Standard: ASTM E336 - Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings

Certification Required: Field acoustical certification is currently not required by most building codes, however the ASTC rating is required by the IBC and IRC codes for demising walls and floor-ceiling assemblies in multi-family dwellings. Field sound transmission loss measurements may be necessary in certain types of buildings to meet the requirements in ANSI/ASHRAE/ICC/USGBC/IES Standard 189.1, LEED, ANSI/ASA S12.60 Guidelines for Schools, FGI Guidelines for Healthcare Facilities, and the International Green Construction Code.

Scope: This test method covers the field measurement of airborne sound transmission loss of interior and building partitions. The data obtained from this test is used to calculate the noise isolation class (NIC), normalized noise isolation class (NNIC) and apparent sound transmission class (ASTC) ratings in accordance with ASTM E413.

Applicable Products: Interior wall partitions and floor-ceiling systems. Only whole partitions can be tested. A whole partition can include an element (such as a window or door), but an element cannot be isolated and tested.

Test Procedure: Testing is performed between two adjacent rooms. The rooms can be oriented side by side or one above the other. The noise reduction (NR) is the difference between the space and time-averaged sound pressure levels measured in both rooms when broadband noise is being generated in the source room. For unfurnished rooms, the NR and the sound absorption in the receiving room is used to calculate the normalized noise reduction (NNR). The NR, receiving room sound absorption and the area of the wall or floor-ceiling partition is used to calculate the apparent transmission loss (ATL).

End Result: The test report will include the noise reduction (NR), normalized noise reduction (NNR), and/or apparent transmission loss (ATL) values from 125 to 4000 Hertz, and the corresponding the noise isolation class (NIC), normalized noise isolation class (NNIC) and apparent sound transmission class (ASTC) ratings respectively.

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