Concept for CBRN Powered Air Purifying Respirator (PAPR) Standard


October 30, 2004

1. Purpose

To develop a NIOSH NPPTL, tight-fitting, powered air-purifying respirator standard for emergency responders that address CBRN materials identified as inhalation and/or possible hazards from terrorist activity. The respirator must meet the minimum requirements identified in the following paragraphs:

  • Paragraph 4.0 Requirements specified in Title 42 CFR, Part 84 applicable paragraphs
  • Paragraph 5.0, Requirements based on existing national and international standards
  • Paragraph 6.0, Special Requirements for CBRN

In response to acts of terrorism and other natural disasters, air-purifying respirators are used to provide respiratory protection in work areas where the hazards are known, characterized, and conditions of oxygen deficiency do not exist. Respirators used under these conditions must be sufficient to provide for contingent use in the event of a secondary device or if additional unknown hazards are encountered exposing the responder to unexpected hazards. In these unexpected situations, the air-purifying respirator must be capable of delivering breathing protection as the responder escapes from the area.

This CBRN standard needs to be universal in defining performance-based requirements that meet the widely varying needs of hazard protection, work rate and comfort. In terms of PAPR requirements and respirators in general, these needs can represent competing performance requirements. For example, moderate to high to panic demand work rates have an influence on physical size and weight of the respirator, which can affect the filter size, weight, and comfort. In addition, the hazard protection required can range from fully known and characterized conditions to the unknown and uncharacterized hazards of the unforeseen event requiring immediate escape.

This concept addresses major performance issues for flow, hazard protection, filter capacity, and particulate efficiency. The concept addresses each of these respirator issues with performance-based requirements. The CBRN Tight-Fitting PAPR concept specifies requirements for breathing performance based on the ability of the respirator to maintain a positive pressure in the breathing zone when tested with a breathing machine. The concept further allows for performance evaluation and approval at a moderate or high work rate. Breathing machines operating at 40 liters per minute (L/min) and 103 L/min volume work rates are used to establish conformance with the requirement. These breathing machine rates are well-recognized criteria used to evaluate self-contained breathing apparatus. Using this concept, a CBRN Tight-Fitting PAPR approval would be issued for either a moderate work rate of high work rate.

Filter hazard protection and capacity for the CBRN Tight-Fitting PAPR concept follows a pattern similar to both the CBRN APR and CBRN APR Escape respirator standards. The concept provides for a minimum required performance consisting of: 99.97 percent particulate efficiency and gas life with the 10 test representative agents (TRAs) defined in the existing CBRN respirator standards.

Canister capacity and particulate efficiency testing is done at flow rates determined by the maximum flow rate of the respirator. In addition to flow, canister capacity, work rate, and particulate efficiency requirements the CBRN Tight-Fitting PAPR concept also addresses CBRN required performance for live agent testing (LAT) for sarin (GB) and mustard (HD) and a laboratory respirator protection level (LRPL) test. Enhanced performance requirements for respirator field of view (FOV), communications, durability conditioning, and battery performance are identified in the CBRN Tight Fitting PAPR concept

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Page last reviewed: November 15, 2004