The Control of Noise at Work Regulations (2005) places a duty on employers to reduce the risk of damage to the hearing of their employees from exposure to noise to the lowest level reasonably practicable.
There are many ways to find out if noise levels at work are a risk to those exposed to it. There are ‘rules of thumb’ for this. A typical example would be if you need to shout at 2 metres from a work colleague or experience stress when noise starts or relief when it stops, then the noise levels are likely to be at or above 85dB(A) and potentially harmful to hearing. It is not advisable to rely on these rules or the human ear alone because of the effects of Temporary Threshold Shift so accurate measurement of noise at work by a competent person with a compliant sound level meter is advisable.
5 ways to measure noise at work accurately
1. How to measure noise at work accurately: Sound level meter
2. How to measure noise at work accurately: Field calibration
Field calibration is a requirement for most occupational and environmental noise monitoring legislation. Noise monitoring equipment such as a sound level meter should be calibrated prior and after each measurement session.
Calibration should be carried out using a suitable acoustic calibrator which fits over the microphone capsule of the sound level meter. This capsule is the most fragile, important and expensive part of your meter and one that can become damaged through accidental misuse and give inaccurate measurements. By using an acoustic calibrator, your meter is typically less than + or – 0.1dB. This will ensure accuracy of your noise measurements.
3. How to accurately measure noise at work: Windshield
A windshield is an important accessory. It reduces the influence of wind during outdoor monitoring. It protects the microphone capsule from moisture and protects it from accidental knocks. It helps protect the capsule from any chemicals that may be in the air. It also prevents from workers who are being monitored from being ‘poked’ in the eye in the event they turn around unexpectedly.
4. How to measure noise at work accurately: Types of measurements
When using a sound level meter, hold it at arm’s length at the ear height for those exposed or at the position the operative’s head would normally be. When measuring machine noise, place yourself 1 meter from the machine at a height of 1.5 meter. When measuring area noise levels, place yourself in gangways etc. to assess risk to office staff, maintenance staff and visitors.
5. How to measure noise at work accurately: Good practice
It is good practice to question workers to find out typical working practices and activities together with durations for each activity. You should make notes also regarding each working position and which ear measured. Allow enough time to get a representative measurement. Write down the LAeq and ‘C’ weighted Peak results reading from your sound level meter. Finally use the higher value of right and left ear measurement and round up to the nearest decibel. For example, 83.7dB(A) should be rounded up to 84dB(A).
How loud is too loud?
Excessive long term exposure to noise can lead to permanent damage to a person’s hearing. It is important to remember that the risk and amount of damage that can be caused depends on the level of noise and the duration that the person is exposed to the noise. Here is a summary for you:
For further advice on noise assessments and surveys, consult the HSE Guidance document L108.
For information on noise measurement technology such as sound level meters or personal noise exposure meters to help gathering noise data at work and complement any risk assessments, consult our website.
Pulsar Instruments have also produced a FREE summary guide for employers on Controlling workplace noise which sets out duties under the Regulations. Download your copy here.
©Pulsar Instruments Published on 6th July 2015. Unauthorised use and/or duplication of the above content or picture without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Pulsar Instruments with appropriate and specific direction to the original content.