230 Welding, Cutting, and
Brazing
230.01 Scope
230.02 Definitions Applicable
to This Section
230.03 General Requirements
230.04 Protection of Employees
230.05 Work in Confined Spaces
230.06 Health Protection and
Ventilation
230.07 Local Exhaust Hoods and
Booths
230.08 Ventilation in Confined
Spaces
230.09 Fluorine Compounds
230.10 Zinc
230.11 Lead
230.12 Beryllium
230.13 Cadmium
230.14 Mercury
230.15 Cleaning Compounds
230.16 Cutting of Stainless
Steels
230.17 Fire Prevention and
Protection
230.18 Welding on or Cutting
of Containers
230.19 Oxygen/Fuel Gas Systems
for Welding and Cutting
230.20 Manifolding of
Oxygen/Fuel Gas Cylinders
230.21 Portable Outlet Headers
230.22 Manifold Operating
Procedures
230.23 Service Piping Systems
230.24 Protective Equipment
230.25 Hose and Hose
Connections
230.26 Pressure-Reducing
Regulators
230.27 Exhibitions and
Demonstrations
230.28 Arc Welding and Cutting
230.29 Resistance Welding
230.30 Flash Welding Equipment
230.
WELDING, CUTTING, AND BRAZING.
(7-1-97)
01. Scope: (7-1-97)
a. Welding, cutting, and brazing shall conform to all other applicable requirements of this standard, as well as the following provisions. Nothing in this standard shall be construed to prohibit better or otherwise safer conditions than specified herein. (7-1-97)
02. Definitions: For definitions of other terms used in this section, see sub-section 010 of this standard. (7-1-97)
a. Welder and welding operator is any operator of electric or gas welding and cutting equipment. (7-1-97)
b. All other welding terms are used in accordance with American Welding Society terms and definitions - A3.0. (7-1-97)
03. General Requirements: (7-1-97)
a. First-aid equipment shall be available at all times. All injuries shall be reported as soon as possible for medial attention. First aid shall be rendered until medical attention can be provided. (7-1-97)
b. A job hazard analysis shall be made, by qualified personnel, of the operations to be performed to determine the safeguards and personal protective equipment that shall be used for each job. (7-1-97)
c. Periodic inspection shall be made by qualified maintenance personnel and records of the same maintained. The welder/operator shall be instructed to report any equipment defects to his supervisor and the use of the welding/cutting equipment shall be discontinued until safety repairs have been completed. (7-1-97)
04. Protection of Employees: (7-1-97)
a. A welder or helper working on a platform, scaffold or runways shall be protected against falling. This may be accomplished by the use of guard railings, safety belts, life lines, or some other equally effective safeguards. (7-1-97)
b. Welders shall place welding cable, hoses, and other equipment so that it is clear of passageways, ladders, and stairways. (7-1-97)
c. Helmets or hand shields shall 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 against injurious rays from adjacent work, and from flying objects. The goggles may have either clear or colored glass, depending upon the amount of exposure to adjacent welding operations. Helpers or attendants shall be provided with proper eye protection. (7-1-97)
d. Goggles or other suitable eye protection shall 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 operation on light work, for torch brazing or for inspection. (7-1-97)
e. All operators and attendants of resistance welding or resistance brazing equipment shall use transparent face shields or goggles, depending on the particular job, to protect their faces and eyes, as required. (7-1-97)
f. Eye protection in the form of suitable goggles shall be provided where needed for brazing operations not covered in sub-section 230.04.c., 230.04.d., and 230.04.e. of this section. (7-1-97)
g. Helmets and hand shields shall be made of a material which is an insulator for heat and electricity. Helmets, shields and goggles shall be not readily flammable and shall be capable of undergoing sterilization. (7-1-97)
h. Helmets and hand shields shall be arranged to protect the face, neck and ears from direct radiant energy from the arc. (7-1-97)
i. Helmets shall be provided with filter plates and cover plates designed for easy removal. (7-1-97)
j. All parts of eye and face protectors shall be constructed of a material which will not readily corrode or discolor the skin. (7-1-97)
k. Goggles shall be ventilated to prevent fogging of the lenses as much as possible. (7-1-97)
l. Cover lenses or plates shall be provided to protect each helmet, hand shield or goggle filter lens or plate. (7-1-97)
m. All glass for lenses shall be tempered, substantially free from striae, air bubbles, waves and other flaws. Except when a lens is ground to provide proper vision, the front and rear surfaces of lenses and windows shall be smooth and parallel. (7-1-97)
n. Lenses shall bear some permanent distinctive marking by which the source and shade may be readily identified. (7-1-97)
o. Table 230.04-A is a guide for the selection of the proper shade numbers. These recommendations may be varied to suit the individual's needs. (7-1-97)
| TABLE 230.04-A | ||
| Welding Operation | Shade No. | |
| Shielded Metal-arc welding - 1/16, 3/32,1/8,5/32 - inch electrodes | 10 | |
| Gas - shielded arc welding (nonferrous) - 1/16, 3/32, 1/8, 5/32 - inch electrodes | 11 | |
| Gas - shielded arc welding (ferrous) - 1/16, 3/32, 1/8, 5/32 - inch electrodes | 12 | |
| Shielded metal - arc welding: | 3/16, 7/32, 1/4 - inch electrodes | 12 |
| 5/16, 3/8 - inch electrodes | 14 | |
| Atomic hydrogen welding | 10 - 14 | |
| Carbon arc welding | 14 | |
| Soldering | 2 | |
| Torch brazing | 3 or 4 | |
| Light cutting, up to 1 inch | 3 or 4 | |
| Medium cutting, 1 inch to 6 inches | 4 or 5 | |
| Heavy cutting, 6 inches and over | 5 or 6 | |
| Gas welding (light) up to 1/8 inch | 4 or 5 | |
| Gas welding (medium) 1/8 inch to 1/2 inch | 5 or 6 | |
| Gas welding (heavy) 1/2 inch and over | 6 or 8 | |
p. All filter lenses and plates shall meet the test for transmission of radiant energy prescribed in ANSI Z87.1 American National Standard Practice for Occupational and Educational Eye and Face Protection. (7-1-97)
q. Where work permits, the welder shall be enclosed in an individual booth painted with a finish of low reflectivity such as zinc oxide (an important factor for absorbing ultra-violet radiations) and lamp black, or shall be enclosed with noncombustible screens similarly painted. Booths and screens shall permit circulation of air at floor level. Workers or other persons adjacent to the welding areas shall be protected from the rays by noncombustible or flame proof screens or shields or shall be required to wear appropriate goggles. (7-1-97)
r. For the protection of the operators of nearby equipment, fire-resistant curtains or suitable shields shall be set up around welding operations and in such a manner that the welder's movements are not hampered. If the welding process cannot be isolated, all persons who may be exposed to the hazard of arc flash shall be properly protected. (7-1-97)
s. Employees exposed to the hazards created by welding, cutting, or brazing operations shall be protected by personal protective equipment in accordance with the requirements of section 050 of this standard. (7-1-97)
t. Except when engaged in light work, all welders shall wear flameproof gauntler gloves. (7-1-97)
u. Flameproof aprons made of leather, or other suitable material shall be worn as protection against radiated heat and sparks. (7-1-97)
v. Woolen clothing is preferable to cotton because it is not so readily ignited and helps protect the welder from changes in temperature. Cotton clothing, if used, shall be chemically treated to reduce its combustibility. All outer clothing such as jumpers or overalls shall be reasonably free of gas, oil, or grease. (7-1-97)
w. Sparks may lodge in rolled-up sleeves or pockets of clothing, or cuffs of overalls or trousers. Sleeves and collars shall be kept buttoned and pockets shall be eliminated from the front of overalls and aprons. Trousers or overalls shall not be turned up on the outside. NOTE: For heavy work, fire-resistant leggings, high boots, or other equivalent means shall be used. (7-1-97)
x. In production work, a sheet metal screen in front of the workers legs can provide further protection against sparks and molten metal in cutting operations. (7-1-97)
y. Capes or shoulder covers made of leather or other suitable materials should be worn during overhead cutting or welding operations. Leather skull caps may be worn under helmets to prevent head burns. (7-1-97)
z. For overhead welding and cutting, or welding and cutting in extremely confined spaces, ear protection shall be used. (7-1-97)
aa. When there is a hazard or exposure to sharp or heavy falling objects, or a hazard of bumping in confined spaces, hard hats or head protectors shall be used. (7-1-97)
05. Work in Confined Spaces: (7-1-97)
a. As used herein, confined space is intended to mean a relatively small or restricted space such as a tank, boiler, pressure vessel, etc., and the requirements of section 043 of this standard shall be complied with. (7-1-97)
b. Ventilation is a prerequisite to work in confined spaces. For ventilation requirements see sub-section 230.08 of this section. (7-1-97)
c. When welding or cutting is being performed in any confined spaces the gas cylinders and welding machines shall be left on the outside. Before operations are started, portable equipment mounted on wheels shall be securely blocked to prevent accidental movement. (7-1-97)
