Chapter 33
WELDING, JOINING, AND THERMAL CUTTING

Contents

Approved by Joe Dionne
NEW 8/10

33.1 Policy
33.2 Scope and Applicability
33.3 Roles and Responsibilities
33.4 Definitions
33.5 Required Work Processes

Work Process A: Procedure
Work Process B: Safe Work Practices
Work Process C: Exposure Assessment
Work Process D: Personal Protective Equipment
Work Process E: Master Chart of Welding and Joining Processes and Master Chart of Allied Processes
Work Process F: Welding, Joining, and Thermal Cutting Hazards
Work Process G: Safe Soldering Work Practices
Work Process H: Guide for Shade Numbers (from ANSI Z49.1:2005)
Work Process I: Filter Lenses for Protection Against Radiant Energy [from 29 CFR 1910.133(a)(5))]

33.6 References

NOTE:
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33.1 Policy

The Welding Safety Program at Lawrence Berkeley National Laboratory (LBNL) ensures that welding, as defined in Section 33.4 (Definitions) below, is performed safely and in conformance with applicable safety standards by qualified and authorized personnel in a manner that ensures acceptable joint quality and integrity.

To provide sufficient time for the  development of policy and procedures not already satisfied by the LBNL Job Hazards Analysis (JHA) program, or the Engineering and Facilities divisions’ welding safety policies and procedures, this policy will be effective on January 1, 2011.

33.2 Scope and Applicability

This policy applies to all Berkeley Lab employees, casual and participating visitors, guests, and subcontractors performing welding at Berkeley Lab.

This policy does not apply to:

• Subcontractors performing repairs on subcontractor-owned equipment that may be operated at Berkeley Lab. Note, however, that other Berkeley Lab requirements apply to these same subcontractors. See PUB-3000 Chapters 10 and 31.
• Subcontractors performing welding where quality and safety requirements are specifically addressed in subcontractor requirements (e.g., structural welding, fabricating components or equipment).

33.3 Roles and Responsibilities

33.3.1 Division Directors

Division directors are responsible for:

• Ensuring that welding performed in their division is performed in accordance with this PUB-3000 chapter, and only by individuals qualified and authorized to do so; and
• Ensuring that documented processes are used to authorize individuals within their division to request welds, weld plans, assign risk categories and/or perform welding. 

33.3.2 Engineering Division

The Engineering Division is responsible for performing high-risk welded joints on research equipment and assemblies.

33.3.3 Engineering Division Director

The Engineering Division Director is responsible for

• Designating qualified welding engineers (see Section 33.3.5 below), or for procuring these services from a qualified vendor to provide welding guidance for research applications; and
• Ensuring the review and approval of high-risk welding designs for research equipment or assemblies prepared by vendors and Berkeley Lab personnel.

33.3.4 Facilities Division

The Facilities Division is responsible for high-risk joints (see definitions) performed on LBNL infrastructure (e.g., buildings, utility piping systems, seismic restraints, etc.).

The Facilities Division Director is responsible for

• Ensuring that qualified welding engineers (see Section 33.3.5 below)  provide welding guidance for building or infrastructure applications, and
• Ensuring the review and approval of high-risk welding designs for building infrastructure, equipment, or assemblies prepared by vendors and Berkeley Lab personnel.

33.3.5 Designated Welding Engineers

Designated welding engineers are engineers who specialize in relevant welding codes, welding design, welding drawing standards, material properties, and quality aspects of welds.  The welding engineer may be appointed by his or her division director as a designated welding engineer. Welding engineering services can be procured from external vendors (e.g., Consolidated Engineering, Inc.).

Designated welding engineers are responsible for:

• Providing Berkeley Lab staff with advice and guidance on weld integrity and welding codes compliance.
• Reviewing and approving welding-related designs/drawings on behalf of their respective division directors.

33.3.6 Work Leads

Work leads are responsible for ensuring that only qualified and authorized workers perform welding, and that the authorizations are documented in the JHA.

