What should I know about hand saws? – Back to top Saws are made in various shapes and sizes and for many uses. Use the correct saw for the job.
Wear safety glasses or goggles, or a face shield (with safety glasses or goggles).Select a saw of proper shape and size for stock being used.Select a saw with the number of teeth per inch (TPI) in order to get the desired finish. For example: a coarse tooth blade (e.g., 2 or 3 TPI) should be used for thicker stock.18 to 32 TPI should be used on thinner metals or plastic (0.5 cm or 1/4 inch). General wood cutting typically requires about 4 TPI.Choose a saw handle that keeps wrist in a natural position in the horizontal plane.Choose saw with a handle opening of at least 12 cm (5 in.) long and 6 cm (2.5 in.) wide and slanted at a 15° angle.
Check the stock being cut for nails, knots, and other objects that may damage or buckle saw.Start the cut by placing your hand beside the cut mark with your thumb upright and pressing against blade. Start cut carefully and slowly to prevent blade from jumping. Pull upward until blade bites. Start with partial cut, then set saw at proper angle.Apply pressure on downstroke only.
Hold stock being cut firmly in place.Use a helper, a supporting bench or vise to support long stock if required.Keep teeth and blades properly set.Protect teeth of saw when not in use.Keep saw blades clean.
- 1 What are the 5 various types of pressure regulators?
- 2 What is the danger of acetylene pressure?
- 3 What are the three types of pressure controls?
- 4 What are the two types of pressure controllers?
- 5 What is the standard temperature and pressure for acetylene?
- 6 What are the 4 rules for acetylene use?
- 7 What is the explosive limit for acetylene?
- 8 What should oxygen level be for welding?
- 9 Why does regulator have two gauges?
- 10 Why does the acetylene regulator have two pressure gauges?
How many pressure gauges are in regulator gas welding plant?
Click here to see our latest technical engineering podcasts on YouTube, – Hoses Hoses between the torch and the gas regulators should be colour-coded; in the UK: red for acetylene, and blue for oxygen. Fittings on the oxygen hose have right-hand threads; while those on the acetylene hose have left-hand threads.
Gas regulators The primary function of a gas regulator is to control gas pressure. It reduces the high pressure of the bottle-stored gas to the working pressure of the torch, and this will be maintained during welding. The regulator has two separate gauges: a high pressure gauge for gas in the cylinder and a low pressure gauge for pressure of gas fed to the torch.
The amount of gas remaining in the cylinder can be judged from the high pressure gauge. The regulator, which has a pressure adjusting screw, is used to control gas flow rate to the torch by setting the outlet gas pressure. Note Acetylene is supplied in cylinders under a pressure of about 15 bar but welding is carried out with torch gas pressures typically up to 2 bar.
Flame traps Flame traps (also called flashback arresters) must be fitted into both oxygen and acetylene gas lines to prevent a flashback flame from reaching the regulators. Non-return spring-loaded valves can be fitted in the hoses to detect/stop reverse gas flow. Thus, the valves can be used to prevent conditions leading to flashback, but should always be used in conjunction with flashback arresters.
A flashback is where the flame burns in the torch body, accompanied by a whistling sound. It will occur when flame speed exceeds gas flow rate and the flame can pass back through the mixing chamber into the hoses. Most likely causes are: incorrect gas pressures giving too low a gas velocity, hose leaks, loose connections, or welder techniques which disturb gas flow.
What is the maximum safe operating pressure for cutting or welding with acetylene?
- By Standard Number
- 1910.253 – Oxygen-fuel gas welding and cutting.
- Part Number: 1910
- Part Number Title: Occupational Safety and Health Standards
- Subpart: 1910 Subpart Q
- Subpart Title: Welding, Cutting and Brazing
- Standard Number:
- Title: Oxygen-fuel gas welding and cutting.
- GPO Source:
1910.253(a) General requirements – 1910.253(a)(1) Flammable mixture, 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.1910.253(a)(2) Maximum pressure,
Under no condition shall acetylene be generated, piped (except in approved cylinder manifolds) or utilized at a pressure in excess of 15 psig (103 kPa gauge pressure) or 30 psia (206 kPa absolute). The 30 psia (206 kPa absolute) limit is intended to prevent unsafe use of acetylene in pressurized chambers such as caissons, underground excavations or tunnel construction.) This requirement is not intended to apply to storage of acetylene dissolved in a suitable solvent in cylinders manufactured and maintained according to U.S.
Department of Transportation requirements, or to acetylene for chemical use. The use of liquid acetylene shall be prohibited.1910.253(a)(3) Apparatus, Only approved apparatus such as torches, regulators or pressure-reducing valves, acetylene generators, and manifolds shall be used.1910.253(a)(4) Personnel,
Workmen in charge of the oxygen or fuel-gas supply equipment, including generators, and 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 generators, and oxygen or fuel-gas distribution piping systems shall be readily available.1910.253(b) Cylinders and containers — 1910.253(b)(1) Approval and marking,1910.253(b)(1)(i) 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 171-179.1910.253(b)(1)(ii) Compressed gas cylinders shall be legibly marked, for the purpose of identifying the gas content, with either the chemical or the trade name of the gas. Such marking shall be by means of stenciling, stamping, or labeling, and shall not be readily removable.
Whenever practical, the marking shall be located on the shoulder of the cylinder.1910.253(b)(1)(iii) Compressed gas cylinders shall be equipped with connections complying with the American National Standard Compressed Gas Cylinder Valve Outlet and Inlet Connections, ANSI B57.1—1965, which is incorporated by reference as specified in §1910.6.1910.253(b)(1)(iv) All cylinders with a water weight capacity of over 30 pounds (13.6 kg) shall be equipped with means of connecting a valve protection cap or with a collar or recess to protect the valve.1910.253(b)(2)(i) Cylinders shall be kept away from radiators and other sources of heat.1910.253(b)(2)(ii) Inside of buildings, cylinders shall be stored in a well-protected, well-ventilated, dry location, at least 20 feet (6.1 m) from highly combustible materials such as oil or excelsior.
Cylinders should be stored in definitely assigned places away from elevators, stairs, or gangways. Assigned storage spaces shall be located where cylinders will not be knocked over or damaged by passing or falling objects, or subject to tampering by unauthorized persons.
Cylinders shall not be kept in unventilated enclosures such as lockers and cupboards.1910.253(b)(2)(iii) Empty cylinders shall have their valves closed.1910.253(b)(2)(iv) Valve protection caps, where cylinder is designed to accept a cap, shall always be in place, hand-tight, except when cylinders are in use or connected for use.1910.253(b)(3) Fuel-gas cylinder storage,
Inside a building, cylinders, except those in actual use or attached ready for use, shall be limited to a total gas capacity of 2,000 cubic feet (56 m 3 ) or 300 pounds (135.9 kg) of liquefied petroleum gas.1910.253(b)(3)(i) For storage in excess of 2,000 cubic feet (56 m 3 ) total gas capacity of cylinders or 300 (135.9 kg) pounds of liquefied petroleum gas, a separate room or compartment conforming to the requirements specified in paragraphs (f)(6)(i)(H) and (f)(6)(i)(I) of this section shall be provided, or cylinders shall be kept outside or in a special building.
Special buildings, rooms or compartments shall have no open flame for heating or lighting and shall be well ventilated. They may also be used for storage of calcium carbide in quantities not to exceed 600 (271.8 kg) pounds, when contained in metal containers complying with paragraphs (g)(1)(i) and (g)(1)(ii) of this section.1910.253(b)(4)(i) 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.1910.253(b)(4)(ii) Oxygen cylinders stored in outside generator houses shall be separated from the generator or carbide storage rooms by a noncombustible partition having a fire-resistance rating of at least 1 hour.
This partition shall be without openings and shall be gastight.1910.253(b)(4)(iii) Oxygen cylinders in storage shall be separated from fuel-gas cylinders or combustible materials (especially oil or grease), a minimum distance of 20 feet (6.1 m) or by a noncombustible barrier at least 5 feet (1.5 m) high having a fire-resistance rating of at least one-half hour.1910.253(b)(4)(iv) 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 13,000 cubic feet (364 m 3 ) of oxygen (measured at 14.7 psia (101 kPa) and 70 °F (21.1 °C)), connected in service or ready for service, or more than 25,000 cubic feet (700 m 3 ) of oxygen (measured at 14.7 psia (101 kPa) and 70 °F (21.1 °C)), including unconnected reserves on hand at the site, it shall comply with the provisions of the Standard for Bulk Oxygen Systems at Consumer Sites, NFPA No.566—1965, which is incorporated by reference as specified in §1910.6.1910.253(b)(5) Operating procedures,1910.253(b)(5)(i) 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 an oily surface, greasy clothes, or enter a fuel oil or other storage tank.1910.253(b)(5)(ii)(A) When transporting cylinders by a crane or derrick, a cradle, boat, or suitable platform shall be used.
