- Created: 2018-03-07
Best practices in air quality management for the automotive industry
by Greg Carmichael, vice president of solutions sales, RoboVent
The automotive manufacturing industry employs 940,000 people in the United States. Of those nearly 1 million workers, some, unfortunately, are at risk for air quality-related health problems due to their exposure to weld fumes and other toxic particulates. Moving beyond OSHA regulations to more stringent indoor air quality (IAQ) control standards, however, could significantly reduce the number of automotive employees at risk for cancer, chronic lung disease and other health problems.
A good place to start when implementing tougher standards is to better understand the exposure risks specific to the automotive industry as well as the economics of IAQ. By doing so, manufacturers are often compelled to go beyond OSHA’s regulations to also adopt guidelines suggested by reputable health organizations, such as the National Institute of Occupational Safety and Health (NIOSH) and the American Conference of Government Industrial Hygienists (ACGIH).
If inhaled, welding fumes, which contain toxins and other harmful compounds, can result in immediate and long-term effects on worker health.
Auto IAQ matters
Most of the production processes used in the automotive industry produce significant dust or fumes, many of them toxic. If these particulates are not controlled, they can cause serious health problems for workers.
Welding: Weld fumes contain many toxic elements and compounds, including hexavalent chromium, manganese, nickel, copper, vanadium, molybdenum, zinc and beryllium. These fumes are made up of tiny particles that are inhaled deeply into the lungs where they have immediate and long-term effects on worker health.
Acute effects of exposure to weld fumes can include shortness of breath and respiratory irritation; eye, nose or throat irritation; and nausea. Long-term exposure can lead to kidney disease, chronic lung disease, several kinds of cancer and neurological damage. Welders can also develop a condition called “metal fume fever,” or welding sickness, which causes flu-like symptoms.
Machining: Machining of engine blocks and other drive train components typically requires the use of lubricants. These create fine oil mists that can be invisible to the eye. In addition to creating slip and fall hazards, when inhaled these mists can lead to asthma, chronic bronchitis, chronically impaired lung function, fibrosis of the lung and cancer.
Cutting and grinding: Larger particulates from cutting and grinding don’t make their way as deeply into the lungs as the fumed particulates from welding, but the large volume of dust produced by these applications does present special health risks.
Fiberglass, metal, glass, plastics and epoxy resins can all cause respiratory irritation; some materials are also carcinogenic when inhaled. Newer materials used in the automotive industry, including carbon fiber and composites, are associated with skin and respiratory irritation, contact dermatitis and chronic interstitial lung disease.
Plastic processing: Polymers and resins generate volatile organic compounds (VOCs) when heated during thermoplastic injection molding or other manufacturing processes. Many of these chemicals are associated with long-term health risks – including respiratory problems, central nervous system effects and cancer – and some present an immediate asphyxiation risk if not controlled.
Rubber manufacturing: Like plastic manufacturing, rubber processing produces volatile emissions that can be toxic with overexposure. Breathing in fumes from rubber processing is associated with cancers of the bladder, stomach and lungs in addition to chronic respiratory problems, skin disorders and possibly even reproductive effects.
OSHA regulates air quality for manufacturing facilities. Automotive manufacturers must meet basic requirements for maintaining IAQ, such as providing adequate ventilation and controlling overall airborne particulate levels.
In addition, OSHA has set specific standards to control worker exposure to toxic elements and compounds produced by industrial processes. Automotive manufacturers should be aware of the chemical makeup of their particulates and the levels that workers are exposed to over the course of an 8-hour shift.
Beyond OSHA, NIOSH and ACGIH set guidelines for exposure to hazardous and toxic substances. So, which of these standards and guidelines should automotive manufacturers follow? Here is how the standards are set, how they are enforced and how they interrelate.
OSHA PELs: OSHA sets permissible exposure limits (PELs) for toxic substances measured as a time-weighted average concentration that must not be exceeded during any 8-hour work shift of a 40-hour workweek. PELs are enforceable by law and failure to comply results in significant fines and penalties. Most automotive manufacturers fall under OSHA’s PELs for general industry.
Some manufacturers using specialized processes, however, may have different exposure limits known as separate engineering control air limits (SECALs). Both PELs and SECALs are set with consideration for human health risk and the technical feasibility of achieving the limit for specific manufacturing processes.
