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|
MINISTRY OF
LABOR - WAR INVALIDS AND SOCIAL AFFAIRS |
SOCIALIST REPUBLIC
OF VIETNAM |
|
No. 41/2013/TT-BLDTBXH |
Hanoi, December 30, 2013 |
NATIONAL TECHNICAL REGULATIONS ON SAFE WORK FOR OXY-FUEL WELDING WORK
Pursuant to Decree No. 106/2012/ND-CP dated December 20, 2012 of the Government on functions, tasks, powers, and organizational structure of the Ministry of Labor - War Invalids and Social Affairs;
Pursuant to Decree No. 127/2007/ND-CP dated August 1, 2007 of the Government on elaborating to Law on Standards and Technical Regulations;
Pursuant to Decree No. 132/2008/ND-CP dated December 31, 2008 by the Government elaborating a number of Articles of the Law on Products and Goods Quality;
At request of Director of Work Safety Department;
Minister of Labor – War Invalids and Social Affairs promulgates National Technical Regulations on work safety for oxy-fuel welding work.
Article 1. “National technical regulations on safe work for oxy-fuel welding work” are attached hereto.
No. QCVN 17:2013/BLDTBXH.
Article 2. The “National technical regulations on safe work for oxy-fuel welding work” comes into effect from June 25, 2014.
Article 3. Ministries, ministerial agencies, Governmental agencies, People’s Committees of provinces and central-affiliated cities and relevant organizations, individuals are responsible for the implementation of this Circular./.
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PP. MINISTER |
NATIONAL TECHNICAL REGULATIONS ON SAFE WORK FOR OXY-FUEL WELDING WORK
Preface
The QCVN 17:2013/BLDTBXH – National Technical Regulations on safe work for Oxy-fuel welding work is prepared by Work Safety Department, issued by Ministry of Labor - War Invalids and Social Affairs under Circular No. 41/2013/TT-BLDTBXH dated December 30, 2013 after consulting Ministry of Science and Technology.
NATIONAL TECHNICAL REGULATIONS ON SAFE WORK FOR OXY-FUEL WELDING WORK
1.1. Scope
These technical regulations prescribe general requirements for safety in oxy-fuel welding work. For oxy-fuel welding works conducted in special conditions (in underground mines, subway tunnels, etc.), comply with other relevant regulations in addition to these regulations.
1.2. Regulated entities
These technical regulations apply to:
1.2.1. Organizations and individuals managing and using oxy-fuel welding equipment.
1.2.2. Regulatory authorities and other relevant organizations, individuals.
1.3. Definitions
In these regulations, the following terms are construed as follows:
1.3.1. “oxy-fuel welding” (otherwise known as “gas cutting”) refers to the method of utilizing the heat when combusting flammable gases (C2H2, CH4, etc.) or H2 and Oxygen to melt metal.
1.3.2. “oxy-welding equipment” refers to equipment and accessories serving welding work, including: acetylene gas generator, gas cylinders for use in oxy-fuel welding work and metal welding, cutting equipment.
1.3.3. “metal welding, cutting equipment” includes: regulator, gas hoses, cutting torch, welding torch.
In addition to terms and definitions mentioned above, these regulations also employ terms and definitions in the following standards:
- TCVN 4245:1996 Technical safety requirements in manufacturing and use of oxygen and acetylene.
- TCVN 6304:1997 Cylinder containing liquefied flammable gas – Safety requirements in preservation, unloading, and transportation.
- TCVN 6713:2013 Gas cylinder – Safety in actions.
2.1. General provisions
2.1.1. The use of oxygen and acetylene must conform to TCVN 4245:1996 Technical safety requirements in manufacturing and use of oxygen and acetylene.
2.1.2. Safety in interactions with gas cylinders must conform to TCVN 6713:2013 Gas cylinder – Safety in actions.
2.1.3. Preservation, unloading, and transportation must conform to TCVN 6304:1997 Cylinder containing liquefied flammable gas – Safety requirements in preservation, unloading, and transportation.
2.2. Specific provisions
2.2.1. General requirements
2.2.1.1. In addition to ensuring fire safety, selection of oxy-fuel welding technology must take into account the possibility of other dangerous and hazardous factors (possibility of mechanical injuries, toxic dust and gas, thermal radiation, gas cylinders tumbling, etc.), and develop occupational safety and hygiene measures to eliminate such factors.
