Guide to Respirator Selection

New standards have been established concerning tolerable concentrations of contaminants in the air. Respirators are necessary to regulate employees' exposure to these contaminants. Check out PE Facts to learn more about new respirator standards and how to select one that's right for you!

On Aug. 24, 2006, OSHA released its final regulation for Assigned Protection Factors (APFs) and Maximum Use Concentrations (MUCs). On Nov. 22, 2006, these new APFs and MUCs went into effect completing the revision of the reserve sections of the standard as published in 1998. The new APFs override the existing ones along with any reference to the old APF tables found in the existing substance-specific standards (except for the 1, 3 Butadiene standard).The substance-specific standards identify several requirements for regulating employee exposure to toxic substances.

The new APFs should be used by employers to determine the exact type of respirator they need based on the level of airborne contaminants workers are exposed to. Selecting the correct respirator should be based on the exposure level of the workplace and the maximum concentration of the contaminant that a certain type of respirator can handle.

OSHA declared that the revision of the APFs makes it easier for employers to comply with standards because it removes many of the requirements found across its substance-specific standards. The new APFs enhance consolidation and standardization of these requirements and conform them to each other and to general APF and MUC requirements found in 29 CFR 1910.134(d)(3)(i)(A) and (B).

Table 1 – Assigned Protection Factors ⁽⁵⁾

Type of respirator ^(1,2)	Quarter Mask	Half Mask	Full Facepiece	Helmet/ hood	Loose-fitting facepiece
Air-Purifying Respirator	5	10 ⁽³⁾	50	-	-
Powered Air-Purifying Respirator (PAPR)	-	50	1,000	25 ⁽⁴⁾/ 1000	25
Supplied-Air Respirator (SAR) or Airline Respirator Demand mode	-	10	50	-	-
Supplied-Air Respirator (SAR) or Airline Respirator Continuous flow mode	-	50	1,000	25 ⁽⁴⁾/ 1000	25
Supplied-Air Respirator (SAR) or Airline Respirator Pressure-demand or positive-pressure mode	-	50	1,000	-	-
Self-Contained Breathing Apparatus (SCBA) Demand Mode	-	10	50	50	-
Self-Contained Breathing Apparatus (SCBA) Pressure-demand or other positive-pressure mode	-	-	10,000	10,000	-

Notes:
¹Employers may select respirators assigned for use in higher workplace concentrations of a hazardous substance for use at lower concentrations of that substance, or when required respirator use is independent of concentration.
²The assigned protection factors in Table 1 are only effective when the employer implements a continuing, effective respirator program as required by this section (29 CFR 1910.134), including training, fit testing, maintenance and use requirements.
³This APF category includes filtering facepieces, and half masks with elastomeric facepieces.
⁴ The employer must have evidence provided by the respirator manufacturer that testing of these respirators demonstrates performance at a level of protection of 1,000 or greater to receive an APF of 1,000. This level of performance can best be demonstrated by performing a WPF or SWPF study or equivalent testing. Absent such testing, all other PAPRs and SARs with helmets/hoods are to be treated as loose-fitting facepiece respirators and receive an APF of 25.
⁵ These APFs do not apply to respirators used solely for escape. For escape respirators used in association with specific substances covered by 29 CFR 1910 subpart Z, employers must refer to the appropriate substance-specific standards in that subpart. Escape respirators for other IDLH atmospheres are specified by 29 CFR 1910.134 (d)(2)(ii).

Highlights of changes made to each substance-specific standard including new APF and special selection requirements for General Industry (1910.1000):

