Selecting Walls for Speech Privacy

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TypeTechnical Report
Series titleResearch Report, NRC Institute for Research in Construction; Volume 314
Physical description25 p.
Subjectspeech privacy, closed offices, speech security, sound transmission; Speech security
AbstractThe sound attenuating properties of walls can be measured in laboratory tests of sound transmission loss versus frequency. These values are often reduced to the single value of the Sound Transmission Class, STC, rating to simplify the rank ordering of the sound insulating properties of walls. However, the average Transmission loss, TL(avg), is now known to be a better indicator of the amount of speech privacy provided by a wall for closed rooms. This report explains this new measure and presents sound transmission loss data for 74 different types of gypsum board walls with calculated TL(avg) and STC values for each type of wall. Changes to wall parameters such as: (a) gypsum board thickness, (b) stud cavity depth, and (c) stud spacing are shown to affect TL(avg) values differently than STC values. It is therefore important to select walls, intended to provide adequate speech privacy, based on their measured TL(avg) values and to not assume that all of the changes that might increase STC values will similarly increase TL(avg) values. To broaden the range of wall types, sound transmission loss data and corresponding TL(avg) and STC values for 20 concrete block walls are also included. This report is intended to familiarize readers with TL(avg) values and to aid in the selection of wall constructions that will provide adequate speech privacy for closed rooms.
Publication date
AffiliationNRC Institute for Research in Construction; National Research Council Canada
Peer reviewedNo
NRC number21625
NPARC number20374721
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Record identifierd5b88b21-a465-4ecd-9d9c-f3d965c19538
Record created2012-07-23
Record modified2016-10-03
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