Welding, Cutting and Brazing 29 CFR 1910, Subpart Q

Covered in Subpart H, but an integral part of welding, cutting, and brazing

Compressed gas hazards Gases used for cutting, brazing,

and “shielding” the weld

Compressed Gases

Most compressed gas cylinders must be periodically tested/recertified (DOT)

All cylinders contain markings/symbols that indicate certification status

Cylinder Inspection

Several of the gases have specific OSHA standards

These gases include acetylene, hydrogen, oxygen, nitrous oxide, ammonia, and LPG

Specific Gases

Basic Fire Prevention

Fire hazards must be removed, or–Guards installed, or–Welding/cutting must NOT take place

Hot work permit should be used to ensure that all fire hazards are controlled

Use of fire watch–1/2 hour after operation ceases

Fire extinguishers must be charged/available

Never weld in the presence of explosive atmospheres

Do not weld on used drums, barrels, tanks, or other containers

Test potentially explosive containers for flammable atmospheres

Shut off cylinder valves when they are not in use

Fire Prevention (cont.)

Protection of Personnel

Keep working surfaces clean and unobstructed Wear eye protection

–Use safety glasses under welding hood Protective clothing must be used per 1910.132 Welding in confined spaces

–Machines located outside of space–Other confined space precautions apply (1910.146)

29 CFR 1910.253 Acetylene

–Flammable–Unstable–Cannot be piped above 15 psi

Oxygen-Fuel Welding

Basic Rules for Oxyacetylene Welding

Blow out cylinder valve Release regulator Stand to one side of regulator Open cylinder valve slowly Not more than 15 psi

Basic Rules (cont.)

Purge oxygen and acetylene passages Light the acetylene Never use oil or grease Do not use oxygen Keep your work area clean

Storage area must be well ventilated Cylinders must be at least 20 feet from

combustibles Valves must be closed Valve protection must be in place Inside storage must be limited to 2,000 cubic feet. Cylinders must be stored in upright position Oxygen must be at least 20 feet from fuel gas or

5 feet with a 1/2 hour fire barrier

Storage of Fuel Cylinders

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 11/2 turns

Gas Cylinder Precautions

Protective Devices

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

Arc Welding

Electric current fuses parent metal and welding rod

Indispensable in metal working

Used for carbon and alloy steels and non-ferrous metals

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”

Shielding

Common Arc Welding Processes

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

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

Installation and Maintenance

Welding Health Hazards

Zinc Cadmium Beryllium Iron Oxide Mercury Lead Fluorides Chlorinated

hydrocarbon solvents

Phosgene Carbon monoxide Ozone Nitrogen Oxides

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Welding Physical Hazards

Ultraviolet radiation Infrared radiation Intense visible light

Lens Shades for Typical Welding

Welding Process Shielded metal arc Gas metal arc Gas Tungsten arc Torch brazing Gas welding

Lens Shade Number 10-14 11-12 12

3 or 4 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.