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-ASR-STP-0115 Revision: 1.1 Date: 21 September 2005

DETERMINATION OF RATED SERVICE TIME, CONSTANT FLOW, ESCAPE, 

OPEN-CIRCUIT, SELF-CONTAINED BREATHING APPARATUS 

STANDARD TESTING PROCEDURE (STP) 

1. PURPOSE

This test establishes the procedures for ensuring that the level of protection provided by the rated 

service time requirements on Constant Flow, Open-Circuit, Self-Contained Breathing Apparatus 

(SCBA) submitted for Approval, Extension of Approval, or examined during Certified Product 

Audits, meet the minimum certification standards set forth in 42 CFR, Part 84, Subpart G, Section 

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

2. GENERAL

This STP describes the Determination of Rated Service Time, Constant Flow, Open-Circuit, SelfContained Breathing Apparatus 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/MATERIALS

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

3.1.1. Electric Timer, calibrated to hundredths of a minute (Precision Scientific 

Company) or equivalent.

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Procedure No. RCT-ASR-STP-0115 Revision: 1.1 Date: 21 September 2005 Page 2 of 8 

3.1.2. Dry gas meter (singer) 28.32 liters per rev or equivalent. 

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. The compressed gas cylinder must meet all applicable Department of Transportation 

requirements for cylinder approval as well as for retesting/requalification. 

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

described in the current ALOSH Facility Laboratory Safety Manual. 

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

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

equipment. 

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

must wear special gloves which protect against lacerations or punctures. 

5. PROCEDURE

Note: Reference Section 3 for equipment, model numbers and manufacturers. For calibration 

purposes use those described in the manufacturer's operation and maintenance manuals. 

5.1. When testing escape self contained breathing apparatus with a constant flow, the flow 

from the unit is monitored with a dry test meter for the duration requested by the 

manufacturer. The flow rate must fall within the parameters called for in the 

manufacturer’s Q.C. plan. 

5.2. Data Analysis 

For constant flow, compare values to the manufacturer’s Q.C. plan. 

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Procedure No. RCT-ASR-STP-0115 Revision: 1.1 Date: 21 September 2005 Page 3 of 8 

Note: This test should be done on a minimum of two respirators, or more if additional testing is 

required (42 CFR, Part 84, Sections 84.12, 84.30, and 84.60). 

6. PASS \FAIL CRITERIA

6.1. The criterion for passing this test is set forth in 42 CFR, Part 84, Subpart G, Section 

84.63(a)(c)(d), and Subpart H, Section 84.95, 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 

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. A constant flow unit must supply air for the rated service time at a flow rate equal to or 

greater than the manufacturer’s specification’s. 

7. RECORDS\TEST SHEETS

7.1. All test data will be recorded on the RATED SERVICE TIME, SPECIAL TEST - 

CONSTANT FLOW, OPEN-CIRCUIT, SELF-CONTAINED BREATHING 

APPARATUS 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 

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Procedure No. RCT-ASR-STP-0115 Revision: 1.1 Date: 21 September 2005 Page 4 of 8 

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-SOP0005-00. 

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Procedure No. RCT-ASR-STP-0115 Revision: 1.1 Date: 21 September 2005 Page 5 of 8 

SPECIAL TEST - RATED SERVICE TIME, CONSTANT FLOW, OPEN-CIRCUIT, 

SELF-CONTAINED BREATHING APPARATUS

Project No : Date: __________ 

Company : ___________________________________________ 

Respirator Type: ___________________________________________ 

Reference: 42 CFR, Part 84, Subpart G, Section 84.63(a)(c)(d). 

Requirement: The unit must supply air for the rated service time at a flow rate equal to or greater than 

the manufacturer’s specification’s. The specifications for this unit call for a flow of 

Procedure: The hood is placed in an airtight tank with the tank outlet connected to a dry test meter. 

The cylinder is turned on and the output monitored for the rated service time. 

Results: 

Unit Time/Min Starting pressure Lpm 

 ________ _____________ ______ 

 ________ _____________ ______ 

 ________ _____________ ______ 

 ________ _____________ ______ 

 ________ _____________ ______ 

 ________ _____________ ______ 

Comments: 

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________ 

Test Engineer: Pass Fail _______ 

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Procedure No. RCT-ASR-STP-0115 Revision: 1.1 Date: 21 September 2005 Page 7 of 8 

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Procedure No. RCT-ASR-STP-0115 Revision: 1.1 Date: 21 September 2005 Page 8 of 8 

Revision History 

Revision Date Reason for Revision 

1.0 23 May 2001 Historic document 

1.1 21 September 

2005 

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

No changes to method 

 

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