Using to Determine Inhaled Contaminant Volumes and Blower Effectiveness in Several Types of Respirators | Zendy

Arthur T. Johnson | Zendy; Frank C. Koh | Zendy; William H. Scott | Zendy; Timothy E. Rehak | Zendy

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Using to Determine Inhaled Contaminant Volumes and Blower Effectiveness in Several Types of Respirators

Author(s) -

Arthur T. Johnson,

Frank C. Koh,

William H. Scott,

Timothy E. Rehak

Publication year - 2011

Publication title -

journal of environmental and public health

Language(s) - English

Resource type - Journals

SCImago Journal Rank - 0.869

H-Index - 35

eISSN - 1687-9813

pISSN - 1687-9805

DOI - 10.1155/2011/402148

Subject(s) - respirator , exhalation , environmental science , inhalation , breathing , ventilation (architecture) , airflow , materials science , anesthesia , medicine , engineering , mechanical engineering , composite material

This experiment was conducted to determine how much contaminant could be expected to be inhaled when overbreathing several different types of respirators. These included several tight-fitting and loose-fitting powered air-purifying respirators (PAPRs) and one air-purifying respirator (APR). CO 2 was used as a tracer gas in the ambient air, and several loose-and tight-fitting respirators were tested on the head form of a breathing machine. CO 2 concentration in the exhaled breath was monitored as well as CO 2 concentration in the ambient air. This concentration ratio was able to give a measurement of protection factor, not for the respirator necessarily, but for the wearer. Flow rates in the filter/blower inlet and breathing machine outlet were also monitored, so blower effectiveness (defined as the blower contribution to inhaled air) could also be determined. Wearer protection factors were found to range from 1.1 for the Racal AirMate loose-fitting PAPR to infinity for the 3M Hood, 3M Breath-Easy PAPR, and SE 400 breath-responsive PAPR. Inhaled contaminant volumes depended on tidal volume but ranged from 2.02 L to 0 L for the same respirators, respectively. Blower effectiveness was about 1.0 for tight-fitting APRs, 0.18 for the Racal, and greater than 1.0 for two of the loose-fitting PAPRs. With blower effectiveness greater than 1.0, some blower flow during the exhalation phase contributes to the subsequent inhalation. Results from this experiment point to different ways to measure respirator efficacy.

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