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. CET-APRS-STP-CBRN-0301 Revision: 1.1 Date: 29 June 2005

DETERMINATION OF CBRN ORGANIC VAPOR (CYCLOHEXANE) 

SERVICE LIFE TEST, AIR-PURIFYING RESPIRATORS 

STANDARD TEST PROCEDURE (STP) 

1. PURPOSE

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

the CBRN Organic Vapor (Cyclohexane) Service Life Test, Air- Purifying Respirators 

Standard Test Procedure submitted for Approval, Extension of Approval, or examined 

during Certified Product Audits meet the certification requirements set forth in 42 CFR 

Part 84, Subpart G, Section 84.63(a)(c)(d); Volume 60, Number 110, June 8, 1995 and 

the Statement of Standard for Chemical, Biological, Radiological, and Nuclear (CBRN) 

Full- Facepiece Air- Purifying Respirator (APR) Dated March 7, 2003. 

 

2. GENERAL

This STP describes the Determination Of CBRN Organic Vapor (Cyclohexane) Service Life 

Test, Air- Purifying Respirators Standard Test Procedure 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 the product passes the test. 

3. EQUIPMENT AND MATERIAL

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

3.1.1. Miller Nelson Research Model 401 Flow-Temperature-Humidity Control 

System or equivalent. This system is an automated system to control the 

airflow, temperature, and humidity of an air supply for an operating 

system. Laboratory air and distilled water are supplied to the unit. The unit 

output is air of the variable volume/flow dependant on the size of unit 

(10% of max flow to max flow in liters per minute (Lpm) ± 2%), and 

relative humidity (10%–98% ± 3%) and temperature (20oC–30o 0

C ± 

0.3%).

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3.1.2. EdgeTech Dew Prime II Hygrometer, Model 2000 or equivalent. A microprocessor based programmable chilled mirror dew point hygrometer . The 

hygrometer uses the dew point and ambient temperature to calculate the 

relative humidity. Ambient temperature range is: -50oC to 130oC ± 0.2oC; 

relative humidity is 1% to 95% ± 0.5% 

3.1.3. Labview software developed for NIOSH Service Life Testing. 

3.1.4 Miran Ambient Air Analyzer, Model 1A with closed loop system or 

equivalent. The analyzer is a single beam variable filter spectrometer with 

a variable pathlength gas cell. For cyclohexane detection, the wavelength 

is set to 3.4 μm and the pathlength to 20.25 meters. Range is 300 to 0.03 

ppm. The closed loop system consists of a stainless steel bellows pump, 

septum and tubing with a sample volume of 5.64 liters. 

3.1.5 Amersham Biosciences High Precision Pump, Model P-500 with 

reservoir. Flow rate range: l ml/hr to 400 ml/hr ± 1.5% of setting. 

3.1.6 Electronic Balance with an accuracy of 0.01 grams. 

3.1.7 Mass Flow Controller, Brooks Instruments, model 5851. Variable flow 

rate depending on use. 

3.1.8 Read out and Control Electronics, Brooks Instruments, Model 0154, 

Power supply and controller for the Brooks Mass Flow Controller or 

equivalent. The flow controllers are an integrally mounted control valve 

module with which stable gas flows can be achieved. Various flow rates 

are used with an accuracy of ± 0.7 % of rate and ± 0.2 % full scale. 

3.1.9 Dry Test Meter, American Meter Company, Model and size depending on 

air flow to be measured. 

3.1.10 Miller Nelson Research, Model SV-2000, Vaporizer system or equivalent. 

Used for vaporizing cyclohexane solution. 

3.1.11 Cyclohexane, ACS grade, 99%. 

3.2. Test fixture for mounting canisters. 

3.3 The test chamber consisting of a 12" x 111⁄2" x 7" air tight metal box with door 

opening lined with gasket material. Two 1⁄2" bulkhead Swaglok® fittings located 

on the backside of the test chamber for the introduction of the test concentration 

and for the exit of the test fixture. This fixture is not commercially available. 

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3.4 Resistance tester consisting of a vacuum source capable of delivering 85 Lpm, a 

6-inch water column slant manometer or electronic manometer and connections 

appropriate for items being tested. See description in RCT-APR-003 and RCTAPR-007. 