Slings or electric magnets shall not be used for this purpose. Valve-protection caps, where cylinder is designed to accept a cap, shall always be in place.1910.253(b)(5)(ii)(B) Cylinders shall not be dropped or struck or permitted to strike each other violently.1910.253(b)(5)(ii)(C) Valve-protection caps shall not be used for lifting cylinders from one vertical position to another.
Bars shall not be used under valves or valve-protection caps to pry cylinders loose when frozen to the ground or otherwise fixed; the use of warm (not boiling) water is recommended. Valve-protection caps are designed to protect cylinder valves from damage.1910.253(b)(5)(ii)(D) 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.1910.253(b)(5)(ii)(E) Cylinders not having fixed hand wheels shall have keys, handles, or nonadjustable wrenches on valve stems while these cylinders are in service.
In multiple cylinder installations only one key or handle is required for each manifold.1910.253(b)(5)(ii)(F) Cylinder valves shall be closed before moving cylinders.1910.253(b)(5)(ii)(G) Cylinder valves shall be closed when work is finished.1910.253(b)(5)(ii)(H) Valves of empty cylinders shall be closed.1910.253(b)(5)(ii)(I) 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.1910.253(b)(5)(ii)(J) Cylinders shall not be placed where they might become part of an electric circuit.
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.1910.253(b)(5)(ii)(K) Cylinders shall never be used as rollers or supports, whether full or empty.1910.253(b)(5)(ii)(L) The numbers and markings stamped into cylinders shall not be tampered with.1910.253(b)(5)(ii)(M) 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.1910.253(b)(5)(ii)(N) No one shall tamper with safety devices in cylinders or valves.1910.253(b)(5)(ii)(O) Cylinders shall not be dropped or otherwise roughly handled.1910.253(b)(5)(ii)(P) 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.1910.253(b)(5)(ii)(Q) A hammer or wrench shall not be used to open cylinder valves. If valves cannot be opened by hand, the supplier shall be notified.1910.253(b)(5)(ii)(R)(1) Cylinder valves shall not be tampered with nor should any attempt be made to repair them.
If trouble is experienced, the supplier should be sent a report promptly indicating the character of the trouble and the cylinder’s serial number. Supplier’s instructions as to its disposition shall be followed.1910.253(b)(5)(ii)(R)(2) Complete removal of the stem from a diaphragm-type cylinder valve shall be avoided.1910.253(b)(5)(iii)(A) 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.1910.253(b)(5)(iii)(B) Cylinders shall be handled carefully. Rough handling, knocks, or falls are liable to damage the cylinder, valve or safety devices and cause leakage.1910.253(b)(5)(iii)(C) 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. Never crack a fuel-gas cylinder valve near other welding work or near sparks, flame, or other possible sources of ignition.1910.253(b)(5)(iii)(D) Before a regulator is removed from a cylinder valve, the cylinder valve shall be closed and the gas released from the regulator.1910.253(b)(5)(iii)(E) 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.1910.253(b)(5)(iii)(F) 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.1910.253(b)(5)(iii)(G) A warning should be placed near cylinders having leaking 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.1910.253(b)(5)(iii)(H) Safety devices shall not be tampered with.1910.253(b)(5)(iii)(I) Fuel-gas shall never 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.1910.253(b)(5)(iii)(J) The cylinder valve shall always be opened slowly.1910.253(b)(5)(iii)(K) 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.1910.253(b)(5)(iii)(L) 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 such wrench shall always be available for immediate use.1910.253(c) Manifolding of cylinders — 1910.253(c)(1) Fuel-gas manifolds,1910.253(c)(1)(i) Manifolds shall be approved either separately for each component part or as an assembled unit.1910.253(c)(1)(ii) Except as provided in paragraph (c)(1)(iii) of this section fuel-gas cylinders connected to one manifold inside a building shall be limited to a total capacity not exceeding 300 pounds (135.9 kg) of liquefied petroleum gas or 3,000 cubic feet (84 m 3 ) of other fuel-gas.
More than one such manifold with connected cylinders may be located in the same room provided the manifolds are at least 50 feet (15 m) apart or separated by a noncombustible barrier at least 5 feet (1.5 m) high having a fire-resistance rating of at least one-half hour.1910.253(c)(1)(iii) Fuel-gas cylinders connected to one manifold having an aggregate capacity exceeding 300 pounds (135.9 kg) of liquefied petroleum gas or 3,000 cubic feet (84 m 3 ) of other fuel-gas shall be located outdoors, or in a separate building or room constructed in accordance with paragraphs (f)(6)(i)(H) and (f)(6)(i)(I) of this section.1910.253(c)(1)(iv) Separate manifold buildings or rooms may also be used for the storage of drums of calcium carbide and cylinders containing fuel gases as provided in paragraph (b)(3) of this section.
Such buildings or rooms shall have no open flames for heating or lighting and shall be well-ventilated.1910.253(c)(1)(v) High-pressure fuel-gas manifolds shall be provided with approved pressure regulating devices.1910.253(c)(2) High-pressure oxygen manifolds (for use with cylinders having a Department of Transportation service pressure above 200 psig (1.36 MPa)).1910.253(c)(2)(i) Manifolds shall be approved either separately for each component part or as an assembled unit.1910.253(c)(2)(ii) 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 (6.1 m) or by a noncombustible barrier at least 5 feet (1.5 m) high having a fire-resistance rating of at least one-half hour.1910.253(c)(2)(iii) Except as provided in paragraph (c)(2)(iv) of this section, oxygen cylinders connected to one manifold shall be limited to a total gas capacity of 6,000 cubic feet (168 m 3 ).
More than one such manifold with connected cylinders may be located in the same room provided the manifolds are at least 50 feet (15 m) apart or separated by a noncombustible barrier at least 5 feet (1.5 m) high having a fire-resistance rating of at least one-half hour.1910.253(c)(2)(iv) An oxygen manifold, to which cylinders having an aggregate capacity of more than 6,000 cubic feet (168 m 3 ) of oxygen are connected, should 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 having a fire-resistance rating of at least one-half hour or in an area with no combustible material within 20 feet (6.1 m) of the manifold.1910.253(c)(2)(v) An oxygen manifold or oxygen bulk supply system which has storage capacity of more than 13,000 cubic feet (364 m 3 ) of oxygen (measured at 14.7 psia (101 kPa) and 70 °F (21.1 °C)), connected in service or ready for service, or more than 25,000 cubic feet (700 m 3 ) of oxygen (measured at 14.7 psia (101 kPa) and 70 °F (21.1 °C)), 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.566-1965.1910.253(c)(2)(vi) High-pressure oxygen manifolds shall be provided with approved pressure-regulating devices.1910.253(c)(3) Low-pressure oxygen manifolds (for use with cylinders having a Department of Transportation service pressure not exceeding 200 psig (1.36 MPa)).1910.253(c)(3)(i) Manifolds shall be of substantial construction suitable for use with oxygen at a pressure of 250 psig (1.7 MPa).
They shall have a minimum bursting pressure of 1,000 psig (6.8 MPa) and shall be protected by a safety relief device which will relieve at a maximum pressure of 500 psig (3.4 MPa). DOT-4L200 cylinders have safety devices which relieve at a maximum pressure of 250 psig (1.7 MPa) (or 235 psig (1.6 MPa) if vacuum insulation is used).1910.253(c)(3)(ii) Hose and hose connections subject to cylinder pressure shall comply with paragraph (e)(5) of this section.
