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Mechanic asphyxiated within steam service passageway in Maryland, July 25, 1987.

Morgantown, WV: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, FACE 87-64, 1988 Nov; :1-5
The case of a 35 year old male mechanic who died by asphyxiation after he attempted to regulate the pressure in an 8 inch steam line was examined. The worker was employed by a small utility company that generated and distributed steam. The company did not have a formal written safety program or written confined space entry procedures. Workers were instructed to work safely. The victim apparently was to reduce the pressure in an 8 inch steam line from about 150 to 30 pounds per square inch (psi). The steam line was located in a concrete vault measuring 10 feet deep by 9 feet wide and 15 feet long. The worker removed several sections of grating from the top of the vault, lowered a ladder and entered the vault. He apparently opened a hand operated valve on the 8 inch steam line. As the steam, at 366 degrees-F, surged through the line, the 4 inch strainer, located about 1 foot downstream of the 8 inch valve, ruptured. The worker proceeded down the passageway to escape the steam until he encountered a louvered door which could only be opened from the other side. The investigation showed that faulty engineering design, due to erroneous expansion and flexibility calculations, was a contributing factor in the rupture of the strainer. It was also determined that the employer should develop written safety procedures including safe entry to a confined space. Had the steam trap been in good working order, the pressure build up that eventually ruptured the valve would not have been possible.
FACE-87-64; NIOSH-Author; Accident-analysis; Region-3; Work-practices; Safety-research; Confined-spaces; Maintenance-workers; Mechanics
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Field Studies; Fatality Assessment and Control Evaluation
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National Institute for Occupational Safety and Health
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division