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s 4664. Relief Valves.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4665. Handling and Filling.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4794. Purpose.
(a) The following Group 10 orders shall apply to the installation and operation of all gas welding and cutting systems when used with gases and oxygen for welding, flame cutting, heating and heat treating operations and includes brazing and soldering. The definitions for brazing and soldering as contained in American National Standards Institute (ANSI)/American Welding Society (AWS) A3.0-94, Standard Welding Terms and Definitions are hereby incorporated by reference.
(b) Where only a portion of a fuel gas system is to be used with oxygen for the operations specified in subsection (a), only that portion of the system shall comply with these orders and shall be separated from the main system by means of a suitable hydraulic back-pressure valve. These orders also govern the storage of calcium carbide and of gases used in these processes and the installation and operation of acetylene generating systems.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4795. Definitions.
Building, as used in this group. A building having occupancy other than that directly associated with the production of acetylene, the storage of calcium carbide, or the storage and manifolding of gases used in welding, flame cutting, heating and heat treating.
Hydraulic Back-Pressure Valve, Hydraulic Seal, Hydraulic Flash Arrester, Hydraulic Valve and Backflow Check Valve. Terms used interchangeably to mean a device designed and constructed to prevent a flash-back from reaching a fuel gas source such as a generator, manifold or cylinder and to prevent accidental mixing of fuel gas and oxygen by reverse flow.
Welder and Welding Operator. Any operator of electric or gas welding and cutting equipment.
Note: All other welding terms are used in accordance with American Welding Society Terms and Definitions-A3.0-1980.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4797. Approval and Marking.
(a) Generators shall be approved and shall be plainly marked with "maximum" rate of acetylene in cubic feet per hour for which they are designed; the weight and size of carbide necessary for a single charge; the manufacturer's name and address; and the name or number of the type of generator.
(b) Auxiliary apparatus such as blowpipes (torches), regulators (pressure-reducing valves), compressors and booster systems, flame arresters and gages shall be approved. (See Section 3206)
(c) Equipment shall be installed and used only in the service for which it is approved.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4798. Rating and Pressure Limitations.
The total hourly output of a generator shall not exceed the rate for which it was approved and marked. Unless specifically approved for higher rating, carbide-feed generators shall be rated at 1 cubic foot per hour per pound of carbide required for a single complete charge.
Note: Authority cited: Section 142.3 Labor Code. Reference: Section 142.3, Labor Code.
s 4799. Training of Operators and Instructions.
Employees in charge of the oxygen or fuel-gas supply equipment including generators, and oxygen or fuel-gas distribution piping systems shall be instructed for this work in accordance with the requirements of Section 3203 of the General Industry Safety Orders before being left in charge. Rules and instructions covering the operation and maintenance of oxygen or fuel-gas supply equipment including generators, and oxygen or fuel-gas distribution piping systems shall be readily available.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4803. Housing of Permanent Stationary Acetylene Generators.
(a) Every stationary generator shall be housed in either an outside generator house or an inside generator room or compartment constructed according to the requirements of these orders.
(b) The space around the generator shall be ample for free, unobstructed operation and maintenance and shall permit ready adjustment and charging.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4804. Outside Generator Houses.
(a) No opening in any outside generator house shall be located within five feet of any opening in another house.
(b) Outside generator houses shall be of one of the types of fire resistant construction listed in Section 4805(b) or of non-combustible construction.
(c) Where a part of the house is to be used for the storage or manifolding of oxygen cylinders, the space to be so occupied shall be separated from the generator and carbide storage sections by partition walls continuous from floor to ceiling, of one of the types of construction listed in Section 4805(b). Such separation walls shall be without openings and shall be joined to the floor, other walls and ceiling or roof in such manner as to effect a permanently gas-tight joint.
(d) Explosion venting for outside generator houses and inside generator rooms shall be provided in exterior walls or roofs. The venting area shall be equal to but not less than 1 square foot per 50 cubic feet of room volume and shall not consist of any one or any combination of the following: Walls of light, non-combustible material preferably single-thickness, single-strength glass; fastened swinging doors in exterior walls opening outward; lightly fastened walls or roof designed to relieve at maximum pressure of 25 pounds per square foot.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4805. Inside Generator Rooms or Compartments.
(a) Acetylene Generators shall not be installed in buildings exceeding one story in height, unless they are installed on the top floor or roof.
