ASTM E336-23 PDF

SIGNIFICANCE AND USE 5.1 The main part of this standard uses procedures originally developed for laboratory measurements of the sound transmission loss of partitions. These procedures assume that the rooms in which the measurements are performed have a sound field that reasonably approximates a diffuse field. Sound pressure levels in such rooms are reasonably uniform throughout the room and average levels vary inversely with the logarithm of the room sound absorption. Not all rooms will satisfy these conditions. Experience and controlled studies (1)6 have shown that the test method is applicable to smaller spaces normally used for work or living, such as rooms in multi-family dwellings, hotel guest rooms, meeting rooms, and offices with volumes less than 150 m3. The measures appropriate for such spaces are NR, NNR, and ATL. The corresponding single number ratings are NIC, NNIC and ASTC. The ATL and ASTC are measurable between larger spaces that meet a limitation on absorption in the spaces to provide uniform sound distribution. 5.2 Annex A1 was developed for use in spaces that are very large (volume of 150 m3 or greater). Sound pressure levels during testing vary markedly across large rooms so that the degree of isolation varies strongly with distance from the common (separating) partition. This procedure evaluates the isolation observed near the partition. The appropriate measure is NR, and the appropriate single number rating is NIC. 5.3 Several metrics are available for specific uses. Some evaluate the overall sound isolation between spaces including the effect of absorption in the receiving space and some evaluate the performance or apparent performance of the partition being evaluated. The results obtained are applicable only to the specific location tested. 5.3.1 Noise Reduction (NR) and Noise Isolation Class (NIC)—Describe the sound isolation found between two spaces. Noise reduction data are based on the space- and time averaged sound pressure levels meeting the require... SCOPE 1.1 The sound isolation between two spaces in a building is influenced most strongly by a combination of the direct transmission through the nominally separating building element (as normally measured in a laboratory) and any transmission along a number of indirect paths, referred to as flanking paths. Fig. 1 illustrates the direct paths (D) and some possible structural flanking paths (F). Additional non-structural flanking paths include transmission through common air ducts between rooms, or doors to the corridor from adjacent rooms. Sound isolation is also influenced by the size of the separating partition between spaces and absorption in the receiving space, and in the case of small spaces by modal behavior of the space and close proximity to surfaces. FIG. 1 Direct (D) and Some Indirect or Flanking Paths (F and Dotted) in a Building 1.2 The main part of this test method defines procedures and metrics to assess the sound isolation between two rooms or portions thereof in a building separated by a common partition or the apparent sound insulation of the separating partition, including both direct and flanking transmission paths in all cases. Appropriate measures and their single number ratings are the noise reduction (NR) and noise isolation class (NIC) which indicate the isolation with the receiving room furnished as it is during the test, the normalized noise reduction (NNR) and normalized noise isolation class (NNIC) which indicate the isolation expected if the receiving room was a normally furnished living or office space that is at least 25 m3 (especially useful when the test must be done with the receiving room unfurnished), and the apparent transmission loss (ATL) and apparent sound transmission class (ASTC) which indicate the apparent sound insulating properties of a separating partition including both the direct transmission and flanking transmission through the support structure. The measurement of ATL ...