WAC
296-307-48505 What requirements apply to flash welding equipment?
(1) Flash welding machines must have a hood to control flying
flash. In cases of high production, where materials may contain
a film of oil and where toxic elements and metal fumes are given
off, ventilation must be provided according to WAC
296-307-50009 through 296-307-50029.
(2) For the protection of the operators of nearby equipment,
fire-resistant curtains or suitable shields must be set up around
the machine and in such a manner that the operator's movements
are not hampered.
(3) If the welding process cannot be isolated, anyone who may
be exposed to the hazard of arc flash must be properly protected.
A qualified person must perform a job hazard analysis on the
operations to be performed on each welding machine to determine
the safeguards and personal protective equipment that shall be
used for each job.
WAC
296-307-48509 What maintenance requirements apply to resistance
welding equipment?
Qualified maintenance personnel must periodically inspect the
equipment and maintain records of the inspections. The operator
must be instructed to report any equipment defects to the supervisor
and the use of the equipment must be discontinued until safety
repairs have been completed.
WAC
296-307-49001 What environmental conditions must be taken
into account when selecting arc welding equipment?
Note: You may ensure that your equipment
is designed for safety by choosing equipment that complies with
the Requirements for Electric Arc-Welding Apparatus, NEMA EW-1-1962,
National Electrical Manufacturers Association or the Safety Standard
for Transformer-Type Arc-Welding Machines, ANSI C33.2-1956, Underwriters'
Laboratories.
(1) Standard machines for arc welding service must be designed
and constructed to carry their rated load with rated temperature
rises where the temperature of the cooling air is a maximum of
40°C (104°F) and where the altitude is a maximum of 3,300 feet,
and must be suitable for operation in atmospheres containing gases,
dust, and light rays produced by the welding arc.
(2) When exposed to the following or other conditions, machines
must be designed to safely meet the requirements of the service.
Open circuit (no load) voltages of arc welding and cutting machines
should be as low as possible consistent with satisfactory welding
or cutting being done. Following are the maximum limits:
(1) For alternating-current machines:
(a) Manual arc welding and cutting-80 volts.
(b) Automatic (machine or mechanized) arc welding and cutting-100
volts.
(2) For direct-current machines:
(a) Manual arc welding and cutting-100 volts.
(b) Automatic (machine or mechanized) arc welding and cutting-100
volts.
(3) When special welding and cutting processes require values
of open circuit voltages higher than the above, means must be
provided to prevent the operator from making accidental contact
with the high voltage by adequate insulation or other means.
Note: For a.c. welding under wet conditions
or warm surroundings where perspiration is a factor, the use of
reliable automatic controls for reducing no load voltage is recommended
to reduce the shock hazard.
(1) A controller integrally mounted in an electric motor driven
welder must be able to carry the rated motor current, must be
able to make and interrupt stalled rotor current of the motor,
and may serve as the running overcurrent device if provided with
the number of over-current units as specified by chapter 296-307
WAC Part T. Starters with magnetic undervoltage release should
be used with machines installed more than one to a circuit to
prevent circuit overload caused by simultaneously starting several
motors upon return of voltage.
(2) On all types of arc welding machines, control apparatus must
be enclosed except for the operating wheels, levers, or handles.
Note: Control handles and wheels should
be large enough to be easily grasped by a gloved hand.
(3) Input power terminals, tap change devices, and live metal
parts connected to input circuits must be completely enclosed
and accessible only by tools.
(4) Terminals for welding leads should be protected from accidental
electrical contact by employees or by metal objects i.e., vehicles,
crane hooks, etc. You may provide protection with:
Dead-front receptacles for plug connections;
Recessed openings with nonremovable hinged covers;
Heavy insulating sleeving or taping; or
Other equivalent electrical and mechanical protection.
If a welding lead terminal that is intended to be used exclusively
for connection to the work is connected to the grounded enclosure,
it must be done by a conductor at least two AWG sizes smaller
than the grounding conductor and the terminal must be marked to
indicate that it is grounded.