2.2.1.2. Oxy-fuel welding work may be implemented fixed in workshops, outdoors, or temporarily in construction sites.
2.2.1.3. When conducting oxy-fuel welding works in areas with risk of fire and/or explosions, comply with regulations on fire and explosion safety.
2.2.1.4. When conducting oxy-fuel welding works in tunnels, compartments, or enclosed spaces, place acetylene equipment, acetylene cylinders and oxygen cylinders outside; assign individuals with firm knowledge in technical safety to supervise and develop specific safety measures to prevent fire, explosions, poisoning and receive approval of individuals in charge. Welders must wear gloves and use safety harness which is connected to location of supervisors.
- Provide ventilation with wind velocity ranging from 0.3 to 1.5 m/s.
- Inspect in order to make sure no noxious and flammable gases are present in tunnels, compartments, and enclosed spaces for welders.
2.2.1.5. Prohibit conducting welding work in tunnels, compartments, and enclosed spaces that contain pressure or flammable, explosive substances.
2.2.1.6. Use of gas
2.2.1.6.1. When connecting valves of loose gas cylinders, do not use brute force. Screw thread of connectors of equipment must fit outlets of valves of gas cylinders.
2.2.1.6.2. Valves of cylinders
- Valves of cylinders must be always closed (leaving the cylinders full or out of gas) except for cases when the cylinders are being used.
- Valve outlets must not point towards humans while open.
- Close the valves after use.
- Cylinder valves must be opened slowly.
- Valves that do not have handles must be accompanied by specific open wrenches which are only used for opening valves and must be left on the valves when cylinders are in use.
- For valves that come with handles, do not use wrenches, hammers, or other tools to open or close the valves.
- Do not use extreme force to operate valves of cylinders.
- Contact gas suppliers in case of any difficulty in valve operation. Do not grease up the valves.
- Automated valves must be operated according to instructions.
- Do not repair residual pressure valves especially closed containers in order to prevent cylinders from being completely empty.
2.2.1.6.3. Do not reduce residual pressure in cylinders below working pressure of the system or lower than the smallest residual pressure necessary to prevent air flow from reversing or other impurities from infiltrating the cylinders. Cylinder valves must be closed to keep the smallest residual pressure ranging from 0.5 bar to 2 bar.
2.2.1.6.4. Prior to removing pressure regulators from cylinders, close the valves and allow the regulators to discharge all gas pressure.
2.2.1.6.5. Regulators, manometers, soft tubes and other tools provided for use with specific types of gases must not be used for cylinders containing other gases.
2.2.1.6.6. Only operate gas cylinders in ventilated areas.
2.2.2. Requirements for gas cylinders in oxy-fuel welding work (including acetylene, oxygen, liquefied petroleum gas cylinders):
2.2.2.1. Mobile gas generators must not be placed in following locations:
- In underground tunnels if ventilation is difficult.
- In public places such as theaters, cinemas, etc.
- In storeys above which people are living or working.
- In areas close to forges, furnaces, boiler rigs and sources of flame.
- In areas with flammable gas.
2.2.2.2. Do not place mobile acetylene cylinders in use on moving vehicles.
2.2.2.3. May place mobile acetylene cylinders and oxygen cylinders on the same trolleys for short-distance movement under following conditions:
- Gas generators and oxygen cylinders must be strapped tightly and cushioned;
- Gas nozzles, welding torches, and cutting torches must be stored in separate locations on the vehicles.
2.2.2.4. When transporting gas cylinders over long distance, discharge all acetylene (pressure according to schedule), calcium hydroxide and calcium carbide residues.
2.2.2.5. Acetylene cylinders that can no longer be filled with acetone and when porous materials have been acetylene degraded must be removed.
2.2.2.6. May only repair mobile acetylene generators after adopting purification methods for acetylene in generators.
2.2.3. Safety requirements in repair of metal welding, cutting equipment
2.2.3.1. Only individuals who have received training and obtained license are allowed to repair equipment for oxygen, acetylene, and liquefied petroleum gas.