d. Where a welder must enter a confined space through a manhole or other small opening, means shall be provided for quickly removing him in case of emergency. When safety harnesses and lifelines are used for this purpose, they shall be so attached to the welder's body that his body cannot be jammed in a small exit opening. An attendant with a pre-planned rescue procedure shall be stationed outside to observe the welder at all times and be capable of putting rescue operations into effect. (7-1-97)
e. When arc welding is to be suspended for any substantial period of time, such as during lunch or overnight, all electrodes shall be removed from the holders and the holders carefully located so that accidental contact cannot occur and the machine disconnected from the power source. (7-1-97)
f. In order to eliminate the possibility of gas escaping through leaks or improperly closed valves, when gas welding or cutting, the torch valves shall be closed and the fuel-gas and oxygen supply 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 practicable, the torch and hose shall also be removed from the confined space. (7-1-97)
g. After welding operations are completed, the welder shall mark the hot metal or provide some other means of warning other workers. (7-1-97)
06. Health Protection and Ventilation. (7-1-97)
a. The requirements in this sub-section have been established on the basis of the following three factors in arc and gas welding which govern the amount of contamination to which welders may be exposed and are as follows: dimensions of space in which welding is to be done (with special regard to height of ceiling); number of welders; and possible evolution of hazardous fumes, gases, or dust according to the metals involved. (7-1-97)
b. It is recognized that in individual instances other factors may be involved in which case ventilation or respiratory protective devices shall be provided as needed to meet the equivalent requirements of this subsection. Such factors would include: atmospheric conditions; heat generated; and presence of volatile solvents. (7-1-97)
c. When welding must be performed in a space entirely screened on all sides, the screens shall be so arranged that no serious restriction of ventilation exists. It is desirable to have the screens so mounted that they are about two (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 workers from the glare of welding. (7-1-97)
d. Local exhaust or general ventilating systems shall be provided and arranged to keep the amount of toxic fumes, gases, or dusts below the maximum allowable concentration as specified in section 300 of this standard. 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 sub-sections 230.09 through 230.16. of this section. (7-1-97)
e. The employer shall ascertain the potentially hazardous materials, associated with welding, cutting, etc. from the suppliers of welding materials and inform the employees of the same either through signs, labels, or other appropriate means. (7-1-97)
f. All filler metals and fusible granular materials shall carry the following notice, as a minimum, on tags, boxes, or other containers, "CAUTION" Welding may produce fumes and gases hazardous to health. Avoid breathing these fumes and gases. Use adequate ventilation. See ANSI Z49.1 Safety in Welding and Cutting published by the American Welding Society. (7-1-97)
g. Brazing (welding filler metals containing significant amounts of cadmium shall 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 with adequate ventilation such as fume collectors, exhaust ventilators, or air supplied respirators. See ANSI Z49.1. If chest pain, cough, or fever develops after use, call a physician immediately. Keep children away when using. (7-1-97)
h. Brazing and gas welding fluxes containing fluorine compounds shall have a cautionary wording to indicate that they contain fluorine compounds. One such cautionary wording recommended by the American Welding Society for brazing and gas welding fluxes reads as follows: 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. (7-1-97)
i. Mechanical ventilation shall be provided when welding and cutting is done on metals not covered in sub-sections 230.09 through 230.16 of this section (for specific material, see the ventilation requirements of sub-sections 230.09 through 230.16 of this section.) (7-1-97)
j. Mechanical ventilation shall be provided for in a space of less than ten-thousand (10,000) cubic feet per welder. (7-1-97)
k. Mechanical ventilation shall be provided in a room having a ceiling height of less than sixteen (16) feet. (7-1-97)
l. Mechanical ventilation shall be provided whenever welding fumes could enter the welders breathing zone. (7-1-97)
m. Mechanical ventilation shall be provided for in confined spaces or where the welding space contains partitions, balconies, or other structural barriers to the extent that they significantly obstruct cross ventilation. (7-1-97)
n. Mechanical ventilation shall be at the minimum rate of two-thousand (2,000) cubic feet per minute per welder, except where local exhaust hoods and booths as per sub-section 230.07 of this section, or airline respirators approved by the U.S. Bureau of Mines for such purposes are provided. Natural ventilation is considered sufficient for welding or cutting operations where the restrictions in sub-section 230.06.i. through 230.06.m. of this section are not present. (7-1-97)
07. Local Exhaust Hoods and Booths. (7-1-97)
a. Freely movable hoods intended to be placed by the welder as near as practicable to the work being welded and provided with a rate of airflow sufficient to maintain a velocity in the direction of the hood of one-hundred (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 three (3) inch wide flanged suction opening are shown in Table 230.07-A. (7-1-97)
| TABLE 230.07-A | ||
| Welding zone | Minimum air flow1 cubic feet/minutes | 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 bearing 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. | ||
b. A fixed enclosure with a top and not less than two (2) sides which surround the welding or cutting operation and with a rate of airflow sufficient to maintain a velocity away from the welder of not less than one-hundred (100) linear feet per minute. (7-1-97)
08. Ventilation in Confined Spaces. (7-1-97)
a. All welding and cutting operations carried on in confined spaces shall be adequately ventilated to prevent the accumulation of toxic materials or possible oxygen deficiency. This applies not only to the welder, but also to helpers and other personnel in the immediate vicinity. All air replacing that withdrawn shall be clean and respirable. (7-1-97)
b. In such circumstances where it is impossible to provide such ventilation, airline respirators or hose masks approved by the U.S. Bureau of Mines or NIOSH for this purpose shall be used. (7-1-97)
c. In areas immediately hazardous to life, hose masks with blowers or self-contained breathing equipment shall be used. The breathing equipment shall be approved by the U.S. Bureau of Mines or NIOSH. (7-1-97)
d. 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 U.S. Bureau of Mines or NIOSH, a worker shall be stationed on the outside of such confined spaces to insure the safety of those working within. (7-1-97)
e. Oxygen shall not be used for ventilation. (7-1-97)
09. Fluorine Compounds: (7-1-97)
a. In confined spaces, welding, or cutting involving fluxes, coverings, or other materials which contain fluorine compounds shall be done in accordance with sub-section 230.08. of this section. A fluorine compound is one that contains fluorine, as an element in chemical combination, not as a free gas. (7-1-97)
b. The need for local exhaust ventilation or airline respirators for welding or cutting in other than confined spaces will depend upon the individual circumstances. However, experience has shown that such protection is desirable for fixed-location production welding and for all 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. (7-1-97)
10. Zinc: (7-1-97)
a. In confined spaces welding or cutting involving zinc-bearing base or filler metals or metals coated with zinc-bearing materials shall be done in accordance with sub-section 230.08 of this section. (7-1-97)
b. Indoors, welding or cutting involving zinc-bearing base or filler metals coated with zinc-bearing materials shall be done in accordance with sub-sections 230.07.a. and 230.07.b. of this section. (7-1-97)
11. Lead: (7-1-97)
a. In confined spaces, welding involving lead-base metals (erroneously called lead-burning) shall be done in accordance with sub-section 230.08 of this section. (7-1-97)
b. Indoors, welding involving lead-base metals shall be done in accordance with sub-sections 230.07.a. and 230.07.b. of this section. (7-1-97)
c. In confined spaces or Indoors, welding or cutting involving metals containing lead, other than as an impurity, or involving metals containing lead, or coated with lead-bearing materials, including paint shall be done using local exhaust ventilation or airline respirators. (7-1-97)
d. Outdoors, welding or cutting involving metals containing lead, other than as an impurity, or involving metals containing lead, or coated with lead-bearing materials, including paint shall be done using respiratory protective equipment approved by the U.S. Bureau of Mines or NIOSH for such purposes. In all cases, workers in the immediate vicinity of the cutting operation shall be protected as necessary by local exhaust ventilation or airline respirators. (7-1-97)
12. Beryllium: (7-1-97)
a. Welding or cutting indoors, outdoors, or in confined spaces involving beryllium-containing base or filler metals shall be done by using local exhaust ventilation and airline respirators unless atmospheric tests under the most adverse conditions have established that the workers' exposure is within the acceptable concentration. In all cases, workers in the immediate vicinity of the welding or cutting operations shall be protected as necessary by local exhaust ventilation or airline respirators. (7-1-97)
