MIL-STD-398 Shields, Operational For Ammunition Operations, Criteria For Design Of And Tests For AcceptanceThis standard establishes minimum design criteria and test methods for acceptance of operational shields developed to protect personnel and assets from accidental or intentional detonation of explosives during ammunition surveillance, maintenance, modification, renovation and demilitarization operations or ammunition loading operations as defined in paragraph V1.E9.3.1.1 of DoDM 6055.09-M.

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MIL-STD-398A

METHOD 101

BLAST OVERPRESSURE MEASUREMENT

1 PURPOSE

1.1 Measurement of blast overpressure is conducted to insure that personnel are not exposed to peak positive incident overpressures greater than 2.3 psi (15.9 kPa), when the operational shield is subjected to a maximum credible incident.

1.2 An acceptable alternative to measuring peak positive incident overpressure is to measure peak positive normal reflected overpressure. Personnel shall not be exposed to maximum positive normal reflected overpressure greater than 5.0 psi (34kN/m2), when the operational shield is subjected to a maximum credible incident.

2. DESCRIPTION OF TEST. A maximum credible incident is created with the operational shield. Blast pressure gages are used to measure blast overpressures.

3. CRITERIA FOR PASSING TEST. The operational shield shall be considered

acceptable if it can be determined from pressure-distance plot of test data, that personnel will not be exposed to peak positive incident overpressures above 2.3 psi (16kN/m2) or peak positive normal reflected overpressure above 5.0 psi (34kN/m2).

4. INSTRUMENTATION. Blast pressure gages and electronic recording system. Based on the equivalent test charge weight of explosives and anticipated peak overpressure, the instrumentation system shall have the necessary response time and bandwidth to acquire data. Instrumentation shall be calibrated in accordance with current procedures in TB 43-180, Calibration Requirements for the Maintenance of Army Materiel.

5. TEST PROCEDURE

5.1 Location of blast gages.

5.1.1 When the shield is tested in a simulated operational bay environment, overpressure readings shall be taken at the following locations:

a. At the center of probable head locations of each operator. For standing locations the gages shall be positioned 65 inches (1.65 meters) above the floor; for sitting locations it shall be 31.5 inches (0.80 meters) above the seat.

b. At representative positions where transient personnel may be located.2

2 Gage locations shall be as designated by the design activity in the test plan and approved by authorized authority.