EXCESSIVE NOISE SCIENCE CAN SOLVE THIS MODERN PROBLEM

Press, Volume XCV, Issue 28259, 23 April 1957, Page 10

EXCESSIVE NOISE SCIENCE CAN SOLVE THIS MODERN PROBLEM

[By

DERWENT M. A. MERCER,

Lecturer in Physics at Southampton

University]

If you accepted a job in the new block of offices along a certain busy road, it would not at first be obvious that you might be exasperated several times a day. The offices are light, pleasant, and attractively laid out. and the amenities are good. Everything in fact appears to be well planned—until you happen to be using the telephone while a heavy lorry grinds by in low gear. Then you simply have to put the instrument down, as you can neither hear nor be heard.

As the busy road happens not only to be on an incline, but also to be used very frequently by these lorries, nearly every call is interrupted like this, and to the annoyance and frustration of the worker must be added the waste of time to the firm. What is even more disturbing however, is this: before the offices were planned, before a line was drawn on paper or a bulldozer moved on to the bare site, any noise control engineer could have forecast that result after an hour’s work. He would have measured the noise from the lorries, found out how frequently they passed, and, by referring to charts and graphs giving acceptable noise levels for office work, would have arrived at a definite conclusion. In this case it would have been that the offices would be satisfactory only if the windows were kept tightly closed, and, consequently, a central air circulating plant would be essential. No such scheme was proposed and not only is the ventilating plant not there, but it is structurally impossible to add it to the building—even- if the heavy cost could be met. So the annoyance continues—apart from conference rooms and executive offices, which just have to be treated. These need the installation of special sound-excluding windows and individual ventilating fans —at a three-figure cost for each room. And this. I can assure you, is happening time and time again all over the world. Designer’s Responsibility

One is reminded of the story of an eminent Victorian architect who had designed, for a college, a superb and graceful Gothic chapel. When completed, it was a beautiful sight, but unfortunately proved to' have quite impossible acoustics. When, later, the great man was dining at High Table at that college, the fault was with some trepidation pointed out to him; he simply said: “Oh yes, I thought you would have trouble with the accoustics!” This thinking is unhappily still common. Why should you—the occupier, or owner, say. of a building—have such a problem to deal with? Would you face the cost and the upheaval of instaling a central heating plant, because your building had been planned with only a small electric fire in each room, on the grounds that this was quite adequate in the summer? This is by no means a silly comparison. It is entirely parallel to the office block mentioned earlier, in which you can telephone quite -comfortably if the windows are tightly shut. Why should we be saddled with such problems not only when they are so annoying, but also when foresight and planning can prevent them?

At this point you may think that I am overstating my case. Surely, you may say, people vary so much in their / reactions to noise that H is impossible to lay down any hard and fast rules? We know of the folk who need complete quiet in order to concentrate, and we have also heard of the writers who can work only when the Light Programme is on at fortissimo strength. With such extremes, is it possible to generalise? The answer is, in fact, that one can do so very well. Groups of people, say, in offices, or in factories, are found to behave in a remarkably similar way with regard to noise; find although, of course, there are the extremes at either end of the scale, it is surprising what a small proportion of the total they form. In any case, there are some facts which are quite independent of one’s own preferences. Above a certain noise level you simply can’t use the telephone, no matter what your personal likes or dislikes about noise; and dictating letters, or carrying on a discus-

sion, becomes particularly wearing if your voice has constantly to be raised. Noise at Home The office noise problem has been investigated very thoroughly in some recent American work. In this, account is taken of two factors; the interference with speech communication due to noise and the effect of the general noise level—for it is tiring to work with, say, a loud machinery hum going on, even though you can talk quite well through it. This was based on surveys in American offices and, as far as checks have been made, it applies well in the United Kingdom. Many of us have the noise problem not in an office, but literally on our own doorstep. Are there any comparable criteria which, faced with the infinite variety of people’s tastes, and the equal variety of the noise producers which surround us, make it possible to give an “acceptable” noise for a home? The answer is still “Yes,” although in this case there are many more variables to take into account. For instance, is the community surrounded by heavy industry, or in a quiet rural setting? Is the noise a general roar, or is it a screech or a -whine like a bandsaw or siren? When these and many other factors are taken into accounts one can predict with considerable accuracy just how people will react to a given noise; even the type of complaints can be foreseen. Incidentally, “taking factors into account” means giving them numerical values. Nor is il simply a vague evaluation. The whole process is on a definite basis and is the result of a long and skilful sorting-out of the different variables for many cases in which not only the noise, but the complaints (slight, vigorous, threats of injunctions, etc.) were known. One rather interesting thing came out when we were trying to apply these curves and numbers to English communities. It appears that although we in this country are as ready to grumble at moderate noises as anyone, it needs a louder noise to make us take strong action, such as instituting legal proceedings. John Q. Citizen in the United States is much readier to pick up his telephone and start raising Cain with h;s local authority. Not all the noise which worries us comes from large industrial concerns. If you live in a flat, it may be from nothing more powerful than the feet of the child above. If your flat is a modern one, you may be doing better than you realise, as our own Building Research Station in Hertfordshire is doing sterling work in investigating soundproof floors and walls, and laying down constructional standards—a fine programme which bears comparison with anything being done elsewhere in the world.

The final answer seems to be this. Some of the noise we are exposed to appears inevitable, either as a consequence of industrial developments or—as in the case of large jet engines—because the most determined efforts have so far not found a solution. But much of the noise can be avoided, and—as far as you can—refuse to be inconvenienced by unnecessary noise, when with an awareness of the problem, and foresight and planning, the noise can be blanketed before it has a chance to reach us.—(Central Press.)