scope:

This International Standard establishes:
- The general concept of the limits of applicability of acoustic measurements in water
resulting from finite-amplitude acoustic effects.
- A method to ensure that measurements are made under quasi-linear conditions in order to
minimise finite-amplitude effects, which may be applied under the following conditions:
- to acoustic fields in the frequency range 0.5 MHz to 15 MHz;
- to acoustic fields generated by plane sources and focussing sources of amplitude gain
up to 12;
- at all depths for which the maximum acoustic pressure in the plane perpendicular to
the acoustic axis lies on the axis;
- to both circular and rectangular source geometries;
- to both continuous-wave and pulsed fields.
- The definition of an acoustic quantity appropriate for establishing quasi-linear conditions.
- A threshold value for the acoustic quantity as an upper limit for quasi-linear conditions.
- A method for the estimation of attenuated acoustic quantities under conditions of nonlinear
propagation in water.