials?

An even more dangerous situation results when the vessel contains residual flammable vapors, whether it is vented to atmosphere or not. This will almost certainly result in an explosion. Flood the vessel with water to just below the cutting or welding point. Get the container cleaned usually by boiling with a caustic if the container is small or purged with a non-flammable gas like nitrogen, carbon dioxide or steam. Have the vessel checked for lack of explosive vapors by a qualified person. Then begin cutting or welding. See Figure 2-28.

Figure 2–28. Using nitrogen or carbon dioxide to purge oxygen from a container which has held flammable materials.