Review of chamber design requirements for testing of personal protective clothing ensembles.

This review focuses on the physical requirements for conducting ensemble testing and describes the salient issues that organizations involved in the design, test, or certification of personal protective equipment (PPE) and protective clothing ensembles need to consider for strategic planning. Several current and proposed PPE ensemble test practices and standards were identified. The man-in-simulant test (MIST) is the primary procedure used by the military to evaluate clothing ensembles for protection against chemical and biological warfare agents. MIST has been incorporated into the current editions of protective clothing and equipment standards promulgated by the National Fire Protection Association (NFPA). ASTM has recently developed a new test method (ASTM F 2588-06) for MIST evaluation of protective ensembles. Other relevant test methods include those described in International Organization for Standardization (ISO) standards. The primary differences among the test methods were the choice of test challenge material (e.g., sulfur hexafluoride, methyl salicylate, sodium chloride particles, corn oil, fluorophore-impregnated silica) and the exercise protocol for the subject(s). Although ensemble test methods and standards provide detailed descriptions of the test procedures, none give specific requirements for chamber design. A literature survey identified 28 whole-body exposure chambers that have been or could potentially be used for testing protective clothing ensembles using human test subjects. Median chamber size, median floor space, and median volume per subject were calculated from 15 chambers (involving human test subjects), where size information is available. Based on the literature survey of existing chambers and the review of the current and proposed standards and test methods, chamber design requirements will be dictated by the test methods selected. Due to widely different test conditions for aerosol/particulate and vapor ensemble testing, it is unlikely that a single chamber could accommodate all types of ensemble testing. With increasing use of the MIST protocol by NFPA for CBRN certification of structural firefighting gear and protective ensembles for first responders, the need for MIST laboratory capability is clear. However, existing chambers can likely be adapted to accommodate MIST with some modifications.