Hose shall have a minimum bursting pressure of 1,000 psig (6.8 MPa).1910.253(c)(3)(iii) The assembled manifold including leads shall be tested and proven gas-tight at a pressure of 300 psig (2.04 MPa). The fluid used for testing oxygen manifolds shall be oil-free and not combustible.1910.253(c)(3)(iv) The location of manifolds shall comply with paragraphs (c)(2)(ii), (c)(2)(iii), (c)(2)(iv), and (c)(2)(v) of this section.1910.253(c)(3)(v) The following sign shall be conspicuously posted at each manifold: LOW-PRESSURE MANIFOLD DO NOT CONNECT HIGH-PRESSURE CYLINDERS MAXIMUM PRESSURE-250 PSIG (1.7 MPA) 1910.253(c)(4) Portable outlet headers.1910.253(c)(4)(i) 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.1910.253(c)(4)(ii) 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.1910.253(c)(4)(iii) Hose and hose connections used for connecting the portable outlet header to the service piping shall comply with paragraph (e)(5) of this section.1910.253(c)(4)(iv) Master shutoff valves for both oxygen and fuel-gas shall be provided at the entry end of the portable outlet header.1910.253(c)(4)(v) 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.1910.253(c)(4)(vi) 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.1910.253(c)(4)(vii) Materials and fabrication procedures for portable outlet headers shall comply with paragraphs (d)(1), (d)(2), and (d)(5) of this section.1910.253(c)(4)(viii) 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.1910.253(c)(5) Manifold operation procedures,1910.253(c)(5)(i) Cylinder manifolds shall be installed under the supervision of someone familiar with the proper practices with reference to their construction and use.1910.253(c)(5)(ii) All manifolds and parts used in methods of manifolding shall be used only for the gas or gases for which they are approved.1910.253(c)(5)(iii) 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.1910.253(c)(5)(iv) The aggregate capacity of fuel-gas cylinders connected to a portable manifold inside a building shall not exceed 3,000 cubic feet (84 m 3 ) of gas.1910.253(c)(5)(v) Acetylene and liquefied fuel-gas cylinders shall be manifolded in a vertical position.1910.253(c)(5)(vi) The pressure in the gas cylinders connected to and discharged simultaneously through a common manifold shall be approximately equal.1910.253(d) Service piping systems — 1910.253(d)(1) Materials and design,1910.253(d)(1)(i)(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, 1967, which is incorporated by reference as specified in §1910.6, insofar as it does not conflict with paragraphs (d)(1)(i)(A)(1) and (d)(1)(i)(A)(2) of this section: 1910.253(d)(1)(i)(A)(1) Pipe shall be at least Schedule 40 and fittings shall be at least standard weight in sizes up to and including 6-inch nominal.1910.253(d)(1)(i)(A)(2) Copper tubing shall be Types K or L in accordance with the Standard Specification for Seamless Copper Water Tube, ASTM B88-66a, which is incorporated by reference as specified in §1910.6.1910.253(d)(1)(i)(B) Piping shall be steel, wrought iron, brass or copper pipe, or seamless copper, brass or stainless steel tubing, except as provided in paragraphs (d)(1)(ii) and (d)(1)(iii) of this section.1910.253(d)(1)(ii)(A) Oxygen piping and fittings at pressures in excess of 700 psi (4.8 MPa), shall be stainless steel or copper alloys.1910.253(d)(1)(ii)(B) Hose connections and hose complying with paragraph (e)(5) 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 250 psi (1.7 MPa) or less and the length of the hose does not exceed 5 feet (1.5 m).
Hose shall have a minimum bursting pressure of 1,000 psig (6.8 MPa).1910.253(d)(1)(ii)(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 psig (1.7 MPa).
A pressure regulating device shall be used at each station outlet when the connected equipment is for use at pressures less than 250 psig (1.7 MPa).1910.253(d)(1)(iii)(A) Piping for acetylene or acetylenic compounds shall be steel or wrought iron.1910.253(d)(1)(iii)(B) Unalloyed copper shall not be used for acetylene or acetylenic compounds except in listed equipment.1910.253(d)(2) Piping joints,1910.253(d)(2)(i) 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.1910.253(d)(2)(ii) 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 °F (427 °C)) filler metal.1910.253(d)(2)(iii) 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 °F (427 °C)) filler metal.1910.253(d)(3) Installation.1910.253(d)(3)(i) Distribution lines shall be installed and maintained in a safe operating condition.1910.253(d)(3)(ii) 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, 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.1910.253(d)(3)(iii) 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.1910.253(d)(3)(iv) 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 open end valves or petcocks shall be used, except that in 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.1910.253(d)(3)(v) 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.
There shall also be provided a shutoff valve in the discharge line from the generator, gas holder, manifold or other source of supply.1910.253(d)(3)(vi) Shutoff valves shall not be installed in safety relief lines in such a manner that the safety relief device can be rendered ineffective.1910.253(d)(3)(vii) Fittings 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 effectively remove grease and dirt but will not react with oxygen. Hot water solutions of caustic soda or trisodium phosphate are effective cleaning agents for this purpose.1910.253(d)(3)(viii) 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.1910.253(d)(3)(ix) 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.1910.253(d)(3)(x) 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.1910.253(d)(4) Painting and signs.1910.253(d)(4)(i) Underground pipe and tubing and outdoor ferrous pipe and tubing shall be covered or painted with a suitable material for protection against corrosion.1910.253(d)(4)(ii) Aboveground piping systems shall be marked in accordance with the American National Standard Scheme for the Identification of Piping Systems, ANSI A13.1−1956, which is incorporated by reference as specified in §1910.6.1910.253(d)(4)(iii) Station outlets shall be marked to indicate the name of the gas.1910.253(d)(5)(i) Piping systems shall be tested and proved gastight at 1½ 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.1910.253(d)(5)(ii) 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.1910.253(e) Protective equipment, hose, and regulators — 1910.253(e)(1) General,
- Equipment shall be installed and used only in the service for which it is approved and as recommended by the manufacturer.1910.253(e)(2) Pressure relief devices,
- 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.1910.253(e)(3) Piping protective equipment,1910.253(e)(3)(i) The fuel-gas and oxygen piping systems, including portable outlet headers shall incorporate the protective equipment shown in Figures Q-1, Q-2, and Q-3.
When only a portion of a fuel-gas system is to be used with oxygen, only that portion need comply with this paragraph (e)(3)(i). Legend: P F -Protective equipment in fuel gas piping. V F -Fuel gas station outlet valve. V O Oxygen station outlet valve. S F -Backflow prevention device(s) at fuel gas station outlet. S O -Backflow prevention device(s) at oxygen station outlet.1910.253(e)(3)(ii) Approved protective equipment (designated P F in Figures Q-1, Q-2, and Q-3) shall be installed in fuel-gas piping to prevent: 1910.253(e)(3)(ii)(A) Backflow of oxygen into the fuel-gas supply system; 1910.253(e)(3)(ii)(B) Passage of a flash back into the fuel-gas supply system; and 1910.253(e)(3)(ii)(C) Excessive back pressure of oxygen in the fuel-gas supply system.
The three functions of the protective equipment may be combined in one device or may be provided by separate devices.1910.253(e)(3)(ii)(C)(1) The protective equipment shall be located in the main supply line, as in Figure Q-1 or at the head of each branch line, as in Figure Q-2 or at each location where fuel-gas is withdrawn, as in Figure Q-3.
Where branch lines are of 2-inch pipe size or larger or of substantial length, protective equipment (designated as P F ) shall be located as shown in either Q-2 and Q-3.1910.253(e)(3)(ii)(C)(2) 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 (see S F, Figures Q-1 and Q-2).1910.253(e)(3)(ii)(C)(3) Flash-back protection shall be provided by an approved device that will prevent flame from passing into the fuel-gas system.1910.253(e)(3)(ii)(C)(4) Back-pressure protection shall be provided by an approved pressure-relief device set at a pressure not greater than the pressure rating of the backflow or the flashback protection device, whichever is lower.
- The pressure-relief device shall be located on the downstream side of the backflow 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.1910.253(e)(3)(iii) If pipeline protective equipment incorporates a liquid, the liquid level shall be maintained, and a suitable antifreeze may be used to prevent freezing.1910.253(e)(3)(iv) Fuel gas for use with equipment not requiring oxygen shall be withdrawn upstream of the piping protective devices.1910.253(e)(4) Station outlet protective equipment,1910.253(e)(4)(i) 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 backflow, as shown in Figures Q-1, Q-2, and Q-3 and designated as S F and S O,1910.253(e)(4)(ii) When approved pipeline protective equipment (designated P F ) is located at the station outlet as in Figure Q-3, no additional check valve, pressure regulator, or hydraulic seal is required.1910.253(e)(4)(iii) A shutoff valve (designated V F and V O ) shall be installed at each station outlet and shall be located on the upstream side of other station outlet equipment.1910.253(e)(4)(iv) 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, 1958, Compressed Gas Association, which is incorporated by reference as specified in §1910.6.1910.253(e)(4)(v) 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, 1957, Compressed Gas Association, which is incorporated by reference as specified in §1910.6.1910.253(e)(4)(vi) Station outlets may terminate in pipe threads to which permanent connections are to be made, such as to a machine.1910.253(e)(4)(vii) 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.1910.253(e)(4)(viii) Where station outlets are equipped with approved backflow and flashback protective devices, as many as four torches may be supplied from one 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 15 cubic feet (0.42 m 3 ) per hour.
This paragraph (e)(4)(viii) does not apply to machines.1910.253(e)(5) Hose and hose connections,1910.253(e)(5)(i) Hose for oxy-fuel gas service shall comply with the Specification for Rubber Welding Hose, 1958, Compressed Gas Association and Rubber Manufacturers Association, which is incorporated by reference as specified in §1910.6.1910.253(e)(5)(ii) When parallel lengths of oxygen and acetylene hose are taped together for convenience and to prevent tangling, not more than 4 inches (10.2 cm) out of 12 inches (30.5 cm) shall be covered by tape.1910.253(e)(5)(iii) Hose connections shall comply with the Standard Hose Connection Specifications, 1957, Compressed Gas Association.1910.253(e)(5)(iv) 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 psi (2.04 MPa).
