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DRAFT FOR DISCUSSION
(1) Goal:Develop a NIOSH, NPPTL,tight fitting, full facepiece, air purifying respirator standard that addresses CBRN materials identified as inhalation hazards and/or possible terrorist hazards using a minimum number of filters for emergency responders. Target: Four (4) filters
* Indicated times are for illustration only. Actual times will be established from hazard modeling and developmental test results. (2) Hazards:NIOSH has been evaluating various lists of chemicals that could be deployed as a result of a terrorist incident. In an effort to reduce the number of certification tests necessary as part of a Chemical Biological Radiological Nuclear (CBRN) Air-Purifying Respirator (APR) standard, efforts have been underway to categorize potential respiratory hazards into families with a representative test chemical identified for each family. The following information is a synopsis of this effort to date. The current carbon technology used in canisters
and cartridges were reviewed from existing certification standards. The
current standards for gas masks in Europe and the U.S. (NIOSH) were reviewed.
The military purchasing specification for ASZM-T carbon for C2A1 military
canisters was also reviewed. The most common parameters identified from
the review of the military specification and the certification standards
were the middle range certification challenges. Some of the test chemicals
were considered to be redundant, since other test chemicals would guarantee
the carbon effectiveness against the chemicals in question (Chlorine,
Hydrogen Chloride, Hydrogen Fluoride, Phosphine, CS & CN Tear Gases).
Carbon tetrachloride and Cyclohexane are the representative chemicals
for organic vapors. Meeting the organic vapor test for a cartridge will
provide protection for all organic vapors having vapor pressures less
than those of carbon tetrachloride and cyclohexane. From the CWA /TIC
list, approximately 61 organic chemicals are cover by this logic, including
GB and HD. The acid gases (32 chemicals) are covered by cyanogen chloride,
hydrogen cyanide, hydrogen sulfide, and sulfur dioxide. Ammonia represents
the base gases, and covers another 4 chemicals on the list. Ethylene oxide,
formaldehyde, phosgene, phosphine and nitrogen dioxide are considered
special case chemicals. Phosphine is a hydride and must be removed catalytically
(copper+2 and silver impregnates on carbon). Therefore, 108
of the 151 chemicals can be addressed through testing these 11 chemicals.
Only one organic vapor test agent, cyclohexane or carbon tetrachloride,
will be used reducing the list to 10 test chemicals. Nine of the test
chemicals are listed in ITF 25.
Hazard mapping: Conduct modeling based on the 'Most Credible Event' (MCE) scenarios developed for the open-circuit SCBA CBRN standard to determine warm zone operational scenarios. Add or delete scenarios depending on the Toxic Industrial Material (TIM) being evaluated. (3) Respirator Use:A. Warm Use: Less than IDLH concentrations, to REL; sustained warm zone support operations; long term use for decon, traffic control, rehabilitation, rescue and recovery; agent known & quantified. B. Crisis Provision: Contingency use for short duration, above IDLH concentrations and high physiological (flow) demand possible; Contingency for unforeseen factors such as secondary device or pockets of entrapped hazard.
* Indicated times are for illustration only. Actual times will be established from hazard modeling and developmental test results. (4) Filter Test Requirements:
Notes: 1.The six (6) APR systems may be used in the Penetration and Permeation test. 2. RCT-APR-STP-0004, Determination of Exhalation Valve Leakage Test, APR, STP, dated March 7, 2002 for HF Breathing Resistance: 3 Respirators. 3. RCT-APR-STP-0014, Determination of Leakage of Drinking Tube and Accessories for Respirator Facepieces STP, dated January 14, 2002, for HF Hydration/Drinking Tube: 3 Respirators. 4. RCT-APR-STP-0064, Determination of Facepiece Carbon Dioxide and Oxygen Concentration Levels of Tight Fitting Powered Air Purifying Respirators with the Blower Unit Off and Tight Fitting Non-Powered Gas Masks with a Tight Fitting Neck Seal STP, dated April 26, 2001 for HF CO2 Test: 3 Respirators.
(1) Crisis is a high use concentration at a high flow rate, 100 liters, per minute. (2) Same test concentrations, different flow rates (5) Special Test Requirements:
The air purifying respirator system, including all components and accessories shall resist the permeation and penetration of distilled sulfur mustard (HD) and Sarin (GB) chemical agents when tested on an upper-torso manikin connected to a breathing machine operating at an air flow rate of 40 liters per minute (L/min), 36 respirations per minute, 1.1 liters tidal volume. Test requirements for distilled sulfur mustard (HD) are shown in Table 1. Table 1: Simultaneous Liquid and Vapor Challenge of APR with Distilled Sulfur Mustard (HD)
** Duration of challenge and minimum service life will be determined from hazard modeling and developmental test results. (1)Vapor challenge concentration will start immediately after the liquid drops have been applied and the test chamber has been sealed. (2)The test period begins upon start of initial vapor generation. (3)Three consecutive sequential test data points at or exceeding 0.6 mg/m3 will collectively constitute a failure where each test value is based on a detector sample time of approximately 2 minutes. (4)The cumulative Ct including all peak data points must not be exceeded for the duration of the test. Test requirements for Sarin (GB) agent are shown in Table 2. Table 2: Vapor Challenge of APR with Sarin (GB)
** Duration of challenge and minimum service life will be determined from hazard modeling and developmental test results. (1)The vapor challenge concentration generation will be initiated immediately after test chamber has been sealed. (2)The test period begins upon initial generation of vapor concentration. (3)Three consecutive sequential test data points at or exceeding 0.087 mg/m3 will collectively constitute a failure where each test value is based on a detector sample time of approximately 2 minutes. (4)The cumulative Ct including all peak data points must not be exceeded for the duration of the test.
