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SECTION B10 : CUTTING
AND WELDING (HOT WORK) OPERATIONS
Introduction
Cutting and welding operations (commonly referred to as hot work) are
associated with machine shops, maintenance, and construction activities,
as well as certain laboratory-related activities, such as glass blowing
and torch soldering. Potential health, safety, and property hazards result
from the fumes, gases, sparks, hot metal and radiant energy produced during
hot work. Hot work equipment, which may produce high voltages or utilize
compressed gases, also requires special awareness and training on the
part of the worker to be used safely. The hazards associated with hot
work can be reduced through the implementation of effective control programs.
Scope and Application
The Occupational Safety and Health Administration
(OSHA) prohibits cutting and welding operations unless appropriate
steps are taken to minimize fire hazards, such as removal or guarding
of combustible materials and, when possible, restricting hot work to specially
designated areas. Departments where hot work is performed are responsible
for ensuring that adequate controls and procedures are in place before
work begins.
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Program Description
Cutting and welding operations often are found in maintenance,
but can also occur in research settings. Adequate controls and procedures
must be used to minimize the hazards associated with these activities.
General Cutting and Welding Controls
Areas where hot work is done should be properly designated
and prepared. Combustible and flammable materials within the work
area should be protected against fire hazards and the operation should
not pose a hazard to others in nearby areas. To help achieve this,
the following controls should be used:
- Cutting and welding operations
restricted to authorized,
properly trained individuals;
- If possible, hot work performed in
a properly designed shop area equipped with all necessary
controls and adequate ventilation;
- Move combustible materials at least 35 feet from the work site.
If this is not possible, protect combustible materials
with metal guards or by flameproof curtains or covers (other than
ordinary tarpaulins);
- Cover floor and wall openings within 35
feet of the work site to prevent hot sparks from
entering walls or falling
beneath floors or to a lower level;
- Fire resistant curtains and
/or tinted shields used to prevent fire, employee
burns, and ultra-violet light exposure.
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Ventilation and Atmospheric
Testing Hot work should not be conducted in the presence of explosive
mixtures of flammable gases, vapors, liquids, or dusts or where explosive
mixtures could develop inside improperly prepared tanks or equipment.
Atmospheric testing and monitoring for combustible gases and vapors
should be done before work begins and at regular, predetermined intervals
thereafter. Ventilation of the work site, either through local or general
exhaust ventilation, should be adequate for the work performed.
Fire Protection
A person other than the operator should perform fire
watch duties and remain at the work site for at least 30 minutes after
hot work operations have ended. Additionally, the following steps
should be taken:
Personal Protective Equipment
Personal protective equipment specifically designed
for hot work should be provided to and used by workers (see Section
B4, Personal Protective Equipment). The potential for toxic fume
emissions from the material being worked on or surface coatings should
be considered, and appropriate steps should be taken to provide for
respiratory
protection.
Cutting and Welding in Confined Spaces
When cutting or welding is to be done in confined spaces,
appropriate entry procedures should be followed (see Section
B9, Confined Space Entry). A model Confined Space Entry Program
is available through the Office of Environmental Health and Safety
(EHS).
Compressed Gas Cylinder Storage and Handling
Storage and handling of compressed gas cylinders are
important parts of many cutting and welding operations. The following
should be observed:
- Oxygen and fuel gas cylinders should be stored separately
with the protective valve caps in place. Except when in use,
oxygen and fuel gas cylinders should be stored at least 20 feet
apart or
separated by a noncombustible wall at least 5 feet high;
- Cylinder carts equipped with a cylinder restraint,
such as a chain or strap, should be used for all transporting
of compressed gas cylinders;
- Cylinders should be secured from tipping, in an
upright position;
- Regulators must be compatible with the cylinder
and its contents. Many regulators are similar in design and
construction. Check the regulator’s model number and compare that with the cylinder’s
requirements.
Hot Work Permits
Hot work permits should be developed by departments where cutting
or welding is performed. Hot work permits can help minimize the risk
of fire during cutting and welding activities by serving as a checklist
for operators and those performing fire watch duties. The person responsible
for issuing permits should be qualified to examine the work site and
ensure that appropriate protective steps, such as those listed in
this section, have been taken. A hot work permit should be issued
at the beginning of each shift for each specific operation.
Training
All persons performing hot work should be trained in
proper equipment operation, handling and storage of welding materials,
compressed gas safety, chemical hazards, and in working procedures,
including the written hot work permit. Additional training may also
be necessary in the proper selection and use of personal protective
equipment. Training in confined space entry is necessary before working
in such areas.
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Roles and Responsibilities
Department
- Develop a hot work permit.
- Provide workers with specific training on hot work
procedures.
Supervisors
- Issue hot work permits.
- Ensure procedures are followed.
EHS
- Provide general training on hot work procedures.
- Provide a periodic audit of hot work procedures.
Individual
- Attend training.
- Follow hot work procedures.
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For More Information Contact an EHS Safety
Engineer at 258-5294.
A Cutting and Welding Self-Audit Checklist is available
through EHS or may be downloaded as a PDF
or a customizable Word document.
The following model programs are available through EHS:
- Hot work permit
- Confined Space Entry Program
- Personal Protective Equipment Hazard Assessment
The following references are available through EHS:
- Safe Storage and Handling of Gases, Airco,
Undated.
- Handbook of Compressed Gases, Compressed
Gas Association, 1966
- Workers Deaths in Confined Spaces, A Summary
of Surveillance Findings and Investigative Case Reports, National
Institute for Occupational Safety and Health, 1994
- American National Standard Safety Requirements
for Confined Spaces, American Society of Safety Engineers, 1989
- Welding, Cutting and Brazing, 29 CFR
1910 Subpart Q
- Personal Protective Equipment, 29 CFR
1910 Subpart I
- Permit Required Confined Spaces, 29 CFR
1910.146
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