13. Cadmium: (7-1-97)
a. Welding or cutting indoors or in confined spaces involving cadmium-bearing or cadmium-coated base metals shall be done using local exhaust ventilation or airline respirators unless atmospheric tests under the most adverse conditions have established that the workers' exposure is within the acceptable concentration. Outdoors, such operations shall be done using respiratory protective equipment such as fume respirators approved by the U.S. Bureau of Mines or NIOSH for such purposes. (7-1-97)
b. Welding, or cutting indoors or in confined spaces involving cadmium-bearing filler metals shall be done using ventilation as prescribed in sub-sections 230.06 of this section. If the work is to be done in a confined space then the requirements of sub-section 230.08 of this section shall be used. (7-1-97)
14. Mercury: (7-1-97)
a. Welding or cutting indoors or in a confined space involving metals coated with mercury-bearing materials including paint, shall be done using local exhaust ventilation or airline respirators unless atmospheric tests under the most adverse conditions have established that the workers' exposure is within the acceptable concentration. (7-1-97)
b. Outdoors, such operations shall be done using respiratory protective equipment approved by the U.S. Bureau of Mines or NIOSH for such purposes. (7-1-97)
15. Cleaning Compounds: (7-1-97)
a. In the use of cleaning materials, because of their possible toxicity or flammability, appropriate precautions such as manufacturer's instructions shall be followed. (7-1-97)
b. Degreasing or other cleaning operations involving chlorinated hydrocarbons shall be so located that no vapors from these operations will reach or be drawn into the atmosphere surrounding any welding operation. In addition, trichloreothrylene and perchlorethylene shall be kept out of atmospheres penetrated by the ultraviolet radiation of gas-shielded welding operations. (7-1-97)
16. Cutting of Stainless Steels: (7-1-97)
a. Oxygen cutting, using either a chemical flux or iron powder or gas-shielded arc cutting of stainless steel, shall be done using mechanical ventilation adequate to remove the fumes generated. (7-1-97)
17. Fire Prevention and Protection. (7-1-97)
a. For elaboration of these basic precautions and of the special precautions of sub-section 230.17.c. through 230.17.r. of this section as well as a delineation of the fire protection and prevention responsibilities of welders and cutters, their supervisors (including outside contractors), and those in management on whose property cutting and welding is to be performed, see Standard for Fire Prevention in Use of Cutting and Welding Processes, NFPA 51B. (7-1-97)
b. The basic precautions for fire prevention in welding or cutting work are: if the object to be welded or cut cannot be readily moved, all movable fire hazards in the vicinity shall be taken to a safe place; if the object to be welded or cut cannot be moved and if all the fire hazards cannot be removed, then guards shall be used to confine the heat, sparks, and slag, and to protect the immovable fire hazards; or if the requirements stated above cannot be followed, then welding and cutting shall not be performed. (7-1-97)
c. Whenever there are floor openings or cracks in the flooring that cannot be closed, precautions shall be taken so that no readily combustible materials on the floor below will be exposed to sparks which might drop through the floor. The same precautions shall be observed with regard to cracks or holes in walls, open doorways, and open or broken windows. (7-1-97)
d. Suitable fire extinguishing equipment shall 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. (7-1-97)
e. Fire watchers shall be required whenever welding or cutting is performed in locations where other than a minor fire might develop, if any of the following conditions exist: appreciable combustible material, in building construction or contents, closer than thirty-five (35) feet to the point of operation; wall or floor openings within a thirty-five (35)foot radius expose combustible material in adjacent areas including concealed spaces in walls or floors; appreciable combustibles are more than thirty-five (35) feet away but are easily ignited by sparks; 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. (7-1-97)
f. Fire watchers shall have fire extinguishers equipment readily available and be trained in its use. They shall be familiar with facilities for sounding an alarm in the event of a fire. They shall 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 shall be maintained for at least a one-half (1/2) hour after completion of welding or cutting operations to detect and extinguish possible smoldering fires. (7-1-97)
g. Before cutting or welding, the area shall be inspected by the individual responsible for authorizing cutting and welding procedures. He shall disseminate precautions to be followed in granting authorization to proceed in the form of a written procedure. (7-1-97)
h. Where combustible materials such as paper clippings, wood shavings or textile fibers are on the floor, the floor shall be swept clean for a radius of thirty-five (35) feet. Combustible floors shall be kept wet, covered with damp sand, or protected by fire-resistant shields. Where floors have been wet down, personnel operating arc welding and cutting equipment shall be protected from possible shock. (7-1-97)
i. Cutting or welding shall not be permitted in the following areas or situations: in areas not authorized by management; in sprinklered buildings while such protection is impaired; in the presence of explosive atmospheres (mixtures of flammable gases, vapors, liquids, or dusts with air), or explosive atmospheres that may develop inside uncleaned or improperly prepared tanks or equipment which have previously contained such materials, or that may develop in areas with an accumulation of combustible dusts; or in areas near the storage of large quantities of exposed, readily ignitable materials, such as bulk sulphur, baled paper, or cotton. (7-1-97)
j. Where practicable, all combustibles shall be relocated at least thirty-five (35) feet from the work site. Where relocation is impossible, combustibles shall be protected with a flameproof cover or otherwise shielded with metal or fire proof 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. (7-1-97)
k. Ducts and conveyor systems that might carry sparks to distant combustibles shall be suitably protected or shut down. (7-1-97)
l. Where cutting or welding is done near walls, partitions, ceiling, or roof of combustible construction, fire resistant shields or guards shall be provided to prevent ignition. (7-1-97)
m. If welding is to be done on a metal wall, partition, ceiling, or roof, precautions shall be taken to prevent ignition of combustibles on the other side, due to conduction or radiation, preferably by relocation of combustibles. Where combustibles are not relocated, a fire watch on the opposite side from the work shall be provided, to prevent ignition. (7-1-97)
n. Welding shall 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. (7-1-97)
o. Cutting or welding on pipes or other metal in contact with combustible walls, partitions, ceilings, or roofs shall not be undertaken if the work is close enough to cause ignition by conduction. (7-1-97)
p. Management shall recognize its responsibility for the safe usage of cutting and welding equipment on its property, and: based on fire potentials of facilities, establish areas for cutting and welding, in other areas; designate an individual responsible for authorizing cutting and welding operations in areas not specifically designed for such processes; 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 advise all contractors about flammable materials or hazardous conditions of which they may not be aware. (7-1-97)
q. The supervisor: (7-1-97)
i. Shall be responsible for the safe handling of the cutting or welding equipment and the safe use of the cutting and welding process; (7-1-97)
ii. Shall determine the combustible materials and hazardous areas present or likely to be present in the work location; (7-1-97)
iii. shall protect combustibles from ignition in accordance with sub-section 230.17.b. of this section; (7-1-97)
iv. Shall see that authorizations from the proper management representative are secured; (7-1-97)
v. Shall determine that the cutter or welder secures his approval that conditions are safe before going ahead; (7-1-97)
vi. Shall determine that fire protection and extinguishing equipment are properly located at the site; (7-1-97)
vii. Where fire watchers are required, shall see that they are available at the site. (7-1-97)
r. Cutting or welding shall be permitted only in areas that are or have been made fire safe. Within the confines of a building or specifically designated facility or area, 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 non-combustible and nonflammable contents, and suitably segregated from adjacent areas. When work cannot be moved practically, as in most construction work, the area shall be made safe by removing combustibles or protecting combustibles from ignition areas. (7-1-97)
s. Before welding, cutting, or heating is commenced on any surface covered by a preservative coating whose flammability is not known, a test shall be made by a competent person to determine its flammability. Preservative coatings shall be considered to be highly flammable when scrapings burn with extreme rapidity. (7-1-97)
