Welding Cutting and Brazing 29 CFR 1910 Subpart

Welding, Cutting and Brazing 29 CFR 1910, Subpart Q

Compressed Gases n Covered in Subpart H, but an integral part of welding, cutting, and brazing n Compressed gas hazards n Gases used for cutting, brazing, and “shielding” the weld

Cylinder Inspection n Most compressed gas cylinders must be periodically tested/ recertified (DOT) n All cylinders contain markings/ symbols that indicate certification status

Specific Gases n Several of the gases have specific OSHA standards n These gases include acetylene, hydrogen, oxygen, nitrous oxide, ammonia, and LPG

Basic Fire Prevention n Fire hazards must be removed, or –Guards installed, or –Welding/cutting must NOT take place n Hot work permit should be used to ensure that all fire hazards are controlled n Use of fire watch – 1/2 hour after operation ceases

Fire Prevention (cont. ) n Fire extinguishers must be charged/available n Never weld in the presence of explosive atmospheres n Do not weld on used drums, barrels, tanks, or other containers n Test potentially explosive containers for flammable atmospheres n Shut off cylinder valves when they are not in use

Protection of Personnel n Keep working surfaces clean and unobstructed n Wear eye protection –Use safety glasses under welding hood n Protective clothing must be used per 1910. 132 n Welding in confined spaces –Machines located outside of space –Other confined space precautions apply (1910. 146)

Oxygen-Fuel Welding n 29 CFR 1910. 253 n Acetylene –Flammable –Unstable –Cannot be piped above 15 psi

Basic Rules for Oxyacetylene Welding n n n Blow out cylinder valve Release regulator Stand to one side of regulator Open cylinder valve slowly Not more than 15 psi

Basic Rules (cont. ) n n n Purge oxygen and acetylene passages Light the acetylene Never use oil or grease Do not use oxygen Keep your work area clean

Storage of Fuel Cylinders n Storage area must be well ventilated n Cylinders must be at least 20 feet from combustibles n Valves must be closed n Valve protection must be in place n Inside storage must be limited to 2, 000 cubic feet. n Cylinders must be stored in upright position n Oxygen must be at least 20 feet from fuel gas or 5 feet with a 1/2 hour fire barrier

Gas Cylinder Precautions n Never lift cylinders by the service valve or valve protection (use slings, net, etc. ) n Keys, handles, hand wheels must be present n Use proper regulator n Open acetylene valve no more than 11/2 turns

Protective Devices n n n Pressure relief valves Backflow preventers Fuel gas hose—red (sometimes black) Oxygen hose—green Hose protection required Pressure-reducing regulators

Arc Welding n Electric current fuses parent metal and welding rod n Indispensable in metal working n Used for carbon and alloy steels and nonferrous metals

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

Common Arc Welding Processes n n n n Shielded metal arc welding (stick welding) Gas metal arc welding (MIG welding) Gas tungsten arc welding (TIG welding) Flux cored arc welding Submerged arc welding Arc cutting Plasma arc cutting

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

Welding Health Hazards n n n n Zinc Cadmium Beryllium Iron Oxide Mercury Lead Fluorides Chlorinated hydrocarbon solvents n n Phosgene Carbon monoxide Ozone Nitrogen Oxides 11006115 Copyright ã 1999 Business & Legal Reports, Inc.

Welding Physical Hazards n Ultraviolet radiation n Infrared radiation n Intense visible light

Lens Shades for Typical Welding Process n Shielded metal arc n Gas Tungsten arc n Torch brazing n Gas welding Lens Shade Number n 10 -14 n 11 -12 n 3 or 4 n 4 -8

Quiz 1. Fuel cylinders must be stored at least _____ feet from combustibles. 2. Shielding is a process used to protect the eyes from welding fume. True or False 3. Three physical welding hazards are ______ radiation, infrared radiation and intense visible light. 4. You should not use oxygen as a substitute for air. True or False 5. As long as they are secure, fuel cylinders can be stored on their side. True or False

Quiz (cont. ) 6. Gas Metal Arc Welding is also known as _______ welding. 7. Exposure to zinc fumes may cause metal fume fever. True or False 8. Cylinder inspection requirements are regulated by the Department of __________. 9. Acetylene has a very narrow flammable range. True or False 10. Backflow prevention should be provided for oxygen cylinders. True or False

Quiz Answers 1. Fuel cylinders must be stored at least 20 feet from combustibles. 2. False. Shielding is a process used to keep air away from the weld. 3. Three physical welding hazards are ultraviolet radiation, infrared radiation, and intense visible light. 4. True. You should not use oxygen as a substitute for air. 5. False. Fuel cylinders must always be stored upright. 6. Gas Metal Arc Welding is also known as MIG welding.

Quiz Answers (cont. ) 7. True. Exposure to zinc fumes may cause metal fume fever. 8. Cylinder inspection requirements are regulated by the Department of Transportation. 9. False. Acetylene has a very wide flammable range. 10. True. Backflow prevention should be provided for all oxygen cylinders.