Welding, Brazing, Cutting: Hot Work Safety Guidelines
Guidelines for welding, brazing, and cutting include fire prevention, hot work permits, fire watch requirements, and prohibited areas to ensure worker safety and prevent accidents. Proper training, fire protection measures, and adherence to standards such as NFPA 51.B are emphasized to mitigate fire risks.
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Welding, Brazing, Cutting = Hot Work Bureau of Workers Comp PA Training for Health & Safety (PATHS) OSHA 29CFR1910.251-255 Subpart Q PPT-018-01 1
General Requirements Fire Prevention & Protection NFPA 51 B Standard for Fire Prevention in Use of Cutting and Welding Processes. Move all fire hazards away from work area. Use guards (fire blankets, etc.) if fire hazards cannot be moved. PPT-018-01 2
General Requirements (cont.) Working on floors with openings/cracks/grating: fire blankets to protect lower level from sparks and slag. Have suitable fire extinguishing agents (extinguisher, water, sand, etc.) ready near cutting and welding operations. PPT-018-01 3
Fire Watch Requirements A fire watch must be available where there is a fire potential or where; Combustible materials are closer than 35 feet to the point of operation. Walls opening within the 35 foot radius, exposing combustible material. Material opposite metal walls and roofs could catch fire from conduction or radiation. PPT-018-01 4
Fire Watch Requirements (cont.) A person acting as a fire watch must have fire extinguishing agents readily available and be trained in their use. A fire watch must be maintained for at least 30 minutes after work ceases. PPT-018-01 5
Before Welding Obtain a burn permit (hot work permit) authorized by the designated responsible person. Sweep away all paper clippings, wood shavings or textile fibers within a radius of 35 feet of cutting/welding operations. PPT-018-01 6
Hot Work Permit PPT-018-01 7
Hot Work Permit (cont.) Is a hot work permit required under related OSHA standards? NO! Is a hot work permit a best practice? YES! PPT-018-01 8
Welding/cutting is prohibited in Areas not authorized by company management. Areas near large quantities of readily-ignitable materials, such as baled paper or cotton. Sprinkler-equipped buildings while sprinklers are impaired or out of order. The presence of explosive atmospheres such as unclean or improperly-prepared tanks. PPT-018-01 9
Management Responsibilities Recognize safe usage of welding/cutting/burning equipment on its property. Establish areas for cutting and welding operations. Protect welding leads from damage by vehicles, slag, etc. PPT-018-01 10
Management Responsibilities (cont.) Designate a responsible individual to authorize hot work permits. Insist that cutters/welders are trained in safe work habits for their specific tasks. Advise all contractors about flammable or hazardous materials. PPT-018-01 11
Welding or Cutting Containers Ensure that used containers (drums, barrels, tanks) have been thoroughly cleaned of flammable materials including grease, tars and acids. All spaces must be vented and purged before welding. Purging with inert gas is recommended. PPT-018-01 12
Confined Spaces Keep all cylinders outside of confined spaces. Turn off gases at cylinders and purge lines when away from the confined-space work area. Remove electrodes (rods) from electrode holders (stingers) and disconnect machine power source. PPT-018-01 13
Working at Heights Workers on platforms, scaffolds or open sided floors must be protected from falls with: A guardrail system or lifeline. Safety harnesses with lanyards. Welding cable and hoses must be kept clear of passageways, ladders and stairways. PPT-018-01 14
Eye Protection Requirements Welders and welders helpers must wear appropriate eye protection. Lens of welding hoods, cutting goggles, and hand shields must: Be arranged to protect face, neck and ears from radiant energy. Be made of tempered glass and free of bubbles. Have lens shade readily identified on glass. PPT-018-01 15
