Approvals: 1st Level 2nd Level 3rd Level 

National Institute for Occupational Safety and Health 

National Personal Protective Technology Laboratory 

P.O. Box 18070 

Pittsburgh, PA 15236 

Procedure No. RCT-APR-STP-0061 Revision: 1.1 Date: 6 September 2005

DETERMINATION OF END OF SERVICE LIFE INDICATOR (ESLI) VISIBILITY TEST, 

AIR-PURIFYING RESPIRATORS 

STANDARD TESTING PROCEDURE (STP) 

1. PURPOSE

1.1. This test establishes the procedure for ensuring that the level of protection provided by 

the end of service life indicator visibility test on respirators with permanent and 

replaceable ESLI requirements on air-purifying respirators submitted for Approval, 

Extension of Approval, or examined during Certified Product Audits, meet the minimum 

certification standards set forth in 42 CFR, Subpart G, Section 84.63(a)(c)(d); Volume 

60, Number 110, June 8, 1995. 

1.2. Regulatory Citation: Federal Register, Vol. 49, No. 140, Thursday, July 19, 1994. 

Notices, pg. 29271.Criteria for Certification of ESLI; All passive ESLI criteria: 

“1. A passive ESLI shall be situated on the respirator so that it is readily visible to the 

wearer.” 

“2. If the passive indicator utilizes color change, the change shall be detectable to people 

with physical impairments such as color blindness.” 

“3. If the passive indicator utilizes color change, reference colors for the initial color of 

the indicator and the final [end point] color of the indicator shall be placed adjacent to the 

indicator.” 

2. GENERAL

This STP describes the Determination of End-of-Service-Life Indicator Visibility Test, AirPurifying Respirators test in sufficient detail that a person knowledgeable in the appropriate 

technical field can select equipment with the necessary resolution, conduct the test, and determine 

whether or not the product passes the test 

3. EQUIPMENT/MATERIAL

3.1. The list of necessary test equipment and materials follows: 

3.1.1. Assembled respirator 

 3.1.2. Respirator users instructions 

 3.1.3. Notepad and pencil

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Procedure No. RCT-APR-STP-0061 Revision: 1.1 Date: 6 September 2005 Page 2 of 5 

4. TESTING REQUIREMENTS AND CONDITIONS

 4.1. Prior to beginning any testing, all measuring equipment to be used must have been 

calibrated in accordance with the manufacturer's calibration procedure and schedule. At 

a minimum, all measuring equipment utilized for this testing must have been calibrated 

within the preceding 12 months using a method traceable to the National Institute of 

Standards and Technology (NIST). 

4.2. Normal laboratory safety practices must be observed. This includes safety precautions 

described in the current ALOSH Facility Laboratory Safety Manual. 

 4.2.1. Safety glasses, lab coats, and hard-toe shoes must be worn at all times. 

4.2.2. Work benches must be maintained free of clutter and non-essential test 

equipment. 

4.2.3. When handling any glass laboratory equipment, lab technicians and personnel 

must wear special gloves which protect against lacerations or punctures. 

5. PROCEDURE 

5.1. The ESLI shall be examined by the Team Leader or his designee subjectively for 

indicator color, reference color, and proximity of the reference color to the indicator 

color. The users instructions will be reviewed for special use instructions and 

information concerning the ESLI. The result of the examination is evaluated as pass or 

fail. 

 5.2. The visibility test will be conducted by the Team Leader or his designee on one facepiece 

with cartridges mounted, (or the facepiece alone, if the indicator is mounted on the 

facepiece), and the ESLI positioned per the manufacturer’s instructions. Three 

Respirator Branch personnel will be selected randomly to don the respirator and verbally 

confirm or deny visibility . 

6. PASS/FAIL CRITERIA

 6.1. The criterion for passing this test is set forth in 42 CFR, Subpart G, Section 

84.63(a)(c)(d); Volume 60, Number 110, June 8, 1995. 

 6.2. This test establishes the standard procedure for ensuring that: 

 84.63 Test requirements; general. 

(a) Each respirator and respirator component shall when tested by the applicant and by 

the Institute, meet the applicable requirements set forth in subparts H through L of this 

part. 

(c) In addition to the minimum requirements set forth in subparts H through L of this 

part, the Institute reserves the right to require, as a further condition of approval, any 

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Procedure No. RCT-APR-STP-0061 Revision: 1.1 Date: 6 September 2005 Page 3 of 5 

additional requirements deemed necessary to establish the quality, effectiveness, and 

safety of any respirator used as protection against hazardous atmospheres. 

(d) Where it is determined after receipt of an application that additional requirements will 

be required for approval, the Institute will notify the applicant in writing of these 

additional requirements, and necessary examinations, inspections, or tests, stating 

generally the reasons for such requirements, examinations, inspections, or tests. 

 6.3. “1. A passive ESLI shall be situated on the respirator so that it is readily visible to the 

wearer.” 

“2. If the passive indicator utilizes color change, the change shall be detectable to people 

with physical impairments such as color blindness.” 

“3. If the passive indicator utilizes color change, reference colors for the initial color of 

the indicator and the final [end point] color of the indicator shall be placed adjacent to the 

indicator.” 

6.4. A pass is defined as the three test personnel confirming visibility of the indicator. A fail 

is one or more denying visibility of the indicator. 

7. RECORDS/TEST SHEETS

7.1. All test data will be recorded on the END-OF-SERVICE-LIFE INDICATOR 

VISIBILITY TEST test data sheet. 

7.2. All videotapes and photographs of the actual test being performed, or of the tested 

equipment shall be maintained in the task file as part of the permanent record. 

7.3. All equipment failing any portion of this test will be handled as follows: 

7.3.1. If the failure occurs on a new certification application, or extension of approval 

application, send a test report to the RCT Leader and prepare the hardware for 

return to the manufacturer. 

7.3.2. If the failure occurs on hardware examined under an Off-the-Shelf Audit the 

hardware will be examined by a technician and the RCT Leader for cause. All 

equipment failing any portion of this test may be sent to the manufacturer for 

examination and then returned to NIOSH. However, the hardware tested shall be 

held at the testing laboratory until authorized for release by the RCT Leader, or 

his designee, following the standard operating procedures outlined in Procedure 

for Scheduling, and Processing Post-Certification Product Audits, 

 RB-SOP-0005-00. 

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Procedure No. RCT-APR-STP-0061 Revision: 1.1 Date: 6 September 2005 Page 5 of 5 

Revision History 

Revision Date Reason for Revision 

1.0 28 March 2002 Historic document 

1.1 6 September 

2005 

Update header and format to reflect lab move from Morgantown, WV 

No changes to method 

 

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