33.3.7 Environment, Health, and Safety Division

The Environment, Health, and Safety (EH&S) Division is responsible for:

• Providing guidance to Berkeley Lab staff on welding-related occupational safety and health hazards, the graded approach, and assisting divisions in developing their welding policies and procedures.
• Assisting divisions in the assessment of worker exposures to hazardous airborne agents and safety hazards during welding, as requested by workers and/or work leads or Division Safety Coordinators.

33.4 Definitions

ANSI: American National Standards Institute

ASME: American Society of Mechanical Engineers

ASSE: American Society of Safety Engineers

AWS: American Welding Society

Perform or performing: These terms, when used in this chapter in the context of welding (as defined below), incorporate all phases of the joining process including but not limited to the design, specification, preparation, fabrication, and inspection of the joint as required by codes relating to the welding process.

Graded approach: Joints are assigned a risk category depending upon the direct consequences of joint failure. Requirements for performing the design, specification, preparation, fabrication, and inspection of the joint depend upon the risk category (see below) and are established using the graded approach. Risk categories are as follows:

• High-risk welded joints: A high-risk welded joint failure has the potential to cause severe injury or death, and/or the release of hazardous materials. Joints on engineered seismic bracing and pressure vessels typically contain high-risk joints. Additionally, welded support stands holding high-value equipment, oxygen and/or flammable gas piping systems, and toxic gas piping systems where the human risk potential has been analyzed and mitigated by an Engineering Note or Safety Note are generally considered high-risk welds.
  
  The welding engineer may be consulted to assist requestors with deciding whether or not their proposed weld meets the definition of a high-risk welded joint.
  
  
• Low-Risk Welded Joints: A low-risk joint failure does not have a recognized potential to cause injury. The risk of property damage due to such a failure is nil to moderate.  Examples include welded joints on lower-value equipment, and welding of most plumbing systems (water, nonhazardous gas, vacuum). Additionally, joints resulting from the following processes are always considered low risk:
  • Soldering using heated irons or guns
  • Resistance spot welding performed solely for the purpose of connecting electrical conductors
  • Joining, blowing, or fusing of glass or quartz for scientific purposes
  Low-risk welded joints may also be created by using other processes. Joe Dionne (ext. 7586), the EH&S Welding Subject Matter Expert (SME), may be consulted to confirm that the failure of the proposed joint poses no risk of injury, and no to little impact to costs.

Qualified: As used in this chapter, qualified persons are those persons who have demonstrated that they possess the knowledge, training, and skills to safely and effectively perform a given welding or joining activity.

Welding: As used in this chapter, the term “welding” includes all joining processes that use heat to join materials with or without a filler material. Examples of such processes are welding, brazing, soldering, and thermal cutting (e.g., severing or removing metal by localized melting, burning, or vaporizing of the work pieces). For technical definitions of these processes, see AWS A3.0:2001, Standard Welding Terms and Definitions).

The term “welding” in this chapter does not include processes known as solvent welding or adhesive bonding (typically used to fuse plastic parts), or using a “bag sealer” to melt plastic sheets.

33.5 Required Work Processes

Work Process A. Procedure

1.  Facilities Division: Customers requiring welding will use the Facilities Division Work Request Center to request a weld.  Depending on the type of weld requested, it will be screened by Facilities Division management and assigned an appropriate welding process, specification, and a qualified welder(s) to complete the work.
1. The Facilities Division will follow their internal welding procedures [Administrative 070 and Operations 346 (Facilities Welding and Brazing)] to ensure that any welding performed meets applicable codes, regulations, and LBNL requirements.
2. For high-risk welds, an Engineering or Safety Note will be prepared to ensure that safety requirements have been satisfied and that the weld meets applicable ANSI, ASME codes, and OSHA welding regulations.
2. Engineering Division: For the engineering, design, fabrication, repair and maintenance of scientific equipment, Engineering Division personnel will screen the customer request to determine the appropriate approach to the specifications and the appropriate welding process, and assign qualified staff [welder(s)] to complete the project.
1. The Engineering Division will follow their internal welding procedure to ensure that any welding performed satisfies applicable codes, regulations, and LBNL requirements.
2.  For high-risk welds, an Engineering or Safety Note will be prepared to ensure that the safety requirements have been satisfied and that the weld meets applicable codes and regulations.
3. All Other Divisions: The vast majority of welding performed by other division personnel is considered “low risk” welding (e.g., soldering, spot welding, and torch brazing). For these types of welding, the LBNL ISM and Job Hazards Analysis processes will satisfy the requirements for welding hazards, controls, training, authorization, and documentation.
1. Should a scientific division need to perform other types of welding, specific policies and procedures equivalent to those of the Facilities Division will need to be developed and implemented. The EH&S Welding Subject Matter Expert Joe Dionne (ext. 7586) may be consulted for the development of welding policy and procedures.

