OSHA's Assigned Protection Factors for Respiratory Protection

OSHA's APF revision offers a single resource for employer compliance, but the wrinkle is that the new OSHA APFs differ from those presented by NIOSH and ANSI.

The safety world was slightly surprised on Aug. 24, 2006, when OSHA released its latest revision to the existing Respiratory Protection Standard, 29 CFR 1910.134. This revision, effective date Nov. 22, 2006, includes definitions and requirements for assigned protection factors (APFs).

    On Jan. 8, 1998, OSHA published the final revised Respiratory Protection Standard. At that time, OSHA omitted the section related to APFs, pending further rulemaking. The agency stated that as an alternative to OSHA's APFs, employers must take into account the best available information for respirator selection. To comply with OSHA prior to the APF standard release, most employers referred to the 1987/2004 NIOSH RSL (respirator selection logic) or the ANSI Z88.2 respiratory protection standard that lists recommended respirator APFs. This scenario resulted in two resources for APFs that assigned different respirator protection factors. Adding to the confusion was the fact that the ANSI Z88.2 standard had not been accredited by ANSI since 2002, as the standard was never reaffirmed.

Understanding Various APF References

    The release of this new OSHA revision offers the advantage of a single resource for employer compliance with OSHA workplace regulations. The wrinkle in this single resource is that the new OSHA APFs are also somewhat different than both NIOSH and ANSI APFs. As defined by NIOSH, an assigned protection factor (APF) is the minimum anticipated protection provided by a properly functioning respirator or class of respirators to a given percentage of properly fitted and trained users.

    As a reference point, the accompanying chart will help to clarify differences in APFs from three different organizations: NIOSH, ANSI and OSHA. NIOSH APF numbers are taken from its updated RSL, released in October 2004. ANSI APF numbers are taken from their Z88.2 standard released in 1992. OSHA's numbers are the new APFs released in August 2006. Please refer to these publications in their entirety for complete information regarding the APFs listed below.

APF Comparison

*A PAPR and constant-flow SAR with hood or helmet has an APF of 25 unless the employer receives evidence provided by the respirator manufacturer that the device was tested and demonstrates a level of protection of greater than 1,000. If so, the device can receive an APF of 1,000. OSHA states that this higher APF level can best be demonstrated by performing a workplace performance study (WPS), a simulated workplace performance study (SWPS) or equivalent testing.

Meeting the Challenges

    The most significant differences between the NIOSH and OSHA APFs are in the area of powered air-purifying respirators (PAPRs) and supplied-air respirators (SARs). These differences greatly impact respirator manufacturers as well as employers who purchase these devices. In the case of PAPRs and SARs with helmet or hood, manufacturers had a very short time frame in which to complete simulated workplace studies to receive a higher APF of 1,000. Employers, on the other hand, need this information in order to continue using their respirators in hazardous locations and maintain compliance. Some employers were forced to switch to a different respirator, which always presents challenges. The new OSHA assigned protection factor for constant-flow supplied-air respirators with full facepieces also is different than that of NIOSH. OSHA assigned an APF of 1,000 to this respirator configuration, while NIOSH gave it an APF of only 50.

    This new OSHA standard on APFs supersedes most of the APFs that have been noted in substance-specific standards previously released by OSHA, making it much easier for employers and employees to follow safe workplace respiratory practices.
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John Hierbaum is product line manager, air-purifying respirators for MSA Co.

Contents copyright 2008 Douglas Publications LLC. All rights reserved.

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