Ductwork - Pressure

5.8.1 Positive pressure

The reference test element shall be placed horizontally with each end of the sample sealed to be

airtight by any means consistent with the use of the material under test. An end cap shall then be

connected to a positive source of pressure.

The sample shall be subject to the test procedure as specified in Table 4 with ps equal to pr+.

5.8.2 Negative pressure

The reference test element similar to that described in 5.8.1 shall be used but the end caps shall be

attached to a stationary fixture so that the duct is maintained at its nominal length. A source of

negative pressure shall be connected to one end and the reference test element subjected to the test

procedure as specified in Table 4 with negative test pressure