Work Process B. Safe Work Practices

Although there are various welding, joining, and allied processes as classified by the American Welding Society [see Work Process E (Master Chart of Welding and Joining Processes and Master Chart of Allied Processes)], the welding processes typically performed at LBNL can be broken down into four categories for safety purposes: 1) Soldering using heated irons or guns, 2) resistance spot welding, 3) open-flame processes, and 4) arc processes. Common process-specific hazards are discussed below. For a more detailed discussion of hazards, see Work Process F (Welding, Joining, and Thermal Cutting Hazards). The following precautions apply regardless of the joint’s risk category:

1. Soldering using heated irons or guns: The soldering of electronic components is usually performed with a soldering iron or gun. A low-melting temperature [melting range of 90 to 450°C (190 to 840°F)] solder flows into the heated joint by capillary action. Hazards are not only posed by the solder but also by the equipment, fluxes, coatings, and cleaning agents. Typical hazards include contact with hot surfaces or corrosive cleaning agents, splatter of flux or unclean surfaces, inhalation and/or eye irritation from vaporized materials, and ingestion of lead from contaminated hands.
   • EHS0243 (Soldering Awareness) is required training.
   • Safety glasses with side shields or goggles shall be worn when soldering with an iron or gun.
   • Soldering must not be performed on combustible surfaces.
   • Hands and face must be washed after soldering and before eating or smoking to prevent the ingestion of lead from solder.
   • Solder waste is recyclable material. It will be collected and managed per the Berkeley Lab metal recycling process. Please bag any waste solder, and place it in the metal recycling hopper. If you wish to mark it with the words "waste solder, recyclable material," please feel free to do so. Generally, it is incorrect to store solder as hazardous waste in your Satellite Accumulation Area. The EH&S Waste Management Group and/or Facilities Division can assist solder users with recycling and/or disposal requirements.
2. Resistance spot welding: The most common resistance welding performed at LBNL is resistance spot welding (RSW). RSW can be performed for structural/mechanical purposes (i.e., welding sheet metal) or for fastening electrical conductors. RSW for structural/mechanical purposes is typically performed using a large, fixed floor standing machine. Handheld RSW benchtop machines are also often used to fasten electrical conductors. Typical RSW hazards include lacerations from handling sharp edges of sheet metal, splatters from discharge, pinching/crushing by electrodes, electrical shock, and burns or fire from sparks.
   • EHS0244 (Safety – Resistance Spot Welding) is required training.
   • Clothing and personal protective equipment (PPE) including:
     • Safety gloves as appropriate to avoid lacerations. When handling sheet metal, leather or other cut-resistant safety gloves should be worn. Safety gloves are usually not necessary during the resistance spot welding of electrical conductors; however, clean gloves may be required to maintain cleanliness.
     • Long-sleeve shirts as appropriate, preferably without pockets
     • Safety glasses with side shields, or goggles
   • Machines must be inspected before each use to ensure that guards and other required safety devices are in place and operational, and that electrical insulation is complete and in good condition.
   • A hot work permit or equivalent authorization from the Berkeley Lab Fire Department is required for any RSW process. Keep combustible material out of the work zone. A fire extinguisher must be immediately available.
3. Open-flame processes: These include soldering, brazing, welding, torch cutting, and other processes that use a handheld torch to heat the joint and filler material. Typical hazards include contact with hot surfaces, inhalation of metal and flux fumes and toxic gases, intense visible and infrared radiation from the heated joint and/or flame, fire due to accidental contact of splashed molten metal or flame with combustible materials, and other hazards inherent to cylinder-fed gases.
   