Chemical	Old Selection Requirements	New Selection Requirements
Asbestos	Follow Table 1. 1910.1001(g)(3) Cannot use disposable respirators	Follow Table 1 found in respiratory protection program 1910.1001(g)(3)(i) Cannot use disposable respirators. 1910.1001(g)(3)(i)
Coal Tar Pitch	None noted.	None noted.
4-Nitrobiphenyl and 13 Carcinogens	None noted for each from 1910.1003-1910.1016.	None noted for each from 1910.1003-1910.1016.
Vinyl Chloride	Follow Table 1 1910.1017(g)(3)(i) When/Where using air-purifying respirators must replace cartridges prior to the expiration of their service life or the end of the shift, whichever comes first. 1910.1017(g)(3)(ii)(A) and 1910.1017(g)(3)(i)(B)	Follow Table 1 found in respiratory protection program 1910.1017(g)(3)(i)(A) Provide an organic vapor cartridge that has a service life of a least one hour when using a chemical cartridge respirator at concentration up to 10ppm 1910.1017(g)(3)(i)(B) Select a canister that has a service life of at least four hours when using a powered air-purifying respirator having a hood, helmet, or full or half facepiece, or a gas mask with a front or back mounted canister, at a concentration up to 25 ppm 1910.1017(g)(3)(i)(C)
Inorganic Arsenic	Follow Table I for arsenic compounds with significant vapor pressure 1910.1018(h)(3) Follow Table II for arsenic compounds without significant vapor pressure 1910.1018(h)(3)	Follow Table 1 found in respiratory protection program 1910.1018(h)(3)(i)(A) Cannot use half-mask respirators for protection against arsenic trichloride due to high absorbtion rate through skin. 1910.1018(h)(3)(i)(B) Full facepiece respirators use at or below concentrations of 500 mg/m3 and half-mask respirators use at or below 100 ug/m3 1910.1018(h)(3)(i)(D)(2)
Lead	Follow Table II. 1910.1025(f)(2)(ii)	Follow Table 1 found in respiratory protection program 1910.134(d)(3)(i)(A). Must use full face respirators only for protection against lead aerosols that cause eye or skin irritation at the use concentrations. 1910.1025(f)(3)(i)(B)
Cadmium	Follow Table 2. 1910.1027(g)(3)(i)	Follow Table 1 found in respiratory protection program 1910.1027(g)(3)(i)(A) Must use full-face respirators only when employee experiences eye irritation. 1910.1027(g)(3)(i)(B)
Benzene	Follow Table 1 1910.1028(g)(3)(i)	Follow Table 1 found in respiratory protection program 1910.1028(g)(3)(i) Use OV cartridge with full facepiece respirator only 1910.1028(g)(3)(i)(C) Ensure that cartridges have minimum service life of 4 hours when tested at 150 ppm benzene at a flow rate of 64 liters per minute, a temperature of 25°C and relative humidity of 85%. For cartridges used on PAPRs, the flow rates for testing must be 115 LPM for tight fitting and 170 LPM for loose fitting. 1910.1028(g)(3)(i)(D)
Coke Ovens	Follow Table I 1910.1029(g)(3)	Follow Table 1 found in respiratory protection program 1910.1029(g)(3) Employers may use a disposable respirator only when it functions as a filter respirator for coke oven emissions particulates. 1910.1029(g)(3)
Cotton Dust	1. Follow Table I 1910.1043(f)(3)(i)	Follow Table 1 found in respiratory protection program 1910.1043(f)(3)(i)(A) Employers must not select or use disposable respirators at concentrations greater than 5 X PEL 1910.1043(f)(3)(i)(A) Employers must use HEPA filters for powered and non powered air-purifying respirators for concentrations greater than 10 X PEL 1910.1043(f)(3)(i)(B)
1,2-dibromo-3-chloropropane	Follow Table 1 1910.1044(h)(3)	Follow Table 1 found in respiratory protection program 1910.1044(h)(3)(i) Must use supplied air only for entry or escape 1910.100(h)(3)(ii)
Acrylonitrile	Follow Table I 1910.1045 If air purifying respirators are used the canister or cartridge must be replaced prior to the expiration of its service life or at the completion of each shift, whichever occurs first 1910.1045(2)(ii)(A) A label must be attached to the cartridge or canister to indicate the date and time at which it is first installed on the respirator 1910.1045(2)(ii)(B)	Follow Table 1 found in respiratory protection program 1910.1045(h)(3)(i)
Ethylene Oxide	Follow Table 1 1910.1047(g)(3)	Follow Table 1 found in respiratory protection program 1910.1047(g)(3)(i) Employers cannot use half masks of any type due to eye irritation or injury 1910.1047(g)(3)(i)
Formaldehyde	Follow Table 1 1910.1048(g)(3)(i) If air-purifying respirators are used, the cartridge must be replaced after 3 hours of use or at end of work shift, whichever comes first, unless cartridge has approved ESLI. 1910.1048(g)(2)(ii)(A) If air-purifying respirators are used with canisters must be replaced after 4 hours of use up to atmospheres of 7.5 ppm, unless canister has approved ESLI	Follow Table 1 found in respiratory protection program 1910.1048(g)(3)(i)(A) If air-purifying respirators are used the cartridge must be replaced as specified by paragraphs 1910.134(d)(3)(iii)(B)(1), which state it must have a NIOSH approved ESLI or 1910.134(d)(3)(iii)(B)(2), which states the use of change-out schedule based on objective data. 1910.1048(g)(2)(ii) Half-facepiece respirators can only be used if worn with gas-proof goggles. 1910.1048(g)(3)(ii)
Methylenedianiline (MDA)	Follow Table 1 1910.1050(h)(3)(i)	Follow Table 1 found in respiratory protection program 1910.1050(h)(3)(i)(A) HEPA filters are used unless MDA is in liquid form or used as part of a process requiring heat, in these two cases a combination OV/HEPA must be used. 1910.1050(h)(3)(i)(D)
1, 3 Butadiene	Follow Table 1 1910.1051(h)(3) A label must be attached to each cartridge to indicate the date and time it is first installed on the respirator 1910.1051(h)(2)(iv)	No change made. Exempted from new APFs.
Methylene Chloride	Follow Table 2 1910.1052(g)(3)	Follow Table 1 found in respiratory protection program 1910.1052(g(3)(i) Cannot use or select half facepiece of any type because MC may cause eye irritation or damage. 1910.1052(g)(3)(i)

Commonly Asked Questions

Q. What is an Assigned Protection Factor (APF)?
A. APFs are numbers that illustrate the level of respiratory protection in a workplace that a respirator or class of respirators is expected to provide to employees when used as part of an effective respiratory protection program. The approved APF table can be found in this document (Table 1) or at 29 CFR 1910.134(d)(3)(i)(A) and (B).

Q. What is a Maximum Use Concentration (MUC)?
A. MUCs are the maximum concentrations of a contaminant in which a specific type of respirator can be used. MUC is typically determined by multiplying the respirator’s APF by the exposure limit of the contaminant. If the level of the contaminant in the workplace is expected to exceed the respirator’s MUC, the employer must select a respirator with a higher APF. Example: Acetone PEL is 1000ppm. If I use a half-mask air-purifying mask with an APF of 10, my MUC would be 10,000 ppm (PEL x APF).

Please Note: The information contained in this publication is intended for general information purposes only. This publication is not a substitute for review of the applicable government regulations and standards, and should not be construed as legal advice or opinion. Readers with specific questions should refer to the cited regulation or consult with an attorney.

Professional Equipment - Your testing & inspection equipment source

Guide to Respirator Selection