Oil-free air or an oil-free inert gas shall be used for the test.1910.253(e)(5)(v) Hose showing leaks, burns, worn places, or other defects rendering it unfit for service shall be repaired or replaced.1910.253(e)(6) Pressure-reducing regulators.1910.253(e)(6)(i) 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, 1958, Compressed Gas Association.1910.253(e)(6)(ii) When regulators or parts of regulators, including gages, need repair, the work shall be performed by skilled mechanics who have been properly instructed.1910.253(e)(6)(iii) Gages on oxygen regulators shall be marked “USE NO OIL.” 1910.253(e)(6)(iv) 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.1910.253(f) Acetylene generators — 1910.253(f)(1) Approval and marking.1910.253(f)(1)(i) Generators shall be of approved construction and shall be plainly marked with the 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.1910.253(f)(1)(ii) Carbide shall be of the size marked on the generator nameplate.1910.253(f)(2) Rating and pressure limitations.1910.253(f)(2)(i) The total hourly output of a generator shall not exceed the rate for which it is approved and marked.
- Unless specifically approved for higher ratings, carbide-feed generators shall be rated at 1 cubic foot (0.028 m 3 ) per hour per pound of carbide required for a single complete charge.1910.253(f)(2)(ii) Relief valves shall be regularly operated to insure proper functioning.
- Relief valves for generating chambers shall be set to open at a pressure not in excess of 15 psig (103 kPa gauge pressure).
Relief valves for hydraulic back pressure valves shall be set to open at a pressure not in excess of 20 psig (137 kPa gauge pressure).1910.253(f)(2)(iii) Nonautomatic generators shall not be used for generating acetylene at pressures exceeding l psig (7 kPa gauge pressure), and all water overflows shall be visible.1910.253(f)(3) Location,
The space around the generator shall be ample for free, unobstructed operation and maintenance and shall permit ready adjustment and charging.1910.253(f)(4) Stationary acetylene generators (automatic and nonautomatic).1910.253(f)(4)(i)(A) The foundation shall be so arranged that the generator will be level and so that no excessive strain will be placed on the generator or its connections.
Acetylene generators shall be grounded.1910.253(f)(4)(i)(B) Generators shall be placed where water will not freeze. The use of common salt (sodium chloride) or other corrosive chemicals for protection against freezing is not permitted. (For heating systems see paragraph (f)(6)(iii) of this section.) 1910.253(f)(4)(i)(C) Except when generators are prepared in accordance with paragraph (f)(7)(v) of this section, sources of ignition shall be prohibited in outside generator houses or inside generator rooms.1910.253(f)(4)(i)(D) Water shall not be supplied through a continuous connection to the generator except when the generator is provided with an adequate open overflow or automatic water shutoff which will effectively prevent overfilling of the generator.
Where a noncontinuous connection is used, the supply line shall terminate at a point not less than 2 inches (5 cm) above the regularly provided opening for filling so that the water can be observed as it enters the generator.1910.253(f)(4)(i)(E) 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.
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.1910.253(f)(4)(ii)(A) Each generator shall be provided with a vent pipe.1910.253(f)(4)(ii)(B) The escape or relief pipe shall be rigidly installed without traps and so that any condensation will drain back to the generator.1910.253(f)(4)(ii)(C) The escape or relief pipe shall be carried full size to a suitable point outside the building.
It shall terminate in a hood or bend located at least 12 feet (3.7 m) above the ground, preferably above the roof, and as far away as practicable from windows or other openings into buildings and as far away as practicable from sources of ignition such as flues or chimneys and tracks used by locomotives.
Generating chamber relief pipes shall not be inter-connected but shall be separately led to the outside air. The hood or bend shall be so constructed that it will not be obstructed by rain, snow, ice, insects, or birds. The outlet shall be at least 3 feet (0.9 m) from combustible construction.1910.253(f)(4)(iii)(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 (5 cm) from the shell.1910.253(f)(4)(iii)(B) 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 (0.3 m) or more above the landing point of the bell.
When the gas holder is located indoors, the room shall be ventilated in accordance with paragraph (f)(6)(ii) of this section and heated and lighted in accordance with paragraphs (f)(6)(iii) and (f)(6)(iv) of this section.1910.253(f)(4)(iii)(C) When the gas holder is not located within a heated building, gas holder seals shall be protected against freezing.1910.253(f)(4)(iii)(D) Means shall be provided to stop the generator-feeding mechanism before the gas holder reaches the upper limit of its travel.1910.253(f)(4)(iii)(E) 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.1910.253(f)(4)(iii)(F) If acetylene is used from the gas holder without increase in pressure at some points but with increase in pressure by a compressor or booster pump at other points, approved piping protective devices shall be installed in each supply line.
- The low-pressure protective device shall be located between the gas holder and the shop piping, and the medium-pressure protective device shall be located between the compressor or booster pump and the shop piping (see Figure Q-4).
- Approved protective equipment (designated P F ) is used to prevent: Backflow of oxygen into the fuel-gas supply system; passage of a flashback into the fuel-gas supply system; and excessive back pressure of oxygen in the fuel-gas supply system.
The three functions of the protective equipment may be combined in one device or may be provided by separate devices. 1910.253(f)(4)(iv)(A) The compressor or booster system shall be of an approved type.1910.253(f)(4)(iv)(B) Wiring and electric equipment in compressor or booster pump rooms or enclosures shall conform to the provisions of subpart S of this part for Class I, Division 2 locations.1910.253(f)(4)(iv)(C) Compressors and booster pump equipment shall be located in well-ventilated areas away from open flames, electrical or mechanical sparks, or other ignition sources.1910.253(f)(4)(iv)(D) Compressor or booster pumps shall be provided with pressure relief valves which will relieve pressure exceeding 15 psig (103 kPa gauge pressure) to a safe outdoor location as provided in paragraph (f)(4)(ii) of this section, or by returning the gas to the inlet side or to the gas supply source.1910.253(f)(4)(iv)(E) Compressor or booster pump discharge outlets shall be provided with approved protective equipment.
(See paragraph (e) of this section.) 1910.253(f)(5) Portable acetylene generators,1910.253(f)(5)(i)(A) All portable generators shall be of a type approved for portable use.1910.253(f)(5)(i)(B) Portable generators shall not be used within 10 feet (3 m) of combustible material other than the floor.1910.253(f)(5)(i)(C) 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.
Generators shall not be used in rooms having a ceiling height of less than 10 feet (3 m). (To obtain the gas-generating capacity in cubic feet per charge, multiply the pounds of carbide per charge by 4.5.) 1910.253(f)(5)(i)(D) Portable generators shall be protected against freezing.
The use of salt or other corrosive chemical to prevent freezing is prohibited.1910.253(f)(5)(ii)(A) Portable generators shall be cleaned and recharged and the air mixture blown off outside buildings.1910.253(f)(5)(ii)(B) When charged with carbide, portable generators shall not be moved by crane or derrick.1910.253(f)(5)(ii)(C) 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.1910.253(f)(5)(ii)(D) 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.1910.253(f)(5)(ii)(E) 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.1910.253(f)(6) Outside generator houses and inside generator rooms for stationary acetylene generators.1910.253(f)(6)(i)(A) No opening in any outside generator house shall be located within 5 feet (1.5 m) of any opening in another building.1910.253(f)(6)(i)(B) Walls, floors, and roofs of outside generator houses shall be of noncombustible construction.1910.253(f)(6)(i)(C) When a part of the generator 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 or carbide storage section by partition walls continuous from floor to roof or ceiling, of the type of construction stated in paragraph (f)(6)(i)(H) of this section.
Such separation walls shall be without openings and shall be joined to the floor, other walls and ceiling or roof in a manner to effect a permanent gas-tight joint.1910.253(f)(6)(i)(D) Exit doors shall be located so as to be readily accessible in case of emergency.1910.253(f)(6)(i)(E) Explosion venting for outside generator houses and inside generator rooms shall be provided in exterior walls or roofs.