   For open-flame processes (often referred to as “oxyfuel gas” processes) not including glassblowing, the following precautions apply:
   • EHS0171 (Pressure Safety) and EHS0241 (Welding, Brazing, and Cutting Safety) are required training.
   • EHS0243 (Soldering Awareness) is required additional training if soldering will be performed using open-flame processes.
   • Open-flame processes included above may only be performed by qualified and authorized workers in accordance with approved division policies and procedures.
   • A hot work permit or equivalent authorization from the Berkeley Lab Fire Department is required for any open-flame (oxyfuel gas) process. Keep combustible material out of the work zone. A fire extinguisher must be immediately available.
   • Welding goggles or safety glasses with side shields must be worn. Guidance for selecting appropriate shade numbers is provided in Work Process H, and appropriate filter lenses in Work Process I.
   • PPE for protection against hot surfaces must be worn. This includes safety gloves and may also include aprons and/or leathers. Closed-toe shoes and long trousers are also required for torch cutting.
   Although glassblowing (including fabricating, sealing, bending, or fire polishing quartz or glass parts) is an open-flame process, the hazards involved in glassblowing are different from those of open-flame processes involving metal parts. Typical hazards include thermal burns from hot glass parts, cuts from sharp (especially newly cut) glass surfaces, exposure to gaseous silica, and the release of hazardous gases due to heating contaminated glassware. The following precautions apply to glassblowing:
   • EHS0171 (Pressure Safety, formerly EHS0231) is required training for all open-flame processes except for those using only a benchtop Bunsen burner.
   • Glassblowing may only be performed by workers qualified and authorized by the Job Hazards Analysis.
   • A hot work permit or equivalent authorization from the Berkeley Lab Fire Department is required for glassblowing except when using a benchtop Bunsen burner. Keep combustible material out of the work zone.
   • Welding goggles (for quartz work), didymium safety glasses with side shields (for glass work), or safety glasses with side shields must be worn.
   • Cut-resistant safety gloves must be worn when cutting glass.
   • Glass edges should be fire polished to remove sharp edges prior to removing it from the work area.
   • Work must be performed in a well-ventilated area.
   • All glassware must be thoroughly cleaned prior to heating/repairing.
4. Arc welding processes: These include shielded metal arc (“stick”), tungsten inert gas, metal inert gas, orbit, submerged arc, arc cutting, and other similar welding processes that use a controlled electrical discharge (arc) between the electrode and the work piece to provide the heat for melting the base metal and filler. Typical hazards include contact with hot surfaces; inhalation of metal and flux fumes or combustion products; intense ultraviolet, visible, and infrared radiation from the arc; toxic gas produced by an arc reaction with air or the shielding gas; fire or burn caused by splashed molten metal, a slag, or a spark; and electric shock. Asphyxiation is also possible if the inert-gas shielded arc welding is performed without adequate ventilation.
   • EHS0241 (Welding, Brazing, and Cutting Safety) is required training.
   • Arc welding processes may only be performed by qualified and authorized workers in accordance with division-approved policies and procedures.
   • A hot work permit from the Berkeley Lab Fire Department is required for any arc welding process. Keep combustible material out of the work zone. A fire extinguisher must be immediately available.
   • Welding goggles, or safety glasses with side shields and a full face helmet, must be worn. Guidance for selecting appropriate shade numbers is provided in Work Process H, and appropriate filter lenses in Work Process I.
   • Work must be performed in a well-ventilated area.
   • Welding screens must be provided to protect passersby against arc radiation.
   • PPE for protection against hot surfaces must be worn. This includes safety gloves and may also include aprons and/or leathers. Closed-toe shoes and long trousers are required. Special protection is required when performing overhead welding.

Work Process C. Exposure Assessment

Potential hazards to individuals performing welding, brazing, soldering, thermal cutting, or similar processes include exposure to fumes, gases, flux chemicals, heat, noise, and radiation. The nature of the exposure is influenced by many factors including the composition of the filler metals and base metals; the welding, cutting, or brazing method; and the presence of paint or coating on the metals being welded. Exposure is an issue for both the operator and for others in the area.

Workers who perform these processes should have their potential exposures evaluated by requesting an exposure assessment. The exposure assessment will evaluate related safety issues such as enclosed/confined spaces, electrical hazards, fire hazards, personal protective equipment (PPE), and ventilation.

