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.
Additional
Information:
ANSI
Z49.1-67 Safety in Welding and Cutting, American National Standards Institute.
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.
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.
References
1. https://www.osha.gov/Publications/OSHA_FS-3647_Welding.pdf
2. http://www.lincolnelectric.com/en-us/education-center/welding-safety/Pages/welding-safety.aspx
3. http://www.millerwelds.com/resources/safetyresources.html
1. https://www.osha.gov/Publications/OSHA_FS-3647_Welding.pdf
2. http://www.lincolnelectric.com/en-us/education-center/welding-safety/Pages/welding-safety.aspx
3. http://www.millerwelds.com/resources/safetyresources.html