Introduction xix
looks into methods for predicting the resulting sound insulation in a finished building.
Here one takes account of all the different sound transmission paths between rooms
putting emphasis on the flanking transmission, sound energy transmitted by way of the
flanking members of the primary partition.
We have, as far as possible, tried to compare the various prediction models
presented with relevant measurement results. A collection of results from sound
insulation tests, compiled by Homb et al. (1983) (see references to Chapter 6), has been
extremely valuable in preparing the Chapters 6 and 8. A number of data, both measured
and predicted results, have also been reproduced from scientific journals and books. By
reproduced we mean that the data are digitized from the original figures and plotted into
new graphs. Permission from individuals and from journal publishers to do so is
gratefully acknowledged.
Commercial program packages have been used for a couple of the examples but
generally the calculations are performed by programs developed by the author and
colleagues at NTNU and SINTEF. Important contributions have also resulted from
cooperation with colleagues from the Katholieke Universiteit Leuven, Belgium, and
l’Université de Maine, Le Mans, France. One of these programs, WinFLAG™, has for
some years been commercially available.
Lastly, some comments must be made on the nomenclature used for the quantities.
The quantities and units recommended by ISO are laid down in a new series of standards
with the main number 80000 of which the acoustics field is covered by part 8. As a
general rule, all quantities having the unit 1 (one) should be denoted factor, i.e. one
should use absorption factor, transmission factor and so on, not absorption coefficient
and transmission coefficient. We shall then reserve the notion “coefficient” for quantities
having a unit different from 1. We have adhered to these recommendations in this book,
which hopefully will not appear confusing for those accustomed to use the word
coefficient whatever the unit might be.
T.E. Vigran