London's Pulse: Medical Officer of Health reports 1848-1972
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Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
Shoreditch 1962
[Report of the Medical Officer of Health for Shoreditch]
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27.
operations at the same time and each dug out 16 square feet, the time being
taken for the work.
Noise pressure readings were taken.
The table given below enumerates the amount of noise produced and the time taken to complete the work by each appliance.
| Appliance | Sound Recordings in Dbs | Times | |||||
|---|---|---|---|---|---|---|---|
| Breaking | surface | Beneath | surface | Time | Total time in minutes | ||
| at 4' | at 20' | at 4' | at 20' | started | finished | ||
| No. 1 Pneumatic Road Breaker | 92.5 | 84 | 95 | 86 | 11.50am | 12.21pm | 31 |
| No.2. Pneumatic Road Breaker | 102 | 89 | 98 | 91.5 | II | 12.22pm | 32 |
| No. 3. Electric Road Breaker | 90 | 78 | 92 | 80 | fl | 12o20pm | 30 |
The decibels readings are extremely intricate to evaluate, therefore
their meanings are amplified thus
60 decibels is 10 times noisier than 50 decibels
70 decibels is 100 times noisier than 50 decibels
80 decibels is 1000 times noisier than 50 decibels
In breaking the surface, the noise made by the pneumatic road breaker with
built-in silencer was almost twice that of the electric road breaker and the
pneumatic road breaker with muffle cover was fourteen times noisier»
At 20 feet distance, with the chisels beneath the surface, the muffled
breaker was fifteen times noisier than the electric road breaker, and the
other pneumatic road breaker was four times noisier than the electric road
breaker.
The electric road breaker took 30 minutes to break a 16 square feet
against 31 minutes and 32 minutes by the other two competitors, but when one
compares the noise made by the electric road breaker with that made by the
pneumatic road breakers, it has been established for the second time beyond
doubt that so far as performance is concerned the electric road breaker equals
that of silenced pneumatic appliances, and produces far less noise for the
same amount of work when used to break up concrete roads.
It is important to note that the electric roadbreaker which costs £130
can be operated from a 13 amp power point and no expensive compressor (£1000)
is required as in the case of the pneumatic road breaker which in itself
produces more noise than this road breaker.