National Institute for Occupational Safety and Health

National Personal Protective Technology Laboratory 

626 Cochrans Mill Road 

Pittsburgh, PA 15236

Procedure No. TEB-CCER-STP-0602 Revision: 1.0 Date: 05 January 2022

DETERMINATION OF CAPACITY OF AS-RECEIVED AND ENVIRONMENTALLY 

TREATED CLOSED-CIRCUIT ESCAPE RESPIRATORS (CCER)

1. PURPOSE

This procedure establishes the test for ensuring that Closed-Circuit Escape Respirators (CCER) 

submitted for Approval, Extension of Approval, or examined during Certified Product Audits, 

meet the certification standards as set forth in Sections 84.303 and 84.304, of Subpart O−Closed 

Circuit Escape Respirators updated requirements to 42 CFR Part 84. 

2. GENERAL

This Standard Testing Procedure (STP) describes the CCER capacity test, and the equipment, 

instruments, materials, and minimum performance criteria in sufficient detail such 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 respirator passes the test. 

3. EQUIPMENT / MATERIALS

3.1 The ABMS instrument and equipment schematic (Figure 1 in the Attachments), includes using a 

LabVIEW digital display, control, and data recording software. 

3.2 The following instruments performing stressor measurements must be capable of breath-bybreath responses and have the following measurement ranges: 

3.2.1 Carbon dioxide (CO2) gas analyzer capable of detecting CO2 from 0.00 to 15.00 

volume %, accurate to within ±0.02% CO2, with a response time of approximately 

100 milliseconds and possessing a digital display readout (resolution) ±0.01% 

(such as AEI Technologies Carbon Dioxide analyzer Model CD-3A or equivalent)

3.2.2 Oxygen (O2) gas analyzer capable of detecting O2 from 0.00 to 100.00 volume %, 

accurate to within ± 0.01% O2, with a response time of approximately 100 

milliseconds and possessing digital display readout (resolution) ±0.01% (such as 

AEI Technologies Oxygen analyzer Model S3-A/I or equivalent gas analyzer) 

3.2.3 Thermocouple modified to induce evaporative cooling from its tip (thermocouple 

wire junction point) and capable of measuring a breathing circuit wet bulb 

temperature ranging from 0 to 100 oC (such as an Omega P/N 5SRTC-TT-T-36-

36 Type ‘T’, 0.005-inch outer diameter thermocouple with appropriate junction 

point covering). 
Procedure No. TEB-CCER-STP-0602 Revision: 1.0 Date: 5 January 2022 Page 2 of 12

3.2.4 Pressure transducer capable of measuring breathing circuit breathing resistance 

from -562.5 to +562.5 mm water (such as a Validyne Model P55D-1-N-2-28-S-4-

A or equivalent pressure transducer)

3.3 Support/control instruments and equipment include the following:

3.3.1 Thermocouple capable of breath-by-breath response and measuring a breathing 

circuit dry bulb temperature ranging from 0 to 100o

C (such as an Omega P/N 

5SRTC-TT-T-36-36 Type ‘T’, 0.005-inch outer diameter thermocouple, or 

equivalent)

3.3.2 Gas sample system electronic moisture removal device, electronic gas chiller 

capable of lowering the automated breathing and metabolic simulator (ABMS)

gas sample system dew point to 3.5 o

C, (such as the DEEC Instadryer or 

equivalent)

3.3.3 CO2 Mass Flow Controller (MFC) capable of measuring 0-5 LPM (such as the 

Brooks SLA5850S CO2, or equivalent) 

3.3.4 N2 MFC capable of measuring 0-1.7 LPM (such as a Brooks SLA5850S or 

equivalent)

3.3.4.1 Activated when N2 flow rates decrease below 1.6 LPM; deactivated 

when N2 flow rates increase above 1.7 LPM.

3.3.5 N2 MFC capable of measuring 0-20 LPM (such as a Brooks SLA5850S or 

equivalent)

3.3.5.1 Activated when N2 flow rates increase above 1.7 LPM; deactivated when 

N2 flow rates decrease below 1.6 LPM

3.3.6 Weigh scale with a 0 to 35,000 mg range with 1 mg scale resolution (such as the 

Ohaus Ranger R71MHD35 weigh scale or equivalent)

3.3.7 Gas spirometer (such as the Collins P-1700-120 Liter scale gas spirometer or 

equivalent)

3.3.8 Timer (accurate to 0.01 percent)

3.3.9 Physitemp Thermalert Model TH-8 temperature indicator, or equivalent, with ‘T’ 

type thermocouple

3.3.10 Electronic barometric pressure transducer (such as the Vaisala PTU300 

electronic barometric pressure transmitter or equivalent)

3.4 Materials required include the following:

3.4.1 Nitrogen (N2) Cylinder – At minimum, High Purity grade containing >99.99% N2

3.4.2 Carbon dioxide cylinder – At minimum, Coleman/Instrument grade containing 

>99.99% CO2
Procedure No. TEB-CCER-STP-0602 Revision: 1.0 Date: 5 January 2022 Page 3 of 12

3.4.3 Calibration gas traceable to recognized international standards containing 80.0% 

oxygen, 12.0% nitrogen, and 8.0% carbon dioxide

3.4.4 Phenolphthalein

3.4.5 Deionized water for the ABMS recirculating water system

4. TESTING REQUIREMENTS AND CONDITIONS

4.1. Prior to beginning any testing, confirm that all measuring equipment and instruments

employed have been calibrated in accordance with the testing laboratory’s calibration 

procedure and schedule. All measuring equipment and instruments utilized must have 

been calibrated using a method traceable to recognized international standards when 

available.