The venting areas shall be equal to not less than 1 square foot (0.09 m 2 ) per 50 cubic feet (1.4 m 3 ) of room volume and may consist of any one or any combination of the following: Walls of light, noncombustible material preferably single-thickness, single-strength glass; lightly fastened hatch covers; lightly fastened swinging doors in exterior walls opening outward; lightly fastened walls or roof designed to relieve at a maximum pressure of 25 pounds per square foot (0.001 MPa).1910.253(f)(6)(i)(F) The installation of acetylene generators within buildings shall be restricted to buildings not exceeding one story in height; provided, however, that this will not be construed as prohibiting such installations on the roof or top floor of a building exceeding such height.1910.253(f)(6)(i)(G) Generators installed inside buildings shall be enclosed in a separate room.1910.253(f)(6)(i)(H) The walls, partitions, floors, and ceilings of inside generator rooms shall be of noncombustible construction having a fire-resistance rating of at least 1 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 exterior wall.1910.253(f)(6)(i)(I) 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 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, which is incorporated by reference as specified in §1910.6.1910.253(f)(6)(ii) Inside generator rooms or outside generator houses shall be well ventilated with vents located at floor and ceiling levels.1910.253(f)(6)(iii) 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.1910.253(f)(6)(iv)(A) Generator houses or rooms shall have natural light during daylight hours. Where artificial lighting is necessary it shall be restricted to electric lamps installed in a fixed position.
Unless specifically approved for use in atmospheres containing acetylene, such lamps shall be provided with enclosures of glass or other noncombustible material so designed and constructed as to prevent gas vapors from reaching the lamp or socket and to resist breakage.
Rigid conduit with threaded connections shall be used.1910.253(f)(6)(iv)(B) Lamps installed outside of wired-glass panels set in gas-tight frames in the exterior walls or roof of the generator house or room are acceptable.1910.253(f)(6)(v) Electric switches, telephones, and all other electrical apparatus which may cause a spark, unless specifically approved for use inside acetylene generator rooms, shall be located outside the generator house or in a room or space separated from the generator room by a gas-tight partition, except that where the generator system is designed so that no carbide fill opening or other part of the generator is open to the generator house or room during the operation of the generator, and so that residue is carried in closed piping from the residue discharge valve to a point outside the generator house or room, electrical equipment in the generator house or room shall conform to the provisions of subpart S of this part for Class I, Division 2 locations.1910.253(f)(7) Maintenance and operation,1910.253(f)(7)(i) Unauthorized persons shall not be permitted in outside generator houses or inside generator rooms.1910.253(f)(7)(i)(A) Operating instructions shall be posted in a conspicuous place near the generator or kept in a suitable place available for ready reference.1910.253(f)(7)(i)(B) When recharging generators the order of operations specified in the instructions supplied by the manufacturer shall be followed.1910.253(f)(7)(i)(C) In the case of batch-type generators, when the charge of carbide is exhausted and before additional carbide is added, the generating chamber shall always be flushed out with water, renewing the water supply in accordance with the instruction card furnished by the manufacturer.1910.253(f)(7)(i)(D) The water-carbide residue mixture drained from the generator shall not be discharged into sewer pipes or stored in areas near open flames.
Clear water from residue settling pits may be discharged into sewer pipes.1910.253(f)(7)(ii) The carbide added each time the generator is recharged shall be sufficient to refill the space provided for carbide without ramming the charge. Steel or other ferrous tools shall not be used in distributing the charge.1910.253(f)(7)(iii) Generator water chambers shall be kept filled to proper level at all times except while draining during the recharging operation.1910.253(f)(7)(iv) 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.1910.253(f)(7)(v) Previous to making repairs involving welding, soldering, or other hot work or other operations which produce a source of ignition, the carbide charge and feed mechanism shall be completely removed.
All acetylene shall be expelled by completely flooding the generator shell with water and the generator shall be disconnected from the piping system. The generator shall be kept filled with water, if possible, or positioned to hold as much water as possible.1910.253(f)(7)(vi) Hot repairs shall not be made in a room where there are other generators unless all the generators and piping have been purged of acetylene.1910.253(g) Calcium carbide storage — 1910.253(g)(1) Packaging.1910.253(g)(1)(i) Calcium carbide shall be contained in metal packages of sufficient strength to prevent rupture.
The packages shall be provided with a screw top or equivalent. These packages shall be constructed water- and air-tight. Solder shall not be used in such a manner that the package would fail if exposed to fire.1910.253(g)(1)(ii) Packages containing calcium carbide shall be conspicuously marked “Calcium Carbide—Dangerous If Not Kept Dry” or with equivalent warning.1910.253(g)(1)(iii) Caution: Metal tools, even the so-called spark resistant type may cause ignition of an acetylene and air mixture when opening carbide containers.1910.253(g)(1)(iv) Sprinkler systems shall not be installed in carbide storage rooms.1910.253(g)(2) Storage indoors,1910.253(g)(2)(i) Calcium carbide in quantities not to exceed 600 pounds (272.2 kg) may be stored indoors in dry, waterproof, and well-ventilated locations.1910.253(g)(2)(i)(A) Calcium carbide not exceeding 600 pounds (272.2 kg) may be stored indoors in the same room with fuel-gas cylinders.1910.253(g)(2)(i)(B) Packages of calcium carbide, except for one of each size, shall be kept sealed.
The seals shall not be broken when there is carbide in excess of 1 pound (0.5 kg) in any other unsealed package of the same size of carbide in the room.1910.253(g)(2)(ii) Calcium carbide exceeding 600 pounds (272.2 kg) but not exceeding 5,000 pounds (2,268 kg) shall be stored: 1910.253(g)(2)(ii)(A) In accordance with paragraph (g)(2)(iii) of this section; 1910.253(g)(2)(ii)(B) In an inside generator room or outside generator house; or 1910.253(g)(2)(ii)(C) 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 paragraphs (f)(6)(i)(H) and (f)(6)(i)(I) of this section and ventilated in accordance with paragraph (f)(6)(ii) of this section. These rooms shall be used for no other purpose.1910.253(g)(2)(iii) Calcium carbide in excess of 5,000 pounds (2,268 kg) 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 (3 m) from such building or buildings, there shall be no opening in any of the mutually exposing sides of such buildings within 10 feet (3 m).
If the storage building is of combustible construction, it shall be at least 20 feet (6.1 m) from any other one- or two-story building, and at least 30 feet (9.1 m) from any other building exceeding two stories.1910.253(g)(3) Storage outdoors,1910.253(g)(3)(i) Calcium carbide in unopened metal containers may be stored outdoors.1910.253(g)(3)(ii) Carbide containers to be stored outdoors shall be examined to make sure that they are in good condition.
What are the 5 various types of pressure regulators?
Among the types of pressure regulators are back pressure, vacuum pressure, differential pressure, pressure-reducing and regulators for specific kinds of fluids like oil and fuel.
What pressure should oxygen and acetylene be set at for cutting?
Oxy-Acetylene Torch Set-Up: Step by Step –
- Secure the oxygen and acetylene tanks in an upright position. If you have cylinder carts, use those to secure them in place.
- Check and remove protective coverings from the tanks. If there are no covers, clean the tanks to remove any debris or dust. Pay close attention to the valves. To clean the valves, stand away from the opening and turn them on and off in a quick motion. This little burst should blow away any dust or debris that may have accumulated.
- Check that the regulators that need to be connected to the valves have matching threads. If they do not, connect the regulator to an adaptor, then connect the adaptor to the valve. Screw them in place by hand, then tighten the connection using a wrench.
- Find the hose for oxygen and the hose for acetylene and attach the proper hoses to the regulators for the proper tanks without contaminating them. Typically, the red hose will be for acetylene and the green hose will be for oxygen.
- Once the hoses are in place, attach the other end to the handle of your cutting torch.
- Connect the torch to the handle and tighten the nut by hand. Make sure that the valves on the torch and on the handle are closed.
Now, it is time to perform some checks before you light your cutting torch and get to work. Before you do the checks, make sure that your regulators are facing away from you! Pre-cutting checklist:
- Slowly, and one at a time, open the valves on both tanks.
- Adjust the screws on the regulators so the gauge reads the proper psi. You will want between 40 and 60 psi for the oxygen tank and 10 psi for the acetylene tank.
- Slightly open both valves on the cutting torch. But, do not open the acetylene valve more than a 1/8 turn or 45 degrees.
- Perform a leak test on all connected parts. To do this, use a solution specifically for leak testing or make a paste using dissolved Ivory soap. Coat the valves, hoses, and regulators. Look for any bubbles that form after a few minutes. If bubbles appear, there is a leak and you must tighten or adjust the connections. Repeat this test until no bubbles appear.
Once all of these steps have been completed and the leak test is a success, you are ready to light the torch by following the manufacturer’s instructions.
What is the danger of acetylene pressure?
Acetylene is an extremely unstable gas. It has a very wide explosive range and it can be dangerously explosive at pressures above 15 psi. It is for these two reasons that acetylene must never be used at hose pressures greater than 15 psi.3.
What are the oxygen pressures for cutting and welding?
RULE OF THUMB (MULTI-HOLE CUTTING TIPS, OXY / FUEL GAS) –
Recommended oxy/ fuel gas (propane, propylene, natural gas) cutting tip pressures also vary widely with size. If you have no manufacturer setting- information, and are cutting less than 1 ½” steel, set the fuel gas regulator for 10 psig, and the oxygen regulator for 45 psig.
