Article supplied by Dupont™ Tyvek®
Risks of Secondary Inhalation
Workers using coveralls that meet the EN 13982-1 Type 5 Standard may be unaware that up to 15% of the hazardous fine particles may be entering inside the suit. If appropriate decontamination procedures are not implemented, this can lead to secondary inhalation of silica particles by the worker and family members, if contaminated garments worn under the disposable coveralls are worn home.
Australian Workplace Exposure Standard for Airborne Contaminants revised December, 2019
Work Health and Safety (WHS) Ministers have agreed by the requisite majority to change the workplace exposure standards (WES) for Respirable Crystalline Silica. As such, the maximum exposure for Crystalline Silica will be reduced by 50%, to a TWA of 0.05 mg/m3.
Crystalline Silica
Silica is Silicon Dioxide, which is a naturally occurring mineral that forms the major part of many rocks and soils (granite, shale, sandstone, sand). It’s also used to make concrete, mortar and composite stones. Composite stones are often used to manufacture benchtops for kitchens and bathrooms, as well as other products.
When workers fabricate these products (cut, saw, grind, drill, polish, etc.), very small silica dust particles are generated, and become airborne.
How particle sizes affect compliance efforts
One of the more dangerous traits of respirable crystalline silica is the extremely small particle size, which allows them to flow when airborne, and travel on air turbulence (even indoors), for long periods of time.
According to the National Institute of Environmental Health Services, the size of dust emissions from silica-containing substances varies from 0.01μm (micrometers) to 100μm in diameter. For perspective, the diameter of the average human hair is about 70-100μm. Depending on their weight, dust particles must typically be 200μm or smaller to become airborne and linger, while 50μm and smaller particles are invisible to the naked eye.
Particulate matter of ≤10μm (PM10) is the approximate size threshold for particles to be able to penetrate the body’s natural defences (mucus membranes, cilia, etc.) and reach deep into the lungs, potentially causing serious health issues such as silicosis.
Implementing a strong “Last Line of Defence” at your work site – Work Clothing that does not collect Dust
Regulations require that disposable protective coveralls for handling hazardous particles meet the EN 13982-1 Type 5 standard. However, as the Total Inward Leakage (TILA) allowed under this standard is very high (15% in 8 out of 10 suits tested); the more stringent standard of EN 1073-2 Class 2 is desirable, as this requires the Average TILA to be less than 2% for 6 suits tested.
The Tyvek® barrier fabric from DuPont is a proprietary non-woven material. Tyvek® is formed from High Density Polyethylene (HDPE) ultrafine continuous fibres which are laid down into a tough, light, homogeneous fabric with inherent vapour breathability characteristics on account of its microscopic lattice structure. This inherent ability to evacuate body moisture, whilst still providing excellent particle holdout, provides the ideal balance of comfort and protection against silica, asbestos and other fine particle hazards.