(b) Generators installed inside buildings shall be enclosed in a separate room. The walls, partitions, floors, and ceilings of inside general rooms shall be of construction having a fire-resistance rating of at least one-hour.
The walls or partitions shall be continuous from floor to ceiling and shall be securely anchored. At least one wall of the room shall be an external wall.
(c) 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 a least 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 80-1970.
(d) A portion of the exterior walls or roof equal to not less than 10 percent of combined areas of the enclosing walls and roof shall be of light, noncombustible material, preferably single-strength glass.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4806. Exits.
In every generator house, room or compartment over 100 sq. ft. in floor area, there shall be two readily accessible exits remotely located from each other. At least one exit door shall give direct access to the outside.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3 Labor Code.
s 4807. Ventilation, Lighting and Heating of Generator Houses or Rooms.
(a) Inside generator rooms or outside generator houses shall be well ventilated with vents located at floor and ceiling levels.
(b) Heating shall be by steam, hot water, enclosed electrically heated elements or other indirect means. Heating by flames or fires shall be prohibited in outside generator houses or inside generator rooms, or in any enclosure communicating with them.
(c) All generator houses or rooms shall have natural lighting during daylight hours. Where artificial lighting is necessary, it shall be restricted to electric lamps installed in accordance with Electrical Safety Orders for hazardous locations. (Title 8, Section 2540.1 et seq.)
(d) All electrical equipment in and around an acetylene generator house, room or compartment shall be installed in accordance with Electrical Safety Orders for hazardous locations.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4808. Protection Against Freezing.
Generators must be placed where water will not freeze. No sodium chloride or other corrosive chemical is permissible as a protection against freezing.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4809. Water Supply Connection.
Water shall not be supplied through a continuous connection to the generator except when the generator is provided with an open overflow or automatic water shutoff which will prevent overfilling of the generator. Where a noncontinuous connection is used, the supply line shall terminate not less than two inches above the opening for filling so that the water can be observed as it enters the generator.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4810. Drain Connection.
Unless otherwise specifically approved, generators shall not be fitted with continuous drain connections leading to sewers but shall discharge through an open connection into a suitably vented outdoor receptacle or residue pit which may have such connections.
Note: An open connection for the sludge drawoff is desirable to enable the generator operator to observe leakage of generating water from the drain valve or sludge cock.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4811. Generator Escape or Relief Pipes.
(a) Each generating chamber shall be provided with an escape or relief pipe, installed without traps so that any condensate will drain back into the chamber.
(b) All relief pipes shall be carried to a suitable point outside the building and shall terminate in a suitable hood or bend located at least 12 feet above the ground and at least three feet from combustible construction. Each generator shall be provided with a vent pipe of Schedule 40 galvanized iron or steel, or equivalent.
(c) Generating chamber relief pipes shall not be interconnected but shall be led separately to the outside air.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4812. Maintenance and Operation.
(a) Relief valves shall be tested in accordance with the manufacturer's recommendation to insure proper functioning. Relief valves for generating chambers shall be set to open at a pressure not in excess of 15 p.s.i.g. Relief valves for hydraulic back-pressure valves shall be set to open at a pressure not in excess of 20 p.s.i.g.
(b) The carbide added each time the generator is charged shall be no more than sufficient to refill the space provided for carbide without ramming the charge. Only wooden, brass or other nonferrous tools shall be used in distributing the charge, or in making any other adjustments on generators or in generator houses or rooms.
(c) At least 1 fire extinguisher of not less than 10B:C rating, listed by the Underwriters' Laboratories or other recognized authority of equivalent standing, shall be kept available for service and in good working order near the generator house or room.
(d) Whenever a person is inside a generator, another person shall be stationed outside the generator to assist in case of emergency. The person in the generator shall be provided with, and shall wear an approved life line and belt. In addition, there shall be provided a suitable ladder giving access to the interior of the generator.
(e) Flash lights used in the generator room or storage building shall be Bureau of Mines permissible type or equivalent.
(f) Nonautomatic generators shall not be used for generating acetylene at pressures exceeding 1 p.s.i.g., and all water overflows shall be visible.
(g) Generator water chambers shall be kept filled to proper level at all times except while draining during the recharging operation.
Whenever repairs are to be made or the generator is to be charged or carbide is to be removed, the water chamber shall be filled to the proper level.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4813. Gas Holders.
(a) Gas holders shall be constructed on the gasometer principle, the bell being suitably guided. The gas bell shall move freely without tendency to bind and shall have a clearance of at least 2 inches from the shell.
