Policy and guidance on control and management of noise in the workplace Policy and Guidance
NOISE Policy The policy of the Medical Research Council is to ensure that all staff work within a safe environment and work to best practice to ensure their health, safety and welfare within the workplace. The MRC requires that its directors and external scientific staff (ESS) team leaders assess whether noise may present a hazard to or impair the work efficiency of staff or visitors. Measures must be introduced to remove or control the unwanted noise. Scope This document examines the procedures and practices which should be in place to comply with The Control of Noise at Work Regulations 2005. The document also draws attention to unwarranted noise not covered by the regulations and gives appropriate guidance to Unit directors, team leaders and supervisory staff on how to assess and control noise levels in both categories. Responsibilities The director or ESS team leader is ultimately responsible for ensuring that the present policy is carried out.
Director s Summary Noise can be defined as unwanted sound which may have a significant effect on the health and welfare of individuals if left uncontrolled. Noise levels at or above those described in The Control of Noise at Work Regulations (CNAWR) 2005 may lead to hearing impairment and possibly permanent damage to the hearing mechanism. Individuals must be protected from exposure to excessive noise. Directors and ESS team leaders need to determine whether any individuals are being exposed to noise levels at or above the noise action levels. Where excessive noise levels are suspected then a noise risk assessment must be carried out by a competent person Noise risk assessments must be recorded Appropriate steps must be taken to control or reduce the level of noise to ensure the safety of individuals. This document also draws attention to sources of unwanted noise that may affect the health and work performance of individuals and gives guidance on what to do if a source of unwanted noise is identified. Directors and ESS team leaders should be aware that individuals may be affected by unwanted noise. Procedures should be in place to control or reduce as far as is reasonably practicable noise levels which impairs performance levels. MRC Health, Safety and Security
Background Noise itself is transmitted through the air as sound waves varying in frequency (the pitch) and energy level (the amplitude). Sound pressure is measured in Pascals (Pa) and the average human ear has a range of detecting pressure from 20uPa to 200Pa. The hearing mechanism within the human ear has evolved into an extremely sensitive organ capable of detecting sound intensity over a wide range. Sound intensity (the physical level of noise) is determined on a logarithmic scale measured in decibels (db). Human hearing measurements are weighted since the human ear differs in its sensitivity to different frequencies. The common weighted measurement (A-weighted) for human hearing is expressed as db(a). Damage to hearing falls into two major categories. These are acute effects which are normally reversible and include acute acoustic trauma (from gunfire or explosions) and temporary threshold shift (TTS). Both normally result from intense stimulation of the auditory nerves in situations where a constantly high level of noise exists e.g. cinemas, disco etc. However, in some instances acoustic trauma from gunfire or explosion can lead to rupture of the tympanic membrane resulting in non-reversible hearing loss. In comparison chronic effects to the hearing mechanism will normally result in permanent damage. Noise induced hearing loss (occupational hearing loss) which results in auditory fatigue and permanent threshold shift (noise induced deafness) are examples of the latter since both are consequences of the effects of long duration exposure to excessive noise levels. The Control of Noise at Work Regulations (CNAWR) 2005 is designed to protect individuals from suffering the damaging effects that prolonged exposure to excessive noise can do to their hearing. The regulations determine three db(a) action levels which if attained require employers to put into place controls to reduce as far as is reasonably practicable the noise to which any employee is subject. The first action level is at 80dB(A), the second at 85dB(A) with a peak sound pressure of 135dB for the lower limit and 137dB for the upper limit, both being C-weighted. The action levels, with the exception of the peak level, are determined by measuring exposure to levels of physical noise over a specified time period resulting in a daily or weekly personal noise exposure or (L EP,d ). The exposure limit values on a daily or weekly basis are 87dB (A-weighted) and a peak sound pressure of 140dB (C-weighted). These latter values must not be exceeded. For the majority of MRC employees the CNAWR will not apply. However, it must be borne in mind that there are other noise sources whilst not necessarily leading to hearing damage can nevertheless be both annoying, distracting or disturbing to people at work. Examples include noisy computer printers or photocopiers working within a relatively confined area, centrifuges and freezers badly sited within either laboratories or corridors and unprotected ultra-sonic devices used to disrupt tissue and cellular materials. Although there is no physiological damage, exposure to annoying sound can be very tiring and stressful. External sources may also produce excessive noise. These may include air extractors, externally sited air conditioning units or traffic noise.