(5) No connections for portable control devices (such as push
buttons to be carried by the operator) must be connected to an
a.c. circuit of higher than 120 volts. Exposed metal parts of
portable control devices operating on circuits above 50 volts
must be grounded by a grounding conductor in the control cable.
(6) Auto transformers or a.c. reactors must not be used to draw
welding current directly from any a.c. power source having a voltage
exceeding 80 volts.
(1) The frame or case of the welding machine (except engine-driven
machines) must be grounded according to the requirements of chapter
296-307
WAC Part T.
(2) Conduits containing electrical conductors must not be used
for completing a work-lead circuit. Pipelines must not be used
as a permanent part of a work-lead circuit, but may be used during
construction, extension or repair if current is not carried through
threaded joints, flanged bolted joints, or caulked joints and
special precautions are used to avoid sparking at connection of
the work-lead cable.
(3) Using chains, wire ropes, cranes, hoists, and elevators to
carry welding current is prohibited.
(4) Where a structure, conveyor, or fixture is regularly used
as a welding current return circuit, joints must be bonded or
provided with adequate current collecting devices and appropriate
periodic inspection should be conducted to ensure that no electrocution,
shock, or fire hazard exists.
(5) All ground connections must be checked to determine that
they are mechanically strong and electrically adequate for the
required current.
WAC
296-307-49011 What requirements apply to supply connections
and conductors?
(1) A disconnecting switch or controller must be provided at
or near each welding machine without a switch or controller mounted
as an integral part of the machine. The switch must meet the requirements
of chapter 296-307
WAC Part T. Overcurrent protection must be provided as specified
in chapter 296-307
WAC Part T. A disconnect switch with overload protection or
equivalent disconnect and protection means, permitted by chapter
296-307
WAC Part T must be provided for each outlet intended for connection
to a portable welding machine.
(2) For individual welding machines, the rated current-carrying
capacity of the supply conductors must be at least that of the
rated primary current of the welding machines.
(3) For groups of welding machines, the rated current-carrying
capacity of conductors may be less than the sum of the rated primary
currents of the welding machines supplied. The conductor rating
must be determined according to the machine loading based on the
use to be made of each welding machine and the allowance permissible
in the event that all the welding machines supplied by the conductors
will not be in use at the same time.
(4) In operations involving several welders on one structure,
d.c. welding process requirements may require the use of both
polarities; or supply circuit limitations for a.c. welding may
require distribution of machines among the phases of the supply
circuit. In such cases, no load voltages between electrode holders
will be two times normal in d.c. or 1, 1.4, 1.73, or 2 times normal
on a.c. machines. Similar voltage differences will exist if both
a.c. and d.c. welding are done on the same structure.
(a) All d.c. machines must be connected with the same polarity.
(b) All a.c. machines must be connected to the same phase of
the supply circuit and with the same instantaneous polarity.
(1) Employees assigned to operate or maintain arc welding equipment
must be acquainted with the requirements of WAC
296-307-490,
296-307-495, and 296-307-500;
if doing gas-shielded arc welding, also Recommended Safe Practices
for Gas-Shielded Arc Welding, A6.1-1966, American Welding Society.
(2) Before starting operations, all connections to the machine
must be checked to make certain they are properly made. The work
lead must be firmly attached to the work; magnetic work clamps
shall be freed from adherent metal particles of spatter on contact
surfaces. Coiled welding cable must be spread out before use to
avoid serious overheating and damage to insulation.
(3) You must ensure that the welding machine frame grounding
is checked with special attention given to safety ground connections
of portable machines.
(4) Cylinders must be kept away from radiators, piping systems,
layout tables, etc., that may be used for grounding electric circuits.
Any practice such as the tapping of an electrode against a cylinder
to strike an arc is prohibited.
(5) There must be no leaks of cooling water, shielding gas or
engine fuel.