4. TESTING REQUIREMENTS AND CONDITIONS

4.1 This test procedure is only valid if the respirator system has first completed 

NIOSH Standard Test Procedure entitled Determination Of Durability Test For 

Environmental, Transportation And Rough Handling Conditions On Chemical 

Biological Radiological Nuclear (CBRN) Full-Facepiece Air-Purifying 

Respirators (APR) Standard Test Procedure (STP). 

4.2 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). 

 

4.3 Any laboratory using this procedure to supply certification test data to NIOSH 

will be subject to the provisions of the NIOSH Supplier Qualification Program 

(SQP). This program is based on the tenets of ISO/IEC 17025, the NIOSH Manual 

of Analytical Methods and other NIOSH guidelines. An initial complete quality 

system audit and follow on audits are requirements of the program. Additional 

details of the Program and its requirements can be obtained directly from the 

Institute. 

4.4 Precision and accuracy (P&A) must be determined for each instrument in 

accordance with laboratory procedures and NIOSH/NPPTL guidance. Sound 

practice requires, under NIOSH Manual of Analytical Methods, demonstrating a 

tolerance range of expected data performance of a plus or minus 25% of a 95% 

confidence interval of the stated standard requirement. NIOSH/NPPTL P&A 

tolerance can be higher but not lower. 

4.5 Compressed gas cylinders must meet all applicable Department of Transportation 

requirements for cylinder approval as well as retesting / requalification. 

4.6 Normal laboratory safety practices must be observed. This includes safety 

precautions described in the current NIOSH Pittsburgh Health and Safety 

Program. 

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

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4.6.2. Workbenches must be maintained free of clutter and non-essential test 

equipment. 

4.6.3 When handling any broken glass laboratory equipment, lab technicians 

and personnel must wear special gloves, which protect against lacerations 

or punctures. 

 4.7 Please refer to Material Safety Data Sheets and the NIOSH Health and 

Safety Manual for the proper protection and care in handling, storing, and 

disposing of the chemicals and gases used in this procedure.

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. Follow individual instruction manuals for set up and maintenance of equipment 

used in this procedure prior to beginning testing. Malfunctioning equipment must 

be repaired or replaced and properly set up and calibrated before starting all tests. 

 5.2 Adjust instrument to read zero and make adjustment for Labview software to read 

0.0 ppm. 

5.3. Verify Infrared Analyzer: Refer to the performance verification procedures in the 

user manual. Inject 0.25 μL of cyclohexane into closed loop system of the IR as 

described in the manual. Once stabilized, the analyzer should read 10 ppm. Make 

adjustment for Labview software to read 10.0 ppm. Disconnect closed loop 

system and allow IR to return to zero reading. 

5.4 Set the high precision pump for delivery of calculated cyclohexane to obtain 2600 

ppm at the testing airflow. See appendix 8.2. 

5.5 Set up test equipment as shown in Figure 1. The humidity reading is controlled by 

the Miller Nelson system and monitored by the Dew Point Hygrometer. The 

sample pickup for the hygrometer is place into the air stream via a tee after the 

Miller Nelson and before the introduction point of challenge agent. The 

thermocouple for the hygrometer is placed in the challenge gas stream 

immediately before the test chamber. 

5.6. Verify the following equipment is on: 

5.6.1 Miller Nelson Flow-Temperature-Humidity Control System. 

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5.6.2 Air and water supplies. 

5.6.3 High precision pump. 

5.6.4 Electronic balance. 

5.6.5 NIOSH Service Life Apparatus Controller software program. 

5.7 Establish the correct humidity and temperature as per the test standard in 

paragraph 6.3. 

5.8 Set the airflow to the required airflow for the test. Verify the airflow from the test 

fixture using the appropriate dry test meter. 

5.9 Fill pump reservoir with cyclohexane. Insert needle from pump to septum tee in 

airline. 

5.10 Weigh and record initial weight of the test canister on Test Data Sheet. 

5.11 Take initial inhalation and exhalation resistances of the canister mounted on the 

facepiece and canister alone as described in RCT-APR-003 and RCT-APR-007. 

Record the values on Test Data Sheet. 

5.12 Make sure diverter valve in the system is diverting the challenge concentration 

airflow to discharge and not into the testing chamber. 

5.13 Mount canister onto test fixture in testing chamber. 

5.14 Start flow from the high precision pump to the needle 

5.15 Record the initial weight of the cyclohexane reserve. 

5.16 Direct challenge concentration airflow into test chamber. 

5.17 Start timer. Airflow out of the fixture is directed into the breakthrough detector. 

Monitor and record the upstream and downstream temperatures of the air stream 

throughout testing. 