The gas holder may be located in the generator room, in a separate room or out of doors. In order to prevent collapse of the gas bell or infiltration of air due to a vacuum caused by the compressor or booster pump or cooling of the gas, a compressor or booster cutoff shall be provided at a point 12 inches or more above the landing point of the bell. When the gas holder is located indoors, the room shall be ventilated, heated, and lighted in accordance with Section 4807.
(b) When the gas holder is not located within a heated building, gas holder seals shall be protected against freezing.
(c) Means shall be provided to stop the generator-feeding mechanism before the gas holder reaches the upper limit of its travel.
(d) When the gas holder is connected to only one generator, the gas capacity of the holder shall be not less than one-third of the hourly rating of the generator.
Note: Authority cited: Section 142.3, Labor Code. Reference: 142.3, Labor Code.
s 4815. General.
(a) Portable generators shall not be used within 10 feet of combustible material other than the floor.
(b) Portable generators shall not be used in rooms of total volume less than 35 times the total gas generating capacity per charge of all generators in the room.
No portable generator shall be used in a room with a ceiling less than 10 feet in height.
(c) Portable generators shall be protected against freezing. The use of salt or other corrosive chemicals to prevent freezing is prohibited.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4816. Operation and Maintenance.
(a) Portable generators shall be cleaned and recharged and the air mixture blown off outside buildings.
(b) Before a portable generator is recharged, partially or completely, it shall be thoroughly cleaned of all sludge and refilled with clean water.
(c) When charged with carbide, generators shall not be moved by crane, hoist or derrick.
(d) When not in use, portable generators shall not be stored in rooms in which open flames are used unless the generators contain no carbide and have been thoroughly purged of acetylene. Storage rooms shall be well ventilated.
(e) When portable acetylene generators are to be transported and operated on vehicles, they shall be securely anchored to the vehicles. If transported by truck, the motor shall be turned off during charging, cleaning, and generating periods.
(f) Portable generators shall be located at a safe distance from the welding position so that they will not be exposed to sparks, slag, or misdirection of the torch flame or overheating from hot materials or processes.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4818. Storage.
(a) Calcium carbide shall be stored in sealed metal containers which are free from punctures, excessive rusting, corrosion or any other damage that might affect their water and air tightness. The contents of damaged containers shall be promptly used or transferred to another container.
(1) The containers shall be provided with a screw top or equivalent. Solder shall not be used in such a manner that the container would fail if exposed to fire.
(2) Containers containing calcium carbide shall be conspicuously marked "Calcium Carbide Dangerous If Not Kept Dry" or with equivalent warning.
(b) Calcium carbide in quantities up to 600 pounds may be stored in sealed metal containers inside buildings in a dry, waterproof, well ventilated place. The seal shall not be broken so long as there is carbide in excess of one pound in any other unsealed package of that size of carbide in the building.
(1) Calcium carbide exceeding 600 pounds but not exceeding 5,000 pounds shall be stored:
(A) In an inside generator room or outside generator house; or
(B) In a separate room in a one-story building which may contain other occupancies, but without cellar or basement beneath the carbide storage section. Such rooms shall be constructed in accordance with Section 4805 and ventilated in accordance with Section 4807. These rooms shall be used for no other purpose.
(2) Calcium carbide in excess of 5,000 pounds shall be stored in one-story buildings without cellar or basement and used for no other purpose, or in outside generator houses. If the storage building is of noncombustible construction, it may adjoin other one-story buildings if separated therefrom by unpierced firewalls; if it is detached less than 10 feet from such building or buildings, there shall be no opening in any of the mutually exposing sides of such buildings within 10 feet of each other. If the storage building is of combustible construction, it shall be at least 20 feet from any other one- or two-story building, and at least 30 feet from any other building exceeding two stories.
(3) Sprinkler systems shall not be installed in carbide storage rooms.
(c) Calcium carbide in sealed metal containers stored out-of-doors shall be on wooden planking or its equivalent so that the containers will not contact the ground or ground water. The containers shall be stored in rows with ample space for easy inspection and under tarpaulins.
(1) Carbide containers to be stored outdoors shall be examined to make sure that they are in good condition. Periodic reexaminations shall be made for rusting or other damage to a container that might affect its water or air tightness.
(2) Containers of carbide which have been in storage the longest shall be used first.