t. Precautions shall be taken to prevent ignition of highly flammable hardened preservative coatings. When coatings are determined to be highly flammable, they shall be stripped from the area to be heated to prevent ignition. (7-1-97)
u. In enclosed spaces, all surfaces covered with toxic preservatives shall be stripped of all toxic coatings for a distance of at least four (4) inches from the area of heat application, or the employees shall be protected by airline respirators, meeting the requirements specified in this section for this type of work. (7-1-97)
v. The preservative coatings shall be removed a sufficient distance from the area to be heated to ensure that the temperature of the unstripped metal will not be appreciably raised. Artificial cooling of the metal surrounding the heating area may be used to limit the size of the area required to be cleaned. (7-1-97)
18. Welding on or Cutting of Containers: (7-1-97)
a. No welding, cutting, or other hot work shall be performed on used drums, barrels, tanks, or other containers until they have been cleaned so thoroughly as to make absolutely 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 shall be disconnected or blanked. (7-1-97)
b. All hollow spaces, cavities, or containers shall be vented to permit the escape of air or gases before preheating, cutting, or welding. Purging with inert gas is recommended. (7-1-97)
19. Oxygen/Fuel Gas Systems for Welding and Cutting. (7-1-97)
a. Mixtures of fuel gases and air or oxygen may be explosive and shall be guarded against. No device or attachment facilitating or permitting mixtures of air or oxygen with flammable gases prior to consumption, except at the burner or in a standard torch, shall be allowed unless approved for the purpose. (7-1-97)
b. Only approved apparatus such as torches, regulators, or pressure-reducing valves, acetylene generators, and manifolds shall be used. (7-1-97)
c. Workers in charge of the oxygen or fuel-gas supply equipment including any oxygen or fuel-gas distribution piping systems shall be instructed and judged competent by their employers for this important work before being left in charge. Rules and instructions covering the operation and maintenance of oxygen or fuel-gas supply equipment including oxygen or fuel-gas distribution piping systems shall be readily available. (7-1-97)
d. All portable cylinders used for the storage and shipment of compressed gases shall be constructed and maintained in accordance with the regulations of the U.S. Department of Transportation, 49 CFR Parts 171-179 and shall meet the requirements of section 210 of this standard. (7-1-97)
e. Oxygen cylinders shall not be stored near highly combustible material, especially oil and grease; or near reserve stocks of carbide and acetylene or other fuel-gas cylinders, or near any other substance likely to cause or accelerate fire; or in an acetylene generator compartment. (7-1-97)
f. Oxygen cylinders in storage shall be separated from fuel-gas cylinders or combustible materials (especially oil or grease), a minimum distance of twenty (20) feet or by a noncombustible barrier at least five (5) feet high having a fire-resistant rating of at least one-half (1/2) half hour. (7-1-97)
g. Where a liquid oxygen system is to be used to supply gaseous oxygen for welding or cutting and the system has a storage capacity of more than thirteen-thousand (13,000) cubic feet of oxygen (measured at fourteen-point-seven (14.7) psia and seventy (70) degrees Fahrenheit), connected in service or ready for service, or more than twenty-five-thousand (25,000) cubic feet of oxygen (measured at fourteen-point-seven (14.7) psia and seventy (70) degrees Fahrenheit), including unconnected reserved on hand at the site, it shall comply with the provisions of the Standard for Bulk Oxygen Systems at Consumer Sites, NFPA 50. (7-1-97)
h. Cylinders, cylinder valves, couplings, regulators, hose, and apparatus shall be kept free from oily or greasy substances. Oxygen cylinders or apparatus shall not be handled with oily hands or gloves. A jet of oxygen must never be permitted to strike any oily surface, greasy clothes, or enter a fuel oil or other storage tank. (7-1-97)
i. Unless cylinders are secured on a special truck regulators shall be removed and valve protection caps, when provided for, shall be put in place before cylinders are moved. (7-1-97)
j. Cylinders not having fixed hand wheels shall have keys, handles, or non-adjustable wrenches on valve stems while these cylinders are in service. In multiple cylinder installations only one key or handle is required for each manifold. (7-1-97)
k. Cylinder valves shall be closed before moving cylinders. (7-1-97)
l. Cylinder valves shall be closed when work is finished. (7-1-97)
m.
Regulators shall have the pressure released
when not in use. (7-1-00)
n.
Valves of empty cylinders shall be closed.
(7-1-97)
o.
Cylinders shall be kept far away from the
actual welding or cutting operation so that
sparks, hot slag or flame will not reach
them, or fire-resistant shields shall be
used. (7-1-97)
p.
Cylinders shall not be placed where they
might become part of an electric current.
Contacts with third rails, trolley wires,
etc.., shall be avoided. Cylinders shall be
kept away from radiators, piping systems,
layout tables, etc.., that may be used for
grounding electric circuits such as for arc
welding machines. Any practice such as the
tapping of an electrode against a cylinder
to strike an arc shall be prohibited.
(7-1-97)
q.
Cylinders shall never be used as rollers or
supports, whether full or empty. (7-1-97)
r.
Unless connected to a manifold, oxygen from
a cylinder shall not be used without first
attaching an oxygen regulator to the
cylinder valve. Before connecting the
regulator to the cylinder valve, the valve
shall be opened slightly for an instant and
then closed. (Always stand to one side of
the outlet when opening the cylinder valve.)
(7-1-97)
s.
A hammer or wrench shall not be used to open
cylinder valve. If valves cannot be opened
by hand, the supplier shall be notified.
(7-1-97)
t.
Complete removal of the stem from a
diaphragm type cylinder valve shall be
avoided. (7-1-97)
u.
Fuel-gas cylinders shall be placed with
valve end up whenever they are in use.
Liquefied gases shall be stored and shipped
with the valve end up. (7-1-97)
v.
Cylinders shall be handled carefully.
Cylinders shall not be subjected to rough
handling, knocks, or falls which are liable
to damage the cylinder, valve or safety
devices and cause leakage. (7-1-97)
w.
Before connecting a regulator to a cylinder
valve, the valve shall be opened slightly
and closed immediately. The valve shall be
opened while standing to one side of the
outlet; never in front of it. Fuel-gas
cylinder valves shall not be cracked near
other welding work or near sparks, flame, or
other possible sources of ignition. (7-1-97)
x.
Before a regulator is removed from a
cylinder valve, the cylinder valve shall be
closed and the gas released from the
regulator. (7-1-97)
y.
Nothing shall be placed on top of an
acetylene cylinder when in use which may
damage the safety device or interfere with
the quick closing of the valve. (7-1-97)
z.
If cylinders are found to have leaky valves
or fittings which cannot be stopped by
closing of the valve, the cylinders shall be
taken outdoors away from sources of ignition
and slowly emptied. (7-1-97)
aa.
A warning shall be placed near cylinders
having leakage, fuse plugs, or other leaking
safety devices not to approach them with a
lighted cigarette or other source of
ignition. Such cylinders should be plainly
tagged; the supplier should be promptly
notified and his instructions followed as to
their return. (7-1-97)
bb.
Safety devices shall not be tampered with.
(7-1-97)
cc.
Fuel-gas shall not be used from cylinders
through torches or other devices equipped
with shutoff valves without reducing the
pressure through a suitable regulator
attached to the cylinder valve or manifold.
(7-1-97)
dd.
The cylinder valve shall always be opened
slowly. (7-1-97)
ee.
An acetylene cylinder valve shall not be
opened more than one and one-half (1 1/2)
turns of the spindle, and preferably no more
than three-fourths (3/4) of a turn. (7-1-97)
ff.
Where a special wrench is required, it shall
be left in position on the stem of the valve
while the cylinder is in use so that the
fuel-gas flow can be quickly turned off in
case of emergency. In the case of manifolded
or coupled cylinders at least one (1) such
wrench shall always be available for
immediate use. (7-1-97)
gg.
When cylinders are transported by powered
vehicle, they shall be secure in a vertical
position. (7-1-97)
hh.
A suitable cylinder truck, cart, chain, or
other steadying device shall be used to
prevent all cylinders from being knocked
over while in use, or in storage, empty or
full. (7-1-97)
ii.
Each oxygen and fuel gas cylinder shall have
a back flow valve and a flash back arrester
between the torch and the regulator.
(7-1-97)
20.
Manifolding of Oxygen/Fuel Gas Cylinders:
(7-1-97)
a.
Manifolds shall be approved either
separately for each component part or as an
assembled unit. (7-1-97)
b.
Except as provided in sub-section 230.20.c.
of this section, oxygen or fuel gas
cylinders connected to one (1) manifold
inside a building shall be limited to a
total capacity not exceeding six-thousand
(6,000) cubic feet of oxygen, three-hundred
(300) pounds of liquefied petroleum gas, or
three-thousand (3,000) cubic feet of other
fuel-gas. More than one (1) such manifold
with connected cylinders may be located in
the same room provided the manifolds are at
least fifty (50) feet apart or separated by
a fire-resistant barrier at least five (5)
feet high having a fire-resistance rating of
at least one-half (1/2) half hour. (7-1-97)
c.
