|Acquisition Program: ||Program Manager for the Joint Service General Purpose Mask (JSGPM)|| Objective: ||To develop an enhanced exhalation system for military chemical, biological, radiological, nuclear (CBRN) respirators that is highly resistant to leakage.
|| Description: ||Military and commercial CBRN respirators (i.e., protective masks) use an outlet valve to remove humid, CO2-ladened, exhaled air from the nosecup of the mask. The outlet valve also serves as a port to expel moisture and sweat that accumulates inside the mask. The outlet valve assembly consists of the following main components: a metal or plastic seat, a thin flexible synthetic rubber disc (outlet valve), and a protective cover. The outlet valve cover not only protects the valve from dust, dirt, wind, and physical damage but also prevents the backflow of outside contaminated air during inhalation by providing a “clean zone” (dead-space) for the filtered exhaled air. Outlet valves are also designed to provide low resistance to airflow (typically less than 20 mm H20 at 85 L/min) to reduce the physiological burden of breathing. An air-tight seal between the outlet valve and the seating surface is critical for the system to function properly. Even the best designs are susceptible to leakage from environmental and in-mask contaminants such as dirt, dust, and dried salts from sweat that can interfere with the seal. Novel technologies, materials, and designs are being sought that will minimize the likelihood of such failures. Concepts for improved respirator exhalation systems are envisioned that use self-cleaning technology, intelligent materials, or other means to clean, purge, and protect the valve from particulate and other foreign matter. The optimal system would have the following characteristics: light weight, low profile, increased durability, low breathing resistance, minimum maintenance, low manufacturing cost, and preferably non-powered. The system must be capable of meeting all interface, safety and support, durability, and operating environment requirements for military protective masks. This includes wear, carry, and long-term storage under adverse environmental conditions associated with military operations. An enhanced exhalation system would decrease inward leakage and would thus provide the wearer with increased protection against CBRN agents and other hazardous contaminants.
|| ||PHASE I: Novel candidate technologies, materials, and designs to enhance the performance of the respirator exhalation system will be investigated. The research should focus on developing an advanced design concept(s) that will substantially reduce the risk of leakage from contaminated or “dirty” outlet valves and other exhalation system components. Concept models will be fabricated and evaluated for proof-of-principle.
|| ||PHASE II: Further develop, fabricate, and characterize the performance of prototype exhalation valve system(s). Appropriate parameters such as breathing resistance, leakage rate, effects of temperature and humidity extremes, self-cleaning capability (i.e., ability to prevent entrapment of dirt, dust and other physical contaminants), and other critical performance factors will be assessed. Based on the results of these evaluations, the optimum design will be determined. Fabricate a minimum of six (6) prototypes for follow-on demonstration testing to validate performance of the optimized exhalation valve prototypes. Two of the six prototypes shall be delivered to the Government for additional testing.
|| ||PHASE III DUAL-USE COMMERCIALIZATION: Phase III includes further development of the novel exhalation valve design for both military and commercial CBRN respirators. The improved exhalation system will directly benefit current and future developmental mask programs such as the Joint Service General Purpose Mask (XM50), the Joint Service Aircrew Mask, and Next Generation General Purpose Mask. The device demonstrated in Phase II will also have duel-use application for a variety of commercial respirators used in the workplace for protection against hazardous industrial airborne contaminants.
|| References: ||1. NIOSH APR CBRN Standard, “Statement of Standard for Chemical, Biological, Radiological, Nuclear (CBRN) Full Facepiece Air Purifying Respirator (APR).” Report prepared by National Institute for Occupational Safety and Health (NIOSH), Revision 2 (4 April 2003).
|Keywords: ||CBRN respirators, outlet valves, exhalation valves, protective masks |