Welding Safety FAQs - Fumes and Gases
Health Effects: Fumes
Q: What compounds are found in common welding fume?
A: The most common compounds in arc welding fume mild steel are iron, manganese and silicon, although other compounds in the electrode or on the base metal may be in the welding fume.
Q: What types of electrode products are likely to have chromium or nickel in the welding fume?
A: Fumes from the use of stainless steel and hard-facing products contain chromium or nickel.
Q: What are the potential health effects that may result from long-term overexposure to chromium or nickel?
A: Asthma has been reported and some forms of these metals are known or suspected to cause lung cancer in processes other than welding. Therefore, it is recommended that precautions be taken to keep exposures as low as possible.
Q: What are the potential health effects that may result from sustained overexposure to manganese?
A: Manganese overexposure may affect the central nervous system, resulting in poor coordination, difficulty in speaking and tremor of arms or legs. This condition is considered irreversible.
Q: What are the long-term health effects associated with exposure to welding fume?
A: Check the specific welding consumable SDS.
Q: What are the potential health effects that may result from overexposure to zinc?
A: Overexposure to zinc may cause fume fever with symptoms similar to the common flu.
Q: What is a common source of zinc in welding fume?
A: Zinc in welding fumes usually comes from welding on galvanised steel.
Q: Where can you find safety instructions regarding welding products that you use?
A: Each welding power source and container of consumable product has a warning label containing specific safety instructions regarding the arc welding product you have chosen to use.
Q: What information is contained on a welding consumable Safety Data Sheet (SDS)?
A: An SDS contains the information on the precautions to observe for the Safe Handling and Use of the product. It also contains additional information, including a summary of the Hazardous Materials used to manufacture the product, a summary of Fire and Explosion Hazard Data, Health Hazard Data and Reactivity Data.
Q: Where can you find the SDS for the consumable product you are using?
A: It is found on the Lincoln Electric website, accessible @ www.weldingsafety.com according to the QR code, on the box.
Q: Since fumes and gases can be dangerous to your health, what steps should you take to protect yourself?
A: 1) Use local exhaust to keep fumes and gases from all breathing zones. 2) Use a respirator unless exposure is below exposure limits
Q: What additional precautions should be followed?
A: If welding consumables are used indoors, use local exhaust. If products that require special ventilation are used outdoors, a respirator may be required.
Q: What types of products generally require special ventilation?
A: Hard-facing and stainless products.
Health Effects: Gases
Q: What are the potential health hazards related to shielding gases used in arc welding?
A: Most of the shielding gases (argon, helium) are non-toxic, but they can displace oxygen in your breathing air causing dizziness, unconsciousness and possible death. Carbon monoxide can displace oxygen also and may pose a hazard if levels exceed 0.5% in the environmental air.
Q: What is one of the most basic safety precautions that a welder can take to protect themselves from overexposure to welding fume?
A: Keep your head out of the fume plume!
Q: Where is the concentration of fumes and gases greatest?
A: Concentration of fumes and gases is greatest in the plume.
Q: How can you keep fumes and gases away from your breathing zone?
A: Keep fumes and gases from your breathing zone and general area using natural ventilation and mechanical ventilation. When welding indoors, fixed or moveable exhaust hoods, or local exhaust at the arc are required.
Q: What precautions must be taken if adequate ventilation cannot be provided?
A: It may be necessary to wear an adequate, CE marked, respirator if adequate ventilation cannot be provided. Refer to what is required by the Risk Analysis of your specific welding conditions.
Q: Does Safety @ Work Regulations require engineering or workplace controls be installed before respirators can be used?
A: Safety @ Work Regulations requires that engineering and workplace controls be installed first and if the controls alone do not keep exposures below applicable limits, use respirators.
Q: What method is used to accurately measure a welder's exposure to welding fume?
A: A welder's exposure can only be determined by having a qualified professional take a sample of the welder's breathing air during the workday.
Q: When is it most important to measure a welder's exposure to welding fume?
A: Always, according to the Safety @ Work Regulation.
Q: What precautions should be taken when welding a base metal, which is plated or painted?
A: If the base metal cannot be cleaned before welding, the composition of the coating should be evaluated.
Q: What should you do if you feel overexposed to welding fumes?