Oxygen cylinders or fuel-gas cylinders
connected to one manifold having an
aggregate capacity exceeding six-thousand
(6,000) cubic feet of oxygen, three-hundred
(300) pounds of liquefied petroleum gas, or
three-thousand (3,000) cubic feet of other
fuel-gas shall be located outdoors, or in a
separate building or room constructed in
accordance with the following: The walls,
partitions, floors, and ceilings shall be of
noncombustible construction having a
fire-resistance rating of at least one (1)
hour. The walls or partitions shall be
continuous from floor to ceiling and shall
be securely anchored. At least one (1) wall
of the room shall be an exterior wall.
Openings from an inside generator room to
other parts of the building shall be
protected by a swinging type self-closing
fire door for a Class B opening and having a
rating of at least one (1) hour. Windows in
partitions shall be wired glass and approved
metal frames with fixed sash. Installation
shall be in accordance with the Standard for
the Installation of Fire Doors and Windows,
NFPA 80. Rooms or outside houses shall be
well ventilated with vents located at floor
and ceiling levels. (7-1-97)
d.
Separate manifold buildings or rooms may
also be used for the storage of cylinders
containing fuel gases as provided in
sub-section 230.19. of this section and
section 210 of this standard. Such building
or rooms shall have no open flames for
heating or lighting and shall be well
ventilated. (7-1-97)
e.
High-pressure fuel gas manifolds shall be
provided with approved pressure regulating
devices. (7-1-97)
f.
An oxygen manifold or oxygen bulk supply
system which has storage capacity of more
than thirteen-thousand (13,000) cubic feet
of oxygen (measured at fourteen-point-seven
(14.7) psia and seventy (70) degrees
Fahrenheit), connected in service or ready
for service, or more than
twenty-five-thousand (25,000) cubic feet of
oxygen (measured at fourteen-point-seven
(14.7) psia and seventy (70) degrees
Fahrenheit), including unconnected reserves
on hand at the site, shall comply with the
provisions of the Standard for Bulk Oxygen
Systems at Consumer Sites, NFPA No. 50.
(7-1-97)
g.
High-pressure oxygen manifolds shall be
provided with approved pressure-regulating
devices. (7-1-97)
h.
Manifolds shall be of substantial
construction suitable for use with oxygen at
a pressure of two-hundred-fifty (250) psig.
They shall have a minimum bursting pressure
of one-thousand (1,000) psig and shall be
protected by a safety relief device which
will relieve at a maximum pressure of
five-hundred (500) psig. NOTE: DOT-4L200
cylinders have safety devices which relieve
at a maximum pressure of two-hundred-fifty
(250) psig (or two-hundred-thirty-five (235)
psig if vacuum insulation is used). (7-1-97)
i.
Hose and hose connections subject to
cylinder pressure shall comply with
sub-section 230.25. of this section. Hose
shall have a minimum bursting pressure of
one-thousand (1,000) psig. (7-1-97)
j.
The assembled manifold including leads shall
be tested and proven gas-tight at a pressure
of three-hundred (300) psig. The fluid used
for testing oxygen manifolds shall be
oil-free and not combustible. (7-1-97)
k.
The location of manifolds shall comply with
the provisions of this sub-section. (7-1-97)
l.
The following sign shall be conspicuously
posted at each manifold: "LOW PRESSURE
MANIFOLD, DO NOT CONNECT HIGH-PRESSURE
CYLINDERS; MAXIMUM PRESSURE, 250-PSIG."
(7-1-97)
21.
Portable Outlet Headers: (7-1-97)
a.
Portable outlet headers shall not be used
indoors except for temporary service where
the conditions preclude a direct supply from
outlets located on the service piping
system. (7-1-97)
b.
Each outlet on the service piping from which
oxygen or fuel-gas is withdrawn to supply a
portable outlet header shall be equipped
with a readily accessible shutoff valve.
(7-1-97)
c.
Hose and hose connections used for
connecting the portable outlet header to the
service piping shall comply with sub-section
230.22. of this section. (7-1-97)
d.
Master shutoff valves for both oxygen and
fuel-gas shall be provided at the entry end
of the portable outlet header. (7-1-97)
e.
Portable outlet headers for fuel-gas service
shall be provided with an approved hydraulic
back-pressure valve installed at the inlet
and preceding the service outlets, unless an
approved pressure-reducing regulator, an
approved back-flow check valve, or an
approved hydraulic back-pressure valve is
installed at each outlet. Outlets provided
on headers for oxygen service may be fitted
for use with pressure-reducing regulators or
for direct hose connection. (7-1-97)
f.
Each service outlet on portable outlet
headers shall be provided with a valve
assembly that includes a detachable outlet
seal cap, chained or otherwise attached to
the body of the valve. (7-1-97)
g.
Materials and fabrication procedures for
portable outlet headers shall comply with
sub-section 230.23.a. through 230.23. aa. of
this section. (7-1-97)
h.
Portable outlet headers shall be provided
with frames which will support the equipment
securely in the correct operating position
and protect them from damage during handling
and operation. (7-1-97)
22.
Manifold Operating Procedures: (7-1-97)
a.
Cylinder manifolds shall be installed under
the supervision of someone familiar with the
proper practices with reference to their
construction and use. (7-1-97)
b.
All manifolds and parts used in manifolding
shall be used only for the gas or gases for
which they are approved. (7-1-97)
c.
When acetylene cylinders are coupled,
approved flash arresters shall be installed
between each cylinder and the coupler block.
For outdoor use only, and when the number of
cylinders coupled does not exceed three (3),
one (1) flash arrester installed between the
coupler block and regulator is acceptable.
(7-1-97)
d.
Each fuel-gas cylinder lead shall be
provided with a back-flow check valve.
(7-1-97)
e.
The aggregate capacity of fuel-gas cylinders
connected to a portable manifold inside a
building shall not exceed three-thousand
(3,000) cubic feet of gas. (7-1-97)
f.
Acetylene and liquefied fuel-gas cylinders
shall be manifolded in a vertical position.
(7-1-97)
g.
The pressure in the gas cylinders connected
to and discharged simultaneously through a
common manifold shall be approximately
equal. (7-1-97)
23.
Service Piping Systems: (7-1-97)
a.
Piping and fittings shall comply with
Section 2, Industrial Gas and Air Piping
Systems, of the American National Standard
Code for Pressure Piping, ANSI B31.1,
insofar as it does not conflict with
sub-sections 230.23.b. and 230.23.c. of this
section. (7-1-97)
b.
Pipe shall be schedule forty (40) and
fittings shall be at least standard weight
in sizes up to and including six (6) inch
nominal. (7-1-97)
c.
Copper tubing shall be Types K or L in
accordance with the Standard Specification
for Seamless Copper Water Tube, ASTM
B88-66a. (7-1-97)
d.
Piping shall be steel, wrought iron, brass,
or copper pipe, or seamless copper, brass,
or stainless steel tubing except as provided
in sub-sections 230.23.e. through
sub-section 230.23.i. of this section.
(7-1-97)
e.
Oxygen piping and fittings at pressures in
excess of seven-hundred (700) psig shall be
stainless steel or copper alloys. (7-1-97)
f.
Hose connections and hose complying with
sub-section 230.24. of this section may be
used to connect the outlet of a manifold
pressure regulator to piping providing the
working pressure of the piping is
two-hundred-fifty (250) psig or less and the
length of the hose does not exceed five (5)
feet. Hose shall have a minimum bursting
pressure of one-thousand (1,000)-psig.
(7-1-97)
g.
When oxygen is supplied to a service piping
system from a low-pressure oxygen manifold
without an intervening pressure regulating
device, the piping system shall have a
minimum design pressure of two-hundred-fifty
(250) psig. A pressure regulating device
shall be used at each station outlet when
the connected equipment is for use at
pressures less than two-hundred-fifty (250)
psig. (7-1-97)
h.
Piping for acetylene or acetylenic compounds
shall be steel or wrought iron. (7-1-97)
i.
Unalloyed copper shall not be used for
acetylene or acetylenic compounds except in
listed equipment. (7-1-97)
j.
Joints in steel or wrought iron piping shall
be welded, threaded, or flanged. Fittings,
such as "L", "T",
couplings, and unions may be rolled, forged,
or cast steel, malleable iron, or nodular
iron. Gray or white cast iron fittings are
prohibited. (7-1-97)
k.
Joints in brass or copper pipe shall be
welded, brazed, threaded, or flanged. If of
the socket type, they shall be brazed with
silver-brazing alloy or similar high melting
point (not less than eight-hundred (800)
degrees Fahrenheit) filler metal. (7-1-97)
l.
