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25
REDUCTION OF UNNECESSARY NOISE FROM ROAD BREAKERS
The significance of this Section of the Annual Report cannot be over
estimated, for progress in this field of administration during the year of
pioneer work commenced in Shoreditch has had repercussions not only throughout
the length and breadth of this Country but throughout the World and in particular
our work has been recognised in Europe, United States of America, Canada
and Rhodesia.
All engaged on this important work pioneered by this Council, particularly
the Chief Public Health Inspector are to be commended on the results of
the research and investigations carried out by them. Compromise and persuasion
have been the hallmark of the success enjoyed. Confidence of al1 the principal
makers and users of pneumatic equipment has been fostered to such a degree that
many who four years ago resented any suggestion of modification to their equipment
now work with us as part of a team with the one objective of ridding roadbreaking
equipment of all unnecessary noise.
After several years hard work of sowing the seed and after many
disappointments, the first major break through came in February this year. At
the invitation of the Chief Public Health Inspector for the very first time,
all the principal makers and users of road breakers met together with members
and officers of local authorities throughout the London Area, Building Research
Station and the National Physical Laboratory representatives, Acoustic
Engineers and others interested in this vital subject to see if we could
together agree a standard of noise from road breakers acceptable to local
authorities and makers alike.
A small working committee was therefore formed to investigate how
best to reach this goal and it was at the suggestion of one of the Engineers on
that Committee that an entirely new approach was made to the subject.
In co-operation with the Chief Public Health Inspector research
continued in an entirely new direction,for contractors had opposed any attemptin
the past to suppress noise on the grounds that this reduced the efficiency
of the breaker, delayed the work, and consequently increased the cost of the
job.
An attempt was made to isolate those of the sounds which annoy and
irritate. Working in accordance with the British Standard Code of Practice
entitled 'Sound insulation and noise reduction dated 1960, our efforts were
devoted to the conversion of the high frequency sounds, (these which cause the
irritation and annoyance) into low frequency sounds which are more acceptable
to the ear.
Our efforts were eventually rewarded and what is now known as a
Noise Converter' , designed to fit any existing type of pneumatic hammer, was
produced and tried out in the field, scientific and subjective tests being
carried out. A dramatic improvement in noise acceptability was immediately
evident. At the same time there was no loss of efficiency in the hammer.
Having gained this measure of success a Conference was called and
some 300 delegates from all parts of the country and overseas met together in