This International standard introduces two metal reference blocks, the hemi-step (HS) and the side-drilled-hole(SDH) blocks. This International Standard establishes procedures for measuring the sound field or beam profilesproduced by search units in contact tests. The search units include straight beam, angle beam (refractedcompressional and refracted shear), focused beam and dual element search units. The diameter or the sidedimension of the search unit shall be no greater than 25 mm. The methodology of this International Standardprovides guidelines for search units to be used for different metals including forged or rolled steel, aluminum ortitanium alloy products. The frequency range of the search units used in this International Standard extends from1 MHz to 15 MHz, where 1 MHz to 5 MHz is best suited for steels and 5 MHz to 15 MHz is best for fine grainstructured alloys such as aluminum products. If this International Standard is to be used for material other thansteels, users should be aware of the fact that the wave velocities in these materials may be different from that ofsteels and the angle beam search units are normally designed based on the steel applications. Snell’s law ofrefraction is described in this International Standard so that correct refraction angles in other materials can becalculated. This International Standard applies to angle beam search units of all practical angles (0° to 70°), and tofocused and dual element search units. This International Standard does not address the use of surface (Rayleigh)wave search units.The procedures in this International Standard can be used in whole, or in part, with other standards. For testingmaterials which are very thick or very thin, the present reference blocks may be made proportionally larger orsmaller to accommodate different search unit beam sizes. This International Standard does not address theestimation of equivalent defect sizes which will require reference blocks with flat-bottom-holes. This InternationalStandard establishes no acceptance criteria; but does establish the technical basis for criteria that may be definedby user parties.