OSHA ALs: Some substances have a separate action level (AL) set by OSHA. This is the exposure level that is considered to create a hazard to workers. If the AL is exceeded, employers must conduct exposure monitoring, initiate a medical surveillance program for employees who are at or above the AL on 30 or more days per year, and provide a respirator to any employee that requests one.
ACGIH TLVs: ACGIH sets threshold limit values (TLVs) for exposure to toxic airborne substances. Unlike OSHA regulations, TLVs are set based purely on human health impact, with no consideration as to technical feasibility of meeting the standard. The TLVs are set based on available scientific literature into health effects, which ACGIH codifies as biological exposure indices (BEIs). Unlike PELs, ACGIH TLVs do not have the force of law.
NIOSH sets recommended exposure limits (RELs) for substances based on available scientific literature on their biological effects on different body systems. They are considered to be authoritative federal guidelines that are used by OSHA and other government agencies to set federal standards and regulations.
While only the OSHA PELs and SECALs have the force of law, it is instructive to look at the separate ACGIH and NIOSH limits for toxic compounds. Often, these limits are lower than the OSHA PEL – sometimes, many times lower.
Forward-thinking manufacturers who want to provide maximum protection for their workers should consider these guidelines, which are based on the best scientific evidence on the exposure levels linked with adverse health impacts, when developing their own internal goals for IAQ.
Improving IAQ beyond the minimum requirements for regulatory compliance can generate real benefits for automotive manufacturers. These benefits include:
- Productivity: OSHA estimates that worker absences and reduced efficiency resulting from poor air quality cost U.S. companies $15 billion annually. Improving air quality can help manufacturers reduce absenteeism due to the health effects of poor air and increase concentration levels and productivity for employees during their shifts.
- Retention and recruiting: Automotive companies competing to recruit welders and other skilled tradespeople will find that a clean, pleasant environment will pay dividends through lower turnover and more successful recruiting efforts for in-demand skilled workers.
- Product quality: Uncontrolled particulates can become a problem for product quality if they permeate sensitive areas such as paint lines or infiltrate electronic components.
- Healthcare and legal costs: Prioritizing worker health will result in lower healthcare costs and a significant reduction in the risk of legal action.
The RoboVent FabPro is a backdraft system, known for effectively collecting fumes in automotive manufacturing settings.
Strategies for IAQ
OSHA mandates that engineering and process controls be used as the first line of defense in meeting PELs for toxic airborne particulates. In most cases, that means installing effective air filtration equipment to remove contaminants from the air and return clean, filtered air to the facility.
The right air quality solution depends on the processes and materials being used and the volume and toxicity of the resulting particulates. An experienced air quality system designer can help automotive manufacturers select the right approach to control toxic particulates. Some strategies that manufacturers can use to optimize the effectiveness and efficiency of their air quality systems include:
- Use hoods, enclosures or partitions where possible to keep dust and fumes contained. Enclosing robotic applications makes particulates easier to capture and reduces the volume of air the dust collector will need to move, minimizing energy and equipment costs.
- Use source capture where possible to control manual weld fumes. The closer to the source you can capture the fumes, the less airflow and energy you will need. Effective source capture systems keep toxic fumes out of the welder’s breathing zone to protect their health.
- Use ambient filtration systems when source capture cannot be used or does not provide high enough capture efficiency. An ambient system will turn over air for the entire facility. They can be used as the primary system when source capture is not technically feasible, as in some cases when working with large components that cannot be easily enclosed. They can also be used alongside a source capture system to provide backup air quality control, especially when working with highly toxic materials.
- Use the right filters for the size, volume and composition of the particulates. A dynamic pulsing system significantly increases filter life by pulsing excess dust off of the filters before it becomes embedded in the filter media.
- Look for energy-saving features like smart control systems and variable frequency drive. These features can reduce energy consumption by 20 to 40 percent.
- If your processes produce a lot of sparks (like cutting, grinding and welding), make sure you have an effective spark arrestance system installed to keep sparks out of the dust collector.
- When working with highly combustible dusts, such as aluminum dusts, make sure your dust collector is equipped with a deflagration system to reduce the risk of a deadly dust collector explosion.
Fortunately, many auto manufacturers are moving beyond OSHA regulations toward standards that are more stringent. Additionally, some automotive manufacturers have implemented tougher air quality standards that they expect their Tier I and Tier II automotive parts suppliers to follow to retain preferred supplier status.
Other companies in the automotive industry are also voluntarily moving to ACGIH recommendations wherever they are technically feasible. These forward-thinking companies will find that their investment in air quality will pay off quickly.