A: Stop welding and get some fresh air immediately. Notify your supervisor and co-workers so the situation can be corrected and other workers are aware of and can avoid the hazard. If you continue to feel the symptoms, see your doctor. Be sure you are following safe practices, as stated upon the consumable labelling and SDS and improve the fume extraction and the ventilation in your area. Do not continue welding until the situation has been corrected.
Q: What does adequate fume extraction mean?
A: Your work area has adequate fume extraction ventilation when it is as near as possible to the source, it meets the requirements for minimum airspeed and other local regulations and it is enough to control worker exposure to the hazardous materials in the welding fumes and gases (so the applicable exposure limit for those materials is not exceeded).
Q: What are the most commonly used exposure limits?
A: Indicative Occupational Exposure Limit Values (IOELVs): Health-based, non-binding values, derived from the most recent scientific data available and taking into account the availability of reliable Measurement techniques. IOELVs are established in relation to a reference period of 8 hours (considering a time-weighted average) and referred to as long-term, exposure limit values.
Occupational Exposure Limit values (OELs): For any chemical agent for which an IOELV has been set at European Union level, EU Member States are required to establish a national occupational exposure limit value.
Threshold Limit Value (TLV): A recommended exposure limit for chemical and physical agents in the workplace, published annually by the American Conference of Governmental Industrial Hygienists (ACGIH) Health & Safety Executive and defines the TLV is as the level at which nearly all workers could be exposed to, throughout their career, without experiencing adverse health effects.
Total Weight Average (TWA) permissible exposure limit (PEL)
The legal limit established by the Occupational Safety and Health Administration (OSHA) that expresses the maximum allowable level of exposure to a given chemical contaminant or physical agent for US, typically expressed in terms of an 8-Hour Time Weighted Average.
Q: Where can you find the applicable limits for the PEL and TLV for substances in welding fume?
A: The IOELV and OELs are listed on the first page of the SDS for compounds in each electrode or flux. IOELVs and OELs for compounds that may be generated from the base plate, its’ coating and any other material in contact with the welding process, may be found in European and local Regulation.
Evaluating the Welding Environment
Q: What steps can you, the welder, take to identify hazardous substances?
A: There are also steps that you should take to identify hazardous substances in your welding environment. Read the product label to review the warnings, safety precautions. Obtain and review the material safety data sheet (SDS) for the electrode which your employer or supervisor has posted in the work place or that you have downloaded from the Internet. You should review the complete SDS to determine specifically, what compounds you may be exposed to when using the product.
Q: Where can the welder find information about materials in the base metal or any coating on the base metal?
A: Obtain a copy of the supplier's SDS for the base metal being welded, as this should be reviewed as well.
Welding Fume Control
Q: What is natural ventilation?
A: Natural ventilation is the movement of air through the workplace caused by natural forces. Outside, this is usually the wind. Inside, this may be the flow of air through open windows and doors.
Q: What is mechanical ventilation?
A: Mechanical ventilation is the movement of air through the workplace caused by an electrical device such as a portable fan or permanently mounted fan in the ceiling or wall.
Q: What is local exhaust?
A: Local exhaust is a mechanical device used to capture welding fume at or near the arc and remove contaminants from the air.
Q: What factors need to be considered when determining the exhaust requirements for your application?
A: The ventilation or exhaust needed for your application depends upon factors such as:
- Workspace volume
- Workspace configuration
- Number of welders
- Welding process and current
- Consumables used (mild steel, hard-facing, stainless, etc.)
- Allowable levels (TLV, PEL, etc.)
- Material welded (including paint or plating)
- Natural airflow
- Minimum airspeed requirements from local law
Q: Name several types of local exhaust that can be used to control exposure to welding fume?
A: Local exhaust of welding fumes can be provided by any of the following: adjustable "elephant trunk" exhaust systems, fume extraction guns or fixed enclosures, or booths with exhaust hoods.
Q: When should an employee's exposure to welding fume be obtained?
A: Exposure should be checked when new ventilation equipment is installed, when the process is modified or when the welder feels uncomfortable. Periodically, exposure should be re-checked, to be sure it is still working properly and is adequate.
Q: When should a respirator be used?
A: In confined spaces or in other circumstances, for example outdoors, a respirator may be required if exposure cannot be controlled to the IOELVs and OELs, PEL or TLV (see SDS and local Regulation)