Joints in seamless copper, brass, or
stainless tubing shall be approved gas
tubing fittings or the joints shall be
brazed. If of the socket type, they shall be
brazed with silver-brazing alloy or similar
high melting point (not less than
eight-hundred (800) degrees Fahrenheit)
filler metal. (7-1-97)
m.
Distribution lines shall be installed and
maintained in a safe operating condition.
(7-1-97)
n.
Piping located inside or outside of
buildings may be placed above or below
ground. All piping shall be run as directly
as practicable, protected against physical
damage, proper allowance being made for
expansion and contraction, jarring and
vibration. Pipe laid underground in earth
shall be located below the frost line and
protected against corrosion. After assembly
piping shall be thoroughly blown out with
air or nitrogen to remove foreign materials.
For oxygen piping, only oil-free air,
oil-free nitrogen, or oil-free carbon
dioxide shall be used. (7-1-97)
o.
Only piping which has been welded or brazed
shall be installed in tunnels, trenches, or
ducts. Shut-off valves shall be located
outside such conduits. Oxygen piping may be
placed in the same tunnel, trench or duct
with fuel-gas pipelines, provided there is
good natural or forced ventilation. (7-1-97)
p.
Low points in piping carrying moist gas
shall be drained into drip pots constructed
so as to permit pumping or draining out the
condensate at necessary intervals. Drain
valves shall be installed for this purpose
having outlets normally closed with screw
caps or plugs. No drips located out of
doors, underground, and not readily
accessible, valves may be used at such
points if they are equipped with means to
secure them in the closed position. Pipes
leading to the surface of the ground shall
be cased or jacketed where necessary to
prevent loosening or breaking. (7-1-97)
q.
Gas cocks or valves shall be provided for
all buildings at points where they will be
readily accessible for shutting off the gas
supply to these buildings in any emergency.
Underground valve boxes or manholes should
be avoided whenever possible. There shall
also be provided a shutoff valve in the
discharge line from the generator, gas
holder, manifold or other source of supply.
(7-1-97)
r.
Shutoff valves shall not be installed in
such a manner that the safety relief device
can be rendered ineffective. (7-1-97)
s.
Fitting and lengths of pipe shall be
examined internally before assembly and, if
necessary, freed from scale or dirt. Oxygen
piping and fittings shall be washed out with
a suitable solution which will not react
with the oxygen. NOTE: Hot water solutions
of caustic soda or trisodium phosphate are
effective cleaning agents for this purpose.
(7-1-97)
t.
Piping shall be thoroughly blown out after
assembly to remove foreign materials. For
oxygen piping, oil-free air, oil free
nitrogen, or oil-free carbon dioxide shall
be used. For other piping, air or inert gas
may be used. (7-1-97)
u.
When flammable gas lines or other parts of
equipment are being purged of air or gas,
open lights or other sources of ignition
shall not be permitted near uncapped
openings. (7-1-97)
v.
No welding or cutting shall be performed on
an acetylene or oxygen pipeline, including
the attachment of hangers or supports, until
the line has been purged. Only oil-free air,
oil-free nitrogen, or oil-free carbon
dioxide shall be used to purge oxygen lines.
(7-1-97)
w.
Underground pipe and tubing and outdoor
ferrous pipe and tubing shall be covered or
painted with a suitable material for
protection against corrosion. (7-1-97)
x.
Aboveground piping systems shall be marked
in accordance with the American National
Standard Scheme for the Identification of
Piping Systems, ANSI A13.1. (7-1-97)
y.
Station outlets shall be marked to indicate
the name of the gas. (7-1-97)
z.
Piping systems shall be tested and proved
gas-tight at one and one-half (1 1/2) times
the maximum operating pressure, and shall be
thoroughly purged of air before being placed
in service. The material used for testing
oxygen lines shall be oil free and
noncombustible. Flames shall not be used to
detect leaks. (7-1-97)
aa.
When flammable gas lines or other parts of
equipment are being purged of air or gas,
sources of ignition shall not be permitted
near uncapped openings. (7-1-97)
24.
Protective Equipment: (7-1-97)
a.
Equipment shall be installed and used only
for the service for which it is approved and
as recommended by the manufacturer. (7-1-97)
b.
Service piping systems shall be protected by
pressure relief devices set to function at
not more than the design pressure of the
systems, and discharging upwards to a safe
location. (7-1-97)
c.
The fuel-gas and oxygen piping systems,
including portable outlet headers shall
incorporate the protective equipment shown
in Figures 230.24-A, 230.24-B, and 230.24-C.
When only a portion of a fuel-gas system is
to be used with oxygen, only that portion
need comply with sub-section 230.24.c. of
this subsection. (7-1-97)
FIGURE 230.24-A
FIGURE 230.24-B
FIGURE 230.25-C
d.
Approved protective equipment (designated Pf
in Figures 230.24-A, 230.24-B, and 230.24-C)
shall be installed in fuel-gas piping to
prevent: back-flow of oxygen into the fuel
gas supply system; passage of a flashback
into the fuel gas supply system; excessive
back pressure of oxygen in the fuel gas
supply system. The three (3) functions of
the protective equipment may be combined in
one device or may be provided by separate
devices. (7-1-97)
e.
The protective equipment shall be located in
the main supply line, as in Figure 230.24-A
or at the head of each branch line as in
Figure 230.24-B, or at least location where
fuel gas is withdrawn, as in Figure
230.24-C. Where branch lines are of two (2)
inch pipe size or larger or of substantial
length, protective equipment (designated as
Pf) shall be located as shown in either
Figure 230.24-B or 230.24-C. (7-1-97)
f.
Back-flow protection shall be provided by an
approved device that will prevent oxygen
from flowing into the fuel-gas system or
fuel from flowing into the oxygen system
(see Sf, Figures 230.24-A and 230.24-B.)
(7-1-97)
g.
Flash back protection shall be provided by
an approved device that will prevent flame
from passing into the fuel-gas system.
(7-1-97)
h.
Back-pressure protection shall be provided
by an approved pressure-relief device set at
a pressure not greater than the pressure
rating of the back-flow or the flashback
protection device, whichever is lower. The
pressure-relief device shall be located on
the downstream side of the back-flow and
flashback protection devices. The vent from
the pressure-relief device shall be at least
as large as the relief device inlet and
shall be installed without low points that
may collect moisture. If low points are
unavoidable, drip pots with drains closed
with screw plugs or caps shall be installed
at the low points. The vent terminus shall
not endanger personnel or property through
gas discharge; shall be located away from
ignition sources; and shall terminate in a
hood or bend. (7-1-97)
i.
If pipeline protective equipment
incorporates a liquid, the liquid level
shall be maintained, and a suitable
antifreeze shall be used to prevent
freezing. (7-1-97)
j.
Fuel gas for use with equipment not
requiring oxygen shall be withdrawn upstream
of the piping protective devices. (7-1-97)
k.
A check valve pressure regulator, hydraulic
seal, or combination of these devices shall
be provided at each station outlet,
including those on portable headers to
prevent back-flow, as shown in Figures
230.24-A, 230.24-B, and 230.24-C and
designated as Sf and So. (7-1-97)
l.
When approved pipeline protective equipment
(designated Pf) is located at the station
outlet as in Figure 230.24-C, no additional
check valve, pressure regulator, or
hydraulic seal is required. (7-1-97)
m.
A shutoff valve (designated Vf and Vo) shall
be installed at each station outlet and
shall be located on the upstream side of
other station outlet equipment. (7-1-97)
n.
If the station outlet is equipped with a
detachable regulator, the outlet shall
terminate in a union connection that
complies with the Regulator Connection
Standards, Compressed Gas Association.
(7-1-97)
o.
If the station outlet is connected directly
to a hose, the outlet shall terminate in a
union connection complying with the Standard
Hose Connection Specifications, Compressed
Gas Association. (7-1-97)
p.
Station outlets may terminate in pipe
threads to which permanent connections are
to be made, such as to a machine. (7-1-97)
q.
Station outlets shall be equipped with a
detachable outlet seal cap secured in place.
This cap shall be used to seal the outlet
except when a hose, a regulator, or piping
is attached. (7-1-97)
r.
When station outlets are equipped with
approved back-flow and flashback protective
devices, as many as four torches may be
supplied from each station outlet through
rigid piping, provided each outlet from such
piping is equipped with a shutoff valve and
provided the fuel gas capacity of any one
torch does not exceed fifteen (15) cubic
feet per hour. This rule does not apply to
machines. (7-1-97)
25.
Hose and Hose Connections: (7-1-97)
a.
