Why workplace noise and environmental noise must not be confused

Companies often request noise measurement, but at first it is not clear whether they need to measure noise for employees or noise spreading from the operation into the surroundings. These are two different tasks.

Workplace noise addresses what noise exposure an employee faces at work. It is typically assessed for operators of production lines, workers at presses, grinders, locksmiths, warehouse staff, maintenance workers or operators of noisy technology. The results serve mainly for job categorisation, occupational health services, design of protective measures and inspection by KHS.

Environmental noise addresses what noise from the facility affects surrounding protected areas. It is typically assessed for residential buildings, protected outdoor areas of buildings, protected indoor areas of buildings or other noise-sensitive development. The results are used in permitting of operation, technology change, neighbour complaints, commissioning, change of use, EIA, JES or at the request of the building authority or KHS.

One noise source can therefore require two different assessments. For example, a compressor in a hall may be significant for employees inside the operation and at the same time may affect the surroundings through an exhaust or building structure. Workplace noise and outdoor noise are nevertheless evaluated differently.

Workplace noise: when employees are the concern

Workplace noise measurement is intended for assessment of employee exposure. The primary question is not whether the operation can be heard by neighbours, but what noise the worker is exposed to during their shift.

Typical situations:

  • production hall with presses, machine tools, saws, grinders or lines,
  • warehouse with handling equipment, conveyors or packaging technology,
  • maintenance using hand tools,
  • boiler plant, compressor room, machine room or technical facilities,
  • workplaces where KHS requires supporting materials for job categorisation,
  • operations where technology is changing and workplace environment assessment must be updated.

For workplace noise, actual employee exposure is essential. It is not enough to know that a machine has a certain noise level. It is necessary to describe who works at it, for how long, in what regime, whether activities alternate and what a characteristic shift looks like.

The output is a workplace noise measurement report that can serve as supporting evidence for job categorisation and communication with KHS.

Environmental noise: when neighbours, development or operation permitting are the concern

Environmental noise is addressed when the facility may affect protected areas outside the workplace itself. The aim is not protection of employees, but protection of the surroundings.

Typical sources of environmental noise:

  • fans, exhausts, cooling and ventilation,
  • compressors and machine rooms,
  • heat pumps,
  • outdoor handling and loading,
  • site traffic,
  • operation of forklift trucks on outdoor areas,
  • crushers, sorting lines, presses or other technologies with noise escaping outdoors,
  • night-time operation,
  • facilities close to residential development.

For environmental noise, the impact of operation on protected areas is assessed. The location of noise sources, operating hours, day or night regime, nearest residential development, building design of the facility and noise propagation outside the site are important.

The output may be a non-work environment noise measurement report or a noise study. It depends on whether actual operation or only a planned project is being evaluated.

When you need measurement and when a noise study

Companies often do not know whether to order noise measurement or a noise study. The main deciding factor is the purpose.

Noise measurement is appropriate if operation already exists and the actual state must be verified. It is typically carried out during inspection, complaint, KHS requirement, after installation of technology or after implementation of noise control measures.

A noise study is appropriate if operation is only being prepared, expanded or changed. It is used especially for project documentation, building permitting, change of use, EIA, JES or for preliminary verification of whether proposed technology can meet hygienic limits in the surroundings.

In practice:

  • if employees and job categorisation are addressed, it is workplace noise measurement,
  • if neighbours or residential development at an existing operation are addressed, it is usually environmental noise measurement,
  • if a new or modified project is addressed, a noise study is usually needed,
  • if the authority requires proof of the actual state after implementation, measurement is usually needed.

Why one report cannot be used for everything

A common mistake is the assumption that any noise measurement will satisfy any requirement. That is not how it works.

A workplace noise measurement report does not prove that operation meets noise limits at the nearest residential development. It is focused on employees, workstations, the shift and job categorisation.

An environmental noise measurement report does not address noise exposure of employees in the hall. It may prove that operation does not disturb the surroundings, but it does not show whether employees need classification into a risk category or hearing protection.

An environmental noise study also does not replace workplace noise measurement. It models noise propagation to protected objects, not personal exposure of a specific employee during a shift.

It is therefore important from the outset to correctly determine what the result should be and for whom the document should be usable.

What KHS or another authority may require

For workplace noise, KHS may require supporting materials for job categorisation in particular. It will be interested in job position, number of workers, shift length, exposure time, measured values and proposed job classification according to the noise risk factor.

