Ear is not equally sensitive at all frequencies and amplitudes of sound pressure. The magnitude of a sound, as perceived by human ear is called its loudness.
Sound is measured with a sound level meter which is usually a portable, self- contained instrument incorporating a microphone, amplifier, a voltmeter and attenuators, the whole of which is calibrated to read sound pressure levels directly. The reference sound pressure, Pr, has an internationally agreed value of 20 µN/m 2. P = root mean square sound pressure, usually in µN/m 2 The sound pressure level is expressed in the unit of decibel (dB). By this, the sound pressure range of interest is compressed between 0 to 130, a range convenicnt to use. It has been found convenient to employ sound pressure level, a quantity, which is proportional to the logarithm of sound pressure. Because of such a wide range, the use of a linear pressure scale has been found to be impractical. The weakest sound pressure disturbance that can be detected by an "average" person at 1,OOO Hz has been found to be 20µN/m 2 and the largest sound pressure perceived without discomfort is of the order of 10 7 µN/m 2. Sound pressure is used as the fundamental measure of sound (amplitude) as it is measurable directly by instruments. Human hearing is sensitive to frequencies in the range of about 20-20,000 Hz (the audio frequency range). For example, the speed of sound is 3,962 rn/s in wood and 5,029 m/s in steel.įrequency is defined as the number of compressions and rarefactions per unit time (sec).
Sound travels much faster in solids than in air. at a temperature of 20° c, is approximately 344 rn/s.
The speed of sound, the frequency and the wave length are related by the equation: These waves are characterised by the amplitude of pressurechanges, their frequency, and the velocity of propagation. Sound waves involve a succession of compressions and rarefactions of an elastic medium such as air. The physical properties and perception of sound or noise are expressed and measured in different concepts and units. However, not all sound waves evoke an auditory sensation, e.g., ultrasound has a frequency too high to excite the sensation of hearing. Physiologically, sound is an auditory sensation evoked by this physical phenomenon. We have to charge for this service and it could cost you more than £200.Physically, sound is a mechanical disturbance propagated as a wave motion in air and other elastic or mechanical media. If your alarm is sounding continuously for more than 20 minutes and we receive complaints about the noise, we have powers to disconnect it. If you have an audible intruder alarm fitted to your property, you must ensure it is regularly maintained. If you require any further information, please contact us.
NOISE POLLUTION CONTROL EQUIPMENT HOW TO
Our leaflets below provide advice and simple tips on how to avoid causing noise nuisance. How can I avoid causing noise nuisance?Īlmost all noise problems can be avoided if consideration is given to how the noisy activity might affect your neighbours. We have to assess the level of noise before taking action to determine whether it can be classed as a noise nuisance. This can include disturbing sleep or being heard clearly over your television. It must be classed as a 'noise nuisance' for us to take action, which means it has to be regularly affecting your quality of life.
NOISE POLLUTION CONTROL EQUIPMENT DOWNLOAD
If we witness a noise nuisance, action we can take includes:
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