Welding exposure assessments will be archived in the Welding Hazards Database or an equivalent LBNL database (e.g., Hazard Management System).

Work Process D. Personal Protective Equipment

Personal protective equipment (PPE) is required for the protection of employees who perform and observe welding to comply with ANSI Z49.1, Sections 4.3 and E4.3 (Safety in Welding, Cutting, and Allied Processes). [See Section 33.6 (References) of this chapter.] Selecting and wearing appropriate protective clothing is also required to minimize the potential for ignition, burning, trapping hot sparks, or electric shock. Employees must satisfy the PPE and protective clothing requirements listed below for their protection against welding hazards typically associated with specific tasks.

General PPE requirements:

• Eye protection: Eye and face protection must comply with OSHA 29 CFR 1910.133 and ANSI Z87.1-1989 (the American National Standard Practice for Occupational and Educational Eye and Face Protection). Guidance on shade numbers and filter lenses can be found in ANSI Z49.1 and 1910.133(a) (5); tables from these two standards are included in Work Process H and Work Process I, respectively.
  
  Safety glasses with side shields or goggles are required to be worn underneath welding helmets. This is to protect the eyes when the helmet or shield is in the raised position.
• Respiratory protection: If required, respiratory protection must comply with Berkeley Lab’s Respiratory Protection Program.
• Head protection may be specified by the Job Hazards Analysis (JHA).
• Foot protection: Safety shoe footwear is typically required for working in shops (see the JHA). Protective footwear is available through Berkeley Lab’s safety shoe vendor.
• PPE for electrical safety: PPE required for electrical safety is addressed in PUB-3000 Chapter 8 (Electrical Safety). For general safety, dry clothing without holes or tears will usually be sufficient to insulate the welder from electric shock.
• Hand protection: Welders must wear protective flame-resistant safety gloves as provided in Work Process B (Safe Work Practices) and other parts of this chapter. Safety gloves made of leather or other suitable materials and with insulating lining to protect workers against exposure to high radiant energy are recommended. All gloves must be in good repair, dry, and capable of protecting workers against electric shock from welding equipment.
• Minimum protective clothing requirements vary depending upon the process used.

 Work Process E

Work Process F

Welding, Joining, and Thermal Cutting Hazards

Introduction

Potential hazards to individuals performing welding, brazing, soldering, thermal cutting, or similar joining processes include exposure to fumes, gases, flux chemicals, heat, noise, and radiation. The nature of the exposure is influenced by many factors including the composition of the filler metals and base metals; the welding, cutting, or brazing method; and the presence of paint or coating on the metals being welded. Exposure is an issue for both the operator and for others in the area. Workers who perform these processes should have their potential exposures evaluated by requesting an exposure assessment. Related safety issues include enclosed/confined spaces, electrical hazards, fire hazards, personal protective equipment (PPE), and ventilation.

1 Personal Exposure Issues

1.1 Fumes

Fumes are solid airborne particles formed by the condensation of vapor. Welding fumes are formed from the vaporization of molten metal. Adverse health effects of exposure to welding fumes can include systemic poisoning, metal-fume fever, pneumoconiosis (lung disease), and irritation of the respiratory tract. The composition of welding fumes depends on the metals involved, as discussed below:

• When the base metal and welding rods are iron or steel, the main component of the fume will be iron oxide. Local exhaust ventilation is usually adequate to control fumes.
• When the base metal is stainless steel, fumes may additionally contain nickel and chromium. Hexavalent chromium and nickel are carcinogens. Immediate symptoms include nausea, headaches, dizziness, and respiratory irritation. Additional PPE may be necessary to adequately control exposures.
• Welding on plated, galvanized, or painted metals may generate fumes that contain cadmium, zinc oxide, or lead. Exposure to zinc-oxide fumes can cause metal fume fever, a condition with flu-like symptoms that typically last 24 hours. Cadmium is a suspected human carcinogen. Typical controls for work with these materials include local exhaust ventilation.
• Lead is a potent, systemic poison that is often found on painted surfaces of older building components including structural steel. Berkeley Lab’s Lead Program requires that lead paint be removed from a surface in an approved manner before it is welded or cut. Other requirements may apply. Any lead-related work should be reviewed by the Berkeley Lab Lead Program Manager.
• Welding fumes can also contain metals such as aluminum, beryllium, copper, mercury, silver, tin, titanium, and vanadium if they are present in the base metal or in coatings on the surface being welded or cut. Controls will be determined on an individual basis via an exposure assessment if these materials are present.
• Fumes from rosin fluxes include pyrolysis decomposition products. Good ventilation is necessary to keep exposure as low as possible.