Hose for oxygen gas service shall comply
with Specification for Rubber Welding Hose,
Compressed Gas and Rubber Manufacturers
Association. (7-1-97)
b.
The colors for hose shall be red for
acetylene and other fuel-gas hose, green for
oxygen hose, and black for inert gas and air
hose. (7-1-97)
c.
When parallel lengths of oxygen and
acetylene hose are taped together for
convenience and to prevent tangling, not
more than four (4) inches out of twelve (12)
inches shall be covered by tape. (7-1-97)
d.
Hose connections shall comply with the
Standard Hose Connection Specifications,
Compressed Gas Association. (7-1-97)
e.
Hose connections shall be clamped or
otherwise securely fastened in a manner that
will withstand, without leakage, twice the
pressure to which they are normally
subjected in service, but in no case less
than a pressure of three-hundred (300) psi.
Oil free air or an oil free inert gas shall
be used for this test. (7-1-97)
f.
Hose showing leaks burns, worn places, or
other defects rendering it unfit for service
shall be repaired or replaced. (7-1-97)
26.
Pressure-Reducing Regulators: (7-1-97)
a.
Pressure-reducing regulators shall be used
only for the gas and pressures for which
they are intended. The regulator inlet
connections shall comply with Regulator
Connection Standards, Compressed Gas
Association. (7-1-97)
b.
When regulators or parts of regulators,
including gages, need repair, the work shall
be performed by skilled mechanics who have
been properly instructed. (7-1-97)
c.
Gages on oxygen regulators shall be marked
"USE NO OIL". (7-1-97)
d.
Union nuts and connections on regulators
shall be inspected before use to detect
faulty seats which may cause leakage of gas
when the regulators are attached to the
cylinder valves. (7-1-97)
27.
Exhibitions and Demonstrations: (7-1-97)
a.
Installation and operation of welding,
cutting, and related equipment shall be done
by, or under the supervision of a competent
operator to insure the personal protection
of viewers and demonstrator as well as the
protection from fire, for materials in and
around the site and the building itself.
(7-1-97)
b.
Cylinders containing compressed gases for
use at the site shall not be charged in
excess of one-half (1/2) their maximum
permissible content. (Cylinders of
non-liquefied gases shall be charged to not
more than one-half (1/2) of their maximum
permissible charged pressure in psig.
Cylinders of liquefied gases shall be
charged to not more than one-half (1/2) the
maximum permissible capacity in pounds).
(7-1-97)
c.
Cylinders located at the site shall be
connected for use except that enough
additional cylinders may be stored at the
site to furnish approximately one (1) days
consumption of each gas used. Other
cylinders shall be stored, in an approved
storage area preferably outdoors, but this
storage area shall not be located near a
building. (7-1-97)
d.
Cylinders in excess of forty (40) pounds
total weight being transported to or from
the site shall be carried on a hand or
motorized truck. (7-1-97)
e.
The site shall be constructed, equipped and
operated in such a manner that the
demonstration will be carried out so as to
minimize the possibility of injury to
viewers. (7-1-97)
f.
Sites involving the use of compressed gases
shall be located so as not to interfere with
the egress of people during an emergency.
(7-1-97)
g.
The fire department shall be notified in
advance of use of the site. (7-1-97)
h.
Each site shall be provided with a portable
fire extinguishers of appropriate size and
type and with a pail of water. (7-1-97)
i.
Observers and combustible materials at the
site shall be protected from flames, sparks,
and molten metal. (7-1-97)
j.
Hoses shall be located and protected so that
they will not be physically damaged.
(7-1-97)
k.
Cylinder valves shall be closed when
equipment is unattended. (7-1-97)
l.
Where caps are provided for valve
protection, such caps shall be in place
except when the cylinders are in service or
connected ready for service. (7-1-97)
m.
Cylinders shall be located or secured so
that they cannot be knocked over. (7-1-97)
28.
Arc Welding and Cutting: (7-1-97)
a.
Welding equipment shall be chosen for safe
application to the work to be done as
specified in sub-section 230.28. of this
section. (7-1-97)
b.
Welding equipment shall be installed safely
as specified by sub-section 230.28. of this
section. (7-1-97)
c.
Workmen designated to operate arc welding
equipment shall have been properly
instructed and qualified to operate such
equipment as specified in sub-section
230.28. of this section. (7-1-97)
d.
Assurance of consideration of safety in
design is obtainable by choosing apparatus
complying with the requirements of Electric
Arc Welding Apparatus NEMA EW-1, National
Electrical Manufacturers Association or the
Safety Standard of Transformer-Type Arc
Welding Machines. ANSI C33.2, Underwriters
Laboratories. (7-1-97)
e.
Standard machines for arc welding service
shall be designed and constructed to carry
their rated load with rated temperature
rises where the temperature of the cooling
air does not exceed 104-degrees Fahrenheit
and where the altitude does not exceed
3,300-feet, and shall be suitable for
operation in atmospheres containing gases,
dust, and light rays produced by the welding
arc. (7-1-97)
f.
Unusual service conditions may exist, and in
such circumstances, machines shall be
especially designed to safely meet the
requirements of the intended service. Chief
among these conditions are: unusually
corrosive fumes, steam or excessive
humidity, excessive oil vapor, flammable
gases, abnormal vibration or shock,
excessive dust, or weather. (7-1-97)
g.
Open circuit (no load) voltages or arc
welding and cutting machines shall be as low
as possible consistent with satisfactory
welding or cutting being done. The following
limits shall not be exceeded: alternate
current machines, manual arc welding and
cutting -- eighty (80) volts; automatic
(machine or mechanized) arc welding and
cutting -- one-hundred (100) volts; direct
current machines, manual arc welding and
cutting -- one-hundred (100) volts;
automatic (machine or mechanized) arc
welding and cutting -- one-hundred (100)
volts. (7-1-97)
h.
When special welding and cutting processes
require values of open circuit voltages
higher than the above, means shall 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.
(7-1-97)
i.
A controller integrally mounted in an
electric motor driven welder shall have
capacity for carrying rated motor current,
shall be capable of making and interrupting
stalled rotor current of the motor, and may
serve as the running over-current device if
provided with the number of over-current
units as specified by the National Electric
Code. Starters with magnetic under voltage
release shall be used with machines
installed more than one (1) to a circuit to
prevent circuit overload caused by
simultaneously starting of several motors
upon return of voltage. (7-1-97)
j.
On all types of arc welding machines,
control apparatus shall be enclosed except
for the operating wheels, levers, or
handles. Control handles and wheels shall be
large enough to be easily grasped by a
gloved hand. (7-1-97)
k.
Input power terminals, tap change devices,
and live metal parts connected to input
circuits shall be completely enclosed and
accessible only by means of tools. (7-1-97)
l.
Terminals for welding leads shall be
protected from accidental electrical contact
by employees or by metal objects i.e.,
vehicles, crane hooks, etc.. Protection may
be obtained by use of: 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 which
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 shall be marked to indicate that it
is grounded. (7-1-97)
m.
No connections for portable control devices
such as push buttons to be carried by the
operator shall be connected to an a.c.
circuit of higher than one-hundred-twenty
(120) volts. Exposed metal parts of portable
control devices operating on circuits above
fifty (50) volts shall be grounded by a
grounding conductor in the control cable.
(7-1-97)
n.
Auto transformers or a.c. reactors shall not
be used to draw welding current directly
from any a.c. power source having a voltage
exceeding eighty (80) volts. (7-1-97)
o.
Installation including power supply shall be
in accordance with the requirements of the
National Electrical Code. (7-1-97)
p.
The frame or case of the welding machine
(except engine driven machines) shall be
grounded under the conditions and according
to the methods prescribed in National
Electrical Code. (7-1-97)
q.
Conduits containing electrical conductors
shall not be used for completing a work-lead
circuit. Pipe-lines shall not be used as a
permanent part of a work-lead circuit, but
may be used during construction, extension
or repair providing current is not carried
through threaded joints, flanged bolted
joints, or caulked joints and that special
precautions are used to avoid sparking at
connection of the work-lead cable. (7-1-97)
r.
Chains, wire ropes, cranes, hoists, and
elevators shall not be used to carry welding
current. (7-1-97)
s.
Where a structure, conveyor, or fixture is
regularly employed as a welding current
return circuit, joints shall be bonded or
provided with adequate current collecting
devices and appropriate periodic inspection
shall be conducted to ascertain that no
condition of electrolysis or shock, or fire
hazard exists by virtue of such use.
(7-1-97)
t.
All ground connections shall be checked to
determine that they are mechanically strong
and electrically adequate for the required
current. (7-1-97)
u.
