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OIL & GAS WELL DRILLING RISKS - WELDING, CUTTING AND BRAZING
All hot work is potentially hazardous and a hazard assessment should be performed to determine where the hazards exist.
Potential Hazard:
Injury and illness caused by hot work (such as, welding fumes, UV light, sparks, noise, or skin injury).
Possible Solutions:
Inspect the work area to ensure that all fuel and ignition sources are isolated by shielding, clearing the area, lockout/tagout, soaking flammable material with water.
Wear appropriate PPE, such as face shield, leather welder's vest, and gauntlet gloves. Use cotton or denim clothing.
Provide UV shielding for arc welding where practical.
Inspect welding and cutting equipment before use (arc or gas welding/burning).
Leak test gas torches, gauges, and hoses.
Review the hot work permit if available.
Ensure the availability of adequate fire watch/fire protection equipment.
Ensure adequate ventilation from toxic welding and cutting fumes.
Special Hazard:
Accumulation of toxic gases within a confined space.
A hazardous atmosphere exists in oxygen-deficient (atmospheric concentration of less than 19.5 percent) or oxygen-enriched (atmospheric concentration of more than 23.5 percent). 29 CFR 1910.146 confined space entry.
Possible Solutions:
Ventilate toxic metal fumes mechanically, if entering a confined space, such as inside of a mud tank, water tank, oil tanks, hoppers, sump, pit or cellar.
Use a written permit system to document authorization to enter, the work to be performed, and the results of the gas monitoring where there is a potential for toxic, flammable, or oxygen-deficient atmosphere. Both a hot work and confined entry permit may be required for welding, cutting or brazing within a confined space.
Eye and face protection is the first and most important category of PPE that comes to mind for a welder. But it’s not the only protective equipment category of importance—protective apparel, respiratory protection, gloves, flame-resistant aprons, leggings, hearing protection, foot protection, as well as protective screens, fire extinguishing equipment, and adequate ventilation are all covered by the ANSI Z49.1:2005 standard, Safety in Welding, Cutting, and Allied Processes, for which the American Welding Society serves as the secretariat. The AWS Safety and Health Committee also makes it available as a free download from the AWS website (www.aws.org/safety/), along with 41 downloadable fact sheets on hazards ranging from welding fumes to burns, slips and falls, noise, radiation, falling objects, electrical hazards, confined spaces, and many more.
The website and the standard's text are worthwhile reading for anyone needing information about recommended health and safety practices for all types of welding.
Table 1 in the standard is the guide for welding helmet lens shade numbers. It lists both minimum protective shade numbers and suggested numbers for shield metal arc welding, gas metal arc welding and flux cored arc welding, gas tungsten arc welding, air carbon arc cutting, plasma arc welding, plasma arc cutting, and carbon arc welding, with higher arc currents necessitating higher shade numbers.
The standard specifies that filter lenses and a welder's helmet or hand shield must comply with ANSI/ISEA Z87.1-2010, Occupational and Educational Eye and Face Protection Devices. "Helmet and hand shield bodies shall be made of material that is thermally and electrically insulating, noncombustible, or self-extinguishing, and opaque to visible, ultraviolet, and infrared radiation," it states in the section 4.2.2., which covers requirements for eye and face protection.
Even when the welder is wearing a helmet, he or she also should wear Z87.1 approved safety glasses with sideshields or goggles, AWS and welding equipment suppliers note.
At the outset this standard explains that it is written to so as to be suitable for issuing it to a welder and shop managers and serve as practical information to help them perform their functions safely, and also that it contains information useful for educators, industrial hygienists, engineers, and others responsible for safety and health in welding.
The standard specifies that protection clothing should "minimize the potential for ignition, burning, trapping hot sparks, or electric shock," and that all welders and cutters shall wear protective, flame-resistant gloves.
Welders are cautioned to keep their protective apparel dry, clean, and in good repair. Oil, grease, or solvents may burn easily, and frayed clothing is especially susceptible to ignition and burning, so it should not be worn while welding or cutting, an explanatory note in the standard states.
Several welding processes may produce high levels of noise. The standard states that noise shall be controlled at the source when feasible and, if control methods can't lower noise exposures within allowable limits, PPE such as ear muffs or ear plugs shall be used.
