COLORIMETRIC CONCEPTS FOR RESIDUAL LIFE INDICATOR

U.S. MILITARY FORCES NEED PROTECTION AGAINST CHEMICAL WARFARE AGENTS SHOULD THESE BE DEPLOYED AGAINST THEM IN SOME FUTURE CONFLICT. TO THIS END, AN EFFECTIVE GAS MASK HAS BEEN DEVELOPED WHICH PROVIDES RESPIRATORY PROTECTION AGAINST ALL KNOWN MILITARY TOXIC CHEMICAL AGENTS.THE MASK USES WHETLERITE, A FINELY GROUND ACTIVATED CARBON, TO ADSORB THE ACTIVE AGENTS FROM THE AIR PRIOR TO ITS INHALATION. FOR LARGE SHELTERS, AIR IS FORCED BY A FAN THROUGH A MECHANICAL COLLECTIVE PROTECTOR WHICH IS ESSENTIALLY A GREATLY ENLARGED VERSION OF A MASK CANISTER. A CURRENT NEED IS FOR A METHOD TO DETERMINE THE RESIDUAL SORPTIVE CAPACITY OF THESE AGENT FILTERS, AFTER THEY HAVE BEEN IN USE FOR SOME TIME. SUCH AN INDICATOR METHOD WILL INSURE PROPER PROTECTION OF PERSONNEL, AND WILL INCREASE THEIR MOBILITY AND DECREASE THEIR LOGISTICS REQUIREMENTS BY ENABLING THEM TO MAKE FULL USE OF THE CANISTERS AND FILTERS. PREVIOUS EFFORTS TO DEVELOP A RESIDUAL LIFE INDICATOR FOR GAS FILTERS HAVE BEEN BASED ON SOPHISTICATED ELECTRONIC CHEMICAL DETECTORS WHICH HAVE PROVED UNRELIABLE. TWO METHODS BASED UPON COLORIMETRIC CHEMICAL REACTIONS ARE PROPOSED FOR DEVELOPMENT.