scope:

NEN-ISO 20155 specifies a test method for determining flow induced in-pipe noise source characteristics of a ship-used pump as a two-port sound source in laboratory conditions by measuring acoustic pressures in the pipe reaches of inlet and outlet. The test method is applicable to all types of centrifugal pumps with a diameter over 50 mm operating under steady conditions. The suitable frequency range of the test method is about 10 Hz to 1 000 Hz, and the upper frequency is dependent on the inner diameter of the pipe, in which the plane acoustic wave propagates.