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-0144 Revision: 1.1 Date: 12 September 2005

DETERMINATION OF CONTINUOUS GAS FLOW ON CONSTANT FLOW, 

CLOSED-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 gas 

flow requirements on Constant Flow, Closed-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), and Subpart H, Section 84.94(a); Volume 60, Number 110, June 8, 1995. 

2. GENERAL

This STP describes the Determination of Continuous Gas Flow on Constant Flow, ClosedCircuit, Self-Contained 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.

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 
Procedure No. RCT-ASR-STP-0144 Revision: 1.1 Date: 12 September 2005 Page 2 of 13 

3.1.2. Dry test - Gas meter, (Singer-American Meter Division - Model DTM-200A) or 

equivalent. 

3.1.3. Wet Test - Gas Meter (Singer-American Meter Company - Model AL17-1) 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 all 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 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 
Procedure No. RCT-ASR-STP-0144 Revision: 1.1 Date: 12 September 2005 Page 3 of 13 

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

5.1. The regulator or constant flow outlet is connected to a calibrated wet test meter (traceable 

to NIST using Dry Test Gas Meter). 

5.2. Flow readings are recorded initially and every 10 minutes for the rated service time of the 

unit. The last 10 minutes are monitored every other minute. 

5.3. Data Analysis 

Record flow readings directly from the wet test gas meter. 

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 84.94(a); 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. 

84.94 Gas flow test; closed-circuit apparatus. 

(a) Where oxygen is supplied by a constant-flow device only, the rate of flow shall be at 

least 3 liters per minute for the entire rated service time of the apparatus. 

7. RECORDS\TEST SHEETS

7.1. All test data will be recorded on the GAS FLOW TEST, CONSTANT FLOW, CLOSEDCIRCUIT, SELF-CONTAINED BREATHING APPARATUS test data sheet. 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 
Procedure No. RCT-ASR-STP-0144 Revision: 1.1 Date: 12 September 2005 Page 4 of 13 

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. 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 
Procedure No. RCT-ASR-STP-0144 Revision: 1.1 Date: 12 September 2005 Page 5 of 13 

GAS FLOW TEST, CONSTANT FLOW, CLOSED-CIRCUIT, 

SELF-CONTAINED BREATHING APPARATUS

Project No. : Date: __________ 

Company : ____________________________________________ 

Respirator Type: ____________________________________________ 

Reference: 42 CFR 84, Subpart H, Section 84.94(a). 

Requirement: Where oxygen is supplied by a constant-flow device only, the rate of flow shall be at 

least 3 liters per minute for the entire rated service time of the apparatus. 

Results: 

Unit #1 Time/Min. Flow/LPM Unit #2 Time/Min. Flow/LPM

 0-1 0-1 _________ 

 1-2 1-2 _________ 

 2-3 2-3 _________ 

 3-4 3-4 _________ 

 4-5 4-5 _________ 

 5-6 5-6 _________ 

 6-7 6-7 _________ 

 7-8 7-8 _________ 

 8-9 8-9 _________ 

 9-10 9-10 _________ 

 10-11 10-11 _________ 

 11-12 11-12 _________ 

 12-13 12-13 _________ 

 13-14 13-14 _________ 

 14-15 14-15 _________ 

 15-16 15-16 _________ 

 16-17 16-17 _________ 

 17-18 17-18 _________ 

 18-19 18-19 _________ 

 19-20 19-20 _________ 

 20-21 20-21 _________ 

 21-22 21-22 _________ 

 22-23 22-23 _________ 

 23-24 23-24 _________ 

 24-25 24-25 _________ 

 25-26 25-26 _________ 

 26-27 26-27 _________ 

 27-28 27-28 _________ 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 
Procedure No. RCT-ASR-STP-0144 Revision: 1.1 Date: 12 September 2005 Page 6 of 13 