Noise levels which do not attract the provisions set out in the CNAWR may come under The Health and Safety at Work etc. Act 1974 (HSAWA). This states that controls should be introduced if, within any activity, it is shown that it poses a risk to the health and welfare of individuals. Unwanted noise may fall into this category. Consideration should be given to the type of work being carried out as this will have some bearing on whether or not a certain noise level is acceptable. Consideration should also be given to the type of equipment being used, its noise level and its position relative to personnel. Requirements The MRC requires directors and ESS team leaders to take the following steps if it is suspected that an MRC employee or visitor is being subjected to physiologically damaging noise levels. A simple rule of thumb is that if you are required to shout to hold a conversation when you are standing within 3 feet of a person then it is too noisy and the noise level should be measured to ascertain what action should be taken. On measuring exposure to noise and finding that it exceeds the first action level (80dB(A)) then you are required to carry out a suitable and sufficient risk assessment that should address: 1. The working practices making changes whenever necessary to reduce the noise level. 2. Ascertain the probable noise arising from the use of equipment and if necessary. 3. Measure the level of noise that the employee may be exposed to during his/her work. If exposure to noise is at or exceeds the second action level (85dB(A)) or exceeds the exposure limit values, then you are required to carry out a risk assessment that considers the following: 1. The level, type and duration of exposure including any exposure to peak sound pressure. 2. Assess the effects of exposure to noise on any person whose health may be at risk from such an exposure. 3. As far as is practicable determine the interaction between the noise and any ototoxic substance being used and the adverse effects on the health and safety of the employee. 4. Assess the risk to the health and safety of the employee if there is a relationship between the noise source and vibrational disturbances. 5. Assess whether there are any indirect effects on the health and safety of employees between noise and audible warning signals or sounds that require to be audible to reduce the risk at work. 6. Examine whether alternative equipment can be used. 7. Ensure that no additional exposure could happen at the workplace beyond normal working hours eg during rest periods. 8. Provide information to the employee concerned following any health surveillance. 9. Provide hearing protectors with the correct attenuation characteristics. 10. Introduce hearing protection zones and manage them by providing training, instructions and supervision.
The general requirement is to reduce noise so far as is reasonably practicable and this applies to all action levels. The flow chart on the following page illustrates the procedures that need to be followed to minimise any noise hazard. It is highly unlikely that MRC employees will be subjected to noise levels at or near the second action level. Some tasks such as working in a print room may be at or near the first action level. It is probable that research specifically aimed at the measurement of hearing efficiency using specific noise frequencies over a specified time will require that the noise levels to which staff, patients or volunteers are subjected to is accurately monitored. Your Regional Health and Safety Co-ordinator will advise you on how to measure noise levels.
Managing Noise Risks Assess the risks Identify noise hazards Estimate likely exposure to noise Identify measures required to eliminate or reduce risks, control exposures and protect employees Make a record of what you will do in an action plan Protect your employees Eliminate or control noise risks Eliminate or reduce risks using good practice and known control and management solutions For the higher-risk cases, plan and put in place technical and organisational noise-control measures Worker information and training Consult workers and allow their participation Give employees information, instruction and training about the risks, control measures, hearing protection and safe working practices Make sure the legal limits on noise exposure are not exceeded And provide hearing protection Protect your employees with hearing protection Make its use mandatory for the high-risk cases (keep working on technical and organisational control measures) Manage the use of hearing protection with zones, instruction and supervision Health surveillance Provide health surveillance (hearing checks) for those at risk Use the results to review controls and further protect individuals Employees co-operate and attend for hearing checks Maintain and use the equipment Maintain any noise-control equipment and hearing protection Ensure that anything supplied is fully and properly used Employees use the controls provided and report any defects Employees use hearing protection where its use is mandatory Review what you are doing Review as things change: Changes in work practices Changes in noise exposures New ways to reduce risks