Quantitative respirator fit tests of tucson fire fighters and measurement of negative pressure excursions during exertion

Jefferey L Burgess, Clifton D. Crutchfield

Research output: Contribution to journalArticlepeer-review


Pressure-demand self-contained breathing apparatus (SCBA) respirators are designed to maintain a positive pressure inside the facepiece at all times and therefore provide a high degree of respiratory protection. However, under conditions of high exertion fire fighters may overbreathe their respirators and transiently develop negative facepiece pressures. For pressure-demand respirators, facepiece leakage requires both negative pressure excursions and poor facepiece fit. Tucson Fire Department (TFD) fire fighters were studied to determine if this overbreathing poses a potential health threat, and if quantitative respirator fit testing could improve fire fighter safety. TFD fire fighters wear SCOTT 4.5 unit pressure-demand SCBA. Controlled negative pressure (CNP) fit testing demonstrated low facepiece leakage (< 10 cc/min at —0.51 inches of water) in 78 percent of 102 TFD fire fighters and in 82 percent of 51 fire fighters fit for a large facepiece using a qualitative technique. The maximum leakage in a fire fighter fit for a large facepiece was 1530 cc/min. Treadmill testing of 10 fire fighters revealed that they all had facepiece negative pressure excursions (mean negative pressure 0.071 ± 0.024 inches of water; mean duration of negative pressure excursions 3.41 ± 2.04%). Application of the maximum measured negative pressure excursion during treadmill testing to the worst facepiece leakage rate measured during CNP fit testing resulted in a calculated protection factor of 4000. All other fire fighters fit for a large facepiece had a calculated protection factor of over 10,000. While not essential, CNP respirator fit testing can provide important information for fire fighters using pressure-demand SCBA. Burgess, J.L.; Crutchfield, C.D.: Quantitative Respirator Fit Tests of Tucson Fire Fighters and Measurement of Negative Pressure Excursions During Exertion.

Original languageEnglish (US)
Pages (from-to)26-29
Number of pages4
JournalApplied Occupational and Environmental Hygiene
Issue number1
StatePublished - Jan 1995

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health


Dive into the research topics of 'Quantitative respirator fit tests of tucson fire fighters and measurement of negative pressure excursions during exertion'. Together they form a unique fingerprint.

Cite this