The matter is further complicated by the fact that aircraft do not radiate sound equally in all directions and tend to be much louder when moving away from a building than when approaching it. The third component of the project is the development of Windows-based software that will be more accurate and easier to use than previous design procedures. Sound insulation calculations are based on the characteristics of the aircraft noise, the sound insulation ratings and the areas of the various facade elements. To be accurate, and meaningful, the calculations must be repeated for a wide range of frequencies and take into consideration differences between laboratory and field conditions. The new software includes a database of more than 100 sound insulation measurements and allows the user to compare various design solutions to quickly and conveniently arrive at an optimum design.
Users can add new sound insulation and aircraft noise data, making the program even more useful.
In addition to calculations in decibels, there will be audible simulations of aircraft sounds experienced indoors for selected design examples. This means that the user will be able to listen to the differences between design options as well as look at the numbers. All components of the project, including the software and an accompanying manual, are expected to be complete by mid-2001 and will be made available for a nominal fee. Notification of availability will be provided in Construction Innovation . The project was undertaken with the support of the Department of National Defence, Transport Canada and the National Research Council, with additional support from Vancouver International Airport.