Combustible Dust
Finely powdered dust from combustible materials such as wood, metal, or grain can be fuel for powerful explosions.
Finely powdered dust from combustible materials can be fuel for powerful explosions.
Dust clouds can develop as result of handling dusty materials or when solid materials are reduced to smaller particles from processes such as grinding, drilling, or crushing.
Airborne combustible dust at an explosive concentration would obscure vision at five feet (1.52 meters) or less. A direct reading instrument may be used to measure actual dust concentrations.
Toxic Gases
Toxic gases may be present in a confined space for many reasons, including:
- The processes being performed within the confined space (for example, in producing polyvinyl chloride, hydrogen chloride is used as well as vinyl chloride monomer, which is carcinogenic).
Toxic gases and vapors from adjacent areas can migrate to and collect in the confined space.
- Toxic gases and vapors from adjacent areas can migrate to and collect in the confined space.
- Vapors may be released from the sludges on the bottom or scales on walls of emptied confined spaces, such as storage tanks, that previously contained flammable or toxic chemicals. Vapor release may be accelerated by wall scraping and sludge removal from confined spaces.
- Confined spaces prevent toxic substances from escaping, diluting, or readily dissipating. Instead, substances can become trapped, and a buildup occurs, whereby the concentrations of toxic substances reach dangerous levels.
- Work activities (welding, painting, etc.) being performed in the confined space.
Knowledge Check Choose the best answer for the question.
2-6. Removing sludge from confined spaces may _____.
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