4.2. Tests will be conducted at the following ambient conditions

4.2.1. Ambient temperatures of 23 oC ± 3 oC; and

4.2.2. Atmospheric pressures of 735 mmHg ± 15 mmHg

4.3. Prior to beginning the Capacity Test Procedure, the CCER will be inspected using the 

manufacturer’s and NIOSH inspection criteria. The manufacturer’s inspection will be 

specific to their respirator unit and are defined in the User Instructions (UI). NIOSH

inspections will include:

4.3.1. Applying a -300mm H2O vacuum to assess the integrity of the breathing tube and 

associated parts of the respirator unit. 

4.3.2. Using a phenolphthalein swab to detect alkaline chemicals present in the CCER

unit user interface.

4.4. Capacity Test Requirements and Conditions

4.4.1. Capacity tests will continuously monitor the stressors listed in Table 1. The 

stressors will be measured at the interface between the CCER and the ABMS

“mouth” by instruments capable of breath-by-breath measurement. Stressor 

measurements will be evaluated as one-minute averages. The operating (overall)

averages of each stressor will be calculated upon the completion of each test as 

the average of the one-minute measurements of the stressor recorded over the 

entire test. 

4.4.2. Capacity tests will conclude when the stored breathing gas supply has been fully 

expended, or any one-minute average stressor measurement is outside the 

acceptable excursion range.

4.4.3. The capacity test is conducted on five units submitted for approval (refer to Table 

3), as follows:
Procedure No. TEB-CCER-STP-0602 Revision: 1.0 Date: 5 January 2022 Page 4 of 12

4.4.3.1. Three units will be tested in the condition in which they are received 

from the applicant.

4.4.3.2. Two units will be tested after being subjected to the environmental 

treatments according to the standard procedure for environmental 

treatments of CCERs.

4.4.4. Each unit will be tested at a constant work rate which depends on the capacity 

specified by the manufacturer, according to the requirements in Table 2. 

5. PROCEDURE

5.1. Initial Startup

5.1.1. Verify all equipment is on and all test system operating parameters are in the 

appropriate range for valid testing.

5.1.2. Calibrate the O2 and CO2 exhaust flows analyzers.

5.1.3. Perform ABMS gas analyzer calibration for O2 and CO2.

5.1.3.1. Confirm the response times for each gas analyzer are within acceptable

ranges as established by the manufacturer.

5.1.4. Verify correct waveform for the specific capacity test.

5.1.4.1. For a CAP 1 test, set the VO2 to 2.50 L/min; see Figure 2.

5.1.4.2. For a CAP 2 test, set the VO2 to 2.00 L/min; see Figure 3.

5.1.4.3. For a CAP 3 test, set the VO2 to 1.35 L/min; see Figure 4.

5.1.5. Mount the CCER unit on the ABMS trachea and perform a leak check for the 

ABMS. Ensure all orifices are properly sealed and that the system is leak tight.

5.2. Perform the capacity test by selecting the appropriate test protocol to set the 

corresponding VO2, VCO2, ventilation rate, and respiratory frequency operating 

conditions just prior to beginning the simulation.

5.2.1. The manufacturer’s recommended start-up procedure for the CCER being tested

must be simulated on the ABMS as closely as possible, as described in the 

manufacturer’s UI.

5.2.2. Monitor the values in Table 1 throughout the test.

5.2.3. Determine the completion time as the time elapsed from test start to when the gas 

supply is fully expended. Expended gas supply is usually indicated when either 

the breathing bag is empty, or (if present) the O2 cylinder is empty, and (as a 

result) peak inhalation pressure begins to spike below -300 mmH2O. The test is 

also stopped if the peak breathing resistance exceeds +200 mmH2O.
Procedure No. TEB-CCER-STP-0602 Revision: 1.0 Date: 5 January 2022 Page 5 of 12

5.3. Data Analysis 

5.3.1. Calculate the achieved capacity as the product of the completion time (in 

minutes) and the VO2 (STPD L/minute) set point used in the test protocol.

5.3.2. Calculate the overall average for each of the stressor measurements using the 

one-minute average values from the test start to when the breathing gas supply is 

fully expended.

5.3.3. Identify the maximum inhaled CO2, minimum inhaled O2, maximum exhaled and 

minimum inhaled breathing resistance, and maximum inhaled wet bulb 

temperature using the one-minute average values from test start to when the 

breathing gas supply is fully expended.

5.3.4. Record the calculated values and completion time on the test data sheet.

6. PASS/FAIL CRITERIA

6.1. The apparatus fails this test and approval if:

6.1.1. Any average stressor measurement (as the overall average stressor from test start 

to when the breathing gas supply is fully expended) is outside the acceptable 

operating average range shown in Table 1 (middle column).