 28-29 28-29 _________ 

 29-30 29-30 _________ 

 30-31 30-31 _________ 

 31-32 31-32 _________ 

 32-33 32-33 _________ 

 33-34 33-34 _________ 

 34-35 34-35 _________ 

 35-36 35-36 _________ 

 36-37 36-37 _________ 

 37-38 37-38 _________ 

 38-39 38-39 _________ 

 39-40 39-40 _________ 

 40-41 40-41 _________ 

 41-42 41-42 _________ 

 42-43 42-43 _________ 

 43-44 43-44 _________ 

 44-45 44-45 _________ 

 45-46 45-46 _________ 

 46-47 46-47 _________ 

 47-48 47-48 _________ 

 48-49 48-49 _________ 

 49-50 49-50 _________ 

 50-51 50-51 _________ 

 51-52 51-52 _________ 

 52-53 52-53 _________ 

 53-54 53-54 _________ 

 54-55 54-55 _________ 

 55-56 55-56 _________ 

 56-57 56-57 _________ 

 57-58 57-58 _________ 

 58-59 58-59 _________ 

 59-60 59-60 _________ 

 60-61 60-61 _________ 

 61-62 61-62 _________ 

 62-63 62-63 _________ 

 63-64 63-64 _________ 

 64-65 64-65 _________ 

 65-66 65-66 _________ 

 66-67 66-67 _________ 

 67-68 67-68 _________ 

 68-69 68-69 _________ 

 69-70 69-70 _________ 

 70-71 70-71 _________ 

 71-72 71-72 _________ 

 72-73 72-73 _________ 

 73-74 73-74 _________ 

 74-75 74-75 _________ 

 75-76 75-76 _________ 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 
Procedure No. RCT-ASR-STP-0144 Revision: 1.1 Date: 12 September 2005 Page 7 of 13 

 76-77 76-77 _________ 

 77-78 77-78 _________ 

 78-79 78-79 _________ 

 79-80 79-80 _________ 

 80-81 80-81 _________ 

 81-82 81-82 _________ 

 82-83 82-83 _________ 

 83-84 83-84 _________ 

 84-85 84-85 _________ 

 85-86 85-86 _________ 

 86-87 86-87 _________ 

 87-88 87-88 _________ 

 88-89 88-89 _________ 

 89-90 89-90 _________ 

 90-91 90-91 _________ 

 91-92 91-92 _________ 

 92-93 92-93 _________ 

 93-94 93-94 _________ 

 94-95 94-95 _________ 

 95-96 95-96 _________ 

 96-97 96-97 _________ 

 97-98 97-98 _________ 

 98-99 98-99 _________ 

 99-100 99-100 _________ 

 100-101 100-101 _________ 

 101-102 101-102 _________ 

 102-103 102-103 _________ 

 103-104 103-104 _________ 

 104-105 104-105 _________ 

 105-106 105-106 _________ 

 106-107 106-107 _________ 

 107-108 107-108 _________ 

 108-109 108-109 _________ 

 109-110 109-110 _________ 

 110-111 110-111 _________ 

 111-112 111-112 _________ 

 112-113 112-113 _________ 

 113-114 113-114 _________ 

 114-115 114-115 _________ 

 115-116 115-116 _________ 

 116-117 116-117 _________ 

 117-118 117-118 _________ 

 118-119 118-119 _________ 

 119-120 119-120 _________ 

 120-121 120-121 _________ 

 121-122 121-122 _________ 

 122-123 122-123 _________ 

 123-124 123-124 _________ 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 
Procedure No. RCT-ASR-STP-0144 Revision: 1.1 Date: 12 September 2005 Page 8 of 13 