(d) No carbide storage room shall be used for the storage of any other material except fuel gas cylinders, singly or manifolded.
(e) Trucks or wheelbarrows used inside carbide storage rooms shall be equipped with rubber or other nonsparking tires.
(f) There shall be no opening from the carbide storage room into any other room or building, except that if there be a partition between the carbide room and a generator room, a doorway will be permitted if all electrical equipment in the carbide room be installed in accordance with Electrical Safety Orders for hazardous locations.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4819. Opening Containers.
Nonferrous tools except copper or copper base alloy tools shall be provided and used for opening carbide containers.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4821. Gas Systems Piping for Welding and Cutting, Materials and Design.
(a) Piping and fittings shall comply with Chapters 1 through 4 of the American National Standard Code for Pressure Piping, ASME B31.1.2001, Power Piping, which is hereby incorporated by reference, insofar as it does not conflict with (b) and (c).
(b) Pipe shall be at least Schedule 40 and fittings shall be at least standard weight in sizes up to and including 6-inch nominal.
(c) Copper tubing shall be Types K or L in accordance with the Standard Specification for Seamless Copper Water Tube, ASTM B88-96 which is hereby incorporated by reference.
(d) Piping shall be steel, wrought iron, brass or copper pipe, or seamless copper, brass or stainless steel tubing, except as provided in Sections 4822 and 4823.
(e) 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.
Note: Authority cited: Section 142.3, Labor Code. Reference:Section 142.3, Labor Code.
s 4822. Oxygen Piping.
(a) Oxygen piping and fittings at pressures in excess of 700 p.s.i.g., shall be stainless steel or copper alloys.
(b) Hose connections and hose complying with Section 4839 of this Article may be used to connect the outlet of a manifold pressure regulator to piping providing the working pressure of the piping is 250 p.s.i.g. or less and the length of the hose does not exceed 5 feet. Hose shall have a minimum bursting pressure of 1,000 p.s.i.g.
(c) 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 250 p.s.i.g. A pressure regulating device shall be used at each station outlet when the connected equipment is for use at pressures less than 250 p.s.i.g.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4823. Acetylene Piping.
Piping for acetylene or acetylenic compounds shall be steel or wrought iron.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4824. Piping Joints.
(a) Joints in steel or wrought iron piping shall be welded, threaded or flanged. Fittings, such as ells, tees, couplings, and unions, may be rolled, forged or cast steel, malleable iron or nodular iron. Gray or white cast iron fittings are prohibited.
(b) 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 800 degrees F) filler metal.
(c) Joints in seamless copper, brass, or stainless steel 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 800 degrees F) filler metal.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4825. Installation -General.
(a) Distribution lines shall be installed and maintained in a safe operating condition. All piping shall be run 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, nitrogen, or carbon dioxide to remove foreign materials. For oxygen piping, only oil-free air, oil-free nitrogen, or oil-free carbon dioxide shall be used.
(b) Oxygen piping shall never be placed in tunnel, trench, manhole or duct where it may be exposed to contact with oil.
(c) Only piping which has been welded or brazed shall be installed in tunnels, trenches or ducts. Shutoff 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.
(d) All drip pots shall be readily accessible and provided with outlets normally closed with screw caps or plugs. No open end valves or pet-cocks shall be used.
(e) Gas cocks or valves shall be provided for all buildings at points outside the buildings where they will be readily accessible for shutting off gas supply to buildings in any emergency.
Note: Authority cited: Section 142.3 Labor Code. Reference: Section 142.3, Labor Code.
s 4826. Testing.
Piping systems shall be tested and proved gas-tight at 1 1/2 times the maximum working 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 non-combustible, flames shall not be used to detect leaks.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4827. Painting and Signs.
(a) Underground pipe and tubing and outdoor ferrous pipe and tubing shall be covered or painted with a suitable material for protection against corrosion.
(b) All oxygen pipe lines shall be painted one color, preferably green, and all fuel gas pipes a different color. Where more than one fuel gas is employed, the pipe lines supplying the different gases shall be painted distinctive colors.
(c) A color chart indicating the colors employed for this purpose shall be prominently displayed.
(d) Signs clearly establishing the location and identity of section shut-off valves shall be provided.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4828. Hydraulic Back-Pressure Valves.
