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        d.  Enclosure 2, Table 2 provides results of testing conducted
    on 16 October.  Kesults show a 7~ percent successful mask fit
    during exercises.

        e.  Enclosure 1, Table 3 provides results of testing conducted
    on 17 october.  Results show a se percent successful mask fit
    during exercises.

        f.  As identified in tables 1, 2, and 3 (No) equates to overall
    failure and (Yes) equates to overall pass.  This is based on a
    protective factor of 6667.

    5.  Equipment durability.  Each Ports Count was operated for 2~
    hours during the operational test.  No equipment failure occurred.

    6.  Equipment maintenance.  The Porta Count required no maintenance
    beyond the operators capability during the test period.  However, it
    was noted that when the Port~ Count required refilling with alcohol
    the indicator failed to turn white.  Cause of this problem was
    moisture being absorbed from sampling mask by the alcohol soaked
    felt.

    7.  Summary of test.

        a.  Conclusion.

            (1)   That the Ports Count is a highly reliable instrument in
    determining the proper fit and sizing of the field protective mask
    when used by trained personnel, and recommended for procurement/
    fielding as a mask fit validation device.

            (2) The Porta Count is not to be considered a mask
    serviceability tester.  Only after repeated attempts to fit a
    particular mask to multiple individuals and failing~ could the mask
    be considered suspect and require further testing at the depot
    level.

            (3) The Ports Count was successful in indentifying the
    proper size mask for each Marine; 98% of all Ilarines tested obtained
    an adequate initial fit.  During the exercises used to validate
    the mask fit,  a 66% fit factor was obtained for the three
    day test.  This means that of the i@e Marines tested 66 maintained
    an adequate seal during all exercises.  Howeverr for the split
    second that the seal is broken during the exercise the hood
    would provide the additional protection required.

            (4) For the best mask fit results,  the individual being
    tested with the Porta Count should wear his/her mask approximately 5
    to ie minutes prior to the test.  This will increase flexibility of
___ the mask rubber allowing an increased conformity to the face and
    decreasing the chance for leakage during the test.  However,  it


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