Delete clause S29C3 and insert NT S29C3 as follows:
(1) The wall constructions to be compared must be tested in accordance with AS 1191.
(2) A horizontal steel platform 510 mm x 460 mm x 10 mm thick must be placed with one long edge in continuous and direct contact with the wall to be tested on the side of the wall on which the impact sound is to be generated.
(3) A tapping machine complying with ISO 140/6 — 1998 (E) must be mounted centrally on the steel platform.
(4) The sound transmission through the wall must be determined in accordance with AS 1191 except that the tapping machine as mounted on the steel platform must be used as the source of sound.
(5) The impact sound pressure levels measured in the receiving room must be converted into normalised levels using a reference equivalent absorption area of 10m2.