(a) In low-pressure fuel gas systems, including acetylene, liquefied petroleum gas, manufactured gas, natural gas, etc., where the gas is piped at a pressure not in excess of 1 p.s.i., an approved hydraulic back-pressure valve shall be employed at every point where fuel gas and oxygen are withdrawn from the piping system. A shut-off valve shall be installed at the inlet of each hydraulic valve.
(b) In fuel gas systems where the gas is piped at a pressure in excess of 1 p.s.i. an approved service regulator, check valve or hydraulic seal shall be employed at every point where fuel gas and oxygen are withdrawn from the piping system. A shut-off valve shall be installed at the inlet of each hydraulic seal, regulator or check valve. Fuel gas for use with equipment not requiring oxygen shall be withdrawn upstream of the piping protective devices.
(c) Maintenance and inspection of hydraulic back-pressure valves shall be in accordance with manufacturer's instructions.
(d) If the station outlet is equipped with a detachable regulator, the outlet shall terminate in a union connection that complies with the Standard Connections for Regulator Outlets, Torches and Fitted Hose for Welding and Cutting Equipment, Compressed Gas Association, Pamphlet E-1-1980.
If the station outlet is connected directly to a hose, the outlet shall terminate in a union connection complying with the Standard Connections for Regulator Outlets, Torches and Fitted Hose for Welding and Cutting Equipment, Compressed Gas Association, Pamphlet E-1-1980.
Station outlets may terminate in pipe threads to which permanent connections are to be made, such as to a machine.
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.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4829. Storage and Use of Cylinders.
s 4834. Manifolds, General.
(a) Manifolds shall be approved either separately for each component part or as an assembled unit.
(b) Each fuel-gas and oxygen cylinder lead shall be provided with a backflow check valve.
(c) The aggregate capacity of fuel-gas cylinders connected to a portable manifold inside a building shall not exceed 3,000 cubic feet of gas.
(d) Acetylene and liquefied fuel-gas cylinders shall be manifolded in a vertical position.
(e) Such manifolds shall be so located and so guarded as to protect them against damage from trucks and from any material being moved in the vicinity.
(f) Cylinder manifolds shall be installed under the supervision of someone familiar with the proper practices with reference to their construction and use.
(g) All component parts used in the methods of manifolding described in Section 4821 shall be approved as to materials, design and construction either separately or as an assembled unit.
(h) All manifolds and parts used in methods of manifolding shall be used only for the gas or gases for which they are approved.
(i) 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, one flash arrester installed between the coupler block and regulator is acceptable.
(j) Fuel gas and oxygen manifolds shall bear the name of the substance they contain in letters at least 1-inch high which shall be either painted on the manifold or on a sign permanently attached to it.
(k) Fuel gas and oxygen manifolds shall be placed in safe, well ventilated, and accessible locations. They shall not be located within enclosed spaces.
( l) Nothing shall be placed on top of a manifold, when in use, which will damage the manifold or interfere with the quick closing of the valves.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4835. Fuel Gas Manifolds. (Acetylene, Liquefied Fuel Gases, and Nonliquified Gases Other Than Acetylene.)
(a) Only cylinders containing gas at approximately equal pressures shall be manifolded.
(b) Except as provided in 4835 (c), fuel-gas cylinders connected to one manifold inside a building shall be limited to a total capacity not exceeding 300 pounds of liquified petroleum gas or 3,000 cubic feet of other fuel-gas. More than one manifold with connected cylinders may be located in the same room provided the manifolds are at least 50 feet apart or separated by a noncombustible barrier at least 50 feet apart or separated by a noncombustible barrier at least 5 feet high having a fire-resistance rating of at least one-half hour.
(c) Fuel-gas cylinders connected to one manifold having an aggregate capacity exceeding 300 pounds of liquified petroleum gas or 3,000 cubic feet of other fuel-gas shall be located outdoors, or in a separate building or room constructed in accordance with Section 4805(b).
(d) Special buildings or rooms, if provided, shall have no other occupancy except that they may be used for the storage of cylinders containing fuel gas and of drums of carbide; such buildings or rooms shall have no open flame for heating or lighting and shall be well ventilated. Signs shall be conspicuously posted in such rooms reading, "Danger No Smoking, Matches or Open Lights," or other equivalent wording.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4836. Oxygen Manifolds.
(a) Oxygen manifolds shall not be located in an acetylene generator room. Oxygen manifolds shall be separated from fuel-gas cylinders or combustible materials (especially oil or grease), a minimum distance of 20 feet or by a noncombustible barrier at least 5 feet high having a fire resistance rating of at least one-half hour.