A disconnecting switch or controller shall
be provided at or near each welding machine
which is not equipped with such a switch or
controller mounted as an integral part of
the machine. The switch shall be in
accordance with the National Electrical
Code. Over-current protection shall be
provided as specified in the National
Electrical Code. A disconnect switch with
overload protection or equivalent disconnect
and protection means, permitted by the
National Electrical Code shall be provided
for each outlet intended for connection to a
portable welding machine. (7-1-97)
v.
For individual welding machines, the rated
current carrying capacity of the supply
conductors shall be not less than the rated
primary current of the welding machines.
(7-1-97)
w.
For groups of welding machines, the rated
current carrying capacity of the rated
primary currents of the welding machines
supplied. The conductor rating shall be
determined in each case 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.
(7-1-97)
x.
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 required
distribution of machines among the phases of
the supply circuit. In such cases, no load
voltages between electrode holders will be
two (2) times normal in d.c. or one (1),
one-point-four (1.4),
one-point-seventy-three (1.73), or two (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. All d.c. machines shall be
connected with the same polarity. All a.c.
machines shall be connected to the same
phase of the supply circuit and with the
same instantaneous polarity. (7-1-97)
y.
Workmen assigned to operate or maintain arc
welding equipment shall be acquainted with
the requirements of sub-sections 230.28 and
230.17. of this section, if doing
gas-shielded arc welding, also Recommended
Safe Practices for Gas-Shielded Arc Welding,
A6.1 American Welding Society. (7-1-97)
z.
Before starting operations, all connections
to the machine shall be checked to make
certain they are properly made. The work
load shall be firmly attached to the work;
magnetic work clamps shall be freed of
adherent metal particles of spatter on
contact surfaces. Coiled welding cable shall
be spread out before use to avoid serious
over-heating and damage to insulation.
(7-1-97)
aa.
Grounding of the welding machine frame shall
be checked. Special attention shall be given
to safety ground connections of portable
machines. (7-1-97)
bb.
There shall be no leaks of cooling water,
shielding gas, or engine fuel. (7-1-97)
cc.
It shall be determined that proper switching
equipment for shutting down the machine is
provided. (7-1-97)
dd.
Printed rules and instructions covering
operation of equipment supplied by the
manufacturers shall be strictly followed.
(7-1-97)
ee.
Electrode holders when not used shall be so
placed that they cannot make electrical
contact with persons, conducting objects,
fuel, or compressed gas tanks. (7-1-97)
ff.
Cables with splices within 10-feet of the
holder shall not be used. The welder shall
not coil or loop welding electrode cable
around parts of his body. (7-1-97)
gg.
The operator shall report any equipment
defect or safety hazard to his supervisor
and the use of the equipment shall be
discontinued until its safety has been
assured. Repairs shall be made only by
qualified personnel. (7-1-97)
hh.
Machines which have become wet shall be
thoroughly dried and tested before being
used. (7-1-97)
ii.
Work and electrode lead cables should be
frequently inspected for wear and damage.
Cables with damaged insulation or exposed
bare conductors shall be replaced. Jointing
lengths of work and electrode cables shall
be done by the use of connecting means
specifically intended for the purpose. The
connecting means shall have insulation
adequate for the service conditions.
(7-1-97)
29.
Resistance Welding:
(7-1-97)
a.
All equipment shall be installed by a
qualified electrician in conformance with
the National Electrical Code. There shall be
a safety-type disconnecting switch or a
circuit breaker or circuit interrupter to
open each power circuit to the machine,
conveniently located at or near the machine,
so that the power can be shut off when the
machine or its controls are to be serviced.
(7-1-97)
b.
Ignition tubes used in resistance welding
equipment shall be equipped with a thermal
protection switch. (7-1-97)
c.
Workers designated to operate resistance
welding equipment shall have been properly
instructed and judged competent to operate
such equipment. (7-1-97)
d.
Controls of all automatic or air and
hydraulic clamps shall be arranged or
guarded to prevent the operator from
accidentally activating them. (7-1-97)
e.
Spot and seam welding machines (nonportable)
shall have all external weld initiating
control circuits operating on low voltages,
not over one-hundred-twenty (120) volts.
(7-1-97)
f.
Stored energy or capacitor discharge type of
resistance welding equipment and control
panels involving high voltage (over
five-hundred-fifty (550) volts) shall be
suitably insulated and protected by complete
enclosures, all doors of which shall be
provided with suitable interlocks and
contacts wired into the control circuit
(similar to elevator interlock). Such
interlocks or contacts shall be so designed
as to effectively interrupt power and short
circuit all capacitors when the door or
panel is open. A manually operated switch or
suitable positive device shall be installed,
in addition to the mechanical interlocks or
contacts, as an added safety measure
assuring absolute discharge of all
capacitors. (7-1-97)
g.
All doors and access panels of all
resistance welding machines and control
panels shall be kept locked and interlocked
to prevent access by unauthorized persons,
to live portions of the equipment. (7-1-97)
h.
All press welding machine operations, where
there is a possibility of the operators
fingers being under the point of operation,
shall be effectively guarded by the use of a
device such as an electronic eye safety
circuit, two (2) hand controls or
protections similar to that prescribed for
mechanical press operations in sub-section
250.21. of this standard. All chains, gears,
operating bus linkage, and belts shall be
protected by adequate guards, in accordance
with sub-section 250.04. of this standard.
(7-1-97)
i.
The hazard of flying sparks shall be
wherever practical, eliminated by installing
a shield guard of safety glass or suitable
fire resistant plastic at the point of
operation. Additional shields or curtains
shall be installed as necessary to protect
passing persons from flying sparks. (See
sub-section 230.04 of this section.)
(7-1-97)
j.
All foot switches shall be guarded to
prevent accidental operation of the machine.
(7-1-97)
k.
Two (2) or more safety emergency stop
buttons shall be provided on all special
multi-spot welding machines, including two
(2) post and four (4) post weld presses.
(7-1-97)
l.
On large machines, four (4) safety pins with
plugs and receptacles (one (1) in each
corner) shall be used so that when safety
pins are removed and inserted in the ram or
platen, the press becomes inoperative.
(7-1-97)
m.
Where technically practical, the secondary
of all welding transformers used in
multi-spot, protection and seam welding
machines shall be grounded. This may be done
by permanently grounding one side of the
welding secondary current circuit. Where not
technically practical, a center tapped
grounding reactor connected across the
secondary for the use of a safety disconnect
switch in conjunction with the welding
control are acceptable alternates. Safety
disconnect shall be arranged to open both
sides of the line when welding current is
not present. (7-1-97)
n.
All portable welding guns shall have
suitable counter-balanced devices for
supporting the guns, including cables,
unless the design of the gun or fixture
makes counterbalancing impractical or
unnecessary. (7-1-97)
o.
All portable welding guns, transformers and
related equipment that is suspended from
overhead structures, eye beams, trolleys,
etc.., shall be equipped with safety chains
or cables. Safety chains or cables shall be
capable of supporting the total shock load
in the event of failure of any component of
the support system. (7-1-97)
p.
When trolleys are used to support portable
welding equipment, they shall be equipped
with suitable forged steel clevis for the
attachment of safety chains. Each clevis
shall be capable of supporting the total
shock load of the suspended equipment in the
event of trolley failure. (7-1-97)
q.
All initiating switches, including
retraction and dual schedule switches,
located on the portable welding gun shall be
equipped with suitable guards capable of
preventing accidental initiation through
contact with fixturing, operator's clothing,
etc.. Initiating switch voltage shall not
exceed twenty-four (24) volts. (7-1-97)
r.
The movable holder, where it enters the gun
frame shall have sufficient clearance to
prevent the shearing of fingers carelessly
placed on the operating movable holder.
(7-1-97)
s.
Grounding. The secondary and case of all
portable welding transformers shall be
grounded. Secondary grounding may be by
center tapped secondary or by a center
tapped grounding reactor connected across
the secondary. (7-1-97)
30.
Flash Welding Equipment: (7-1-97)
a.
Flash welding machines shall be equipped
with 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 shall be provided in accordance
with sub-sections 230.06 through 230.07 of
this section. (7-1-97)
b.
For the protection of the operators of
nearby equipment, fire-resistant curtains or
suitable shields shall be set up around the
machine and in such a manner that the
operators movements are not hampered.
(7-1-97)
c.
If the welding process cannot be isolated,
all persons who may be exposed to the hazard
of arc flash shall be properly protected.
(7-1-97)
231.--239.
(RESERVED)