2.2.3.2. Dismantling and repairing of welding, cutting equipment for oxygen, acetylene, and liquefied petroleum gas on separate tables. Tables where oxygen equipment is placed must not contain grease.
2.2.3.3. Parts and components after repair must be rid of grease, cleaned with hot water, and dried.
2.2.3.4. Cutting torches and welding torches after repair must be tested and only brought into operation if qualified.
2.2.3.5. If any leak occurs during operation, immediately cease operation in order to repair.
2.2.4. Safety requirements for oxy-fuel welding work equipment manufacturing and storage locations, and oxy-fuel welding work locations
2.2.4.1. Workshops
- Workspace area must be at least 4 m2 per welder (excluding area of equipment and passages).
- Width of passage must be at least 1 m.
- Height from floor level to the lowest point of the roof must be at least 3.25 m.
- Compartments must be made from barely flammable or non-flammable materials with the minimum fire resistance category of category II.
- The floor must be made from non-flammable materials with poor thermal conductivity and easy to clean.
- Natural and artificial lighting must conform to regulations on lighting in workplace.
- Airiness must be guaranteed.
2.2.4.2. Welding, cutting areas
- All metal welding and cutting works using flame must be conducted at least 10 m away from mobile acetylene generators; at least 1.5 m away from gas nozzles; and at least 3 m from gas extraction points.
- Workshops where assembly and welding of large metal pieces are conducted must be equipped with assembly shelves and lifting, transport equipment.
2.2.4.3. Cylinder storage
2.2.4.3.1. Cylinders containing flammable gas must be preserved in outdoor or indoor storage according to design approved by competent authority.
2.2.4.3.2. Do not store cylinders containing flammable gases in supermarket, cinema, clubs, hotels, conference halls.
2.2.4.3.3. Preservation area of flammable gas cylinders must be airy; flammable gas cylinders must not be preserved in areas lower than their surrounding elevation, in underground tunnels, or in basements.
2.2.4.3.4. Inspect expiry date of gas cylinders before using unexpired cylinders for welding and cutting.
- Do not use all of the gas in a cylinder. In case of oxygen, remaining gas pressure must be at least 0.5 at. With respect to acetylene cylinders, pressure of remaining gas in the cylinders must not be lower than values under schedule below:
|
Temperature oC |
< 0 |
From 0 to 15 |
Exceeding 15 to 25 |
Exceeding 25 to 35 |
|
Minimum residual pressure, at |
0.5 |
1.0 |
2.0 |
3.0 |
- Do not use jute threads or cotton threads to cushion oxygen cylinders.
2.2.4.3.5. Prior to performing cutting and welding works:
- Tidy up workspace.
- Inspect tightness of joints in welding, cutting equipment, nozzles, and tubes.
- Examine conditions of gas generators, regulators, tubes, switch valves, and fire extinguishers.
2.2.4.3.6. When conducting welding and cutting work from elevated positions, conform to applicable regulations and law.
2.2.4.3.7. When welding and cutting electrical equipment, develop precautions to prevent electrical discharge to the equipment.
2.2.4.3.8. Do not conduct welding or cutting works on equipment or pipelines carrying pressure.
2.2.4.3.9. When conducting metal welding and cutting underwater, adopt safety measures properly in relevant technical standards and regulations.
2.2.5. Metal welding, cutting equipment (regulator, gas hoses, cutting torch, welding torch)
2.2.5.1. Before installing regulator valves to cylinders, inspect conditions of screw threads of fixing plates and screw plugs. Do not use damaged step-down converters. When cylinder valves are damaged, do not attempt to repair but instead return to refill stations.
2.2.5.2. When installing regulators to cylinders, use specialized open wrenches. Do not tighten fixing plates when cylinder valves are open.
2.2.5.3. Do not attach 3-way adapters to gas nozzle to fuel multiple welding torches.
2.2.5.4. Soft tubes must not be longer than 20 m (from fire extinguishers to welding torches). In other cases, consent of individuals in charge is required.
2.2.5.5. Gas nozzles of each type of gas must be used accordingly.
2.2.5.6. Do not allow gas cylinders nozzles to make contact with electrical wires and conductive parts. Do not place heat sources near nozzles and do not place heavy objects on nozzles.