(b) An oxygen manifold, to which cylinders having an aggregate capacity of more than 6,000 cubic feet of oxygen are connected, shall be located outdoors or in a separate noncombustible building. Such a manifold if located inside a building having other occupancy, shall be located in a separate room of noncombustible construction.
(c) Manifolds shall be of substantial construction suitable for use with oxygen at a pressure of 250 p.s.i.g. They shall have a minimum bursting pressure of 1,000 p.s.i.g. and shall be protected by a safety relief device which will relieve at a maximum pressure of 500 p.s.i.g. DOT-4L200 cylinders have safety devices which relieve at a maximum pressure of 250 p.s.i.g. (or 235 p.s.i.g. if vacuum insulation is used).
(1) Hose and hose connections subject to cylinder pressure shall comply with Section 4839.
(2) Hose shall have a minimum bursting pressure of 1,000 p.s.i.g.
(3) The assembled manifold including leads shall be tested and proven gas-tight at a pressure of 300 p.s.i.g. The fluid used for testing oxygen manifolds shall be oil free and noncombustible.
(4) The following sign shall be conspicuously posted at each manifold:
Low-Pressure Manifold Do Not Connect High-Pressure Cylinders Maximum Pressure -
250 P.S.I.G.
(d) 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.
(1) 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.
(2) Hose and hose connections used for connecting the portable outlet header to the service piping shall comply with Section 4839.
(3) Master shutoff valves for both oxygen and fuel-gas shall be provided at the entry end of the portable outlet header.
(4) 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.
(5) Materials and fabrication procedures for portable outlet headers shall comply with Sections 4822, 4823 and 4824.
(6) 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.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4837. Liquid Oxygen.
Where liquid oxygen in a quantity exceeding 100 gallons is to be used for welding and cutting, the container or containers shall be located outside or in a special building having no other occupancy except that related to the handling and gasification of the oxygen and shall comply with the provisions of Article 139, Oxygen, Sections 5500-5509, of this Title.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4838. Pressure Regulators.
(a) Regulators or automatic reducing valves shall be used only for the gas and at the pressure for which they are intended. Defective oxygen and fuel gas pressure regulators, including their gauges, shall not be used.
(b) When regulators or parts of regulators, including gauges, need repair, the work shall be performed by skilled mechanics who have been properly instructed.
(c) Gauges on oxygen regulators shall be marked "USE NO OIL."
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4839. Hose.
(a) Fuel gas hose and oxygen hose shall be easily distinguished from each other. The contrast may be either by different colors or by surface characteristics readily distinguishable by the sense of touch. Oxygen and fuel gas hoses shall not be interchangeable. A single hose having more than one passage shall not be used.
Note: Red is generally accepted as the color for fuel gas, while green is used for oxygen hose.
(1) Hose for oxy-fuel gas service shall comply with the Specification for Rubber Welding Hose, 1979, Rubber Manufacturers Association.
(2) When parallel lengths of oxygen and acetylene hose are taped together for convenience and to prevent tangling, not more than 4 inches out of 12 inches shall be covered by tape.
(3) Hose connections shall comply with the Standard Connections for Regulator Outlets, Torches and Fitted Hose for Welding and Cutting Equipment, Compressed Gas Association, Pamphlet E-1-1980.
(4) 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 300 p.s.i. Oil-free air or an oil-free inert gas shall be used for the test.
(5) Manifold hose connections, including both ends of the supply hose that lead to the manifold, shall be such that the hose cannot be interchanged between fuel gas and oxygen manifolds and supply header connections. Adapters shall not be used to permit the interchange of hose. Hose connections shall be kept free of grease and oil.
(6) All hose in use, carrying acetylene, oxygen, natural or manufactured fuel gas, or any gas or substance which may ignite or enter into combustion, or be in any way harmful to employees, shall be inspected at the beginning of each working shift.
(7) Hose which has been subject to flashback, or which shows evidence of severe wear or damage, shall be tested to twice the normal pressure to which it is subject, but in no case less than 300 p.s.i. Defective hose, or hose in doubtful condition, shall not be used.
(8) Hose showing leaks, burns, worn places, or other defects rendering it unfit for service shall be repaired or replaced.
(9) Boxes used for the storage of gas hose shall be ventilated.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4840. Compressor or Booster Pumps -Fuel Gas and Acetylene-Oxygen Systems.
