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667 HAZWOPER for General Site Workers VIII
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Mechanical Hazards

If activation of electrical or mechanical equipment would cause injury, each piece of equipment should be manually isolated using lockout/tagout procedures to prevent inadvertent activation before workers enter or while they work in a confined space.

Each piece of equipment should be manually isolated using lockout/tagout procedures.

The interplay of hazards associated with a confined space, such as the potential of flammable vapors or gases being present, and the build-up of static charge due to mechanical cleaning, such as abrasive blasting, all influence the precautions which must be taken.

  • To prevent vapor leaks, flashbacks, and other hazards, workers should completely isolate the space.
  • To completely isolate a confined space, the closing of valves is not sufficient.
  • All pipes must be physically disconnected or isolation blanks bolted in place.
  • The pipes blanked or disconnected should be inspected and tested for leakage to check the effectiveness of the procedure.
  • Other areas of concern are steam valves, pressure lines, and chemical transfer pipes.

A less apparent hazard is the space referred to as a void, such as double walled maritime vessels, which must be given special consideration in blanking off and inerting. Other special precautions must be taken in cases where flammable liquids or vapors may re-contaminate the confined space.

Knowledge Check Choose the best answer for the question.

3-2. If activation of electrical or mechanical equipment would cause injury, each piece of equipment should be manually isolated using _____.