Listening through walls

As security and privacy issues continue to loom in importance, Canadian government researchers are applying themselves to the problem of security within meeting rooms.
The Institute for Research in Construction at the National Research Council of Canada in Ottawa is doing the work in collaboration with the Royal Canadian Mounted Police and Public Works and Government Services Canada.
The researchers are studying how easily speech is transmitted through different wall assemblies and with different background noise from ventilation equipment. They used volunteers with negligible hearing loss and conducted extensive listening tests to create an index of measurements.
The measurements and assessment protocols will be incorporated into a practical guide for rating the speech security of rooms. The procedures are also being included as part of a proposed new National Security Code for Buildings and will be prepared for a working group at ASTM.
For more details see IRC Research Report 170 at http://irc.nrc-cnrc.gc.ca