(a) Compressor or booster pumps shall be provided with pressure relief valves which will relieve pressure exceeding 15 p.s.i.g. to a safe outdoor location as provided in Section 4811 or by returning the gas to the inlet side or to the gas supply source.
(b) Compressor or booster pump discharge outlets shall be provided with approved protective equipment. (See Section 4828.)
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4845. General Precautions.
(a) Mixtures of fuel gases and air or oxygen may be explosive and shall be guarded against. No device or attachment facilitating or permitting mixture of air or oxygen with combustible gases prior to consumption, except at the burner or in a standard torch or blowpipe, shall be allowed unless approved for the purpose.
(b) Backflow 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. The backflow protection device shall be installed on either the torch or at each station outlet (i.e. the point at which gas is withdrawn from the permanent piping) either upstream or downstream of the shutoff valve for the oxygen or fuel gas station outlet valve(s).
(c) Acetylene shall not be generated, piped (except in approved cylinder manifolds) or utilized at a pressure in excess of 15 pounds per square inch gauge pressure.
(d) The use of liquid acetylene shall be prohibited.
(e) Oil or grease shall not be permitted to come in contact with oxygen cylinders, valves, regulators or other fittings. Oxygen cylinders and apparatus shall not be handled with oily hands or gloves, or greasy materials. A jet of oxygen shall not be permitted to strike an oily surface, greasy clothes or enter a fuel oil or other storage tank.
(f) Oxygen shall not be used from a cylinder or cylinder manifold unless a pressure-reducing device intended for use with oxygen, and so marked, is provided.
(g) 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.
Note: Low pressure air-gas torches may be used on small cylinders provided there is no shutoff valve on the torch.
(h) Welding 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. 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.
(i) Cylinders shall be handled carefully.
Note: Rough handling, knocks, and falls are liable to damage the cylinder, valve or safety devices and result in leakage.
(j) Before connecting a regulator to a cylinder valve, the valve shall be opened slightly and closed immediately. (This action is generally termed "cracking" and is intended to clear the valve of dust or dirt that might otherwise enter the regulator.) The valve shall be opened while standing to one side of the outlet; never in front of it. A fuel-gas cylinder valve shall never be opened up, cracked near other welding work or near sparks, flame, or other possible sources of ignition.
(k) Before a regulator is removed from a cylinder valve, the cylinder valve shall be closed and the gas released from the regulator.
(l) 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.
(m) Cylinders having leaking fuse plugs or other leaking safety devices shall be plainly tagged, and the supplier shall be promptly notified of the condition and his instructions followed. A warning shall be placed near the cylinders prohibiting any approach to them with a lighted cigarette or other source of ignition.
(n) Safety devices shall not be tampered with.
(o) The cylinder valve shall always be opened slowly.
(p) An acetylene cylinder valve shall not be opened more than one and one-half turns of the spindle, and preferably no more than three-fourths of a turn.
(q) Torches in use shall be inspected at the beginning of each working shift for leaking shutoff valves, hose couplings, and tip connections. Defective torches shall not be used. Clogged torch tip openings shall be cleaned with suitable cleaning wires, drills, or other devices designed for such purpose.
(r) Torches shall be lighted by friction lighters or other approved devices, and not by matches or from hot work.
(s) Unalloyed copper shall not be used for acetylene or acetylenic compounds except in listed equipment.
(t) 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.
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.
(u) If pipeline protective equipment incorporates a liquid, the liquid level shall be maintained, and a suitable antifreeze may be used to prevent freezing.
(v) Cylinders shall be kept far enough 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 provided.
(w) No person, other than the gas supplier, shall attempt to mix gases in a cylinder. No one, except the owner of the cylinder or person authorized by him, shall refill a cylinder.
(x) Cylinders containing oxygen or acetylene or other fuel or gas shall not be taken into confined spaces.
(y) When operations are suspended for any substantial period of time, such as during lunch or overnight, gas cylinders shall be shut off. Where practicable the torch and hose shall be removed from the confined space. Upon completion or discontinuance of welding operations, the welder shall provide some means of warning other workers of the location of hot metal.
Note: See Section 5150 for ventilation requirements for welding, brazing and cutting.
Exception: Hydrogen cylinders. See suppliers instructions before connecting the regulator.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4846. Storage of Cylinders.
Note: Authority cited: Section 142.3, Labor Code.
s 4847. Use of Cylinders.
s 4848. Fire Prevention and Suppression Procedure.
