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An evaluation of catalytic emission controls to prevent carbon monoxide poisonings from houseboat generator exhaust.

Earnest GS; Hall RM; Garcia A; McCleery R
Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, EPHB 171-38a, 2006 Oct; :1-33
Working under an interagency agreement with the United States Coast Guard, researchers from the National Institute for Occupational Safety and Health (NIOSH) evaluated carbon monoxide (CO) emissions, exposures, and controls from gasoline-powered generators on houseboats. This evaluation was part of a series of studies conducted by NIOSH investigators during the past several years to identify and recommend effective engineering controls to reduce the CO hazard and prevent CO poisonings on houseboats and other recreational marine vessels. The performance of two (14-KW and 20-KW) Westerbeke, Safe-CO(TM) generators were tested after being used on rental houseboats for the boating season. Prior to performing the testing, a damaged oxygen sensor was replaced on the 14-KW generators and both old and new catalysts were evaluated. Each of the evaluated generators had between 1,000 and 3,000 hours of use and were equipped with catalytic converters and electronic fuel injection systems. A 12.5-KW Westerbeke generator was also tested that had been retrofitted with a Zenith electronic fuel injection (EFI) retrofit kit. Each of the engineering control devices were designed to improve generator performance and reduce CO emissions. The houseboat containing the 14-KW generator had been modified so that testing could be accomplished using either a side exhaust or stack exhaust configuration. The performance of the two Westerbeke Safe-CO(TM) generators used for a season of boating was impressive; average CO concentrations at various locations on the boat was generally below 5 parts per million (ppm). Peak CO concentrations were all well below 20 ppm. Both older and brand new catalysts were evaluated. The new catalysts seemed to perform slightly better than the ones used for a season. CO concentrations were slightly lower under the no load conditions as compared to loaded. CO concentrations measured directly in the exhaust stack were approximately 200 ppm for the fully warmed generator. That compares to CO concentrations NIOSH researchers measured which exceeded 10,000 ppm on older Westerbeke generators without the Safe-CO(TM) control systems. When comparing side versus stack exhaust, the lower stern deck in the side exhaust configuration resulted in slightly higher concentrations.. Use of the Safe-CO(TM) generator resulted in low ambient CO concentrations for both side and stack exhaust configurations. Use of the vertical exhaust stack with the Safe-CO generator is recommended to ensure redundancy in the system in the event that the catalyst or oxygen sensor performance degrades with time. Development and commercialization of the Westerbeke Safe- CO(TM) system is a major advancement in control systems to ensure a safe environment around houseboats and other marine vessels. The performance of the Westerbeke generator retrofitted with a Zenith EFI system was also good. CO concentrations measured on the boat were also typically below 5 ppm; however, the CO concentration measured directly in the exhaust was higher than the Safe-CO(TM) generators. The Zenith electronic fuel injection (EFI) system did not perform as well when the generator was under load, and CO concentrations measured directly in the exhaust were substantially higher.
Control-technology; Region-9; Poison-control; Poison-gases; Engineering-controls; Emission-sources; Marine-workers; Fuels; Exhaust-gases; Exhaust-ventilation
National Institute for Occupational Safety and Health, Division of Applied Research and Technology, MS - R5, 4676 Columbia Parkway, Cincinnati, OH 45226
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Field Studies; Control Technology
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NIOSH Division
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Research Tools and Approaches: Control Technology and Personal Protective Equipment
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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