Its important to set the correct range otherwise the sound level meter may be overloaded or under loaded I.E not record a measurement at all
the instrument display will report over or under loading by displaying a warning symbol
the range to use is very much dependant on whether the noise generally of a static or fluctuating nature
as a starting point and general rule for fluctuating noise use a scale where the average level is in the middle of the scale
for static noise use a scale where the average reading is approximately two thirds of the way up the scale
Sound level meters often have a number of different frequency and time weightings which can be used in different situations
for measurements that are to comply with for example the noise at work regulations, noise should be measured using LEQ with the A frequency weighting
the measurement of the peak sound pressure should be made with C frequency weighting, if in doubt always refer to the regulations that you are required to meet
for octave band measurements use the Z or linear frequency weighting

A broadband measurement is as its name suggests a measurement of noise level across a broad spectrum of frequencies
if the noise your required to measure doesn’t fluctuate much and is significantly below legal limits then using broadband measurements as the basis of your noise risk assessment is probably fine in a lot of cases
however for fluctuating sound or high noise levels measuring and understand the pitch or frequency of the noise is just as important as the loudness
some machinery can emit high noise levels at very high frequencies for example an ultrasonic cleaner or very low frequencies for example a rumbler
in the case of hearing protection the assumed protection values or attenuations stated by the manufacturers vary at different frequencies
the ability to measure the sound levels at different frequencies is therefore essential when selecting hearing protection

When using a sound level meter the following points should be followed
Measurements should be taken at the operators ear position preferably in the absence of the operator
if the equipment can’t be used without the operator then place the instrument 10 centimetres from each ear
you only need to report one measurement if the result is the same at each ear
if the sound level in the work area is generally the same measurements should be taken at five or more workstations representive of the distribution of workers
in the case of noise predominating from a single machine or line measurements should be taken at the operators position and of three or more of those nearby
if any measurement is recorded at or above 85DBA then the sound level should be measured at every operators position
When taking measurement using a dosebadge it should be mounted on the shoulder of the wearer within 10 centimetres of their left or right ear
make sure that nothing can touch the dosebadge otherwise the measurements may be compromised

Hearing protection should not be considered as a long term solution to protecting workers from noise exposure
the reason for this statement is two fold
firstly the performance of hearing protection is very dependent upon the fit and condition of protection
incorrect fitting of earplugs for example can reduce their performance by as much as 22 decibels its essential therefore that instruction is given before use
earmuff performance depends upon the effectiveness of the cushion seal around the ear, any relaxation of the stiffness of the headband will reduce the seal pressure resulting in reduced attenuation
perspiration will overtime harden the surface of the plastic seals making them less effective
muffs should kept in good condition and the seals cleaned regularly and replaced when they harden and secondly wear rates
if hearing protection was not worn for one hour during an eight hour shift the maximum protection that can be achieved is nine decibels irrespective of the performance of the protector
there are many different types of hearing protection but by far the most important requirement for protectors is comfort rather than absolute performance
in reality comfort usually means choice as personal preferences differ

The principle aim of a factory noise survey is for it to be carried out in a reasonable timeframe with the results communicated to management using a report with actions and timescales
in most cases noise surveys should be carried out every two years or sooner as partial surveys if an area changes due to for example a new piece of equipment or process
the object is to access the risk to personnel so don’t bother with walkways or areas where no one works
the measurement results should be marked up on an up to date factory floor plan consider segregating areas into hearing protection zones if this is appropriate
ensure the drawings and therefore areas of the factory are marked accordingly for large sites it may be prudent to undertake a pre survey, survey to identify the noisy areas
any area that records less than 80 decibels when the meter is set to a-weighted slow is likely to have an 8hour LEQ of less than 80 decibels and can largely therefore be ignored