1.2 Toxic Gases

Welding may result in exposure to shielding gases, gases created by the welding process, and decomposition products of fluxes used in welding or brazing. Workers must recognize the symptoms of overexposure to the toxic gases described below, and stop the operation until additional protective measures have been implemented:

• Inert gases such as argon and helium may be used as shielding gases. Semi-inert shielding gases include carbon dioxide, oxygen, nitrogen, and hydrogen. Although these gases are not toxic, some are flammable, and thus proper controls must be used when working with combustibles and equipment to reduce the risk of fire. In enclosed spaces, it is possible for the inert shielding gas to displace oxygen and result in asphyxiation.
• Carbon monoxide is formed by incomplete combustion, particularly when carbon dioxide is used as the inert gas shield. Welding operations that use carbon dioxide as the inert gas shield may produce hazardous concentrations of carbon monoxide in poorly ventilated areas. Carbon monoxide is odorless, colorless, and tasteless. Overexposure can result in headache, nausea, weakness, dizziness, visual disturbances, in personality changes, loss of consciousness, or death. Air monitoring can evaluate the levels of carbon monoxide produced during welding operations. Controls can include ventilation; however, respiratory protection is generally not effective protection against carbon monoxide.
• Phosgene gas may be formed when ultraviolet radiation decomposes chlorinated hydrocarbon solvents. Phosgene reacts with moisture in the lungs to produce hydrogen chloride, which mixes with water to form hydrochloric acid, which in turn destroys lung tissue. Solvents must be removed from materials before they are welded. In addition, chlorinated solvents must be located far away from welding operations or any operation that generates ultraviolet radiation or intense heat.
• Ozone is produced by the interaction of ultraviolet light from the welding arc with the surrounding air. Ozone is produced in greater quantities by gas metal arc welding [GMAW, also known as metal inert gas (MIG) or short-arc welding], gas tungsten arc welding [GTAW, also known as tungsten inert gas (TIG) or heli-arc welding], and plasma arc cutting. Ozone formation is greater when aluminum is welded. Ozone is a highly active form of oxygen and can cause great irritation to all mucous membranes, and long-term negative effects on the lungs. Symptoms of ozone overexposure include headache, chest pain, and dryness of the upper respiratory tract. Excessive exposure can cause pulmonary edema.
• Nitrogen oxide (NO) and nitrogen dioxide (NO₂) are produced when ultraviolet light from the welding arc interacts with nitrogen and oxygen in the air. Nitrogen oxides are produced in greater quantities by GMAW (or MIG or short-arc welding), GTAW (heli-arc or TIG welding), and plasma arc cutting. NO₂, one of the oxides formed, has the greatest adverse health effect. NO₂ is irritating to the eyes, nose, and throat. Dangerous concentrations can be inhaled without any immediate discomfort but can result in delayed symptoms including shortness of breath, chest pain, and fluid in the lungs (pulmonary edema).
• Fluoride compounds are found in the coatings of several types of fluxes used in welding. Exposure to these fluoride compounds may irritate the eyes, nose, and throat. Repeated exposure to high concentrations of fluorides in the air over a long period of time may result in fluid in the lungs and bone damage. Exposure to fluoride dusts and fumes may also produce skin rashes.
• Products containing both fluoride and hydrogen compounds may produce corrosive and toxic hydrofluoric acid, which can irritate the skin, eyes, nose, and throat.

1.3 Heat (Burns)

Welding can produce sparks and spatter. Hot metal and sparks are generated by the cutting process, and the work piece and equipment can get hot. Flying sparks, hot metal spatter, hot work pieces, and hot equipment can cause burns.