2.2.5.7. Do not use damaged gas nozzles. When nozzle lengthening or connection is required, length of connected segment must not be lower than 3 m and no more than 2 joints are allowed per nozzle.
2.2.6. Requirements for materials, chips, preservation, and transportation
2.2.6.1. Surface of chips and parts before welding and cutting must be rid of paint, grease, rust, and dust. Edges of chips and parts must be rid of swarf before welding.
2.2.6.2. When cleaning greases on surfaces of objects in preparation for welding, use non-flammable and non-toxic substances.
2.2.6.3. Preservation, transportation, and arrangement of welding chips, materials, and final products must not affect operational safety, obstruct natural lighting, transport route, passages, and obstruct the use of fire prevention devices, personal protective equipment.
3. Safety conditions of oxy-fuel welding equipment during use
3.1. Only use oxy-fuel welding equipment certified for conformance to regulations and labelled as per applicable laws.
3.2. Oxy-fuel welding equipment must be transported, stored, preserved, and maintained according to manufacturers’ instructions and applicable regulations.
3.3. Safety assurance work for oxy-fuel welding equipment must comply with Section 2 (technical provisions) of these Regulations.
3.4. In addition, the following specific provisions must be complied with:
3.4.1. Operators are responsible for safely operating cylinders and gas therein (oxygen, acetylene, or liquefied petroleum gas), and returning cylinders to manufacturers or suppliers in safety conditions similar to when receiving the cylinders. Operators must adopt precautions below.
3.4.2. Only trained individuals authorized by cylinder owners and licensed by competent authority shall preserve cylinders and components thereof.
3.4.3. Operators must not remove or alter labels on cylinders. Only cylinder owners are allowed to remove and alter labels on cylinders.
3.4.4. Operators must not remove signs of cylinder manufacturers which allow distinguishing the gases in such cylinders; must not repaint cylinders; must not add more labels or signs. Operators shall rely solely on signs of cylinders to recognize gases in the cylinders.
3.4.5. Operators must not alter, change, obstruct, remove, or repair any part of the cylinders, including regulator components, valves, and any other parts if any.
3.4.6. When gas cylinders are contaminated or suspected to have been contaminated by impurities or external liquid via valves, operators must distinguish and mark the cylinders in question and inform gas suppliers about the contamination.
3.4.7. Do not use cylinders for any purpose other than supplying gas.
3.4.8. Gas cylinders must not be positioned in such a way that they become parts of electrical circuit.
When using cylinders in combination with arc welding, do not do grounding. Separate cylinders from the flame.
3.4.6. Do not place cylinders in temperature above 65 oC. Do not allow the flame or any heat source to make direct contact to any part of a cylinders or any electrical system. If ice or snow remains on cylinders or related components, thaw at room temperature or warm water no hotter than 50 oC under consent of suppliers.
Unless otherwise permitted by suppliers, cylinders must not be operated in too low of an artificial temperature. Cylinders are designed for operation in temperature ranging from -20 oC to 50 oC.
3.4.10. Do not use cylinders found to be leaking gas. Leaking cylinders must be placed in well-ventilated areas and reported to suppliers.
3.4.11. Do not discharge gas cylinders directly at humans or blankly into the air. Operators must return the cylinders to manufacturers or suppliers for proper handling.
3.4.12. Valves can be protected by caps or sheltering components. Operators must keep caps on the cylinders at all time during use unless the cylinders are linked with distribution equipment. Place the caps back on before returning the cylinders to manufacturers. Operators must not remove valve sheltering components.
3.4.13. When moving gas cylinders:
- Operators must not roll or drag cylinders when moving them.
- Employ hand trucks, forklifts or simple loading and unloading equipment suitable for the cylinders.
- When loading cylinders for transport, the cylinders must be fastened, especially heavy cylinders or large cylinders.. Employ cushion to prevent falling or collision between cylinders, and between cylinders and other surfaces.
- Do not valve sheltering components or magnet to lift cylinders with volume greater than 12 liters.
- Do not employ ropes or chains to hang cylinders except for cases where cylinders are specifically designed for such methods by manufacturers. May employ shelves or pallets suitable for cylinders to lift and lower the cylinders.
- Individuals operating with cylinders must wear shoes and gloves.
