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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: Two (2) 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 agents 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). Cyclohexane is the representative chemical for organic vapors. Meeting the organic vapor test for a cartridge will provide protection for all organic vapors having vapor pressures less than that of 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. 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 10 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. Optional approval requirements for manufacturers are identified in the following paragraphs.
The interface between the filter and the facepiece
or respirator system shall use a standard thread in accordance with European
Standard EN148.1. The filter shall be readily replaceable without use
of special tools. The interface connector on the facepiece shall be the
female thread and gasket-sealing gland as identified in EN148.1. The filter
shall use a male thread in accordance with EN148.1. For respirators where
the filter canister is not directly attached to the facepiece, (i.e.,
not mask mounted) a female thread and gasket sealing gland connector complying
with EN 148.1 must be securely attached to a harness system to provide
strain relief between the filter and the remaining respirator system.
The facepiece resistance to airflow shall be less than or equal to 10 mm water column when tested at 85 liters per minute.
The filter resistance to airflow shall be less than or equal to 55 mm water column when tested at 85 liters per minute in the initial condition.
The resistance to airflow for the respirator less facepiece shall be equal to or less than 60 mm water column height when tested at 85 liters per minute.
The maximum weight of a mask mounted (chin style) filter shall be 500 grams. The maximum size of a mask mounted (chin style) filter shall be such that the filter shall pass (with the threaded connector perpendicular to the diameter opening) through a 5-inch diameter opening.
The leakage of the facepiece shall not exceed that
indicated by a change of 10 mm H20 in 1 minute when tested with 95 to
100 mm H20 negative pressure. The test shall be performed using a mannequin
head and a pressure of negative 95 to 100 mm H20 created in the cavity
of the facepiece. The inhalation port of the mask shall be fitted with
a test filter weighted to 500 grams and sized to the maximum permissible
dimensions of (6)(b)(2)(d). The exhalation valve shall be moistened for
the test.
(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 Fogging Two 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. Interpretation of Results Performance Rating (%) = VACHAMBEREX
/ VAINITIAL X 100 (1) 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-Communication 1) 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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