1.4 Flux

Flux is commonly used in brazing and soldering. Depending on the chemical composition of the flux, there may be hazards such as skin irritation or burns due to corrosive flux.

2 Noise

Noise should be controlled at the source as much as possible. When controls are not adequate to keep noise levels within acceptable levels, hearing protection must be used. When hazards to the ear canals exist, flame-resistant plugs or equivalent protection must properly fit in the worker’s ear canals. LBNL has established a Hearing Conservation Program to protect employees from noise. Noise dosimetry is used to monitor an employee’s exposure to noise. Required measures for hearing protection and other actions are determined by the results of this monitoring.

3 Radiation

The operations discussed below produce radiation that is either non-ionizing or ionizing. Sources of non-ionizing radiation include ultraviolet (UV) light, visible light, and infrared (IR) light. Sources of ionizing radiation include X-rays.

• UV light is generated by the electric arc in the welding process. Skin exposure to UV light can result in severe burns, in many cases without prior warning. UV radiation can also damage the lens of the eye. Many arc welders are aware of the condition known as "arc eye," a sensation of sand in the eyes. This condition is caused by excessive eye exposure to UV light. Exposure to UV rays may also increase the effects of some industrial chemicals (coal tar and cresol compounds, for example) on the skin.
• Visible light radiation is a hazard for the welding operator and others nearby. Exposure of the human eye to intense visible light can produce adaptation, pupillary reflex, and shading of the eyes. Such actions are protective mechanisms to prevent excessive light from being focused on the retina. In the arc-welding process, eye exposure to intense visible light is prevented by the welder's helmet. However, some individuals have sustained retinal damage due to careless "viewing" of the arc. At no time should the arc be observed without appropriate eye protection.
• Exposure to IR radiation produced by the electric arc and other flame cutting equipment may heat the skin surface and the tissues immediately below the skin surface. Except for this effect, which can progress to thermal burns in some situations, IR radiation is not dangerous to welders. Welders must use a welder's helmet (or tinted glasses) and protective clothing to protect themselves from IR (and UV) radiation.
• Ionizing radiation can be a hazard if thoriated tungsten electrodes are used. Additionally, grinding thoriated electrodes can generate dust that may create an inhalation hazard for welders.  Check the label of the electrodes. If you find that they are thoriated electrodes, contact an EH&S Industrial Hygienist for technical assistance in evaluating potential exposure risk.
• Ionizing radiation can also be produced by electron beam welding. Presently, electron beam welding is not performed at LBNL.

4 Related Safety Issues

4.1 Compressed Gas Safety

Compressed gases are used in many types of welding. Any use of compressed gas including gas cylinder use, handling, storage, securing, pressure regulating, fittings selection, leak testing, pressure relief, as well as those types and markings must be in accordance with regulatory requirements.

4.2 Enclosed or Confined Spaces

Welding, cutting, and brazing processes can introduce additional hazards into enclosed or confined spaces such as attics, mechanical equipment, and vessels.  Some enclosed spaces are classified as “Confined Spaces,” and are subject to the requirements of LBNL’s Confined Spaces Program.  Special requirements apply for welding, cutting, and brazing in enclosed or confined spaces. These situations must be analyzed by a Task-based Job Hazards Analysis. Cylinders containing oxygen, acetylene, or another fuel gas cannot be taken into confined spaces.

4.3 Electrical Hazards

Electric shock from welding and cutting equipment can result in death or severe burns. Additionally, serious injury can occur if the welder falls as a result of the shock. All of the following are electrically energized when the power is “on”: The welding circuit (including the electrode and work piece), input power and machine internal circuits, the wire, reel of wire, drive rolls, and all other metal parts touching the energized electrode. Additionally, an incorrectly installed or improperly grounded equipment or work piece is a hazard.

4.4 Fire Hazards

Welding, cutting, and allied processes produce molten metal, sparks, slag, and hot work surfaces. These can cause a fire or an explosion if precautionary measures are not followed. Flying sparks are the main cause of fires and explosions in work that involves welding and cutting. Sparks can travel up to 35 feet (10.7 meters) from the work area. Sparks and molten metal can travel greater distances when falling. Sparks can pass through or become lodged in cracks, clothing, pipe holes, and other small openings in floors, walls, or partitions.

