Monthly Round Up of Important Ideas and Standards in
Industrial Hygiene and Safety
IN THIS ISSUE:Testing For Confined Space Entry
Limited accessibility and poor ventilation make entering confined spaces a serious hazard. The type of work conducted inside confined spaces, such as welding, painting, scraping, sanding, and using solvents for degreasing may produce toxic atmospheres. In addition, contaminants produced by processes that take place near the confined space may enter and accumulate within the space. Some confined spaces common to the workplace include underground vaults and pipes, storage tanks, reaction vessels, boilers, sewers, and tunnels.
“Confined space entry is a serious matter. More often than not, fatalities related to entering a confined space come in pairs,” explains Gary R. Ticker, CIH, CSP, of OccuSafe, Inc. “The first fatality is the original entrant, and the second fatality is the coworker who tries unsuccessfully to rescue the first person.”
These deaths and injuries may be due to the potential dangers of the atmosphere within the confined space. Oxygen-enriched atmospheres, may cause combustible materials to burn violently when ignited. Oxygen-depleted atmospheres may lead to oxygen deprivation. Explosive or flammable atmospheres may result from flammable gases or vapors mixing with dust in the air. Toxic or explosive atmospheres can be produced from the material normally stored in the confined space or the work conducted during entry. When a hazardous material is stored within a confined space, the dangers are magnified. The chemical can be absorbed by the walls and give off toxic vapors when removed or when residual materials are cleaned. The material can also produce toxic vapors that remain in the atmosphere due to poor ventilation.
“Detailed and effective preparation, training, and practice are the only way to make entering confined spaces safe,” explains Ticker.
To ensure confined space entry is safe for workers, these points should be addressed:
- Prepare to enter a confined space. Determine which chemicals may be present and select a specific method of detection. Learn to use the appropriate personal protective equipment and clothing, and provide respiratory protection.
- Test the atmosphere regularly. Ongoing tests for oxygen deficiency and flammability must take place within any confined space because factors that lead to a volatile atmosphere may vary. Explosive meters that test these factors as well as specific chemicals are widely available, and may be handheld or worn on the belt or collar. These meters may be set to alarm at levels lower than 19.5% or greater than 23.5% O2 and 10% of the explosive limits.
- Know the signs of oxygen deprivation. The normal atmosphere is composed of approximately 21% oxygen and 79% nitrogen. An atmosphere containing less than 19.5% oxygen is considered oxygen-deficient. As oxygen levels fall symptoms may worsen from rapid breathing and accelerated heartbeat to poor muscular coordination, fatigue, nausea, vomiting, inability to perform, unconsciousness and death.
- Be prepared to stop. If the contaminants within a confined space cannot be determined or monitored safely, it may be necessary to stop entry until more information is available.
OccuSafe Industrial Hygiene & Safety, Inc. provides skills and expertise to recognize, evaluate and control hazards and injuries in the areas of industrial hygiene, occupational safety and health. OccuSafe services companies of all sizes in a range of industries.
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