(a) The employer shall establish a fire prevention and suppression procedure whenever any of the operations and processes covered by Sections 4794(a) and 4850(a) are conducted on its property. The employer shall issue and implement instructions on fire prevention and suppression procedures based upon the requirements contained in American National Standards Institute (ANSI/ASC) Z49.1-94, Safety In Welding, Cutting and Allied Processes, Chapters 3 and 6 and National Fire Protection Association (NFPA) 51B-1999, Standard for Fire Prevention During Welding, Cutting, and Other Hot Work, Chapter 3, which are hereby incorporated by reference.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4850. General.
(a) Group 11 orders shall apply to all electrical equipment when used to perform electric welding, cutting, heating and other operations and processes pertaining to electric welding and includes resistance brazing and resistance soldering. The definitions for resistance brazing and resistance soldering as contained in American National Standards Institute/American Welding Society, ANSI/AWS A3.0-94, Standard Welding Terms and Definitions, are hereby incorporated by reference.
(b) All electrical equipment used to perform operations and processes noted in subsection (a) shall be installed and maintained in accordance with the California Electrical Safety Orders and chapters 11, 12 and 13 of the American National Standards Institute, ANSI/ASC Z49.1-94, Safety in Welding, Cutting and Allied Processes, which are hereby incorporated by reference.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 4851. Arc Welding and Cutting.
(a) Where the work permits, the welder shall be enclosed in an individual booth painted with a finish of low reflectivity, such as zinc oxide and lamp black, or shall be enclosed with noncombustible screens having a similar low reflectivity finish. 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 flameproof screens or shields or shall be required to wear appropriate goggles.
(b) Welding machines shall be left on the outside of a confined space and heavy portable equipment shall be blocked to prevent accidental movement.
(c) When operations are suspended for any substantial period of time, such as during lunch or overnight, welding machines shall be shut off at some point outside the confined space. Where practicable, the electrodes and electrode holders shall be removed from the confined space. All electrodes shall be removed from the holders and the holders carefully located to prevent accidental contact. Upon completion or discontinuance of welding operations, the welder shall provide some means of warning other workers of the location of hot metal.
(d) Manual Electrode Holders.
(1) The employer shall ensure that only manual electrode holders intended for arc welding and cutting and capable of handling the maximum current required for such welding or cutting shall be used.
(2) Current-carrying parts passing through those portions of the holder gripped by the user and through the outer surfaces of the jaws of the holder shall be insulated against the maximum voltage to ground.
(e) Welding Cables and Connectors.
(1) Arc welding and cutting cables shall be insulated, flexible and capable of handling the maximum current required by the operations, taking into account the duty cycles.
(2) Only cable free from repair or splice for 10 feet (3 m) from the electrode holder shall be used unless insulated connectors or splices with insulating quality equal to that of the cable are provided.
(3) When a cable other than the lead mentioned in Subsection (e)(2) wears and exposes bare conductors, the portion exposed shall not be used until it is protected by insulation equivalent in performance capacity to the original.
(4) Insulated connectors of equivalent capacity shall be used for connecting or splicing cable. Cable lugs, where used as connectors, shall provide electrical contact. Exposed metal parts shall be insulated.
(f) Ground Returns and Machine Grounding.
(1) Ground return cables shall have current-carrying capacity equal to or exceeding the total maximum output capacities of the welding or cutting units served.
(2) Structures or pipelines, other than those containing gases or flammable liquids or conduits containing electrical circuits, may be used in the ground return circuit if their current-carrying capacity equals or exceeds the total maximum output capacities of the welding or cutting units served.
(3) Structures or pipelines forming a temporary ground return circuit shall have electrical contact at all joints. Arcs, sparks or heat at any point in the circuit shall cause rejection as a ground circuit.
(4) Structures or pipelines acting continuously as ground return circuits shall have joints bonded and maintained to ensure that no electrolysis or fire hazard exists.
(5) Arc welding and cutting machine frames shall be grounded, either through a third wire in the cable containing the circuit conductor or through a separate wire at the source of the current. Grounding circuits shall have resistance low enough to permit sufficient current to flow to cause the fuse or circuit breaker to interrupt the current.
(6) Ground connections shall be mechanically and electrically adequate to carry the current.
(g) When electrode holders are left unattended, electrodes shall be removed and holders placed to prevent employee injury. (continued)