Welding
A person in a welding helmet is shown welding on a piece of metal.
Date Posted: 05/11/2024
According to the National Fire Protection Agency (NFPA), there are, on average, 4,630 structure fires involving hot work per year. Any time equipment that produces a spark or open flame or a process that generates excessive heat, there is a risk of fire or explosion. Flames and sparks are the leading causes of fire or explosions during welding and cutting. Sparks can travel up to 35 feet in a work area. Sparks can also pass through wall/ceiling/floor openings or be lodged within cracks during the welding and cutting. Combustibles such as wood, paper, rags, dust, and flammable liquids can also increase the risk of fire and explosion.
Your First Considerations
Due to the hazardous nature of the work, try to eliminate the need for hot work when feasible. Hot work hazards can be avoided with an alternative job completion method. Some options include the following:
Screwed, flanged, or clamped pipe.
Manual hydraulic shears.
Mechanical bolting or pipe cutting.
Compressed air-actuated fasteners.
Hazards of Hot Work
Hot work can unite all three parts of the fire triangle: oxygen, fuel, and an ignition source.
Oxygen Enrichment
Oxygen is present in the ambient air at approximately 21% by volume. Therefore, unsafe practices involving pure oxygen can cause oxygen enrichment (over 22 percent by volume) in the workplace and increase the risk of fire or explosion.
Fuel Sources in the Work Area
Fuel includes anything that can be ignited. Examples of common fuels include the following:
Materials such as wood, plastic, insulation, and roofing materials, including those in concealed spaces.
Flammable and combustible liquids or gases such as fuel, paint, and cleaning solvents.
Simple combustibles include rags, paper, cardboard, lumber, and furnishings.
Ignition (Heat) Sources
Ignition sources can be as simple as the hot work itself. Ignition results when any heat source sufficient to ignite a fuel does so. It can occur through the direct or indirect application of heat. Direct application of heat includes welding, cutting, and burning. The indirect application includes heat from metal surfaces to fuel sources on the other side (e.g., through to the other side of a bulkhead) and sparks traveling to a distant fuel source (e.g., to a pool of liquid or other combustible material).
Health Hazards
Hot work may generally be completed without mechanical ventilation or respiratory protective equipment. Still, where an unsafe accumulation of contaminants exists because of unusual physical or atmospheric conditions, suitable mechanical ventilation or respiratory protective equipment may be required. Specific health hazards that may be created by hot work include, but are not limited to:
Chronic
Lung cancer
Chronic Obstructive Pulmonary Disease (COPD)
Occupational asthma
Ocular melanoma
Acute
Irritation of the throat or lungs
Acute irritant-induced asthma
Metal fume fever
Acute pneumonia
When do I Need to Use a Hot Work Permit?
A Hot Work Permit is required for any temporary operation involving open flames or producing heat and sparks, which could ignite nearby items unless they are protected or the work is completed in a designated area. This includes, but is not limited to, welding, burning, cutting, brazing, grinding, and soldering. The Hot Work Permit is a formal process to ensure that potential safety issues are addressed in the area where you will be doing the work and that someone else agrees it is safe to do it.
Personal Protective Equipment for Hot Work
Welding and cutting can produce hazards such as sparks, spatter, radiation (infrared, ultraviolet, and blue light), slag, heat, hot metal, fumes and gases, and even electric shock. Since these hazards may cause burns, injury, or death, it is essential always to wear proper PPE.
Eye and Face Protection
Wear a helmet with a filter lens and cover plate that complies with ANSI Z87.1 for protection from radiant energy, flying sparks, and spatter.
Helmets and hand shields must protect the face, forehead, neck, and ears to a vertical line in the back of the ears from the direct radiant energy from the arc and direct weld spatter.
Helmets shall be made of material that complies with ANSI Z49.1.
Filter lenses and cover plates must meet the tests prescribed in ANSI Z87.1.
Wear approved safety glasses with side shields (or goggles) under your helmet.
The safety glasses with side shields (or goggles) protect against flying metal, slag chips, grinding fragments, wire wheel bristles, and similar hazards, which can ricochet under the helmet. Choose a filter lens shade according to the Lens Shade Selector Chart in ANSI Z49.1
Head and Ear Protection
Wear a fire-resistant welder’s cap or head covering under your helmet. It will protect your head from flying sparks, spatter, and burns.
When working overhead, wear approved earplugs or muffs. They prevent sparks, spatter, and hot metal from entering your ears and causing burns.
If hazardous noise is present, wear approved earplugs or muffs to protect your hearing and prevent hearing loss.
Body Protection
Wear oil-free protective clothing. Heavier materials such as leather or Flame-Resistant Clothing (FRC), chemically treated to reduce its combustibility or inherently flame-resistant, are preferable to lighter materials because they are more difficult to ignite. After repeated washing or cleaning, clothing treated with flame-resistant materials may lose some protective characteristics. Materials that can melt and cause severe burns should not be used as clothing when welding or cutting.
Use long-sleeved shirts (no t-shirts), and button the cuffs, pockets, and collar. This protects your arms and neck from radiation exposure and skin burns.
Wear heavy, long pants without cuffs that overlap the tops of your work shoes.
Keep clothing clean (free of oil, grease, or solvents that may catch fire and burn quickly).
Wear leather aprons and sleeves as needed. Leather protects better than most materials.
Firewatch
A fire watch is a person(s) responsible for closely observing hot work operations to detect the signs of a potential fire. A fire watch is accountable for stopping work if necessary and carrying out the steps for restoring safe conditions within the hot work area. However, the person performing the hot work must be someone other than the fire watch. That worker is concentrating on their work and will only be able to react slowly enough should a fire ignite. Therefore, another employee or employee must be assigned to fire watch duty. Similarly, personnel actively engaged as the fire watch cannot perform other tasks. Their focus and responsibility are to watch for and respond to fires during hot work.
Note: Fire watches are responsible for stopping work if any changes occur during hot work that can result in or contribute to the spread of fire (e.g., the introduction of flammable/ combustible materials).
References
OSHAfactsheet-Eye Protection During Welding
NFPA 51B: Standard for Fire Prevention During Welding, Cutting, and Other Hot Work
