Fit Testing of Respiratory Protection in the US

Geoff Betsinger, CIH3M Company

Vice President, ISRP

European Section General Meeting March 10, 2011

Respiratory Use in the US Workplace

• An estimated 5 million workers are required to wear respirators in 1.3 million workplaces throughout the United States.

• US OSHA requires fit testing tight fitting respirators as part of a respiratory protection program.

• Respiratory protection standard is usually always in the OSHA “Top 10 list” of cited standards for violations every year

Protection Factor • Protection Factor = Co / Ci

• Co = Concentration outside the respirator

• Ci = concentration inside the respirator

Fit Factor• Fit Factor = Co / Ci

• Co = Concentration outside the respirator during a quantitative fit test

• Ci = concentration inside the respirator during a quantitative fit test

Workplace Protection Factor (WPF)

• A measure of protection provided in the workplace, under the conditions of that workplace, by a properly selected, fit tested and functioning respirator while it is correctly used and worn.

Simulated Workplace Protection Factor

• A surrogate measure of the workplace protection provided by a respirator, which is done in a laboratory simulation which has been shown to have a stated correlation to workplace protection factors.

History of Fit Testing Requirements in U.S.• 1963 – Respiratory Protective Devices Manual, AIHA and

ACGIH 1963– Introduced iso-amyl acetate fit test for gas and vapor

cartridges– Stressed the importance of proper fit during training for

respirator use.• 1969 - ANSI Z88.2-1969– Adopted much of what was introduced by AIHA and ACGIH

regarding respirator fit.– Introduced irritant smoke fit testing for high efficiency

particulate respirators

History of Fit Testing Requirements in U.S.• Since 1971, US Occupational Safety and Health Administration (29 Code of Federal

Regulations 1910.134) has mandated that fit testing be part of a Respiratory Protection Program.– 1971 - Adopted wording from ANSI Z88.2– In 1998 OSHA published fit testing procedures and requirements for

respiratory protection program;• Selection • Medical evaluations

• Fit-testing of tight-fitting respirators • Use• Maintenance• Air quality, quantity, and flow for atmosphere-supplying respirators • Training in respiratory hazards • Training in respirator use and maintenance• Evaluating program effectiveness

– Employer provides respirators, training and medical evaluations at no cost to employee

Fit Testing Requirements

• All tight-fitting respirators• Positive pressure respirators

– Fit test facepiece in negative pressure mode• Use filters with facepiece• Use a surrogate

– Either QLFT or QNFT• QNFT minimum requirements– 100 for half facepieces– 500 for full facepieces

• QNFT required for negative pressure full facepiece if claiming APF > 10

Fit Testing Requirements

• Frequency– Prior to initial use– If a different make or size respirator is used – Annually thereafter– Change in employee’s physical condition affecting

fit

Acceptable Fit Test Methods

QLFT QNFT

Half facepiece, neg. pressure Yes Yes

Full facepiece, neg. pressure, used up to 10 x PEL (Fit Factor <100)

Yes Yes

Full facepiece, neg. pressure, used at greater than 10 x PEL (Fit Factor >100)

No Yes

Tight fitting facepieces used with PAPRs, supplied air or SCBA

Yes Yes

Loose fitting respirators (e.g. helmets, hoods) or escape type respirators

Not required

Not required

Fit Test Protocols in appendix A of 29 CFR 1910.134

• Qualitative fit testing– Isoamyl acetate– Saccharin solution aerosol– Irritant fume– Bitrex

• Quantitative fit testing– Generated aerosol– Ambient aerosol (Portacount)– Controlled negative pressure (now includes

REDON protocol)

History of APF• Historically, Assigned Protection Factors in the US were

based on Fit Testing– 1965 Bureau of Mines • Half mask (10 X TLV) and full face respirators

(100 X TLV)• Based on quantitative fit testing

– 1975 NIOSH and OSHA published Respirator Decision Logic with protection factors based on quantitative fit test studies performed by Hyatt (1975).12

– ANSI Z88.2-1980 contained the first ANSI Z88.2 Respiratory Protection Factor Table.• Based mainly on fit test studies by Hyatt and

gave higher protection factors to Quantitatively fit tested respirators

History of APF• 1987 NIOSH revised RDL – Lowered some APF based on WPF results

• e.g. PAPR with loose fitting reduced to 25

• 1992 ANSI revised Z88.2– Changes based on WPF studies and lack of correlation

between Fit Factors and Workplace performance. 1 – Where WPF studies did not exist laboratory studies

and design analogies were used.– Abandoned higher APF based on Quantitative Fit

Testing

History of OSHA APF Development

• 1998 OSHA published Final Respiratory Protection Standard– Did not include APF or Maximum Use

Concentration (MUC)• 2004 NIOSH published Respiratory

Selection Logic with 1987 APF tables.– NIOSH stated that when OSHA publishes

APF then NIOSH will consider revisions• 2006 OSHA published APF table• Today, NIOSH has not revised RSL

Health Care and TB Respiratory Protection

• For several years this past decade Health Care in the US was exempt from OSHA enforcement of fit testing for respirators worn to reduce TB exposure.– Wicker amendment was added as a rider to the

appropriations bill which prevented money to be spent on enforcement of fit testing for TB exposure.

– Strong push to enforce fit testing from Health and Safety groups.

– Amendment was not added in 2008 and enforcement resumed.

