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-0109 Revision: 1.1 Date: 21 September 2005

DETERMINATION OF EXHALATION AIRFLOW RESISTANCE, DEMAND, 

TYPE C AND CE, SUPPLIED-AIR RESPIRATORS 

STANDARD TESTING PROCEDURE (STP) 

1. PURPOSE

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

exhalation resistance requirements on Type C and CE, Demand, Supplied-Air Respirators 

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), and Subpart J, Section 84.156(b); Volume 60, Number 110, June 8, 1995. 

2. GENERAL

This STP describes the Determination of Exhalation Airflow Resistance, Demand, Type C and 

CE, Supplied-Air 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/MATERIALS

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

3.1.1. A 300 cubic foot gas cylinder of compressed air or equivalent.

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Procedure No. RCT-ASR-STP-0109 Revision: 1.1 Date: 21 September 2005 Page 2 of 14 

3.1.2. A Helicoid calibrated pressure gauge and connecting fittings or equivalent. 

3.1.3. Air regulator, Model 8, from Matheson Gas Products or equivalent. 

3.1.4. Dwyer Slant Manometer 0-3", F. W. Dwyer Manufacturing Co., Michigan City, 

Indiana 

3.1.5. ISI Anthropometric Test heads with tube for measuring breathing resistance and 

air flows - Model SR-085 or equivalent. 

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Procedure No. RCT-ASR-STP-0109 Revision: 1.1 Date: 21 September 2005 Page 3 of 14 

3.1.6. Ground Glass Joint 

3.1.7. Pinch Clamp 

3.1.8. Positive pressure source calibrated at 85 lpm or Lead fume chamber or 

equivalent. (See figure 1. and 3.) 

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 all safety precautions 

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Procedure No. RCT-ASR-STP-0109 Revision: 1.1 Date: 21 September 2005 Page 4 of 14 

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. Set up respirator as per manufacturer’s instructions using maximum pressure and 

minimum hose length. 

5.2. Mount the facepiece on an anthropometric head with tube for measuring breathing 

resistance. Insert a ground glass joint connector at the breathing port at backside of head. 

Note: If a dust test is in progress, you must check with the lab technician before touching the 

silica dust chamber. 

5.3. The procedure for turning on the silica dust chamber (positive pressure source) is: 

5.3.1 Turn on the main power for the silica dust chamber. 

5.3.2 Turn on the exhaust on the silica dust chamber. 

5.3.3 Turn on the air-supply (on front of silica dust chamber). 

5.3.4 Turn on the positive pressure blower, and adjust. 

5.3.5 Set chamber pressure to .5 in of H20. 

5.4. Turn on air supply to respirator and adjust to manufacturer’s maximum air pressure. 

5.5. Plug anthropometric head into port on chamber marked positive resistance. (See Figure 

2. and 3.) 

5.6. Turn on positive flow control valve on front panel of chamber. (See Figure 1. and 3.) 

5.7. Adjust bottom of meniscus to calibrated 85 1pm line. (See Figure 1. and 3.) 

5.8. Read the scale on the slant manometer. Readings will be in inches of water. (See data 

analysis). 

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Procedure No. RCT-ASR-STP-0109 Revision: 1.1 Date: 21 September 2005 Page 5 of 14 

5.9. The procedure for turning off the dust chamber is as follows: 

5.9.1 Turn off the positive flow control. 

5.9.2 Turn off the main air valve. 

5.9.3 Shut off the exhaust on the dust chamber. 

5.9.4 Turn off the air supply to the respirator. 

5.10. Data Analysis 

To convert inches of water to mm of water, multiply reading in inches by 25.4. 

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

required (42 CFR, Part 84, Section 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 J, Section 84.156(b); 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. 

84.156 Air Flow Resistance Test; Type C Supplied-Air Respirators, Demand Class, 

minimum requirements. 

(b) The exhalation resistance to a flow of air at a rate of 85 liters (3 cubic feet) per minute 

shall not exceed 25 millimeters (1 inch of water). 

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Procedure No. RCT-ASR-STP-0109 Revision: 1.1 Date: 21 September 2005 Page 6 of 14 

7. RECORDS\TEST SHEETS

7.1. All test data will be recorded on the AIRFLOW EXHALATION RESISTANCE, 

DEMAND CLASS, TYPE C AND CE, SUPPLIED-AIR RESPIRATORS test data sheet. 

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

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-SOP0005-00. 

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Procedure No. RCT-ASR-STP-0109 Revision: 1.1 Date: 21 September 2005 Page 7 of 14 

AIRFLOW EXHALATION RESISTANCE, DEMAND CLASS, TYPE C AND CE, 

SUPPLIED-AIR RESPIRATORS

Project No : Date: __________ 

Company : ___________________________________________ 

Respirator Type: ___________________________________________ 

Reference: 42 CFR, Part 84, Subpart J, Section 84.156(b). 

Requirement: (b) The exhalation resistance to a flow of air at a rate of 85 1pm. (3 cfm.) Shall not 

exceed 25 mm (1 inch) of H20 col. Ht. 

Results: Air Flow 85 1pm. (3 cfm.) 

 Exhalation Resistance: ____________ 

Comments : 

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________ 

 

 

 

 

Test Engineer: PASS FAIL________ 

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Procedure No. RCT-ASR-STP-0109 Revision: 1.1 Date: 21 September 2005 Page 8 of 14 

Figure 1. 

Silica Dust Chamber Control Panel 

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Procedure No. RCT-ASR-STP-0109 Revision: 1.1 Date: 21 September 2005 Page 9 of 14 

Figure 2. 

Silica Dust Chamber Control Panel 

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Procedure No. RCT-ASR-STP-0109 Revision: 1.1 Date: 21 September 2005 Page 10 of 14 

Figure 3. 

Test Setup 

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Procedure No. RCT-ASR-STP-0109 Revision: 1.1 Date: 21 September 2005 Page 14 of 14 

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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