What are the three types of pressure controls?
Pressure-control valves are found in practically every pneumatic and hydraulic system. They help in a variety of functions, from keeping system pressures below a desired limit to maintaining a set pressure level in part of a circuit. Different types of pressure control valves include relief, reducing, sequence, counterbalance, safety, and unloading.
- All of them are typically closed valves, except for reducing valves, which are usually open.
- For most of these valves, a restriction is necessary to produce the required pressure control.
- One exception is the externally piloted unloading valve, which depends on an external signal for its actuation, which normally comes from a digital pressure regulator,
In certain applications, like ventilators and anesthesia machines, the flow must be consistent at all times. Variations in the flow of gases can lead to serious injury or death. That’s why control valves are so important.
What are the two types of pressure controllers?
What is a Pressure Regulator? – Pressure regulators are mechanical valves that use feedback to control pressure in both pneumatic and hydraulic systems. There are basically two types of regulators: one regulates upstream pressure (back-pressure regulators) and the other regulates downstream pressure (pressure-reducing regulators). They can be as simple as a manually controlled valve to a complex, automated precision system with a pressure sensing element in a feedback loop. The feedback comes from the pressure that is being regulated and this feedback controls the regulator output, either mechanically or electronically.
Mechanical feedback is accomplished using a spring-loaded or pressure-controlled diaphragm, bellows or piston, which controls a valve that acts to increase or decrease the flow through the regulator based on the pressure being regulated. This mechanical regulation of flow acts to control the pressure.
In an electronic regulator, the input from a pressure transmitter is used to adjust a valve or valves that control the pressure. For the purpose of this post, we will concentrate on pressure-reducing regulators. These regulators reduce a relatively high incoming pressure to a lower outgoing pressure in order to protect sensitive components downstream, or to precisely control a pressure-sensitive process or measurement.
Fluid dynamics is a complex subject and tells us that a fluid flowing through a restriction loses energy; pressure-reducing regulators take advantage of this property to regulate pressure. Pressure in any system is defined as the force per unit area within that enclosed system. Pressure is influenced by the quantity of the fluid present (number of molecules), the volume in which it is contained, and the fluid temperature.
Most pressure regulators work to control the number of molecules that are allowed to enter (or exit) the system and thus control the system pressure. Another type, briefly discussed below, is a regulator that controls pressure by increasing the force applied to a closed system.
What is the standard temperature and pressure for acetylene?
|Critical Temperature:||97.3° F|
|Critical Pressure:||905.5 psia|
|Critical Density:||0.231 g/ml|
|Latent Heat of Sublimation @ -119.2° F.:||193.46 cal/mol|
What is the normal working pressure for acetylene?
The maximum working line or hose pressure for acetylene is 15 P.S.I. (It becomes unstable above 15 P.S.I.) 17. Acetylene cylinders have an internal filler, which is saturated with acetone to help stabilize the gas.
What are the 4 rules for acetylene use?
Rule # 1: Blow out the cylinder valves before attaching the regulators. Rule # 2: Release the adjusting screw before opening the cylinder valve. Rule # 3: Don’t stand in front of the regulator when opening the cylinder valve. Rule #4: Open the cylinder valve slowly.
What are the main hazards of acetylene?
Hazard Class: 2.1 (Flammable) Acetylene is a FLAMMABLE GAS. Stop flow of gas or let fire burn itself out. POISONOUS GASES ARE PRODUCED IN FIRE, including flammable Hydrogen gas. CONTAINERS MAY EXPLODE IN FIRE.
What is the explosive limit for acetylene?
Acetylene Flammability limit Threshold limit value Acetylene : Description and use Description Acetylene is an alkyne hydrocarbon chemical compound, discovered by Edmund Davy in England in 1836. It is in the form of a colourless gas dissolved in acetone under pressure.
- In its pure form, it is an extremely flammable gas which can spontaneously explode when subject to high pressure (in excess of two atmospheres) or to a sharp rise in temperature.
- It is obtained from the reaction of water with calcium carbide in specially designed devices called acetylene generators or from the thermal cracking of hydrocarbons.
It is generally found in pressurised cylinders, dissolved in acetone permeating a porous material. Flammability: The risk of fire is very high. If mixed with air containing 30% acetylene it could catch fire at 305°C. It is therefore important to work away from sources of sparks, open flames or heat and to not smoke whilst using this product.
It could catch fire when in contact with strong oxidising agents. Explosiveness: The risk of explosion is very high. Acetylene forms explosive mixtures with air between concentrations of 2.5% and 82%. It can explode when in contact with chlorine and with fluorine. USE Acetylene is primarily used as a raw material in the chemical industry.
Particularly in the synthesis of numerous organic compounds (chloroethene, vinyl acetate, acrylates, 1,4-butanediol, etc.) or to fuel the flame of an oxyacetylene torch, which is used frequently in welding or for cutting metals. It is used in other sectors:
for chemical analysis by atomic absorption in the glass industry as a fuel component for lighting buoys, beacons and lighthouses as a fuel component for motor boats to manufacture carbon black
Acetylene : Warnings and caution GHS hazard statements H220 – Extremely flammable gas. H280 – Contains gas under pressure; may explode if heated. Can displace oxygen and quickly cause suffocation. EUH 006 – Explosive with or without contact with air. GHS precautionary statements P210 – Keep away from heat, sparks, open flames, hot surfaces.
No smoking. P377 – Leaking gas fire: Do not extinguish, unless leak can be stopped safely. P381 – Eliminate all ignition sources if safe to do so. P410+P403 – Protect from sunlight. Store in a well-ventilated place. P241 – Use explosion-proof electrical/ventilating/lighting/./equipment. Acetylene : Related products Aucun produit disponible n’est actuellement lié à la détection de ce gaz.
What are the proper oxygen and acetylene settings?
Download Article Download Article An oxy acetylene torch is an affordable and versatile tool used by many people to heat, weld, solder, and cut metal. It uses extreme heat to function, and setting it up properly is one of the most important steps in using it safely. Using pressure-reducing regulators, connecting gas supplies, and safely lighting the torch flame are all essential parts of learning how to use an oxy acetylene torch.
- 1 Fasten oxygen and acetylene cylinders in an upright position. If you have a cylinder cart, place both the oxygen and acetylene cylinders into it. If not, they should be securely fastened with a chain to a workbench, a wall, or a post. Cylinders should not be able to be knocked or pulled over.
- Cylinders should only be used and stored in the vertical position.
- 2 Clean the valve outlet of accumulated dust or dirt. Stand so the outlet is facing away from your body and open the valve a 1/4 turn, very quickly, and then close it. This will clear out any dust or dirt that may have settled in the valve. It needs to be cleaned out otherwise the debris might get into other parts of the torch and cause it to malfunction.
- Warning: never clear a fuel gas cylinder near other welding work that is in progress or near sparks or flames.
- 3 Connect the oxygen and acetylene regulators to their cylinders. The regulators let you see how much pressure you’re using while working and are essential to safely starting and operating an oxy acetylene torch.
- If the regulator and cylinder have different threads (meaning they don’t fit into each other), you will need to use an adaptor, which can be purchased at any local hardware store.
- 4 Tighten the nuts of the regulator connections with a wrench. Don’t assume because you have turned the nut as far as you can with your hand that it is tight enough. Use a wrench with a fixed opening (rather than an adjustable wrench) that is designed specifically for welding tools. You can buy these from a hardware store or a specific apparatus supplier.
- If you ever need to make an adjustment after the cylinder has been opened and used, make sure to close the cylinder valve before tightening the nut again.
- 5 Rotate the pressure-adjusting screw to the left until it turns freely. Do this for each regulator. The valve in the regulator needs to be closed before cylinder pressure is admitted. Turning the pressure-adjusting screw counter-clockwise removes the pressure from the spring in the regulator.
- When the screw turns freely, you should be able to just tap it with your finger and see it move, rather than having to apply pressure.
- 6 Open the oxygen and the acetylene valves very slowly. Make sure you can see the cylinder-pressure gauges, but don’t stand directly in front of the valves. Open the valves slowly to protect yourself and your machine from any potential combustion.
- Open the oxygen valve very slightly at first and pause until the pressure gauge hand isn’t moving any more before moving on to open the valve fully.
- The acetylene valve should never be opened more than 1 and 1/2 turns.
- 7 Leave the wrench on the acetylene valve while it is open. Basically, if you have an emergency you won’t have to waste time looking for an appropriate wrench. If it’s on there, you’ll be able to close the cylinder valve right away.
- In general, it’s smart to work in an area where you can reach all your tools without having to search for them. Think ahead when you are starting a project and bring your tools to your workspace before beginning.