(6) You must ensure that the machine has proper switching equipment
for shutting down.
(7) Printed rules and instructions covering operation of equipment
supplied by the manufacturers must be strictly followed.
(8) Electrode holders when not in use must be placed so that
they cannot make electrical contact with persons, conducting objects,
fuel or compressed gas tanks.
(9) Cables with splices within 10 feet of the holder are prohibited.
The welder should not coil or loop welding electrode cable around
parts of the body.
(1) The operator should report any equipment defect or safety
hazard to the supervisor and discontinue using the equipment until
its safety is ensured. Repairs must be made only by qualified
persons.
(2) Machines that have become wet must be thoroughly dried and
tested before being used.
(3) Work and electrode lead cables should be frequently inspected
for wear and damage. Cables with damaged insulation or exposed
bare conductors must be replaced. Lengths of work and electrode
cables must be joined by connecting means specifically intended
for the purpose. The connecting means must have insulation adequate
for the service conditions.
WAC
296-307-49501 What basic fire prevention precautions must
be taken?
For more information on these basic precautions and the special
precautions of WAC
296-307-49503, including fire protection and prevention responsibilities
of welders, cutters, their supervisors (including outside contractors),
and management, see the Standard for Fire Prevention in Use of
Cutting and Welding Processes, NFPA Standard 51B, 1962.
The basic precautions for fire prevention in welding or cutting
work are:
(1) If the object to be welded or cut cannot readily be moved,
all movable fire hazards in the vicinity must be taken to a safe
place.
(2) If the object to be welded or cut cannot be moved and if
all the fire hazards cannot be removed, then guards must be used
to confine the heat, sparks, and slag, and to protect the fire
hazards.
(3) If the requirements of this section cannot be met, then welding
and cutting are prohibited.
WAC
296-307-49503 What special fire prevention precautions must
be taken?
When the nature of the work to be performed falls within the
scope of WAC
296-307-49501(2), certain additional precautions may be necessary:
(1) Wherever there are floor openings or cracks in the flooring
that cannot be closed, precautions must be taken so that no readily
combustible materials on the floor below will be exposed to sparks
that drop through. The same precautions must be observed with
regard to cracks or holes in walls, open doorways, and open or
broken windows.
(2) Suitable fire extinguishing equipment must be maintained
in a state of readiness for instant use. Such equipment may consist
of pails of water, buckets of sand, hose, or portable extinguishers
depending upon the nature and quantity of the combustible material
exposed.
(3) The following requirements apply to fire watch:
(a) Fire watchers are required whenever welding or cutting
is performed in locations where other than a minor fire might
develop, or any of the following conditions exist:
(i) Appreciable combustible material, in building construction
or contents, closer than 35 feet to the point of operation.
(ii) Appreciable combustibles are more than 35 feet away
but are easily ignited by sparks.
(iii) Wall or floor openings within a 35-foot radius expose
combustible material in adjacent areas including concealed
spaces in walls or floors.
(iv) 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.
(b) Fire watchers must have fire extinguishing equipment readily
available and be trained in its use. They must be familiar with
facilities for sounding an alarm in the event of a fire. They
must 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. A fire watch must be
maintained for at least a half hour after completion of welding
or cutting operations to detect and extinguish possible smoldering
fires.
(4) Before cutting or welding is permitted, the area must be
inspected by the individual responsible for authorizing cutting
and welding operations. The responsible individual must designate
precautions to be followed in granting authorization to proceed,
preferably in the form of a written permit.
(5) Where combustible materials such as paper clippings, wood
shavings, or textile fibers are on the floor, the floor must be
swept clean for a radius of 35 feet. Combustible floors must be
kept wet, covered with damp sand, or protected by fire-resistant
shields. Where floors have been wet down, employees operating
arc welding or cutting equipment must be protected from possible
shock.
(6) Cutting and welding are prohibited in the following situations:
(a) In areas not authorized by management.
