Noise Safety

Sound is transmitted through the air as oscillations of low and high pressure emanating from the source. This could be a musical instrument, a human voice, a hammer striking an anvil or a power drill. In each case kinetic energy, such as the bowing of a violin string, is converted into sound energy which can be transmitted over a distance to be heard by a human (or animal) ear. The more energy that is used to create the sound, the louder the resulting signal will be.

The ear is a very sensitive organ and can be easily damaged. The most common causes of hearing loss are attributed to occupational factors and industries such as demolition, construction and engineering have the highest incident rates. As we age, there is an inevitable decline in our capacity to hear, especially at higher frequencies.

Symptoms and effects from Noise

Continuous exposure to high noise levels can cause a persistent ringing or buzzing in the ears, known as tinnitus. This could be a precursor to permanent long-term hearing loss. The delicate structures in the ear can also be physically damaged if exposed to a sound level above 130dB (equivalent to a gun shot or firework discharged close to the ear). 

Noise cannot only cause damage to a person’s hearing but can also negatively affect their mental health and wellbeing. Continuous noise can increase stress levels which can also lead to heart disease.

Hearing damage will affect a worker’s ability to hear warning alarms or approaching vehicles. This could be hazardous to the worker and others, especially where the job requires coordination and teamwork. 

What employers must do.

• Identify the equipment that produces noise and obtain the sound levels (in dB) associated with each appliance. The manufacturer will provide this information, usually shipped with the appliance, but can also be obtained via their web site. A hand-held sound level meter can also be used or a smartphone app (although not as accurate).

Note. The dB value alone is not enough information, even though you can assume that a tool with a value of 78dB(A)  compared to a tool with 75dB(A) is likely to be more hazardous. (N.B. Our hearing function and the units of sound (dB) are on a logarithmic scale. In summary, every increase of 3dB is a ‘doubling’ of the sound level.)

• To complete the picture and to correctly assess the risk, the duration of the activity where the worker is exposed to noise must be identified. This can simply be the time spent in a noisy area (such as a compressor room) or the ‘trigger’ time of a tool or piece of equipment, (i.e. for how long the tool is generating the noise).

Example. A cavity wall insulation engineer drills 40 holes into masonry during, each hole takes 60 seconds. The total trigger time is therefore 2400 seconds (40 Minutes).

Obtaining the trigger time should be either ‘observed’ or established using sound level meters or personal monitors (or dosimeters, which are very expensive). Estimating this value often leads to under-estimation and leads to false results leaving the worker unprotected.

Once accurate information is obtained then the simplest way to determine if the exposure levels are safe, is to use the HSE Noise Calculator which establishes the daily exposure rates from several tools deployed on the same day. An alternative is to use the HSE ready reckoner.

Either method requires only the two values determined above (for each appliance) and this returns a simple points score translating to two measures, the Lower Exposure Action Value (LEAV) and/or the Upper Exposure Action Value (UEAV) 

• Identify who can be exposed to the noise whether they are individuals or groups of workers. Other issues should be considered, for example, have they ever suffered from problems caused by exposure to noise under previous employers. Issue Noise self-assessment forms to relevant employees.

Employers must reduce the risks from noise to the lowest level reasonably practicable and to reduce exposure to as low as is reasonably practicable if it is above the LEAV.

Record the findings. 

I.e., Create and develop a Noise risk assessment to include the following:

• The employees’ activities, operations and Noise self-assessment.
• A description of the tools deployed. (Note. Similar tools made by the same manufacturer may have different sound levels).
• Any noise control measures already in place; (E.g. Using a hand-held sound level meter to gather data, sourcing only from manufacturers with comparatively low-levels of noise, or for example, using personal sound monitors to record ‘live’ data).
• The likely sound levels and sources of this data, (manufacturers’ information, databases, observations of trigger times, consultants’ advice etc.)
• The people who are likely to exceed the exposure action value and/or the exposure limit value.
• The immediate measures taken to reduce exposure below the lower exposure action value if the assessment shows it is likely to be exceeded. (For example, rotation of work activities, factoring in regular breaks from using noisy equipment or presence in a noisy area, ensuring tools have a regular maintenance schedule and are in good order.)
• Provide information and training to those exposed to noise. 
• Identify those who should undergo health surveillance. (Workers exposed to the higher levels of noise or are already suffering from exposure to noise).
• Any further information necessary to help you comply with your duty to reduce exposure and control risk. 
• The date of the assessment.
• The person who conducted the assessment.

To ensure controls remain effective and continue to protect the employee, the assessment should be reviewed at least annually or if there are changes to the work processes or equipment used. 

If you need any further guidance with Noise safety please contact Spectra