- 1 Use a hose and hose connections specific to welding and cutting. Oxygen hoses will have a green cover, while acetylene hoses will have a red cover. Never interchange these hoses as they are meant for different substances. If one of your hoses have broken, replace it—don’t use tape of any sort to try and patch the hole.
- A hose with a natural rubber liner is okay for acetylene service.
- 2 Do not use any oil or grease on the hoses. All the connections from the gas supplies to the torch are metal-to-metal, and they don’t require lubricants or sealants. Similarly, don’t use any pipe-fitting tools to connect the hoses to the torch.
- Don’t force connections—if the threads don’t run together easily by hand, either the threads are damaged or the parts aren’t meant to go together.
- 3 Attach the oxygen hose to the oxygen regulator and to the torch. The torch should have identifying marks on the body or the handle showing where the hose should be connected. Most torches have 2 oxygen connections because 1 is used for the cutting jet and 1 is used for the preheat flames.
- Most new oxy acetylene torches come with built in adapters, but double-check with the manufacturer’s instructions to be safe.
- 4 Connect the acetylene hose to the acetylene regulator and to the torch. Sometimes the torch doesn’t specify which connection is for the acetylene, though the oxygen will be clearly marked. Whichever connection is not for the oxygen is for the acetylene.
- Double check your connections before moving on to make sure everything is hooked up to the right place.
- 5 Tighten the hose connections with a wrench. Don’t trust your hand strength to tighten these connections for you. Use a non-adjustable wrench to securely fasten both the oxygen and acetylene hoses to the torch.
- Having tight connections is extremely important because they will keep both the oxygen and acetylene from leaking.
- 1 Close both torch valves. For the oxygen, turn the pressure-adjusting screw on the regulator until the gauge reads about 25 psi. For the acetylene, turn the pressure-adjusting screw on the regulator until the gauge reads about 10 psi.
- It is very important to test for leaks before starting your project. Leaks can cause harm to you or your surroundings and may lead to spontaneous combustion of the cylinders.
- 2 Apply a leak-test solution with a brush. Apply the solution to the cylinder valves, the cylinder and regulator connections, and all the hose connections. You can either buy a solution from the store for this specific purpose, or you can dissolve Ivory soap in water to make a thin paste for the same results.
- Any work brush you have on hand will do; just make sure it hasn’t been compromised by oil or gas.
- 3 Check the leak-test solution for bubbles. Bubbles indicate that either oxygen or acetylene is coming through the connectors and the connection needs to be tightened or reattached completely. The bubbles won’t be big, like in a pot of boiling water; rather, they will be small and will make the surface of the testing solution look uneven.
- Give the solution 1-2 minutes to sit before checking for leaks.
- 4 Release all pressure from any system that has a leak. Reattach or retighten as needed, and apply the leak-test solution a 2nd time to test the torch for leaks again. After completing the testing, make sure to turn off both the oxygen and acetylene.
- If after you’ve tested and refastened any leaking areas you are still seeing bubbles, that may indicate you have a leaky hose and need to get a new one before moving on with your project.
- 1 Turn the oxygen regulator pressure-adjusting screw. Slowly do this until you reach the desired pressure. The pressure will be indicated on the delivery-pressure gauge. Then you will close the torch oxygen valve. If you are using a cutting torch, open only the torch cutting oxygen valve.
- Don’t set the pressure higher than what the equipment manufacturer recommends.
- 2 Adjust the acetylene adjuster screw to the desired working pressure. Do not exceed 15 psi. Close the acetylene valve immediately after you obtain the right pressure. You shouldn’t open the valve more than 1 full turn.
- If you open the valve too fast or too far, you may cause the canister to combust.
- 3 Do not release acetylene or other gasses near sources of ignition. Also, make sure you are working in a well-ventilated area. It is advisable to keep a fire extinguisher in your workspace in case there are any explosions or emergencies.
- Heating, welding, and cutting cause smoke and fumes that are bad to breathe in and that can irritate the skin.
- 1 Check the manufacturer’s instructions for the torch before beginning. Though most torches follow the same operating procedure, the manufacturer’s instructions may have helpful tips or warnings that are specific to your torch. Read it thoroughly before following steps or tips from any other sources.
- You can also search the manufacturer online to check out more information regarding your tool. A lot of sites have community forums where people post tips and stories about their experiences that you can learn from.
- 2 Open the torch acetylene valve 1/2 turn and light the flame. Use a friction lighter rather than a match for this step. A friction lighter is also called a torch striker, and these can be found at hardware stores. You will see a flame coming out of your torch. If for some reason there isn’t a flame, turn off the acetylene valve and check your connections.
- Remember to not have the oxygen gas flowing when you go to light the torch.
- 3 Reduce the acetylene flow by adjusting the torch acetylene valve. The flame should start to produce black smoke around the edges. Once the black smoke appears, start to increase the acetylene flow back up again just enough to get rid of the black smoke. The flame should still be attached to the tip (it shouldn’t appear as though it has “jumped away” from it).
- The lighting procedure should result in a neutral flame, which is blue in color and which does not make a hissing sound.
- 4 Stop working if the flame suddenly goes out. This is called “backfire” and can happen it the torch comes into direct contact with the metal. If this happens, go ahead and relight the torch again right away. If backfire occurs repeatedly without contact with the work, it may be due to incorrect operating pressures or a loose nozzle in the torch.
- If in doubt, turn off the gasses and check your machine over before proceeding.
- 5 Turn off the torch if there is flashback. Flashback is when there is a pronounced hissing or squealing noise. This means there is something wrong with the torch or with the set up. After turning off the torch and investigating the cause, wait until the torch has cooled before attempting to light it again.
- If your torch keeps experiencing flashback, there may be a damaged piece that needs to be returned or replaced.
Add New Question
- Question Why is the head of an oxy acetylene torch made of brass? Because it is a corrosion resistant metal that will not create sparks when struck against other substances.
- Question Which tip should I use to heat the metal up? There is a tip called a rose bud that produces a large area to heat metals. A brazing tip can work on smaller areas.
- Question How many gauges are needed on the acetylene bottle? Two. A Cylinder Pressure Gauge and a Working Pressure Gauge. The CPG will show about 200psi on a full acetylene bottle and decrease as it is used. The WPG indicates the gas pressure to the torch and is set by the regulator.
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- Keep animals and children away from your work area when operating an oxy acetylene torch.
- If you have long hair, tie it back or tuck it into a bandanna or cap.
- Keep the torch tip clean.
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- Never attempt to repair hoses with tape of any sort.
- Never use torches, regulators, or hoses in need of repair.
Advertisement Article Summary X To set up an oxy acetylene torch, start by cleaning any dust or dirt from the valve outlet. Next, attach the pressure-reducing regulators that allow you to safely start and operate the torch. You’ll also need to connect the gas supplies, like the oxygen and the acetylene hoses, to the torch.
What are the acetylene and oxygen pressures?
Pressure control for oxyacetylene welding – The pressure of the two gas cylinders is adjusted by turning the regulator screw on each cylinder clockwise. You must first open the gas bottle taps by turning them anticlockwise by a quarter turn. The adjustment of the pressure of the oxygen bottle must be set between 0.8 and 1.5 bar.
- The one for the acetylene bottle needs to be between 0.3 and 0.5 bar.
- You will then open the valves of your blowtorch.
- This adjustment will lower the pressure that you will need to readjust before welding.
- Open the blue oxygen valve on the torch first, until you have a light flow, then open the red acetylene valve fully.
Always light your flame with a specially and never with a lighter. : The pressure setting for oxy-acetylene welding- Express
What should oxygen level be for welding?
The choice of shielding method will depend on the application. For tube welding, the simplest method is balloon or puddle containment. Groove containment is used for linear welds. If the configuration is more complex, the use of a trailing torch – a versatile tool that is easy to set up – is recommended, provided that the welder can intervene directly.
- What techniques and different tools can be used to measure the level of oxygen remaining in a tube? An oxygen meter is a tool that measures the amount of oxygen in the ambient air,
- This value, the amount of oxygen remaining, is expressed as a percentage.
- It can be useful when going down a sewer for example, seeing as they emit gases.
As carbon is heavier than oxygen, it is vital to check the oxygen level while going down to avoid danger zones. For welding, it is crucial to be able to measure the residual oxygen level in the air at all times, which should not exceed 0.0001%. If a device is used that measures between 0 and 20 %, the welder will not be able to know whether the threshold value for welding has been reached.
It is obvious that this type of device is not at all suitable for executing welds and that it makes more sense to use a PPM (parts per million) reader. This tool delivers a much higher accuracy by measuring up to the fourth digit behind the decimal point. At what oxygen level should the weld be started? Root porosity occurs at an oxygen level of 500 to 800 ppm.