Radiation Hazards Results of excessive exposure to ultraviolet radiation: Causes eyes to feel like they are full of sand. Can lead to premature cataracts of the eyes. Protect against ultraviolet radiation, sparks, fumes and slag. Wear protective clothing and respirators. Provide warning signs to warn of hot metal. Use ventilation or suitable respiratory protection. PPT-018-01 16
Ventilation General - mechanical, 2000fpm 10,000 ft3 per welder ceiling less than 16 feet around structural barriers Local - mechanical, 100 linear fpm in weld zone When ventilation cannot meet the needs supplied, air respirators shall be used. PPT-018-01 17
Ventilation (cont.) Mostly require local exhaust ventilation or airline respirators (reference OSHA standard): Fluorine compounds Zinc Lead Beryllium Cadmium Mercury Stainless steel Chlorinated hydrocarbons PPT-018-01 18
Acetylene Liquefied petroleum gas Formed when calcium carbide is submerged in water or in petrochemical processes. Very unstable at pressures over 15 psi. Never operate above 15 psi. LEL = 2%, UEL=100% PPT-018-01 19
Acetylene (cont.) Does not require high storage pressure (the case with most LP gases). Is usually pressurized around 250 psi. Turns to liquid over 300 psi. Acetone liquid in cylinder lying horizontally takes at least 1 hour to settle to bottom when cylinder is set up vertically. PPT-018-01 20
Acetylene Gas Cylinders Gases in a typical acetylene cylinder: Acetylene gas 36% Acetone 42% Porous filler 8-10% Reserve volume 10-12% Cylinders are filled with a porous material with millions of voids to help keep pressure from building up. PPT-018-01 21
Oxygen Cylinders Oxygen will not burn but will support combustion. Oxygen is pressurized around 2,200 psi and the cylinder is hollow. PPT-018-01 22
Oxygen Cylinders (cont.) Keep oil and grease off oxygen cylinder valves and fittings (oil and grease will burn violently). Protect valves of oxygen cylinders (if valves are knocked off, the cylinder becomes a bomb ). Separate oxygen cylinders from fuel gas cylinders or combustible materials by a distance of at least 20 feet. PPT-018-01 23
To Begin Welding or Cutting Oxygen = threads-right-handed threads-left handed hoses-green Acetylene = hoses-red Crack cylinders to blow out dirt or dust. Open acetylene cylinders no more than 1 turns (3/4 turn recommended). Do not stand in front of regulator when turning it on, the diaphragm in the regulator could blow outward. PPT-018-01 24
To Begin Welding or Cutting Light acetylene first. Open acetylene valve. Adjust to no more than 15psi (5 to 7psi is common, depending on size of metal to be cut). Then turn on oxygen. Adjust valve at torch head to fine tune flame to where blue flame is about 1/4 inch. NOTE: Each fuel-gas cylinder lead should have a back-flow check valve and flash-back arrestor. PPT-018-01 25
To Stop Welding or Cutting Shut oxygen valve off first, then acetylene. Oxygen cylinder valves should be opened entirely. Turn main valve off and bleed lines. Mark empty cylinders MT or Empty with railroad chalk. When moving cylinders, roll them on their bottom edges. PPT-018-01 26
Special Precautions Welding fumes from zinc, cadmium, beryllium, lead, mercury and stainless steel are addressed in OSHA standards. Argon gas used in MIG welding operations must be handled as an inert gas and stored accordingly. PPT-018-01 27
Safe Handling of Gas Cylinders When transporting cylinders, secure vertically and with gauges unattached. Do not pry frozen cylinders - use warm water because of the fuse plug on the cylinder bottom. Do not use valve caps to lift cylinders. Improper and unsafe storage PPT-018-01 28
Safe Torch Handling Clean torch tips with tip cleaners, wires, etc. Do not re-light torch tip with hot metal. Welding Tip Orifice Cleaner Tip Cleaner in Use PPT-018-01 29
Review Only do hot work in designated/authorized areas. Ensure permit is in place and all parties are aware. Ensure fire protection equipment is readily available. Ensure fire watch is posted for at least 30 minutes after work is done. PPT-018-01 30
Review (cont.) If welding above openings/gratings ensure guarding is in place. Ensure welding gases and equipment are stored properly and safely. Ensure compressed gas cylinders are handled correctly. PPT-018-01 31
Any Questions? PPT-018-01 32
