MIL-STD-962-SUP Defense Standards Format and ContentThis standard establishes the format and content requirements for the preparation of standards prepared either by DoD activities or by contractors for the DoD.

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MIL-STD-962D

MIL-STD-202G METHOD 112E SEAL

1.  PURPOSE.  The purpose of this test method is to determine the effectiveness of the seal of a component part which has an internal cavity which is either evacuated or contains air or gas.

1.1  Definitions.

a.   Standard leak rate.  Standard leak rate is defined as the quantity of dry air at 25°C in atmospheric cubic centimeters flowing through a leak or multiple leak paths per second when the high-pressure side is at 1 atmosphere (760 mm Hg absolute) and the

low-pressure side is at a pressure of not greater than 1 mm Hg absolute.  Standard leak rate shall be expressed in units of atmospheric cubic centimeters per second (atm cm3/s).

b.   Measured leak rate.  Measured leak rate (R1) is defined as the leak rate of a given package as measured under specified conditions and employing a specified test medium. Measured leak rate shall be expressed in units of atmospheric cubic centimeters per second (atm cm3/s).  For the purpose of comparison with rates determined by other methods of testing, the measured leak rates must be converted to equivalent standard leak rate.

c.   Equivalent standard leak rate.  The equivalent standard leak rate of a given package, with a measured leak rate (R1), is defined as the leak rate of the same package with the same leak geometry, which would exist under the standard conditions of 1.1a.  The formula (does not apply to procedure IIIb) in 5.4.3.2.3 represents the L/R1  ratio and gives the equivalent standard leak rate of the package with a measured leak rate (R1) where the package volume and leak test conditioning parameters influence the measured value of (R1).  The equivalent standard leak rate shall be expressed in units of atm cm3/s.

Change 1 resulted in revision E of this test method.

29 May 2002

(THIS IS AN EXAMPLE ONLY.  THE REQUIREMENT IS IN 5.18.4.1.) FIGURE 8.  Example of change for standard containing individual tasks, requirements, or test

methods.

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