(b) In sprinklered buildings while such protection is impaired.
(c) In the presence of explosive atmospheres (mixtures of flammable
gases, vapors, liquids, or dusts with air), or where explosive
atmospheres may develop inside uncleaned or improperly prepared
tanks or equipment that have previously contained such materials,
or that may develop in areas with an accumulation of combustible
dusts.
(d) In areas near the storage of large quantities of exposed,
readily ignitable materials such as bulk sulphur, baled paper,
or cotton.
(7) Where practical, all combustibles must be relocated at least
35 feet from the worksite. Where relocation is impractical, combustibles
must be protected with flameproofed covers or otherwise shielded
with metal or asbestos guards or curtains. Edges of covers at
the floor should be tight to prevent sparks from going under them.
This precaution is also important at overlaps where several covers
are used to protect a large pile.
(8) Ducts and conveyor systems that might carry sparks to distant
combustibles must be suitably protected or shut down.
(9) Where cutting or welding is done near walls, partitions,
ceiling, or roof of combustible construction, fire-resistant shields
or guards must be provided to prevent ignition.
(10) If welding is to be done on a metal wall, partition, ceiling,
or roof, precautions must be taken to prevent ignition of combustibles
on the other side, due to conduction or radiation, preferably
by relocating combustibles. Where combustibles are not relocated,
a fire watch on the opposite side from the work must be provided.
(11) Welding must not be attempted on a metal partition, wall,
ceiling, or roof having a combustible covering nor on walls or
partitions of combustible sandwich-type panel construction.
(12) Cutting or welding on pipes or other metal in contact with
combustible walls, partitions, ceilings or roofs must not be undertaken
if the work is close enough to cause ignition by conduction.
(13) You are responsible for the safe use of cutting and welding
equipment on your property and:
(a) Based on fire potentials of plant facilities, you must
establish areas and procedures for cutting and welding;
(b) You must designate an individual responsible for authorizing
cutting and welding operations in areas not specifically designed
for such processes;
(c) You must insist that cutters or welders and their supervisors
are suitably trained in the safe operation of their equipment
and the safe use of the process; and
(d) You must advise all contractors about flammable materials
or hazardous conditions of which they may not be aware.
(14) The supervisor must:
(a) Ensure that cutting and welding equipment is handled and
used safely.
(b) Determine the combustible materials and hazardous areas
present or likely to be present in the work location.
(c) Protect combustibles from ignition by the following:
(i) Have the work moved to a location free from dangerous
combustibles;
(ii) If the work cannot be moved, have the combustibles moved
to a safe distance from the work or have the combustibles
properly shielded against ignition; and
(iii) See that cutting and welding are so scheduled that
plant operations that might expose combustibles to ignition
are not started during cutting or welding.
(d) Secure authorization for the cutting or welding operations
from the designated management representative.
(e) Determine that the cutter or welder secures their approval
that conditions are safe before going ahead;
(f) Determine that fire protection and extinguishing equipment
are properly located at the site; and
(g) Ensure fire watches are available at the site when required.
(15) Cutting or welding is permitted only in areas that are or
have been made fire safe. Within the confines of an operating
plant or building, cutting and welding should preferably be done
in a specific area designed for such work, such as a maintenance
shop or a detached outside location. Such areas should be of noncombustible
or fire-resistive construction, essentially free of combustible
and flammable contents, and suitably segregated from adjacent
areas. When work cannot be moved practically, as in most construction
work, the area must be made safe by removing combustibles or protecting
combustibles from ignition sources.
WAC
296-307-49505 What precautions must be taken when welding
or cutting containers?
(1) No welding, cutting, or other hot work may be performed on
used drums, barrels, tanks or other containers until they have
been cleaned thoroughly enough to be certain that there are no
flammable materials present or any substances such as greases,
tars, acids, or other materials which when subjected to heat,
might produce flammable or toxic vapors. Any pipe lines or connections
to the drum or vessel must be disconnected or blanked.
