Welding, Cutting and Brazing

Compressed Gases Covered in Subpart H, but an integral part of welding, cutting and brazing Compressed gases-hazards compressed energy flammable, asphyxiants, oxidizers Gases are used for cutting, brazing and “shielding” the weld

Cylinder Inspection DOT requirement--most compressed gas cylinders must be periodically tested/recertified Ref. 49 CFR 171-179 All cylinders contain markings/symbols that indicate recertification status

Specific Gases Acetylene, hydrogen, oxygen, nitrous oxide, anhydrous ammonia, and liquefied petroleum gas all have specific regulations that apply to them Ref. 1910.100 series

Fire Prevention-Basic Precautions Fire hazards must be removed, or Guards shall be installed, or Welding/cutting must NOT take place Hot work permit should be used to ensure all fire hazards are controlled

Precautions Fire extinguishers must be charged/present Use of fire watchers 1/2 hour after operation ceases Never weld in the presence of explosive atmospheres Not on used drums, barrels, tanks or other containers--test for flammable vapors Electrodes protected Shut off valves of cylinders when not in use

Protection of Personnel Working surfaces Eye Protection use safety glasses under welding hood Protective clothing must be used- 1910.132 Confined Spaces machines located outside of space other confined space precautions apply

Oxygen-Fuel Welding 29 CFR 1910.253 Acetylene-very wide range of flammability Is extremely unstable Is generated inside the cylinder when acetone reacts with calcium silicate Acetylene must not be piped above 15 psi

Storage of Cylinders Well-ventilated--20 ft. from combustibles Valves must be closed Valve protection must be in place Inside storage limited to 2,000 cu. ft. Store in upright position Oxygen at least 20ft from fuel gas or 5 ft with a 1/2 hour fire barrier

Gas Cylinder Precautions Never lift cylinders by the service valve or valve protection (use slings, net etc.) Keys, handles, hand wheels must be present Use proper regulator Open acetylene valve no more than 1 1/2 turns

Protective Devices Pressure relief valves must be used Backflow preventers for oxygen Fuel gas hose-red (sometimes black) Oxygen hose-green Hose protection required Pressure-reducing regulators

Arc Welding Electric current jumps a gap, resulting temperature melts parent metal and welding rod Indispensable in metal working Used in carbon and alloy steels and non- ferrous metals

Shielding Air must be kept away from weld area Shielding, protects the integrity of the weld joint Flux or gas mixture is used as a “shield”

Common Arc Welding Processes Shielded Metal-Arc Welding Gas Metal Arc Welding Gas Tungsten Arc Welding Flux Cored Arc Welding Submerged Arc Welding Arc Cutting Plasma Arc Cutting

Installation & Maintenance Welding machine must be grounded Work area must be dry and free of hazards Connections must be tightly made Splices within 10 ft of holder are prohibited Cables must be maintained and conductors well-insulated

References Information provided by OSHA Compliance Suite- Boyer Safety Services 1-800-664-8401