ASTM E492-04

The evaluation of the impact sound-insulating performance of a floor-ceiling assembly begins with the measurement of the sound pressure levels in the room below the test specimen. The spectrum of the noise in the room below is determined by the following:

5.1.1 The size and the mechanical properties of the floor-ceiling assembly, such as its construction, surface, mounting or edge restraints, stiffness, or internal damping,

5.1.2 The acoustical response of the room below, and

5.1.3 Inevitably, the characteristics and placement of the object or device producing the impacts and the nature or degree of the actual impact itself.

This test method is based on the use of a standardized tapping machine of the type specified in 8.1.1 and placed in specific positions on the floor. This machine produces a continuous series of uniform impacts at a uniform rate on a test floor and generates in the receiving room broadband sound pressure levels sufficiently high to make accurate and reproducible measurements possible. The tapping machine itself, however, is not designed to simulate any one type of impact, such as produced by male or female footsteps.

Note 1—Caution: Because of its portable design, the tapping machine does not simulate the weight of a human walker. Therefore, the creak or boom of a limber floor assembly caused by such footstep excitation may not be reflected in the single number impact rating derived from test results obtained by this test method. The degree of correlation between the results of tapping machine tests in the laboratory and the overall field performance of floors under typical conditions of domestic impact excitation may be subject to some variation, depending on both the type of floor construction and the nature of the impact excitation.

1.1 This test method covers the laboratory measurement of impact sound transmission of floor-ceiling assemblies using a standardized tapping machine. It is assumed that the test specimen constitutes the primary sound transmission path into a receiving room located directly below and that a diffuse sound field exists in this room.

1.2 Measurements may be conducted on floor-ceiling assemblies of all kinds, including those with floating-floor or suspended ceiling elements, or both, and floor-ceiling assemblies surfaced with any type of floor-surfacing or floor-covering materials.

1.3 This test method prescribes a uniform procedure for reporting laboratory test data, that is, the normalized one-third octave band sound pressure levels transmitted by the floor-ceiling assembly due to the tapping machine.

1.4 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.