Sound Transmission In Buildings Research Articles

The Tenth Sir Richard Fairey Memorial Lecture: Sound transmission in buildings

Sound transmission through walls, ceilings, windows, doors, etc., depends on (1) mass per unit area, (2) bending stiffness, (3) damping, (4) variation in bending stiffness (because of struts or other anisotropies), (5) stiffness and damping of interlayers and sound bridges (in cases of double walls), (6) size and shape of partitions, (7) mounting conditions, (8) influence of flanking walls, (9) unwanted effects such as slits, etc. The first three parameters and to a certain degree also the fourth and fifth can be dealt with theoretically by investigating walls of infinite size. In this way many of the results obtained in buildings can be explained at least qualitatively. The influences of size, shape, mounting conditions and the influence of flanking transmission can be understood best by applying energy balance equations, and in this way the average behaviour of reasonably large constructions can be explained. Even though sound transmission has been investigated for approximately 80 years, there still remain some open questions especially with respect to inhomogeneous walls and multiple walls of finite size.

American and European Standard Methods for Measurement of Sound Transmission in Buildings

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The National Physical Laboratory

THE report for 1939 of the National Physical Laboratory covers 100 pages (London: H.M. Stationery Office. 2s. 6d. net). During the year there has been no great falling off in the experimental work done for, and the advice given to, industry both for immediate purposes and for long-range projects for opening up new possibilities, or in the testing of instruments or the maintenance of exact standards of measurement. But the War has raised new problems for solution which have come from the Services and the civil defence departments. Changes of staff to and from industry, to the Admiralty, the Air Ministry and the Forces have been more numerous than usual. Among the investigations of the year may be mentioned those on the physical properties of carbon steels, light aluminium and magnesium alloys, ship propellers, new aircraft, the reduction of sound transmission in buildings, electrical insulating materials and the propagation of ultra-short radio waves. Members of the staff have continued to give lectures on the work of the Laboratory at provincial centres, to serve on technical committees at home, and to attend international conferences on scientific and technical questions abroad.

Progress in Building Research

PROGRESS towards the solution of many building problems is recorded in the annual report for 1938 of the Building Research Board recently issued by the Department of Scientific and Industrial Research (London: H.M. Stationery Office. 3s. 6d. net). One of those pressing most urgently for investigation is that of sound transmission in buildings, and in this sphere of activity the report claims that the position of these inquiries has been very much advanced during the past year. It has been made clear that in buildings with a normal continuous rigid construction it is virtually impossible to obtain a higher degree of sound insulation between two neighbouring rooms greater than that obtainable with 9-inch brick walls on a concrete floor resting on sound insulators. Reviewing, therefore, the results of experiments in the small steel frame building at the Research Station, in which various types of construction can be tested, it is claimed that practical suggestions for construction to cut down sound transmission can now be advanced.