The measured laboratory respiratory protection level (LRPL) for each full facepiece, air purifying respirator shall be 1000, when the APR facepiece is tested in a negative pressure mode in an atmosphere containing 20-40 mg/m3 corn oil aerosol of a mass median aerodynamic diameter of 0.4 to 0.6 micrometers. (6) Design Requirements:
Interchangeable consumable filter cartridges and canisters are not required, as part of CBRN APR certification, but optional approval requirements for manufacturers will be identified. Interchangeability concept will use existing European standards, EN 136 and EN 148.
(1) Pass / Fail Criteria is determined after APR has been subjected to Hot, Cold, Humidity and Vibration environmental exposure sequence order. Pass / Fail Criteria for Drop test is determined after 3 drops, 1 drop per axis, is completed.
Subpart A: General Provisions Subpart B: Application For Approval Subpart D: Approval and Disapproval Subpart E: Quality Control Subpart F: Classification of Approved Respirators Subpart G: General Construction and Performance
84.110 Gas Masks; description. 84.111 Gas masks; required components 84.112 Canisters and cartridges in parallel; resistance requirements 84.113 Canisters and cartridges; color and markings; requirements 84.114 Filters used with canisters and cartridges; location; replacement 84.115 Breathing tubes; minimum requirements 84.116 Harnesses; installation and construction; minimum requirements 84.117 Gas mask containers; minimum requirements 84.118 Half-mask facepieces, full facepieces, and mouthpieces; fit; minimum requirements 84.119 Facepieces; eyepieces; minimum requirements 84.120 Inhalation and exhalation valves; minimum requirements 84.121 Head harnesses; minimum requirements 84.123 Exhalation valve leakage test Appendix A - Full Facepiece FoggingTwo individuals with a visual acuity of 20/70 better shall perform each test while wearing the apparatus according to manufacturers directions. Test participants shall be assigned a properly sized and fitted test respirator for each environmental exposure condition. All participants shall be trained in the donning and usage of the respirator per manufacturer's instructions. Prior to testing, visual acuity shall be recorded for each subject while wearing the respirator using Snellen Eye Test charts or an equivalent method. Test 1 The APR shall be cold soaked in an environmental chamber at minus 21oC (-6oF)for 4 hours. At the start of each cold temperature wear trial a test participant shall enter the test chamber (maintained at -21oC) and sit quietly for five minutes. Once the five minute rest period transpires, subjects shall self-don their assigned respirator. A visual acuity test shall then be administered to quantify the impact of any lens fogging on vision. The test participant shall then complete a 12-minute work-rest-work regimen comprised of five minutes of exercise, 2 minutes of rest, and an additional five minutes of exercise with the exercise periods consisting of treadmill walking at 4.8 km/hr (3 mph) on a level grade. Visual acuity tests shall be repeated at the end of each walk period (i.e., after five minutes of walking and at the end of the 12 minute period immediately following the treadmill walk). Test 2 The APR shall be conditioned in an environmental chamber at 15.5oC (60oF), 75% RH for 4 hours. At the start of each cool/humid temperature wear trial a test participant shall enter the test chamber (maintained at 15.5 C) and sit quietly for five minutes. Once the five minute rest period transpires, subjects shall self-don their assigned respirator. A visual acuity test shall then be administered to quantify the impact of any lens fogging on vision. The test participant shall then complete a 12-minute work-rest-work regimen comprised of five minutes of exercise, 2 minutes of rest, and an additional five minutes of exercise with the exercise periods consisting of treadmill walking at 4.8 km/hr (3 mph) on a level grade. Visual acuity tests shall be repeated at the end
of each walk period. where VAchamber x = visual acuity score during chamber test at time x and VAintial = visual acuity score obtained with the mask prior to testing.Visual acuity performance ratings calculated from measurements taken post-donning and at the end of each treadmill walk shall be averaged for each individual subject to obtain an average visual acuity performance rating for each subject based on the environmental condition.Average performance rating for each test participant shall be greater than or equal to 70% for both Test 1 and Test 2 to meet the fogging requirement. Appendix B-Communication1) Speech intelligibility testing shall be accomplished through the use of the Modified Rhyme Test (MRT), which evaluates a listener's ability to comprehend single words and provides an indication of speech transmission of the selected words. The MRT consists of multiple lists of 50 monosyllabic, phonetically balanced words each. A sample word list is provided in Table 1.Table 1. Sample MRT stimulus word list
2) Three test listeners consisting of two males and
one female shall comprise the subject test panel. All participants shall
be tested for "normal" hearing prior to testing by a qualified individual.
(2)
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