Workplace protection factors of HSE approved negative pressure full-facepiece dust respirators during asbestos stripping: preliminary findings

Our plain-English summary of Workplace protection factors of HSE approved negative pressure full-facepiece dust respirators during asbestos stripping: preliminary findings, by S.N. Tannahill, R.J. Willey, M.H. Jackson (The Annals of Occupational Hygiene, 1990).

The study

• Authors: S.N. Tannahill, R.J. Willey, M.H. Jackson
• Journal: The Annals of Occupational Hygiene
• Published: 1990;34(6):547-52
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

This research was designed to evaluate the workplace protection factors of Health and Safety Executive Approved, negative pressure full-facepiece dust respirators, during asbestos stripping. A standard method to measure the concentration of asbestos fibres inside full-facepiece respirators has been developed and the workplace protection factors have been calculated from the data obtained. The respirators in this study are approved for use by the Health and Safety Executive in concentrations of up 900 times the Control Limit [HEALTH AND SAFETY EXECUTIVE, Guidance Note EH 41 (1985)] but the preliminary test results suggest that this level is inappropriately high for this type of respiratory protective equipment.

In plain English

This preliminary field study measured how well three Health and Safety Executive (HSE) Approved negative pressure full-facepiece dust respirators, labelled A, B and C, protected workers during asbestos stripping. The work ranged from removing ceiling tiles containing asbestos to removing asbestos lagging. The authors sampled asbestos fibres outside each respirator and inside the facepiece at the same time, taking six pairs of samples per worker. They divided the outside level by the inside level to give a 'workplace protection factor'. For respirator A these ranged from 11 to 2090 (geometric mean 200), and 16% were above 900. For respirator B they ranged from 26 to 3493 (geometric mean 577), and 40% exceeded 900. Limited data for respirator C gave 17 to 500 (geometric mean 120), and none exceeded 900. Protection factors rose as outside fibre concentrations rose, for reasons the authors called unclear. The authors concluded that a nominal protection factor of 900 is inappropriately high for these respirators and suggested 100. They said no substantive conclusions could yet be drawn about other recorded factors.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Field study (preliminary findings) measuring workplace protection factors: fibre concentration outside the respirator divided by fibre concentration inside it, from samples taken at the same time
• Who was studied: Asbestos workers wearing three HSE Approved negative pressure full-facepiece dust respirators (A, B, C). Six paired in-mask and lapel samples were taken from each worker. The number of workers is not stated.
• Exposure: Asbestos fibres during asbestos stripping operations, from removing ceiling tiles containing asbestos to removing asbestos lagging. Fibre type is not specified.
• Main results:
  • For all three respirators, protection measured in the workplace differed considerably from the protection implied by HSE literature and manufacturers' data
  • Respirator A: workplace protection factors ranged from 11 to 2090, with a geometric mean of 200. Only 16% were above 900.
  • Respirator B: workplace protection factors ranged from 26 to 3493, with a geometric mean of 577. 40% exceeded 900.
  • Respirator C (limited data): workplace protection factors ranged from 17 to 500, with a geometric mean of 120. None exceeded 900.
  • Workplace protection factors increased as the outside (challenge) fibre concentration increased. The reason was unclear to the authors.
• The authors' conclusion: The authors concluded that a nominal protection factor of 900 is inappropriately high for the negative pressure full-facepiece respirators they evaluated. Based on the geometric mean, they suggested 100 as more appropriate.
• Limitations the authors state:
  • No substantive conclusions could yet be drawn about how the other recorded factors (from the questionnaire) affected protection
  • Only limited data were collected for respirator C

Topics

Medical terms in this study, explained in our Lexicon: Assigned Protection Factor, Respirator.

Related studies

• Physiological and subjective responses to working in disposable protective coveralls and respirators commonly used by the asbestos abatement industry — M.K. White, T.K. Hodous, et al. (1989)
• Evaluation of respirator filters for asbestos fibers — Y.S. Cheng, T.D. Holmes, et al. (2006)
• Health effects of respirator use at low airborne concentrations — J.H. Lange (2000)
• Performance of power assisted respirators during simulated asbestos removal — M.P. Clayton, A.E. Bailey, et al. (2002)
• Pollution of the environment and building interiors during asbestos removal as a result of lack of negative pressure in the working areas — A. Obmiński (2024)
• Personal exposure to asbestos dust during clearance certification — S. Bailey, A. Conchie, et al. (1988)

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