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Concept for Full Facepiece Air Purifying Respirator (APR) Standard


NOTE: This page is archived for historical purposes and is no longer being maintained or updated.

April 30, 2002


Develop a NIOSH NPPTL 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

  Short Duration Long Duration
TIMs 15 minutes 60 minutes
TIMs plus CO 15 minutes 60 minutes


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 synopses 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 and nitrogen dioxide are considered special case chemicals. Arsine is a hydride and must be removed catalytically (copper+2 and silver impregnates on carbon). Therefore, 104 of the 151 chemicals can be addressed through testing these 11 chemicals. Nine of the test chemicals are listed in ITF 25.

Chemicals Organization Using as Test Agent
Ammonia NIOSH & EN
Cyclohexane Organic Vapor- EN
Carbon Tetrachloride Organic Vapor- NIOSH
Cyanogen Chloride Military
Ethylene Oxide NIOSH
Formaldehyde NIOSH
Hydrogen Cyanide
NIOSH, EN & Military
Hydrogen Sulfide NIOSH & EN
Nitrogen Dioxide NIOSH & EN
Phosgene Military
Sulfur Dioxide NIOSH & EN

Hazard mapping: Conduct modeling based on the ‘Most Credible Event’ scenarios developed for the open-circuit SCBA CBRN standard to determine warm zone operational scenarios. Add or delete scenarios depending on TIM being evaluated.

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 & quantitified.

B. Crisis Provision: Initial assessment to a suspicious occurrence; use as entry & egress device to the point of a recognized hazard & additional protection needed; Short duration, above IDLH concentrations, high physiological (flow) demand.

Filter Configuration Long1 Duration
Less Than IDLH
(Panic Demand)
Short3 Duration
Less Than IDLH
Filter #1,
TIM’s less CO
Full Facepiece
Back or Chest
60 Minutes 20 Minutes  
Filter #2,
TIM’s plus CO
Full Facepiece
Back or Chest
60 Minutes 20 Minutes  
Filter #3,
TIM’s less CO
Full Facepiece
Mask Mounted
  5 Minutes 15 Minutes
Filter #4,
TIM’s plus CO
Full Facepiece
Mask Mounted
  5 Minutes 15 Minutes

1. Rescue, recovery, rehabilitation

2. Site Assessment, potential threat or escape

3. Escape from low threat situations

Filter Test Requirements:

  Warm Zone
Non IDLH Challenge
High Challenge
64 lpm flow (200 lpm peak)
high flow 100 lpm (300 lpm peak)   x
Rough handling x x

Crisis is high use concentration at high flow rate, 300 liters per minute.

Permeation / Penetration Requirements:

Respirator system and component level testing.

Design Requirement:

Interchangeable consumable filter cartridges and canisters.

Rough handling (transportability, temperature range, survivability)

Operation Oriented (donning, field of view/acuity, flow, resistance, storage life, usage life)

Long term field auditing/maintenance procedures/ inspection The U.S. Government's Official Web PortalDepartment of Health and Human Services
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