4.5 Ventilation

Ventilation is required for welding, cutting, or brazing in enclosed spaces or spaces where partitions or barriers significantly obstruct cross ventilation. The ventilation may be portable units or fixed systems. Fixed ventilation includes extractor arms and fume hoods. If mechanical ventilation is inadequate to maintain adequate air quality, supplied-air respirators must be used.

Work Process G: Safe Soldering Work Practices

Work Process H (from ANSI Z49.1:2005)

* As a rule of thumb, start with a shade that is too dark to see the weld zone. Then go to a lighter shade that provides a sufficient view of the weld zone without going below the minimum. In oxyfuel gas welding, cutting, or brazing where the torch or the flux produces a high yellow light, it is desirable to use a filter lens that absorbs the yellow or sodium line in the visible light spectrum.

* As a rule of thumb, start with a shade that is too dark to see the weld zone. Then go to a lighter shade that provides a sufficient view of the weld zone without going below the minimum. In oxyfuel gas welding, cutting, or brazing where the torch or the flux produces a high yellow light, it is desirable to use a filter lens that absorbs the yellow or sodium line in the visible light spectrum.

Work Process I [from 29 CFR 1910.133(a)(5)]

Footnote (*) as a rule of thumb, start with a shade that is too dark to see the weld zone. Then go to a lighter shade that provides a sufficient view of the weld zone without going below the minimum. In oxyfuel gas welding, cutting, or brazing where the torch and/or the flux produce a high yellow light, it is desirable to use a filter lens that absorbs the yellow or sodium line in the visible light spectrum.

Footnote (**): These values apply where the actual arc is clearly seen. Experience has shown that lighter filters may be used when the arc is hidden by the work piece.

¹ A similar table is available from 29 CFR 1926.102 and applies to construction activities. The above table is more detailed, and thus is reproduced here.

Footnote (*): As a rule of thumb, start with a shade that is too dark to see the weld zone. Then go to a lighter shade that gives a sufficient view of the weld zone without going below the minimum. In oxyfuel gas welding or cutting where the torch produces a high yellow light, it is desirable to use a filter lens that absorbs the yellow or sodium line in the visible light of the (spectrum) operation.

33.6 References

ANSI/ASSE Z87.1-2003, Occupational and Educational Personal Eye and Face Protection Devices, American Society of Safety Engineers, Des Plaines, IL 60018

ANSI Z87.1:1989, American National Standard Practice for Occupational and Educational Eye and Face Protection, American Society of Safety Engineers, Des Plaines, IL 60018

ANSI Z49.1 1999, Sections 4.3 and E4.3, Safety in Welding, Cutting and Allied Processes, American Welding Society, Miami, FL 33126

ANSI Z49.1:2005, Safety in Welding, Cutting and Allied Processes, American Welding Society, Miami, FL 33126

ASME Boiler and Pressure Vessel Code (2004), Sections I through XII including applicable code cases, American Society of Mechanical Engineers, Fairfield, NJ 07007

ASME B31, Code for Pressure Piping, sections as defined by 10 CFR 851.27 (date varies by substandard), American Society of Mechanical Engineers, and Fairfield, NJ 07007

AWS A3.0:2001, Standard Welding Terms and Definitions, American Welding Society, Miami, FL 33126

OSHA Standards:

General Industry (29 CFR 1910)

1910 Subpart I, Personal Protective Equipment

1910 Subpart Q, Welding, Cutting, and Brazing

Construction Industry (29 CFR 1926)

1926 Subpart E, Personal Protective and Life Saving Equipment

1926 Subpart J, Welding and Cutting

Related PUB-3000 Chapters:

Chapter 4, Industrial Hygiene

Chapter 6, Safe Work Authorizations

Chapter 7, Pressure Safety and Cryogenics

Chapter 8, Electrical Safety

Chapter 10, Construction Safety

Chapter 12, Fire Prevention and Protection

Chapter 13, Gases

Chapter 19, Personal Protective Equipment

Chapter 25, Shop Safety and Power Tools

Chapter 31, On-Site Subcontractor/Vendor Safety Program

Chapter 32, Job Hazards Analysis

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