Noise & Ultrasound
Noise is an inevitable consequence of activities in a workplace but the noise level at work is usually no more than encountered in many other aspects of life, for example groups of people conversing, traffic noise, city ‘bustle’, children playing, etc.
However there some work activities which create noise levels above what most people would describe as comfortable. This “intrusive” noise is if for example you have to raise your voice to hold a conversation beyond a couple of meters or if noisy powered tools are used. Other work activities which might cause extremely loud continuous or sometimes sudden explosive noises include machinery, workshops, manufacturing and laboratory activities – such as hammering, rapidly moving belts, pneumatic impacts, high pressure release, high speed fans etc. Noise levels in such work places need to be assessed and if necessary measures put in place both to prevent noise interfering with communication and making warnings harder to hear and to protect workers – the result of not doing so could be immediate and permanent hearing damage.
People exposed to intrusive noise levels for continuous periods or intermittent periods of at least half an hour regularly during the working day sometimes experience temporary deafness afterwards. Even though their hearing usually recovers within a few hours, this should not be ignored because continued exposure could result in permanent damage.
Anyone with a concern about intrusive noise in their workplace should seek advice from the Health and Safety Department via HealthSafetyHelpdesk at warwick dot ac dot uk as this department is able to measure the sound levels with a special sensitive noise meter, the results will indicate what course of action to take (see section on noise risk assessment and action levels).
Noise is measured in decibels (dB). An ‘A weighting’ sometimes written as ‘dB(A)’, is used to measure average noise levels, and a ‘C weighting’ or ‘dB(C)’, to measure peak, impact or explosive noises. A 3dB change in noise level is actually either a halving or doubling of the sound pressure level and may only just be noticed by the human ear. This is simply due to the way in which our ears work.