The discolored part is more than dangerous – at this stage we will assume that the weld has hardly been inert.800 ppm corresponds to 0.08% oxygen, a figure undetectable by a standard oxygen meter. The threshold value, meaning the accepted percentage at which the weld will be triggered, can be configured precisely to meet the requirements of the specification.
- For sensitive industries such as the pharmaceutical industry, welding will be done with oxygen levels below 100 ppm, resulting in a very clean weld.
- For the strictest environments, the accepted values will sometimes be at only 20 ppm.
- AXXAIR power supplies provide the user with a table showing the different colors according to the oxygen level in ppm.
How much does a PPM reader cost? Needless to say, you should not pinch pennies when it comes to investing in a tool like this. Basic oxygen meters are available from 100 Euros, while a PPM reader will cost between 700 and 3000 Euros. It is more than obvious though, that these two products cannot be compared.
- This very precise tool is more than necessary when welding at very high standards.
- For more basic applications where inerting does not play such a crucial role, it can of course be done without one.
- This is why AXXAIR offers this equipment as an optional add-on for the entire range of its orbital welding power supplies.
How to choose the proper shielding gas Gases are classified according to their purity, described by a two-digit label: 4.6, 5.2, 6.0 etc. The first digit corresponds to the number of “9”s and the second digit expresses the first number after the “9”s. But let’s not forget the other parameters playing a crucial role:
The quality of the pipes connected to the gas cylinders The cleanliness of the tubes to be welded, since dirt can release gases at high temperatures The quality of inerting using flanges or non-hermetic balloons Sufficient flow, sufficient gas outlet The density of the gas The positioning of the gas inlet and outlet
The slightest discrepancy in this entire chain will provoke a welding defect. When should the oxygen levels be measured? The answer is as simple and straightforward as it gets: before, during and after welding, Of course, the arc should not be started before checking the quality of the inerting.
The oxygen level must be checked throughout the welding process (Remember the risk of poor gas diffusion or air currents?). It is obvious that if the inerting is stopped instantly after the completion of the weld bead, the result will suffer because the overall temperature of the workpiece does not drop immediately.
For a tube made of stainless steel for example, it is necessary to wait until the work piece is cooled down to a level below 150 to 200 degrees Celsius to avoid any post-weld discoloration. What means of control are available? The primary means of control will always remain common sense.
Use consistent parameters. For standard piping assemblies with diameters ranging from 1″ to 6″, inerting is performed at between 5 and 10 liters per minute. The gas outlet will have to be correctly dimensioned so that the pressure inside the pipe does not rise. Again, there is a simple rule of thumb: a hole with a diameter of 5 mm is supplied with 5 liters per minute.
So, means of control are an adapted flow rate, proper dimensioning of the gas outlet and above all: a good dose of patience. Many welders start the arc too quickly before making sure that the inerting is executed well in order to boost productivity. And there is a reason for it: if the ideal inerting time is calculated to be 3 minutes for example and the welder starts welding after only 20 seconds, this certainly makes a difference in the day’s production.
But this time saved has it’s cost at the end of the production process: if the oxygen level is too high, the quality of the weld is lowered and the tube risks becoming a scrap piece. This is why AXXAIR strongly recommends the use of a PPM reader, but here again the final requirements must be taken into account.
What to do when a stainless steel tube presents with a golden or blue discoloration? If, despite all these precautions, a golden or blue discoloration is visible on stainless steel, it is an indication to the welder that the chrome layer of the surface has been destroyed.
- In this case, it is always possible to carry out a surface treatment by passivation, which can be done mechanically with suitable tools.
- The metal is exposed and the entire chromium layer is removed over a large area.
- This protective layer will re-form in a few hours.
- The passivation can also be carried out with a chemical method or by electrolysis.
In fact, many solutions for this problem can be found on the market. Tracking the inerting The welding procedure specification (WPS) will give you all necessary indications about the inerting parameters, Usually, the quantities and times of inerting are recorded manually during the entire process.
How many pressure gauges are in regulator?
What factors go into selecting regulator gauges? First, to fully understand and answer the question we must clarify the difference between a regulator and a gauge. Often, and mistakenly, a regulator is referred to as a “gauge” or “set of gauges”. The truth is a regulator is a device whose function is to take an unusable high pressure from a gas cylinder or pipeline and convert it into a usable, safe, and constant lower pressure.
A gauge is a simpler device whose function is only to indicate and read-out either or both high and low pressures that, in this case, are flowing through the regulator. Cylinder regulators typically have two gauges: a high-pressure or “inlet” gauge, and a low-pressure “outlet” or “delivery gauge”. SELECTING THE RIGHT GAUGE Gauges are selected for a regulator or other applications, considering the regulators intended supply or inlet pressure and designed outlet pressure.
Two of the major considerations are accuracy and safety. Accuracy: Virtually all applications using gases require some degree of accuracy to ensure proper and safe performance. A common comparison would be the accuracy a driver would demand from the speedometer in an automobile he or she was operating.
In the industrial or welding gas industry we look to an accuracy like that suggested by the Compressed Gas Association (CGA) in their E-4 standard for gas pressure regulators. In standard gauges most commonly used in our industry, Grade B are accurate within 2% – 3% of the gauge span or gauge face reading, depending somewhat where on the gauge face the pressure is read.
See the drawing example using a 100 PSIG gauge. Safety: There are an innumerable number of choices in our industry of gauge pressure ranges to choose from when selecting a gauge for a regulator or other use. The trick is to choose a gauge that provides the reading accuracy required while still providing durable and safe operation.
Again, referring to standards like CGA E-4 1994 (5.7.2) we select gauges so that the maximum operating pressure to which they would normally be exposed in service is not greater than 80% of the gauge range. We also take into consideration all other factors that may affect pressures such as those related to temperature, gas mode, etc.
THE “CENTER HALF RULE” A good rule of thumb to use when selecting a regulator, and in this case a particular gauge for a gas application requiring a specific pressure, is to select one that will read the pressure required in the center half of the gauge range but not disregarding hazards such as those associated with over pressurization. : What factors go into selecting regulator gauges?
Why does regulator have two gauges?
Regulators A gas pressure regulator is a mechanical device which attaches to the delivery valve on the cylinder. The regulator is designed to work at the maximum pressure for a given cylinder and regulate the output- delivery- to a lower pressure for use.
They are equipped with safety devices to limit the release rate of gas if a fault occurs. There are two pressure gauges – one on the cylinder side to indicate the contents pressure and the other on the delivery side. There is an adjustment control to set the delivery pressure to the desired level. Regulators must be subject to regular inspection and replaced every 5 year for non-corrosive gases.
The body of the regulator is stamped for date of manufacture, More frequent replacement cycles are required for corrosive gases – Where a regulator performs the function of ‘flow control’ and is not regarded as the primary Protective Device, then it will not be regarded as Primary Regualtor and hence will not subject to the 5 year replacement requirement.
|Gas regulators fitted to two differing cylinders|
Why does the acetylene regulator have two pressure gauges?
Acetylene Regulator 1 stage 2 gauge Side Entry (AE3002LXSEEXT) Acetylene Regulator 1 Stage 2 gauge Side Entry Long (AE3002LXSEEXT) The design of this regulator ensures that pressure is reduced from cylinder pressure and can be set to a maximum working pressure (specific to each model).
These actions take place within one chamber, making this particular style ideal for use where maintaining precise pressure settings over a period of time is essential. This product features two gauges, which display bottle contents and output pressure. The output pressure is controlled by the center dial (pressure adjustment knob), which, when fully wound out, sets the pressure to 0 bar.
Two-gauge regulators enable pressure settings to be read from a distance and controlled more accurately.
Target Applications The appropriate regulator can be used in Oxygen/Acetylene Cutting/Welding, laser-cutting or to deliver Argon/CO2 shielding gas in MIG or TIG welding. Features
2 Gauges Displays – Bottle contents & Output pressure Output pressure controlled by the dial Fits vertical outlets valves Maximum outlet pressure 1.5 BAR
|Valve Entry||Extended Side Entry|
|Input Fittings||5/8″ BSP (Oxy/Acet/Argon/Nitro)|
|BS341-1.8/DIN 477 #6 (CO2)|
|British Standards||BS EN ISO 2503:2009|
|Outlet Pressure||1.5 BAR|
|Cylinder Fittings||5/8 in BSP LH|
|British Standard||BS EN ISO 2503:2009|
A carriage charge is applied to orders, for standard 1-2 day shipments to mainland destinations within the United Kingdom. Other destinations and premium services are available but subject to additional freight charges. : Acetylene Regulator 1 stage 2 gauge Side Entry (AE3002LXSEEXT)
How many gauges are fitted in both oxygen and acetylene tanks?
A device used to control pressure from the tanks by reducing pressure and regulating flow rate. Oxygen regulators have a female fitting with a right hand thread. Acetylene regulators have a male fitting with a left hand thread. Both types will have two gauges on them.