5.18 Run test until breakthrough of 10 ppm is observed or requested minimum service 

life is surpassed. Weigh and record the final weight of the cyclohexane reservoir. 

5.19 Direct challenge concentration airflow out of test chamber. 

5.20 Calculate and record the challenge concentration of the cyclohexane, see 

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Procedure No. CET-APRS-STP-CBRN-0301 Revision: 1.1 Date: 29 June 2005 Page 6 of 11 

attachment 8.2. 

5.21 Weigh and record final weight of the test canister on Test Data Sheet. 

5.22 Take final inhalation and exhalation resistances of the canister mounted on the 

facepiece and canister alone as described in RCT-APR-003 and RCT-APR-007. 

Record the values on Test Data Sheet. 

5.23 Allow clean air to purge through test chamber for 5 minutes. 

5.24 Repeat steps 5.7 through 5.21 for each test described in section 6.3. 

5.25 When all tests are completed turn off cyclohexane flow, set temperature and 

humidity to zero and allow air to pass through the system for 30 minutes. 

6. PASS OR 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); 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. Organic Vapor (Cyclohexane) Test for CBRN Canisters. 

6.3.1. Resistance to airflow of both canister and system will be taken before and 

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Procedure No. CET-APRS-STP-CBRN-0301 Revision: 1.1 Date: 29 June 2005 Page 7 of 11 

after each test. 

6.3.2. Three canisters will be tested at 64 Lpm, continuous air flow, 25% ± 5% 

relative humidity (RH), 25oC ± 5oC and 2600 ppm cyclohexane. Minimum 

service life will be 15, 30, 45, 60, 90 or 120 minutes as per manufacturer 

request. 

6.3.3. Three canisters will be tested at 64 Lpm, continuous air flow, 80% ± 5% 

RH, 25oC ± 5oC and 2600 ppm cyclohexane. Minimum service life will be 

15, 30, 45, 60, 90 or 120 minutes as per manufacturer request. 

 

6.3.4 Three canisters will be tested at 100 Lpm, continuous air flow, 50% ± 5% 

RH, 25oC ± 5oC and 2600 ppm cyclohexane. Minimum service life must 

be 5 minutes. 

6.3.5 End of service life concentration is 10 ppm cyclohexane. 

7. RECORD AND TEST SHEETS

7.1. All test data will be recorded on the CBRN Organic Vapor (Cyclohexane) Service 

Life 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 CET Team 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 CET Team 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 Branch Chief, or the Branch Chief’s designee, following the 

standard operating procedures outlined in Procedure for Scheduling, and 

Processing Post-Certification Product Audits, RB-SOP-0005-00. 

8. ATTACHMENTS

8.1. Bench Top Set-Up. 

8.2. Calculations for cyclohexane. 

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8.3. Data Sheet. Uncontrolled Copy 

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Procedure No. CET-APRS-STP-CBRN-0301 Revision: 1.1 Date: 29 June 2005 Page 9 of 11 

Attachment 8.2: Calculations for cyclohexane 

Cyclohexane: 

Molecular weight = 84.2 g/mol 

1 ppm = 3.44 mg / m3 @ 25 o

C ; 760 mm Hg 

1. Calculations for injection rate of cyclohexane. 

Injection rate (ml/hr) = Conc (ppm) X 3.44 ((mg / m3

)/ppm) X Airflow (L/min) X 60 min 

1000 (mg/g) X 1000 (L/m3

) X 0.7785 (g/ml) 

 

2. Calculations for actual challenge concentration. 

Conc (ppm) = amount delivered (g) X 24.45 (L/mol)

 Airflow (Lpm) X Test time (min) X 84.2 (g/mol) 

 64 Lpm 100 Lpm 

2600 ppm 44.12 ml/hr 68.93 ml/hr

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Attachment 8.3: Test Data Sheet Uncontrolled Copy 

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Procedure No. CET-APRS-STP-CBRN-0301 Revision: 1.1 Date: 29 June 2005 Page 11 of 11 

Revision History 

Revision Date Reason for Revision 

1.0 20 September 2004 Historic document 

1.1 29 June 2005 Update header and format. 

No changes to method 

 

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