Workplace noise

What is workplace noise and what damage does it cause?

The primary harm caused by noise is occupational hearing loss or deafness: a progressive, painless, and irreversible hearing loss caused by repeated exposure to high noise levels over many years. It is listed as an occupational disease and is one of the most frequently reported in industry. Noise also produces non-auditory effects: it hinders communication and the perception of warning signals, increases mental workload and stress, and is associated with cardiovascular and sleep disturbances in cases of prolonged exposure.

Exposure is characterized by two metrics. The equivalent daily exposure level, expressed in A-weighted decibels and referring to an eight-hour workday, describes the cumulative dose of noise; the peak level, in C-weighted decibels, describes very intense impulsive noises that can cause immediate harm. Royal Decree 286/2006 defines both and, for activities with significant daily variation, allows the use of the weekly exposure level.

The regulation transposes Directive 2003/10/EC and applies to all activities in which workers are or may be exposed to risks arising from noise, with particularities for the music and leisure sectors, which had a specific code of conduct.

Exposure values ​​and tiered obligations

Article 5 of Royal Decree 286/2006 establishes three levels, which determine increasing obligations:

• Lower exposure levels that trigger an action: 80 dB(A) daily exposure and 135 dB(C) peak. Below these levels, the employer must provide hearing protection to exposed individuals, inform and train them about the risks, and offer audiometric testing every five years.
• Upper exposure action levels: 85 dB(A) and 137 dB(C). Above these levels, the use of hearing protection is mandatory, a program of technical and organizational measures to reduce exposure must be developed and implemented, areas must be marked and delimited, and audiometric monitoring must be carried out at least every three years.
• Exposure limit values: 87 dB(A) and 140 dB(C). These limits must not be exceeded under any circumstances; compliance is verified by taking into account the attenuation provided by the hearing protection used. If these limits are exceeded, the employer must take immediate action to reduce exposure below the limit, determine the causes, and implement corrective measures.

These values ​​are taken from the text of the standard and should always be checked against the current consolidated text before using them in a report.

How is it evaluated?

1. Identification of the sources and exposed positions, based on the general risk assessment.
2. Measurement by competent personnel, using integrating sound level meters or dosimeters compliant with instrument regulations, under representative conditions and with the declared uncertainties; the UNE-EN ISO 9612 standard describes the measurement strategy.
3. Calculation of the daily or weekly exposure level and the peak level per position or homogeneous exposure group.
4. Comparison with the values ​​of article 5 and determination of the applicable obligations.
5. Frequency: the evaluation and measurement are repeated at least every three years when the lower values ​​are exceeded and every year when the upper values ​​are exceeded, and whenever conditions change.
6. Recording and preservation of the results, with access for workers and their representatives.

Organizational application: measures in order of preference

Article 4 of Royal Decree 286/2006 requires eliminating at their source or reducing to the lowest possible level the risks derived from noise, and orders the following measures:

• Working methods and equipment selection. Quieter processes and equipment that generates the least possible noise, paying attention to manufacturer information and machine emission regulations.
• Design and layout of workplaces. Separation of sources, enclosures, booths, absorbent materials, distance.
• Technical reduction. Damping, insulation, silencers, equipment and facility maintenance.
• Work organization. Limiting the duration and intensity of exposure, breaks in quiet areas, rotation.
• Personal protection. Suitable hearing protectors compatible with other equipment should be used as a last resort, with training on their use and fitting; their actual attenuation depends on correct use throughout the exposure.

Health surveillance is carried out according to the specific noise protocol, and individual results are communicated to the person; the employer only receives the conclusions in terms of fitness and the need to review the assessment when damage is detected.

Limits and common mistakes

1. To assume that the use of hearing protectors solves the problem, when the standard requires a technical and organizational reduction program above the upper values.
2. Measuring with unsuitable instruments or under unrepresentative conditions, or without declaring the uncertainty.
3. Forget the peak level in tasks with impulsive noise (stamping, shooting, compressed air).
4. Choosing protectors with excessive attenuation that isolate from alarm signals and communication, thus reducing their actual use.
5. Do not repeat the evaluation after changes in machinery or process.
6. Assuming that a level below 80 dB(A) eliminates the non-auditory effects of noise on tasks requiring concentration or customer service.

Regulatory framework in Spain and Europe

• Royal Decree 286/2006 . Protection of the health and safety of workers against risks related to exposure to noise: values, assessment, measures, individual protection, health surveillance.
• Technical guide for the assessment and prevention of risks related to noise exposure (INSST) . Criteria for the application of Royal Decree 286/2006.
• Royal Decree 1299/2006 . List of occupational diseases, which includes hearing loss or deafness caused by noise.
• Directive 2003/10/EC . Minimum provisions on the exposure of workers to risks arising from physical agents (noise).

The noise emissions from machinery are regulated by machinery marketing regulations and Royal Decree 212/2002 on noise emissions from outdoor machinery. The UNE-EN ISO 9612 standard establishes the method for determining workplace noise exposure.