Arguments Against Fit Testing• Biggest complaint regarding fit testing is that it is time

consuming and costly.– Same argument for many health and safety policies

• Initiatives have been taken from academia and industry.– NIOSH No Fit Test Respirator Workshop 2008

• Explored technologies that could improve or abbreviate fit testing and also technologies that could make fit testing not necessary

• Hosted by the University of Minnesota and final report can be downloaded; http://www.sph.umn.edu/ce/presentations/nofit.asp

– Nelson, T., Janssen, L., Development of an Abbreviated Qualitative Fit Test Using Bitter Aerosol

– TSI Q Fit

Can Fit Factors’ Predict Workplace Performance?

• Because Work Place Protection Factor studies showed that Work Place Protection Factors and Fit Factors are not equal, studies have been performed in the US to try to find a correlation between FF and WPF. Most have shown no correlation or, at best, a weak correlation.(2-7)

– Best correlation expected to be where respirators are poor fitting but since it is unethical to expose workers that fail a respiratory fit test to concentrations exceeding OELs it is difficult to perform a study.

– Additionally, aerosol size distribution in the workplace is much different than in fit test protocols

Does Fit Testing Increase Work Place Protection?

• Absolutely!• Studies have demonstrated that when fit testing is performed work place

protection provided to the respirator wearer is increased.– Centers for Disease Control. Morbidity and mortality Weekly Report

1998/47(48):1045-1049. -“The findings in this report indicate that fit testing N95 respirators is essential in programs employing these respirators and can eliminate poorly fitting respirators, ensuring at least the expected level of protection.”

– Zhuang et. al. – “…study supported the relevance of fit-testing as part of a respirator program.”6

– Coffey et. al. – “The study also supports the value of some fit-test methods as a screening tool to identify workers with poorly fitting respirators.”4

• In 1999, Colton compared WPF studies performed in Europe that did not require fit testing to WPF studies performed in the US that did require fit testing. – When WPF included fit testing the 5th percentile WPF was 25-30. – When fit testing was not performed the 5th percentile WPF was 2.1

WPF Studies and Fit TestingColton 3M JHH 199911

Does Fit Testing Increase Work Place Protection?

• More recently, Lee et. al.8 and Reponen et. al.9 demonstrated increased protection factors with ‘good fit versus poor fit’.

“Protection Factors” of subject in NaCl chamber (includes both filter penetration and face seal leakage)

Summary and Conclusions

• Since 1971, OSHA has required and enforced fit testing of tight fitting respiratory protection in the US.

• When fit testing is performed as part of a complete Respiratory Protection Program the wearer is better protected than when fit testing is not performed.

Bibliography1. Dixon, S.W., and T.J. Nelson: Workplace protection factors for negative pressure half-mask facepiece respirators.

J. Int. Soc. Resp. Prot. 2(4):347–361 (1984).2. Gaboury, A., D.H. Burd and R.S. Friar: Workplace Protection Factor Evaluation of Respiratory Protective

Equipment in a primary Aluminum Smelter. Appl. Occup. Environ. Hyg. 8(1):19-25 (1993).3. Myers, W.R., M.J. Peach, K.Cutright and W. Iskander: Workplace Protection Factor Measurements on Powered-

Air Purifying Respirators at a Secondary Lead Smelter: Results and Discussion. Am. Ind. Hyg. Assoc. J. 45(10):681-688 (1984).

4. Coffey, Christopher C., Campbell, Donald L., Myers, Warren R. and Zhuang, Ziqing: Comparison of Sic Respirator fit-Test Methods with an Actual Measurement of Exposure in a Simulated health Care Environment: Part II – Method Comparison Testing. Am. Ind. Hyg. Journ., 59:12, 862-870 (1998)

5. WORKPLACE PROTECTION FACTOR STUDY ON A FULL FACEPIECE RESPIRATOR Colton, C.E., Johnston, A.R., Mullins, H.E. and Rhoe, C.R., 3M Occupational Health and Environmental Safety Division, 3M Center Bldg. 260-3B-02, St. Paul, MN 55144. Prepared for presentation on May 25, 1989 at the American Industrial Hygiene Conference, St. Louis, Missouri

6. Zhuang, Z., C.C. Coffey, P.A. Jensen, D.L. Campbell, R.B. Lawrence, and W.R. Myers: Correlation between quantitative fit factors and workplace protection factors measured in actual workplace environments at a steel foundry. Am. Ind. Hyg. Assoc. J. 64:730–738 (2003).

7. Han, D.: Correlations between workplace protection factors and fit factors for filtering facepieces in the welding workplace. Ind. Hlth. 40:328–334 (2002).

8. Grinshpun, S.A., H. Haruka, R.M. Eninger, T. Reponen, R.T. McKay, S. Lee: Performance of an N95 Filtering Facepiece Particulate Respirator and a Surgical Mask During Human Breathing: Two Pathways for Particle Penetration. Journal of Occ. & Env. Hyg. 6:593-603 (2009).

9. Lee, S.A., S.A. Grinshpun, T Reponen: Respiratory Performance Offered by N95 Respirators and Surgical Masks: Human Subject Evaluation with NaCl Aerosol Representing Bacterial and Viral Particle Size Range: Ann. Occup. Hyg., Vol. 52, No. 3, pp. 177-185, (2008).

10. Reponen, T., S. Lee, S.A. Grinshpun, E. Johnson, R. McKay: Respiratory Performance Offered by N95 Respirators and Surgical Masks: Human Subject Evaluation with NaCl Aerosol Representing Bacterial and Viral Particle Size Range: Ann. Occup. Environ. Hyg. pp. 1-8, (2010).

11. Colton, C., Filtering facepieces: Study supports need for fit testing. 3M Job Health Highlights Volume 17, Number 2, 1999.

12. Hyatt, E. C. (1975), Respirator Protection Factors, Los Alamos Scientific Laboratory Report: LA-6084-MS.