(2) All hollow spaces, cavities, or containers must be vented
to permit the escape of air or gases before preheating, cutting
or welding. Purging with inert gas is recommended.
WAC
296-307-49507 What precautions must be taken when welding
in confined spaces?
(1) When arc welding work is stopped for a substantial time,
such as during lunch or overnight, all electrodes must be removed
from the holders and the holders carefully located so that accidental
contact cannot occur and the machine be disconnected from the
power source.
(2) In order to eliminate the possibility of gas escaping through
leaks or improperly closed valves, when gas welding or cutting,
the torch valves must be closed and the gas supply to the torch
positively shut off at some point outside the confined area whenever
the torch is not to be used for a substantial period of time,
such as during lunch hour or overnight. Where practical, the torch
and hose must also be removed from the confined space.
(1) Helmets or hand shields must be used during all arc welding
or arc cutting operations, excluding submerged arc welding. Goggles
should also be worn during arc welding or cutting operations to
provide protection from injurious rays from adjacent work, and
from flying objects. The goggles may have either clear or colored
glass, depending on the amount of exposure to adjacent welding
operations. Helpers or attendants must have proper eye protection.
(2) Goggles or other suitable eye protection must be used during
all gas welding or oxygen cutting operations. Spectacles without
side shields, with suitable filter lenses are permitted for use
during gas welding operations on light work, for torch brazing,
or for inspection.
(3) All operators and attendants of resistance welding or resistance
brazing equipment must use transparent face shields or goggles,
depending on the job, to protect their faces or eyes as required.
(4) Suitable goggles must be provided where needed for brazing
operations not above.
(1) Helmets and hand shields must be made of a material that
is an insulator for heat and electricity. Helmets, shields and
goggles must be not readily flammable and must be able to be sterilized.
(2) Helmets and hand shields must be arranged to protect the
face, neck and ears from direct radiant energy from the arc.
(3) Helmets must have filter plates and cover plates designed
for easy removal.
(4) All parts must be constructed of a material that will not
readily corrode or discolor the skin.
(5) Goggles must be ventilated to prevent fogging of the lenses
as much as practical.
(6) Cover lenses or plates should be provided to protect each
helmet, hand shield, or goggle filter lens or plate.
(7) All glass for lenses must be tempered, substantially free
from scratches, air bubbles, waves and other flaws. Except when
a lens is ground to provide proper optical correction for defective
vision, the front and rear surfaces of lenses and windows must
be smooth and parallel.
(8) Lenses must be marked with the source and shade.
(9) Following is a guide to select proper shade numbers. Individual
needs may vary.
Note: In gas welding or oxygen
cutting where the torch produces a high yellow light it
is desirable to use a filter or lens that absorbs the
yellow or sodium line in the visible light of the operation.
10
11
12
12
14
10-14
14
2
3 or 4
3 or 4
4 or 5
5 or 6
4 or 5
5 or 6
6 or 8
(10) All filter lenses and plates must meet the test for transmission
of radiant energy prescribed in ANSI Z 87.1-1968--American National
Standard Practice for Occupational and Educational Eye and Face
Protection.
(11) Where the work permits, an arc welder should be enclosed
in an individual booth painted with a finish of low-reflectivity
such as zinc oxide (an important factor for absorbing ultraviolet
radiations) and lamp black, or must be enclosed with noncombustible
screens similarly painted. Booths and screens must permit circulation
of air at floor level. Employees or other persons adjacent to
the welding areas must be protected from the rays by noncombustible
or flameproof screens or shields or must be required to wear appropriate
goggles.
(1) Employees exposed to the hazards created by welding, cutting,
or brazing operations must be protected by personal protective
equipment according to the requirements of chapter
296-307 WAC Part H. Appropriate protective clothing required
for any welding operation will vary with the size, nature and
location of the work to be performed.
