Level of daily personal noise exposure (L_EP, d) of an employee taking account of the level of noise and the duration of exposure and covering all noise.
The L_EP, d, which corresponds to L_EX,8h defined in international standard ISO 1999: 1990 clause 3.6, is expressed in decibels.

Employer's duties
Every employer shall:

1. conduct a suitable and sufficient risk assessment for activities liable to expose employees to noise at or above a lower exposure action value and identify the control measures that need to be taken, recording the significant findings;
2. ensure that risk from the exposure of his employees to noise is either eliminated at source or, where this is not reasonably practicable, reduced to as low a level as is reasonably practicable;
3. for noise at or above an upper exposure action value , reduce exposure to as low a level as is reasonably practicable by establishing and implementing a programme of organisational and technical measures, excluding the provision of personal hearing protectors, which is appropriate to the activity;
4. ensure that employees are not exposed to noise above an exposure limit value ;
5. ensure employees are placed under suitable health surveillance, which shall include testing of their hearing, where a risk assessment indicates that there is a risk to the health of employees who are, or who are liable to be, exposed to noise and keep appropriate records;
6. make personal hearing protectors available upon request to any employee likely to be exposed to noise at or above a lower exposure action level;
7. if unable to reduce the noise by other means to below an upper exposure action value, provide personal hearing protectors to any employee who is so exposed;
8. where employees may be exposed at or above an upper exposure action value, ensure the area is designated a "hearing protection zone ";
9. ensure all control measures are maintained in an efficient state and good working order.