The standard identifies several materials for which special ventilation precautions must be taken if the materials are present as "other than trace constituents in welding, brazing, or cutting operations and unless breathing zone sampling under the most adverse conditions" shows that the level of hazardous constituents are within allowable limits. They include antimony, arsenic, barium, chromium, cobalt, copper, lead, manganese, mercury, and nickel.
An OSHA fact sheet1 explains methods for controlling welders’ exposures to welding fumes and gases, notably through general ventilation and local exhaust ventilation. The sheet explains that fume hoods, fume extractor guns, and vacuum nozzles should be kept close to the plume source to remove the maximum amount of fume and gases, portable or flexible exhaust systems should be positioned to draw fume and gases away from the welder’s breathing zone, and exhaust ports should be positioned away from other workers. This 2013 fact sheet recommends that shop managers consider substituting a process that generates less fume or uses a less toxic consumable. Welding should not be done in confined spaces without ventilation, according to OSHA’s regulations, and respiratory protection may be required if work practices and ventilation can’t reduce fume and gas exposures to safe levels.
Acute exposures to welding fume and gases can cause eye, nose, and throat irritation, dizziness, and nausea, which prolonged exposures to welding fume may cause lung damage and lung, larynx, or urinary tract cancers.
OSHA standards applicable to welding include:
Welding, Cutting & Brazing -- 29 CFR 1910 Subpart Q
Welding & Cutting -- 29 CFR 1926 Subpart J
Welding, Cutting & Heating -- 29 CFR 1915 Subpart D
Permit-required confined spaces -- 29 CFR 1910.146
Confined & Enclosed Spaces & Other Dangerous Atmospheres in Shipyard Employment -- 29 CFR 1915 Subpart B
Hazard Communication -- 29 CFR 1910.1200
Respiratory Protection -- 29 CFR 1910.134
Air Contaminants -- 29 CFR 1910.1000 (general industry), 29 CFR 1915.1000 (shipyards), and 29 CFR 1926.55 (construction)
Fire Prevention
Obviously, it is imperative to remove combustible items from the area or ensure they are protected from fire hazards before welding commences. Welding curtains can be assembled quickly to prevent nearby personnel from sparks, UV light, and fumes.
Fire extinguishing equipment should be ready for use where welding and cutting work is being done. The ANSI Z49.1 standard states that, where fire sprinkler protection is in place, "it shall remain operable during the welding or cutting." This section of the standard also states that it is permitted to temporarily shield automatic sprinkler heads with noncombustible sheet material or damp cloth guards, when the heads could be activated by the heat of the work.
A key practice the authorities stress is to ensure containers are thoroughly cleaned and rendered safe before welding or cutting on them may begin. "Even a water tank should be considered hazardous unless a qualified person has declared it safe to weld or cut," an explanatory note in the ANSI Z49.1 standard states.
Canada's Protective Eyewear Standard
The Canadian Standards Association standard Z94.3.1, Selection, use, and care of protective eyewear, contains similar provisions. It establishes six classes, with each class having a specific use:
Class 2C -- direct non-ventilated goggles with radiation protection
Class 3 -- welding helmets
Class 4 -- hand shields
Class 5C -- non-rigid helmets with radiation protection
Class 6B -- faceshields with radiation protection
Class 7B -- respirator facepiece with radiation protection
The Canadian Centre for Occupational Health & Safety's website, www.ccohs.ca, offers these recommendations for welding helmet selection and use:
Choose a tight-fitting helmet to help reduce light reflection into the helmet through the space between the shell and the head.
Wear the helmet correctly. Do not use it as a hand shield.
Protect the shade lens from impact and sudden temperature changes that could cause it to crack.
Use a cover lens to protect the filter shade lens. Replace the cover lens if it gets scratched or hazy.
Make sure to replace the gasket periodically if your helmet uses one.
Replace the clear retaining lens to protect your eyes from broken pieces.
Clean lenses periodically.
Discard pitted or damaged lenses.
Consulting these standards and sources will help welders and shop managers ensure all welding and cutting processes are completed safety.
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