(2) The following suggestions may be helpful when choosing protective
clothing:
(a) Except when engaged in light work, all welders should wear
flameproof gauntlet gloves.
(b) Flameproof aprons made of leather, asbestos, or other suitable
material may help to protect against radiated heat and sparks.
(c) Woolen clothing is better than cotton because it is less
easily ignited and helps to protect the welder from changes
in temperature. Cotton clothing, if used, should be chemically
treated to reduce its combustibility. All outer clothing such
as jumpers or overalls should be reasonably free from oil or
grease.
(d) Sparks may lodge in rolled-up sleeves, pockets, or cuffs.
Therefore sleeves and collars should be buttoned, and clothing
should have no front pockets. Trousers or overalls should be
uncuffed.
(e) For heavy work, fire-resistant leggings, high boots, or
other equivalent means should be used.
(f) In production work a sheet metal screen in front of the
employee's legs can provide further protection against sparks
and molten metal in cutting operations.
(g) Capes or shoulder covers made of leather or other suitable
materials should be worn during overhead welding or cutting
operations. Leather skull caps may be worn under helmets to
prevent head burns.
(h) For welding and cutting overhead or in extremely confined
spaces, ear protection is sometimes desirable.
(i) Where there is exposure to sharp or heavy falling objects,
or a hazard of bumping in confined spaces, hard hats or head
protectors must be used.
WAC
296-307-50007 What other requirements apply to employee protection?
(1) You must ensure that a welder or helper working on platforms,
scaffolds, or runways is protected against falling by using railings,
safety belts, life lines, or other equally effective safeguards.
(2) Welders must place welding cable and other equipment so that
it is clear of passageways, ladders, and stairways.
(2) When welding or cutting in a confined space, the gas cylinders
and welding machines must be left outside. Before operations are
started, heavy portable equipment mounted on wheels must be securely
blocked to prevent accidental movement.
(3) Where a welder must enter a confined space through a manhole
or other small opening, means must be provided for quickly removing
the welder in case of emergency. When safety belts and lifelines
are used, they must be attached so that the welder's body cannot
be jammed in a small exit opening. An attendant with a preplanned
rescue procedure must be stationed outside to observe the welder
at all times and be able to put rescue operations into effect.
(4) After welding operations are completed, the welder must mark
the hot metal or provide some other means of warning other employees.
WAC
296-307-50011 What general requirements apply to welding ventilation?
(1) The following three factors in arc and gas welding must be
considered when determining the amount of contamination to which
welders may be exposed:
(a) Dimensions of space in which welding is to be done (especially
ceiling height);
(b) Number of welders; and
(c) The possibility of hazardous fumes, gases, or dust according
to the metals involved.
(2) Other factors involved may require ventilation or respiratory
protective devices as needed to meet the requirements of this
section. Such factors include:
(a) Atmospheric conditions;
(b) Heat generated; and
(c) Presence of volatile solvents.
(3) When welding must be performed in a space entirely screened
on all sides, the screens must be arranged so that no serious
restriction of ventilation exists. The screens should be mounted
so that they are about 2 feet above the floor unless the work
is performed at so low a level that the screen must be extended
nearer to the floor to protect nearby employees from the glare
of welding.
(4) Local exhaust or general ventilating systems must be provided
and arranged to keep the amount of toxic fumes, gases, or dusts
below the maximum allowable in chapter
296-62 WAC.
Note: A number of potentially hazardous
materials are employed in fluxes, coatings, coverings, and filler
metals used in welding and cutting or are released to the atmosphere
during welding and cutting. These include but are not limited
to the materials itemized in WAC
296-307-50019 through 296-307-50029.
(5) You must determine which potentially hazardous materials
are associated with welding and cutting and inform employees through
signs, labels or other appropriate means.
(a) Welding may produce fumes and gases hazardous to health.
Avoid breathing these fumes and gases. Use adequate ventilation.