 124-125 124-125 _________ 

 125-126 125-126 _________ 

 126-127 126-127 _________ 

 127-128 127-128 _________ 

 128-129 128-129 _________ 

 129-130 129-130 _________ 

 130-131 130-131 _________ 

 131-132 131-132 _________ 

 132-133 132-133 _________ 

 133-134 133-134 _________ 

 134-135 134-135 _________ 

 135-136 135-136 _________ 

 136-137 136-137 _________ 

 137-138 137-138 _________ 

 138-139 138-139 _________ 

 139-140 139-140 _________ 

 140-141 140-141 _________ 

 141-142 141-142 _________ 

 142-143 142-143 _________ 

 143-144 143-144 _________ 

 144-145 144-145 _________ 

 145-146 145-146 _________ 

 146-147 146-147 _________ 

 147-148 147-148 _________ 

 148-149 148-149 _________ 

 149-150 149-150 _________ 

 150-151 150-151 _________ 

 151-152 151-152 _________ 

 152-153 152-153 _________ 

 153-154 153-154 _________ 

 154-155 154-155 _________ 

 155-156 155-156 _________ 

 156-157 156-157 _________ 

 157-158 157-158 _________ 

 158-159 158-159 _________ 

 159-160 159-160 _________ 

 160-161 160-161 _________ 

 161-162 161-162 _________ 

 162-163 162-163 _________ 

 163-164 163-164 _________ 

 164-165 164-165 _________ 

 165-166 165-166 _________ 

 166-167 166-167 _________ 

 167-168 167-168 _________ 

 168-169 168-169 _________ 

 169-170 169-170 _________ 

 170-171 170-171 _________ 

 171-172 171-172 _________ 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 
Procedure No. RCT-ASR-STP-0144 Revision: 1.1 Date: 12 September 2005 Page 9 of 13 

 172-173 172-173 _________ 

 173-174 173-174 _________ 

 174-175 174-175 _________ 

 175-176 175-176 _________ 

 176-177 176-177 _________ 

 177-178 177-178 _________ 

 178-179 178-179 _________ 

 179-180 179-180 _________ 

 180-181 180-181 _________ 

 181-182 181-182 _________ 

 182-183 182-183 _________ 

 183-184 183-184 _________ 

 184-185 184-185 _________ 

 185-186 185-186 _________ 

 186-187 186-187 _________ 

 187-188 187-188 _________ 

 188-189 188-189 _________ 

 189-190 189-190 _________ 

 190-191 190-191 _________ 

 191-192 191-192 _________ 

 192-193 192-193 _________ 

 193-194 193-194 _________ 

 194-195 194-195 _________ 

 195-196 195-196 _________ 

 196-197 196-197 _________ 

 197-198 197-198 _________ 

 198-199 198-199 _________ 

 199-200 199-200 _________ 

 200-201 200-201 _________ 

 201-202 201-202 _________ 

 202-203 202-203 _________ 

 203-204 203-204 _________ 

 204-205 204-205 _________ 

 205-206 205-206 _________ 

 206-207 206-207 _________ 

 207-208 207-208 _________ 

 208-209 208-209 _________ 

 209-210 209-210 _________ 

 210-211 210-211 _________ 

 211-212 211-212 _________ 

 212-213 212-213 _________ 

 213-214 213-214 _________ 

 214-215 214-215 _________ 

 215-216 215-216 _________ 

 216-217 216-217 _________ 

 217-218 217-218 _________ 

 218-219 218-219 _________ 

 219-220 219-220 _________ 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 
Procedure No. RCT-ASR-STP-0144 Revision: 1.1 Date: 12 September 2005 Page 10 of 13 

 220-221 220-221 _________ 

 221-222 221-222 _________ 

 222-223 222-223 _________ 

 223-224 223-224 _________ 

 224-225 224-225 _________ 

 225-226 225-226 _________ 

 226-227 226-227 _________ 

 227-228 227-228 _________ 

 228-229 228-229 _________ 

 229-230 229-230 _________ 

 230-231 230-231 _________ 

 231-232 231-232 _________ 

 232-233 232-233 _________ 

 233-234 233-234 _________ 

 234-235 234-235 _________ 

 235-236 235-236 _________ 

 236-237 236-237 _________ 

 237-238 237-238 _________ 

 238-239 238-239 _________ 

 239-240 239-240 _________ 

Comments : 

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________ 

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________

_____________________________________________________________________________________ 

Test Engineer: PASS FAIL________ 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 
Procedure No. RCT-ASR-STP-0144 Revision: 1.1 Date: 12 September 2005 Page 11 of 13 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 
Procedure No. RCT-ASR-STP-0144 Revision: 1.1 Date: 12 September 2005 Page 12 of 13 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 
Procedure No. RCT-ASR-STP-0144 Revision: 1.1 Date: 12 September 2005 Page 13 of 13 

Revision History 

Revision Date Reason for Revision 

1.0 24 May 2001 Historic document 

1.1 12 September 

2005 

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

No changes to method 

 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy 

Uncontrolled Copy 

 Uncontrolled Copy