Physical factors
Identifying, mapping and controlling physical factors, such as heat, noise and vibration, and chemical and biological risk factors at the workplace is called occupational hygiene.
Occupational hygiene is assessed during workplace visits, with measurements and during health checks. Work instructions and communication are also needed. Health risks are reduced with technical means, protective equipment and training, among other measures.
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Noise and sound environment
Noise is sound that is harmful to the hearing. Noise that is dangerous to health due to its volume, frequency and duration can cause hearing loss. Noise is the most common cause of occupational diseases.
Noise that contains sudden sharp sounds, i.e. impulsive noise, is particularly harmful. Even low noise levels can be distracting in tasks that require concentration in open-plan offices, for example. The experience of a sound as noise is influenced by individual perceptions.
In addition to the hearing organs, noise affects many physiological functions, such as heart rate, blood pressure and respiratory rate. Noise can also be generally distracting and affect concentration and sleep.
The Government Decree on the Protection of Workers from the Dangers of Noise defines action values for different levels of continuous noise and impulsive noise at work. The assessment of noise exposure is mainly based on daily exposure.
Lower action value
- 80 dB(A), assessed without hearing protectors
- peak sound pressure level of impulsive noise 135 dB(C)
The employer must provide the employee with personal hearing protectors. In addition, the employee has the right to have their hearing tested.
Upper action value
- 85 dB(A), assessed without hearing protectors
- peak sound pressure level of impulsive noise 137 dB(C)
The employee must wear hearing protectors. Noise hazard areas must be marked and access to them must be restricted, if necessary. In addition, the employer must prepare a noise control programme.
Limit value
- 87 dB (A), assessed with hearing protectors
- peak sound pressure level of impulsive noise 140 dB(C)
The employer must take measures to reduce exposure below the limit value.
Whether the sound environment is distracting or not depends more on situational factors than on the physical properties of the noise. Situational factors include the need to concentrate at work, mood, tiredness and external pressure. Individual characteristics such as sensitivity to noise, hearing loss or anxiety also contribute to how distracting the noise is. Talking, ringing phones and walking in corridors are most disturbing, while the sounds of machines or traffic are less distracting.
Good acoustics in an open space
- absorption on the ceiling and walls
- high room dividers (170 cm), glass panels on the top
- textile carpets
- soundproofing and locations of access routes and break rooms
- soundproof office pods and phone booths
- a large open space is better than several small spaces
- office etiquette.
Common open-plan office etiquette
- use of spaces in different situations (work tasks, breaks)
- tidiness and order of the workstation
- communication in the work community
- use of radio, phone and communication devices with sound on
- movement in the workspace
- how others are informed of tasks that require concentration.
Noise exposure at the workplace can be reduced with machine casings, partitions, sound attenuators and by adding sound-absorbing materials to walls and ceilings. It is important to pay attention to the noise level of devices already at the procurement stage.
Hearing protectors should keep noise levels inside the ear at 75–79 decibels during an 8-hour working day. Hearing protectors that attenuate noise too effectively may make voice contact difficult.
Noise control programme
- Investigating the reasons why the limit values are exceeded.
- Setting goals for reducing noise exposure.
- Exploring technical control measures, measures related to work arrangements and measures focusing on the source of the noise.
The noise control programme can be part of the occupational safety and health action programme.(opens in a new window, you will be directed to another service)
Vibration
Harmful vibration is hand-arm vibration, which is transmitted from a tool to the hand, or whole-body vibration, which enters the body from a vibrating surface, such as a machine seat.
Occupational diseases caused by vibration have decreased considerably due to automation and product development of machinery. Typical symptoms of hand-arm vibration include vibration white finger, numbness and loss of sensation in the fingers and weakened grip strength. Whole-body vibration increases symptoms in the lower back.
- The Government Decree on Vibration lays down exposure action values of 2.5 m/s² for hand-arm vibration and 0.5 m/s² for whole-body vibration.
- The limit values are 5 m/s² for hand-arm vibration and 1.15 m/s² for whole-body vibration.
If the exposure exceeds the action value, the employer must draw up a vibration control programme, which is similar in content to the noise control programme.
If the exposure exceeds the limit value, immediate measures must be taken to reduce the exposure below the limit value. The limit value may be temporarily exceeded if the exposure varies considerably from one work phase to another.(opens in a new window, you will be directed to another service)
Thermal conditions
Thermal conditions in the working environment refer to cold and hot working conditions and thermal comfort. In addition to temperature, thermal conditions consist of air humidity, air flow rate and thermal radiation. Thermal conditions are also affected by a person’s body heat production, i.e. the physical effort involved in the work and the manner of performance, as well as clothing. In addition, individual differences affect thermal comfort.
Thermal comfort
Thermal comfort describes a person’s satisfaction with the ambient temperatures. Work performance decreases by about 2% per every degree when the temperature is above 25 °C. Low temperatures make it difficult to perform tasks that require manual skills. The temperature range of 21–25 °C is considered pleasant in thermal comfort recommendations.
Discomfort is also caused by draught. Draught is caused by air currents that are cooler than the air in the room. The feeling of draught increases when the ambient air temperature drops below 20 °C.
If the work is carried out in exceptionally hot or cold temperatures, occupational health care must assess the need for health checks in the workplace survey and, if necessary, perform periodic health checks for employees.
No mandatory limit values have been set for thermal conditions. The occupational safety and health authority has prepared recommendations for temperature and air flow rate according to the physical effort involved in the work:
- light desk work: recommended temperature 21–25 °C, air flow rate less than 0.1 m/s
- other light work: recommended temperature 19–23 °C, air flow rate less than 0.1 m/s
- moderate work: recommended temperature 17–21 °C, air flow rate less than 0.5 m/s
- hard work: recommended temperature 12–17 °C, air flow rate less than 0.7 m/s.
