It is difficult for the urban apartment dweller to believe that the United States National Bureau of Standards was testing home sound insulation as long ago as 1922! It has been publishing the results of such testing since 1939. Its latest guide to noise control in dwellings was published in 1967.
Builders and architects know the laboratory-tested values of more than a hundred varieties of door, floor, and wall constructions. They can get design information from the FHA, and from companies that specialize in noise-rated construction products, such as Owens-Corning and U.S. Gypsum. With this information they can select the proper sound-insulating wall, a floor construction that stops the noise of your neighbors' footsteps, and the proper materials for halls, doors, windows, as well as techniques for plugging acoustic leaks in piping and wiring openings in walls and floors and installing plumbing and appliances to operate quietly.
The builder and designer can specify the sound-insulating quality of the wall partition desired, as well as floor/ceiling construction. Methods of evaluating the acoustic quality of a finished room have been used in the Netherlands since 1948.
Mechanical equipment—such as central air conditioning motors and dishwashers—can be mounted on isolation mounts on special flooring to prevent sound transmission. Pipes can be isolated from the building structure to prevent converting the structure into a sounding box. Plumbing noises can be eliminated by proper choice of fixtures and careful installation.
One undesirable feature of air conditioning (and mechanical ventilating) is the noise made by rushing air. This noise can be controlled by reducing the velocity of the air stream, lining the air ducts with sound-absorbent materials, or equipping the outlets with mufflers. Fan noise can be reduced by increasing the number of fan blades and staggering the design of the blades to prevent the formation of irritating tones.
The noise of mechanical ventilating and central air conditioning, with its noisy air flow and cooling tower noise, is controllable. ASHRAE, the professional society of the industry, has published detailed technical reports on how to sound-control all types of air conditioning installations. It has evolved a system of noise standards and criteria for single-family homes, apartment houses, churches, offices and schools.
As a matter of fact, silencing techniques are so sophisticated, one company puts out a Short Form for busy designers to use in "calculating the amount and type of noise control desired." Noisy systems can also be quieted after installation. It is cheaper, however, to introduce noise control at the design stage.
A small detail such as not installing medicine cabinets in the walls and back to back will help eliminate noise transmission between bathrooms.
American Standard advertises a deluxe model kitchen garbage disposal unit that "is a conversation piece...because every word praising it will be easily heard." If this advertising copy is accurate, the disposal is quiet because the outer shell is constructed of heavy, extra thick fiber glass insulation with a shock-absorbent rubber mounting that cushions noise and minimizes vibration.
Builders, especially in a competitive market, will not incorporate noise control provisions without an incentive. That incentive can be made a part of local building codes by requiring that in addition to standards for fireproofing and safety, homes be built to noise insulation standards. Europeans have long recognized the need for government to provide this incentive. Germany led the way in 1938, and since then, building codes including noise specifications have been adopted in Austria, Belgium, Denmark, England, Finland, France, the Netherlands, Norway, Scotland, Sweden, and Switzerland; not to mention Bulgaria, Czechoslovakia, and the Soviet Union.
Apparently, not all of these countries require that private building meet their national standards. However, private builders, as in Switzerland, are encouraged to adhere to them, by the realization that a new tenant who finds himself deprived of the peaceful use of his apartment can go to court and obtain a rent reduction.