See ANSI Z 49.1-1967, Safety in Welding and Cutting, published
by the American Welding Society.
(b) Brazing (welding) filler metals containing cadmium in significant
amounts must carry the following notice on tags, boxes, or other
containers:
WARNING CONTAINS CADMIUM-POISONOUS
FUMES MAY BE FORMED ON HEATING Do not breathe fumes. Use
only adequate ventilation such as fume collectors, exhaust
ventilators, or air-supplied respirators. See ANSI Z 49.1-1967.
If chest pain, cough, or fever develops after use call
physician immediately. Keep children away when using.
(c) Brazing and gas welding fluxes containing fluorine compounds
must have a cautionary wording to indicate that they contain fluorine
compounds. The American Welding Society recommends the following
for brazing and gas welding fluxes:
CAUTION CONTAINS
FLUORIDES This flux when heated gives off fumes that may
irritate eyes, nose and throat. Avoid fumes. Use only
in well-ventilated spaces. Avoid contact of flux with
eyes or skin. Do not take internally.
WAC
296-307-50013 What ventilation must be provided for general
welding and cutting?
(1) Mechanical ventilation must be provided when welding or cutting
is done on metals not covered in WAC
296-307-50019 through 296-307-50029
in the following locations:
(a) In a space of less than 10,000 cubic feet per welder.
(b) In a room with a ceiling height of less than 16 feet.
(c) In confined spaces or where the welding space contains
partitions, balconies, or other structural barriers to the extent
that they significantly obstruct cross-ventilation.
(2) Ventilation must be at the minimum rate of 2,000 cubic feet
per minute per welder.
Exception: This requirement does not apply
where local exhaust hoods and booths that meet the requirements
of WAC
296-307-50015, or airline respirators approved by the Mine
Safety and Health Administration (MSHA) and the National Institute
for Occupational Safety and Health (NIOSH) for such purposes are
provided. Natural ventilation is considered sufficient for welding
or cutting operations where the restrictions in subsection (1)
of this section are not present.
WAC
296-307-50015 What requirements apply to local exhaust hoods
and booths?
Mechanical local exhaust ventilation may be provided by either
of the following:
(1) Freely movable hoods intended to be placed by the welder
as near as practical to the work being welded and provided with
a rate of airflow sufficient to maintain a velocity in the direction
of the hood of 100 linear feet per minute in the zone of welding
when the hood is at its most remote distance from the point of
welding. The rates of ventilation required to accomplish this
control velocity using a 3-inch wide flanged suction opening are
shown in the following table:
Welding
Zone
Minimum
air flow cubic feet/minute1
Duct
Diameter Inches2
4
to 6 inches from arc or torch
150
3
6
to 8 inches from arc or torch
275
3
1/2
8
to 10 inches from arc or torch
425
4
1/2
10
to 12 inches from arc or torch
600
5
1/2
1When
brazing with cadmium brazing materials or when cutting
on such materials increased rates of ventilation may be
required. 2Nearest half-inch duct diameter based on 4,000
feet per minute velocity in pipe.
(2) A fixed enclosure with a top and at least two sides that
surround the welding or cutting operations and with a rate of
airflow sufficient to maintain a velocity away from the welder
of not less than 100 linear feet per minute.
WAC
296-307-50017 What ventilation must be provided in confined
spaces?
(1) All welding and cutting operations carried on in confined
spaces must be adequately ventilated to prevent the accumulation
of toxic materials or possible oxygen deficiency. This applies
to welders, helpers, and other employees in the immediate vicinity.
All replacement air must be clean and respirable.
(2) In circumstances where it is impossible to provide such ventilation,
airline respirators or hose masks approved by the Mine Safety
and Health Administration (MSHA) and the National Institute for
Occupational Safety and Health (NIOSH) for this purpose must be
used.
(3) In areas immediately hazardous to life, hose masks with blowers
or self-contained breathing equipment must be used. The breathing
equipment must be approved by the Mine Safety and Health Administration
(MSHA) and the National Institute for Occupational Safety and
Health (NIOSH).
