National Institute for Occupational Safety and Health

National Personal Protective Technology Laboratory 

626 Cochrans Mill Road 

Pittsburgh, PA 15236

Procedure No. TEB-CCER-STP-0604 Revision: 1.0 Date: 5 January 2022

DETERMINATION OF CAPACITY TEST OF CLOSED-CIRCUIT ESCAPE RESPIRATORS (CCER)

AT MANUFACTURER’s RECOMMENDED MINIMUM TEMPERATURE

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 minimum certification standards 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 at the manufacturer’s 

minimum operating temperature, 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 should 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-0604 Revision: 1.0 Date: 5 January 2022 Page 2 of 11

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-S4-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)

3.3.11. Environmental chamber (such as the Russells Technical Products Model WMD288-GCMD-6-6-AC Modular Construction Temperature & Humidity Test 

Chamber, or equivalent). The ABMS must be located adjacent to the 

environmental chamber to allow the CCER to be tested while inside the chamber 

using appropriate means of connection.
Procedure No. TEB-CCER-STP-0604 Revision: 1.0 Date: 5 January 2022 Page 3 of 11

3.3.12. BlueStar Color touch screen controller, or equivalent, including data trending, 

cascade temperature control, ethernet communications capabilities, Windows 

embedded architecture, user settable deviations alarms with reporting, data 

exporting capabilities to .csv files, and 90 days data storage.

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

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 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 must have been 

calibrated using a method traceable to recognized international standards when available.

4.1.1. Tests will be conducted at an atmospheric pressure of 735 mm Hg ± 15 mm Hg.

4.1.2. Tests will be conducted at the manufacturer-recommended cold-temperature 

operating limit specified in the application and provided in the User Instructions

(UI).

 

4.2. Capacity Test Requirements and Conditions

4.2.1. 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. 

4.2.2. 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.

4.2.3. The capacity test is conducted at the manufacturer’s recommended minimum 

operating temperature on two units submitted for approval.
Procedure No. TEB-CCER-STP-0604 Revision: 1.0 Date: 5 January 2022 Page 4 of 11

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

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

5. PROCEDURE

5.1. Store the CCER at the manufacturer-recommended minimum temperature.

5.1.1. The CCER unit to be tested will be placed inside the environmental chamber.

5.1.2. The controlled temperature of the chamber will be adjusted to the manufacturerrecommended cold-temperature operating limit specified in the application and 

provided in the UI.

5.1.3. The CCER unit to be tested will then be maintained in the chamber at the cold 

temperature limit for at least 24 hours before testing can be started.

5.1.4. Just before the capacity test is begun, using care not to activate the unit 

prematurely, the sample unit will be opened and deployed into the as-worn 

configuration and then attached to the ABMS.

5.1.5. The controlled temperature of the chamber is maintained at the cold temperature 

limit throughout the capacity test.

5.2. Calibrate the O2 and CO2 exhaust flows analyzers.

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

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

ranges as established by the manufacturer.

5.2.2. Verify correct waveform for the specific capacity test.

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

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

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

5.2.3. 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.

5.3 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 operation.

5.3.1 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 UI.

5.3.2 Monitor the stressor values in Table 1 throughout the test.
Procedure No. TEB-CCER-STP-0604 Revision: 1.0 Date: 5 January 2022 Page 5 of 11

5.3.3 The protocol (work rate) must correspond to the capacity test requirements in 

Table 2 corresponding to the capacity rating specified by the CCER manufacturer.

5.4 Data Analysis 

5.4.1 Calculate the achieved capacity as the product of the completion time (in minutes) 

and the VO2 (L/minute) used in the test protocol.

5.4.2 Calculate the overall average for each of the stressor measurements using the oneminute average values from the test start to when the gas supply is fully expended.

5.4.3 Determine the completion time as the time elapsed from test start to when the

breathing gas supply is fully expended. Expended breathing 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 

mm H2O.

6. PASS/FAIL CRITERIA

6.1. The apparatus fails the 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. If from the test start up to the completion time any one-minute average stressor 

measurement 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 

indicated for the rating in Table 2.
Procedure No. TEB-CCER-STP-0604 Revision: 1.0 Date: 5 January 2022 Page 6 of 11

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 AND 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 AT MANUFACTURER’S 

MINIMUM TEMPERATURE, STP 0604.

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

CAPACITY AT MANUFACTURER’S MINIMUM TEMPERATURE, STP 0604

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-0604 Revision: 1.0 Date: 5 January 2022 Page 7 of 11

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

Device 

ID

Test Test 

date

Completion 

time

Calculated 

capacity

Indicate 

minimum 

capacity

Comments

Capacity at 

cold 

temperature 

limit

Capacity at 

cold 

temperature 

limit

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
Procedure No. TEB-CCER-STP-0604 Revision: 1.0 Date: 5 January 2022 Page 8 of 11

Figure 1: ABMS Schematic
Procedure No. TEB-CCER-STP-0604 Revision: 1.0 Date: 5 January 2022 Page 9 of 11

Figure 2. Example graph for CAP 1 Test, showing breathing gas volumetric flow rate (y-axis) vs. time (xaxis)
Procedure No. TEB-CCER-STP-0604 Revision: 1.0 Date: 5 January 2022 Page 10 of 11

Figure 3: Example graph for CAP 2 Test, showing breathing gas volumetric flow rate (y-axis) vs. time (xaxis).

Figure 4: Example graph for CAP 3 Test, showing breathing gas volumetric flow rate (y-axis) vs. time (xaxis).
Procedure No. TEB-CCER-STP-0604 Revision: 1.0 Date: 5 January 2022 Page 11 of 11

Revision History

Revision Date Reason for Revision

00 18 August 2011 Initial Review

1.0 22 December 

2011

Administrative changes – Document number changed

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

release of the proposed rule

Former document number - STP-00001-PSDB-0009

0.1 4 April 2014 New document number to reflect numbering in the approval library, 

normalization of format. The only changes made in the procedure 

are in section 5.1. The order of events has been changed to reflect 

the fact that that the CCER sample will undergo the 24-hour, cold 

soak in the as-carried (packaged) configuration. Notes have been 

added at sections 5.2.1. and 5.4.1.1. to clarify termination criteria 

and data evaluation. The cold operating temperature has been 

clarified in section 5.1.2. Document accessibility enhancements 

affected. Other minor grammatical edits have been applied for 

clarity, but there are no changes to procedure from historical 

document.

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

Examples waveforms were added as Figures.