4. Requirements for oxy-fuel welders
4.1. Only individuals who have received training in oxy-fuel welding work, occupational safety and issued with certificate for occupational safety are allowed to perform oxy-fuel welding work. Periodic training for occupational safety and hygiene for oxy-fuel welders must be conducted at least once every 6 months.
4.2. Only individuals at 18 years of age or higher, having adequate health and training in specialty, and safety technique are allowed to conduct underwater welding, cutting works.
4.3. Female workers are not allowed to conduct oxy-fuel welding in tunnels, compartments, and enclosed spaces.
4.4. Welders and cutters must not deliberately repair welding equipment, welding torches, cutting torches, etc.
4.5. After finishing work, close all valves; loosen screws in depressurizing components and release all residual gas in nozzles.
4.6. Do not use oxygen to dust off clothes and equipment, or ventilate work area.
4.7. Welders must not remove or install cylinder valves.
4.8. When installing regulators to cylinders, use specialized open wrenches. Do not tighten fixing plates when cylinder valves are open.
5. Regarding personal protective equipment
5.1. Oxy-fuel welders must be equipped with personal protective equipment, welding goggles, aprons, shoes, gloves, and other protective equipment as per the law.
5.2. Personal protective equipment for welders must be able to protect against sparks, mechanical impact, hot metal dust, and harmful radiations.
5.3. When conducting welding work in environment containing chemicals (acid, alkali, grease products, etc.), electromagnetic field and when conducting welding work on pre-heated components, welders must be equipped with protective clothing made of materials that can provide protection against such impacts.
5.4. When welding and cutting in environment with risks of electrical incidents (in tunnels, compartments, enclosed spaces, damp places, etc.), in addition to protective clothing, welders must be equipped with insulated gloves and shoes; welding positions must be installed with insulated mats or platforms.
5.5. Gloves of welders must be made of barely flammable materials that can withstand mechanical impact.
5.6. Shoes of welders must be made of barely flammable materials that can withstand mechanical impact.
5.7. Hats of welders and cutters must be made from barely flammable and insulated materials. When working in such conditions that can potentially cause mechanical injuries, welders must be equipped with proper hats.
5.8. When welding and cutting in environment that produces toxic gas without specific suction equipment, welders must be equipped with appropriate respiratory protective equipment.
6. Technical safety inspection of oxy-fuel welding equipment
6.1. Acetylene generators and gas cylinders for used in oxy-fuel welding work must be initially inspected before being brought into operation, periodically inspected, and irregularly inspected according to inspection procedures promulgated by Ministry of Labor - War Invalids and Social Affairs.
Technical safety inspection of oxy-fuel equipment shall be conducted by conformity assessment bodies designated by Work Safety Department, Ministry of Labor - War Invalids and Social Affairs.
6.2. Safety inspection of metal welding and cutting equipment shall be conducted on a regular basis by entities employing these equipment.
6.3. Inspection frequency:
- 3 years for acetylene generators.
- 5 years for gas cylinders.
Inspection frequencies above can be shortened and reason therefor must be included in inspection records.
7. Examination, inspection and actions against violations
7.1. Inspection and actions against violations of these regulations shall be implemented by government labor inspectors.
7.2. Quality inspection of oxy-fuel welding equipment shall conform to Law on Products and Goods Quality.
8. Responsibilities of organizations and individuals
8.1. Organizations and individuals manufacturing, importing, circulating, and operating oxy-fuel welding equipment are responsible for complying with these regulations.
8.2. These regulations serve as the basis for enabling quality inspection agencies to conduct inspections, and as the basis for enabling certification bodies to certify conformity.
9. Organization for implementation
9.1. Work Safety Department, Ministry of Labor – War Invalids and Social Affairs are responsible for inspecting compliance with these regulations.
9.2. Local labor regulatory agencies are responsible for guiding, inspecting, and examining compliance with these technical regulations.
9.3. Difficulties that arise during the implementation of this Circular should be reported to the Ministry for consideration./.
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This translation is made by THƯ VIỆN PHÁP LUẬT, Ho Chi Minh City, Vietnam and
for reference purposes only. Its copyright is owned by THƯ VIỆN PHÁP LUẬT
and protected under Clause 2, Article 14 of the Law on Intellectual Property.Your comments are always welcomed