(4) Where welding operations are carried on in confined spaces
and where welders and helpers are provided with hose masks, hose
masks with blowers or self-contained breathing equipment approved
by the Mine Safety and Health Administration (MSHA) and the National
Institute for Occupational Safety and Health (NIOSH), an employee
must be stationed on the outside of such confined spaces to ensure
the safety of those working within.
WAC
296-307-50019 What requirements apply to welding fluorine
compounds?
In confined spaces, welding or cutting involving fluxes, coverings,
or other materials that contain fluorine compounds must be done
according to WAC
296-307-50017.
“Fluorine compound” means a compound that
contains fluorine as an element in chemical combination, not as
a free gas.
Note: The need for local exhaust ventilation
or airline respirators for welding or cutting in other than confined
spaces will depend on the circumstances. However, such protection
is desirable for fixed-location production welding and for all
production welding on stainless steels. Where air samples taken
at the welding location indicate that the fluorides liberated
are below the maximum allowable concentration, such protection
is not necessary.
(1) In confined spaces welding or cutting involving zinc-bearing
base or filler metals or metals coated with zinc-bearing materials
must be done according to WAC
296-307-50017.
(2) Indoors, welding or cutting involving zinc-bearing base or
filler metals coated with zinc-bearing materials must be done
according to WAC
296-307-50015.
(1) In confined spaces, welding involving lead-base metals (erroneously
called lead-burning) must be done according to WAC
296-307-50017.
(2) Indoors, welding involving lead-base metals must be done
according to WAC
296-307-50015.
(3) In confined spaces or indoors, welding or cutting involving
metals containing lead, other than as an impurity, or involving
metals coated with lead-bearing materials, including paint, must
be done using local exhaust ventilation or airline respirators.
Outdoors, such operations must be done using respiratory protective
equipment approved by the Mine Safety and Health Administration
(MSHA) and the National Institute for Occupational Safety and
Health (NIOSH) for such purposes. In all cases, employees in the
immediate vicinity of the cutting operation must be protected
as necessary by local exhaust ventilation or airline respirators.
Note: See chapter 296-62
WAC for additional requirements on lead.
Welding or cutting indoors, outdoors, or in confined spaces
involving beryllium-containing base or filler metals must be done
using local exhaust ventilation and airline respirators unless
atmospheric tests under the most adverse conditions have established
that employee exposure is within the acceptable concentrations
defined by WAC 296-307-62625.
In all cases, employees in the immediate vicinity of the welding
or cutting operations must be protected as necessary by local
exhaust ventilation or airline respirators.
(1) Welding or cutting indoors or in confined spaces involving
cadmium-bearing or cadmium-coated base metals must be done using
local exhaust ventilation or airline respirators unless atmospheric
tests under the most adverse conditions have established that
employee exposure is within the acceptable concentrations defined
by chapter 296-62
WAC. Outdoors, such operations must be done using respiratory
protective equipment such as fume respirators approved by the
Mine Safety and Health Administration (MSHA) and the National
Institute for Occupational Safety and Health (NIOSH) for such
purposes.
(2) Welding (brazing) involving cadmium-bearing filler metals
must be done using ventilation as prescribed in WAC
296-307-50015 or 296-307-50017
if the work is to be done in a confined space.
Note: See chapter 296-62
WAC for additional requirements on cadmium.
Welding or cutting indoors or in a confined space involving
metals coated with mercury-bearing materials, including paint,
must be done using local exhaust ventilation or airline respirators
unless atmospheric tests under the most adverse conditions have
established that employee exposure is within the acceptable concentrations
defined by WAC 296-307-62625.
Outdoors, such operations must be done using respiratory protective
equipment approved by the Mine Safety and Health Administration
(MSHA) and the National Institute for Occupational Safety and
Health (NIOSH) for such purposes.
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