For environmental noise, KHS or the building authority may address the impact of operation on protected areas. It will be important where the nearest residential objects are, what noise sources are in operation, whether work takes place at night, what the operating regime is and whether hygienic limits are met.

For new projects, a noise study may be required before implementation. For existing operations, measurement of the actual state may be required. For facilities with night-time operation, assessment is usually more sensitive because night-time noise has a stricter impact on the surroundings and often triggers complaints.

What supporting materials to prepare for workplace noise

For workplace noise it is advisable to prepare in particular:

  • list of job positions,
  • number of employees in individual positions,
  • shift length and shift pattern,
  • description of work activities,
  • list of noisy machines and equipment,
  • actual time spent working at noisy sources,
  • information on alternation of activities,
  • hearing protectors used,
  • existing job categorisation, if any,
  • KHS requirement, if issued.

The most important thing is not just a list of machines, but the real work regime. If a worker stands at a noisy machine for 30 minutes per shift, that is a different exposure than working at it for 6 hours.

What supporting materials to prepare for environmental noise or a noise study

For environmental noise it is advisable to prepare in particular:

  • description of operation and noise sources,
  • site plan or map overlay,
  • location of nearest residential or other protected development,
  • operating hours of noise sources,
  • distinction between day and night operation,
  • data on fans, exhausts, cooling, compressors and technology,
  • information on outdoor handling and transport,
  • project documentation, if it is a new project,
  • authority requirement or KHS opinion.

For a noise study, acoustic parameters of equipment are also important. It is not enough to know that a fan or compressor will be installed. Its sound power, location, operating hours, radiation direction and any noise control measures must be known.

Most common mistakes by companies

The most common mistake is ordering measurement without a clear purpose. The company then receives a report that may be technically correct but is not usable for the specific procedure.

Another common mistake is confusing workplace noise and environmental noise. Employees, neighbours and authorities address different questions. It is therefore necessary to state at the time of commissioning whether it concerns job categorisation, complaint, operation permitting, building permitting or verification of compliance with conditions.

Underestimation of night-time operation is also a problem. Even a source that appears insignificant during the day can be decisive for the surroundings at night. This typically concerns ventilation, cooling, compressors, exhausts, loading or irregular technological sounds.

For workplace noise, exposure time is often estimated incorrectly. If an unrealistic time spent working at a noisy source is entered into the calculation, the result may be overestimated or underestimated.

Practical procedure for a company

First clarify why you are addressing noise. If it concerns employees, job categorisation or occupational health services, it will be workplace noise measurement. If it concerns neighbours, residential development, building permitting or the facility, it will be environmental noise or a noise study.

Then gather basic supporting materials. For workplace noise, describe job positions, shifts, machines and exposure times. For environmental noise, describe noise sources, operating hours, equipment location and nearest protected objects.

It is then possible to propose the correct scope of measurement or study. The aim is not to measure as many places as possible, but to choose a procedure that matches the authority requirement and gives the company a usable output.

Output for authorities and internal documentation

For workplace noise, the output is a report usable for assessment of work environment and job categorisation. It helps document what employee exposure is and what measures are needed.

For environmental noise, the output is a protected-area noise measurement report or a noise study. These documents are used in communication with KHS, the building authority, investor, designer or when handling complaints.

For more complex operations it may be appropriate to combine both approaches. For example, a manufacturing company may need workplace noise measurement for employees and at the same time a noise study for expansion of operation towards surrounding development.

Factual basis of the article

The topic is based mainly on the following legal and methodological sources:

  • Act No. 258/2000 Coll., on public health protection,
  • Government Regulation No. 272/2011 Coll., on protection of health from adverse effects of noise and vibration,
  • Decree No. 432/2003 Coll., setting conditions for classification of jobs into categories,
  • methodological guidelines of the Ministry of Health for noise measurement and assessment,
  • methodological information of the National Institute of Public Health on job categorisation.

Useful links:

Summary and next step

Workplace noise and environmental noise are two different tasks. Workplace noise addresses protection of employees, job categorisation and supporting materials for KHS in the area of work environment. Environmental noise addresses the impact of operation on protected development, neighbours and operation permitting.

If a company does not know which type of measurement it needs, it is advisable first to send the authority requirement, a brief operation description, list of noise sources, information on workplaces and location of the nearest surrounding development. We will verify whether you need workplace noise measurement, environmental noise measurement or a noise study for the facility or project.