Hot work is any work that involves burning, welding, using
fire- or spark-producing tools, or that produces a source of ignition. Welding and cutting operations are common to drilling and servicing
operations.
Test for flammable gases in the work area before starting
any hot work. Potentially hazardous areas include, but are not limited to, well
heads, fuel tanks, mud tanks, tank batteries, gas separators, oil treaters, or
confined spaces where gases can accumulate.
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Fig. 1. Hot work - welding
|
 Hot
Work, Fire, and Explosive Hazards |
Fig. 2. Welding with fire control
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Workers performing hot work such as welding, cutting, brazing, soldering, and grinding are exposed to the risk of fires
from ignition of flammable or combustible materials in the space, and from leaks
of flammable gas into the space, from hot work equipment.
Potential Hazard:
- Getting burned by fires or explosions during hot work.
Possible Solutions:
The basic precautions for fire prevention are:
-
Perform hot work in a safe location, or with fire hazards removed or
covered. [1910.252(a)(1)(i)]
-
Use guards to confine the heat, sparks, and slag, and to protect the immovable
fire hazards. [1910.252(a)(1)(ii)]
Special Precautions:
-
Do not perform hot work where flammable vapors or combustible materials
exist.
Work and equipment should be relocated outside of the hazardous areas, when
possible. [1910.252(a)(1)(ii)]
-
Make suitable fire-extinguishing equipment immediately available. Such equipment
may consist of pails of water, buckets of sand, hose, or portable
extinguishers. [1910.252(a)(2)(ii)]
-
Assign additional personnel (fire watch) to guard against fire while hot work
is being performed in locations where anything greater than a minor fire might
develop [1910.252(a)(2)(iii)(A)],
or if any of the following conditions exist:
-
Appreciable combustible material is closer than 35 feet to
the point of operation.
-
Appreciable combustibles are more than 35 feet away but are
easily ignited by sparks.
-
Wall or floor openings within a 35-foot radius expose
combustible material in adjacent areas including concealed spaces in walls or
floors.
-
Combustible materials are adjacent to the opposite side of
metal partitions, walls, ceilings, or roofs and are likely to be ignited by
conduction or radiation.
Fire watchers shall:
-
Have fire-extinguishing equipment
readily available and be trained in its use.
-
Be familiar with
facilities for sounding an alarm in the event of a fire.
-
Watch for fires in all exposed areas, try to extinguish them only when
obviously within the capacity of the equipment available, or otherwise
sound the alarm.
-
Maintain the fire watch at least a half
hour after completion of welding or cutting operations to detect and
extinguish possible smoldering fires. [1910.252(a)(2)(iii)(B)]
Potential Hazard:
- Getting burned by a flash fire or explosion that results from an accumulation of flammable gases, such as Methane or Hydrogen Sulfide, around
the wellhead area.
Possible Solutions:
-
Monitor the atmosphere with a gas detector. If a flammable or combustible gas
exceeds 10 percent of the lower explosive level (LEL), the work must be stopped.
-
Identify the source of the gas and repair the leakage.
Additional References:
-
OSHA Standards
- 1910.106, Flammable and Combustible Liquids.
- 1910.252, Welding, Cutting, and Brazing - General Requirements.
- 1910.253, Oxygen-fuel gas welding and cutting.
- 1910.254, Arc welding and cutting.
- 1910.255, Resistance welding.
-
API RP54, Recommended Practice for Occupational Safety for Oil and Gas Well
Drilling and Servicing Operations
-
API Publication 2201
-
NFPA 30, 51-B, Flammable and Combustible Liquids Code, National Fire Protection Association
-
Hot Work.
AESC, 12 KB PDF, 2 pages.
|
| Welding,
Cutting and Brazing |
Fig. 3. Welding - hot work
|
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). 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:
-
AESC Recommended Safe Procedures and Guidelines for
Oil and Gas Well Servicing. Section X, Welding, Cutting and Brazing and Hot
Work, pp. 77-80, April 2000.
-
ANSI Z49.1-67 Safety in Welding and Cutting, American National Standards Institute.
-
AWS Z49.1-88, Safety in Welding and Cutting and Applied Processes, American Welding society.
|
| Cylinder
Storage |
Fig. 4. Properly stored cylinders
|
Potential Hazard:
- Falling or rolling injuries from improper gas cylinder storage
Possible Solutions:
- Ensure cylinders are properly stored in an upright position and chained in separate racks.
- Store full and empty cylinders separately.
Potential Hazard:
- Valve opening or break off, exposing workers to toxic fumes and flammable
gas, caused by improper gas cylinder storage
Possible Solutions:
- Store cylinder properly.
- Always remove gauges and regulators, and install protective valve caps
before transporting.
Potential Hazard:
- Gas cylinders causing fires or explosions
Possible Solutions:
- Store cylinders in a dry, well-ventilated location.
- Avoid storing flammable substances in the same area as gas
cylinders.
- Avoid storing cylinders of oxygen within 20 feet of cylinders
containing flammable gases.
- Store all cylinders upright and chained in separate racks.
- Store full and empty cylinders separately.
Additional Information:
-
Compressed Gas Cylinders.
AESC, 16 KB PDF, 3 pages.
|
| Grinding |
Fig. 5. Hand grinding
|
Potential Hazard:
- Grinding (that results in sparks, noise, eye and
skin injury from flying metal filings, grinding wheel pieces, etc.).
- Having fingers or hands caught in the grinding wheel, resulting in amputation.
- Being struck by portable grinder.
Possible Solutions:
-
Wear appropriate PPE, such as face shield. Use cotton or denim clothing.
-
Inspect grinding equipment before use.
-
Review the hot work permit if available.
-
Ensure the availability of adequate fire watch/fire protection equipment.
|
| Well
Site Ignition Sources |
Fig. 6. Ignition source
|
There
are a
number
of
potential
sources
of
ignition
for
flammable
gases
and
liquids
on the
drill
site. It
is
necessary
to
provide
for a
general
ignition
safety
program
which
could
pre-empt
potential
hazards
of fire
and
explosion.
Potential Hazard:
- Ignition and explosions of
flammable
gases
or
vapors
from:
- Internal-combustion engine
sparks
- Open flames from any source
- Smoking
- Welding operations
- Electric power tools
- Two-way radios
- Vehicles with catalytic
converters
- Portable generators
Possible Solutions:
- Provide spark arrestors for
internal-combustion engines.
- Post "NO SMOKING" signs
wherever
a
flammable
gas
or
vapor
hazard
exists.
- Locate "spark producing"
equipment or facilities well away from
potential hazard areas.
- Prohibit vehicles with catalytic
converters from the immediate vicinity
of the rig.
- Prohibit open flames from the vicinity
of the rig.
Additional Information:
- API, 500, 505
- API, RP54
- IADC, Accident
Prevention Reference Guide
-
AESC, Recommended
Safe
Procedures
and
Guidelines
for
Oil
and
Gas
Well
Servicing
- 1910.106, OSHA Flammable and Combustible Liquids.
- 1910 Subpart S, OSHA Electrical
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