6.1.2. Any one-minute average stressor measurement (minimum to maximum stressor 

from test start to when the breathing gas supply is fully expended) is outside the 

acceptable excursion range shown in Table 1 (last column).

Table 1: Monitored Stressors and their Acceptable Ranges

Stressor Acceptable Range

Operating Average

Acceptable Range

Excursion

Average inhaled CO2 <1.5% ≤4%

Average inhaled O2 >19.5% ≥15%

Peak Breathing Resistances ∆P ≤ 200 mm H2O -300 ≤ ∆P ≤ 200 mm H2O

Wet-bulb temperature <43 ̊C ≤50 ̊C

6.2. The apparatus fails certification if the achieved capacity is below the minimum capacity as 

indicated in Table 2.
Procedure No. TEB-CCER-STP-0602 Revision: 1.0 Date: 5 January 2022 Page 6 of 12

Table 2: Capacity Test Requirements (all volumes are given at standard temperature (0°C) and 

pressure (760 mm Hg), dry)

Capacity

Rating

Capacity

(L)

VO2 

(L/min)

VCO2 

(L/min)

Ve

(L/min)

RF 

(Breaths/min)

Cap 1 20 ≤ L ≤ 59 2.50 2.50 55 22

Cap 2 60 ≤ L ≤ 79 2.00 1.80 44 20

Cap 3 L ≥ 80 1.35 1.15 30 18

VO2=volume of oxygen consumed/min; VCO2=volume of carbon dioxide produced/min; 

Ve = ventilation rate; RF = respiratory frequency

7. RECORDS / TEST SHEETS

7.1. Data shall be recorded and stored as an attached data sheet to include the following

information in the TEST DATA SHEET (INCLUDING PRE-TEST CHECK DATA)

FOR DETERMINATION OF CCER CAPACITY, STP 0602.

TEST DATA SHEET (INCLUDING PRE-TEST CHECK DATA) FOR DETERMINATION OF CCER 

CAPACITY, STP 0602

Date Barometric 

Pressure 

(mm Hg)

S/N # Manufacturer 

Date

Expiration 

Date

Phenolphthalein 

(Pass or Fail)

Oxygen 

Flow Rate 

(LPM)

CCER Leak Flow 

Rate (mL/min)

Case 

Integrity

Case Seal Secure 

Tape or 

Latch

Oxygen 

Indicator 

(psig)

Oxygen 

Starter

Temperature 

Indicator

Moisture 

Indicator

Waveform/Protocol

Oxygen 

Response 

(ms)

Carbon 

Dioxide 

Response 

(ms)

Oxygen 

Criteria 

Time 

(ms)

Carbon 

Dioxide 

Criteria Time 

(ms)

ABMS 

Leak Rate 

(mL/min)

ABMS Leak 

Rate with CCER 

(mL/min)

Technician 

Initials

Comments
Procedure No. TEB-CCER-STP-0602 Revision: 1.0 Date: 5 January 2022 Page 7 of 12

Table 3: Example Test Summary Data for all CCER Units Submitted for NIOSH Approval

8. ATTACHMENTS

8.1 Figure 1: Schematic of the ABMS

8.2 Figure 2: Graph for CAP 1 Test

8.3 Figure 3: Graph for CAP 2 Test

8.4 Figure 4: Graph for CAP 3 Test

Device 

ID

Test Test 

date

Completion 

time

Calculated 

Capacity

Indicate 

Minimum 

Capacity

Comments

As-received

As-received

As-received

Environmental 

treatments

Environmental 

treatments
Procedure No. TEB-CCER-STP-0602 Revision: 1.0 Date: 5 January 2022 Page 8 of 12

Figure 1: Schematic of the ABMS 
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Figure 2: Example graph for CAP 1 Test, showing breathing gas volumetric flow rate (y-axis) vs. time (xaxis).
Procedure No. TEB-CCER-STP-0602 Revision: 1.0 Date: 5 January 2022 Page 10 of 12

Figure 3: Example graph for CAP 2 Test, showing breathing gas volumetric flow rate (y-axis) vs. time (xaxis).
Procedure No. TEB-CCER-STP-0602 Revision: 1.0 Date: 5 January 2022 Page 11 of 12

Figure 4: Example graph for CAP 3 Test, showing breathing gas volumetric flow rate (y-axis) vs. time (xaxis).
Procedure No. TEB-CCER-STP-0602 Revision: 1.0 Date: 5 January 2022 Page 12 of 12

Revision History

Revision Date Reason for Revision

0 10 November 2010 Initial Record

1.0 Final Review

1.0 22 November 2011 Administrative changes – Document number changed

2.0 3 April 2012 Administrative changes were made to include information from the 

release of the proposed rule and TEB suggested changes.

Former document number - STP-00001-PSDB-0006

0.0 25 March 2014 New document number (TEB-CCER-STP-0602) to reflect numbering 

in the approval library, normalization of format. No changes to 

procedure from historical document.

1.0 05 January 2022 Changes were made to the equipment and materials and the procedure. 

Examples waveforms were added as figures.