The relative air humidity should be 30–50%.
The limit between the thermal comfort zone and hot work is considered to be +28 °C. Heat exposure can occur even at lower temperatures if the work is very heavy.
The occupational safety and health authority has issued a recommendation for breaks in hot work. According to the recommendation, if the temperature exceeds 28 °C, employees should take a 10-minute break or work for 10 minutes in a cooler space per hour. If the temperature rises above 33 °C, the duration of the breaks or time spent working in a cooler space must be 15 minutes.
Measures to control the risks of hot work
- Insulation of hot objects, pipes and processes
- Cooling of workspaces
- Cooling of the workstation
- Personal protective equipment
- Reduced exposure time, regular breaks.
The body temperature begins to decrease during cold work because the body loses heat more than it can produce. Cold damage begins to occur at temperatures below +10 °C.
There are no limit values for cold work that could be used to assess the health risk. In some sectors, the collective agreements set out frost limits for outdoor work.
Lighting
The workplace must have suitable and sufficiently efficient lighting as required by the work and in accordance with the needs of employees. If possible, part of the lighting should be natural light. Due to individual characteristics and age, employees performing the same work have different needs in terms of the level of lighting, glare reduction and the colour of the light.
The basic requirements for good lighting include a sufficient level of lighting, effective glare reduction, correct surface brightness or luminance ratios, correct orientation of lighting and appropriate colour features of the light.
Low, uneven or glaring lighting, particularly in access routes, stairs, intersections and near drive-in doors, increases the risk of accidents.
The unit of illuminance is lux (lx = lm/m2), which is the ratio of the amount of light falling on the surfaces of the workspace (lm) to the surface area. There is a European standard for work lighting (EN-SFS 12464-1: Light and lighting. Lighting of work places), which sets out recommendations for the level of lighting in different working environments.
Ventilation and air conditioning
Ventilation refers to removing exhaust air from the building and bringing fresh air into the workspace. Air conditioning is used to control the ambient temperature, humidity and air flow with supply, exhaust or recirculated air. The characteristics of good indoor air are an appropriate room temperature and air humidity, purity and freshness.
The most efficient way to remove impurities generated in production processes is to remove them as close to their source as possible by means of local extraction.
According to the Occupational Safety and Health Act, there must be enough satisfactory air to breathe in the workplace, and ventilation must be sufficiently effective and fit for purpose. The volume of air in a workspace intended for permanent use must be at least 10 cubic metres per employee. When calculating this, a maximum of 3.5 metres of the height of the room is taken into account.
If the workplace is equipped with mechanical ventilation, it must be kept in working order and the equipment must be kept clean.
Indoor air quality is affected by the condition of the building and the ventilation and heating equipment. The level of cleaning, building materials and cleaning chemicals used in cleaning also affect indoor air quality.
Confined spaces, tanks and silos
Work performed in confined spaces, such as tanks, silos, canals, trenches or cargo holds, may involve a risk of oxygen deprivation, poisoning or explosion. Before starting the work, it is necessary to determine the possible gas levels, the adequacy of breathable air and the ventilation of the space for the duration of the work.
Radiation
Radiation is classified into ionising and non-ionising radiation. Non-ionising radiation includes ultraviolet radiation, visible radiation (light), infrared radiation and laser radiation.
Radioactive substances emit ionising radiation. Ionising radiation is also generated by X-ray equipment, for example. Radiation is used in health care, industrial activities and research. The use of radiation must be acceptable, pre-planned and safe.
The most serious health risks of non-ionising radiation are caused by exposure to ultraviolet (UV) radiation from the sun. The largest group of employees exposed to artificial UV radiation are welders. In laboratories, short-wave UV radiation is used to destroy bacteria and other micro-organisms.
Protection from UV radiation from the sun must be taken into account when working outdoors. An effective means of protection against strong solar radiation is to wear appropriate clothing, headgear and sunglasses.
Indoors, UV radiation sources must be isolated from the rest of the working environment by placing them in a separate space or by placing safety panels around the work site in welding and cutting work, for example.
Metal, foundry and glass industry workers are exposed to high levels of infrared radiation near heating and melting furnaces and in rolling mills where incandescent metals are handled. If infrared radiation is absorbed into the eye, it can cause clouding of the lens. Infrared radiation can be controlled by using reflective films and curtains, the effectiveness of which is based on their ability to reflect and absorb radiation.
Laser radiation is used for purposes such as cutting, welding and
surface treatment of materials. The advantage of laser is that it can deliver a high amount of thermal energy to a small area.
The power of laser radiation does not diminish as the distance increases in the same way as that of light and other types of optical radiation. Laser radiation does not penetrate deep into the tissue, and its harmful effects mainly affect the skin and different parts of the eye. If the laser beam enters the eye before the eye’s closing reflex activates, it can cause irreversible damage.
The employer must be aware of the safety classes of the laser devices used at the workplace because the obligations are based on them. The safety classes for laser devices are 1, 1M, 2, 2M, 3R, 3B and 4, of which class 4 lasers are the most dangerous.
Radon is an invisible and odourless noble gas found in the indoor air of homes and workplaces. The ground under the building is the main source of radon. Long-term exposure to high radon levels significantly increases the risk of lung cancer.
The Radiation Act obligates employers to carry out a radon measurement at the workplace if it is reasonable to assume that the radon levels at the workplace exceed the reference level of radon exposure laid down in the law. The aim is to protect human health from the harmful effects of radiation. Most of the average radiation dose received by Finns comes from radon present in indoor air.
The radon levels in workspaces must be measured at least in the following cases:
- In all workspaces located partially or fully underground.
- In areas where at least 10% of the annual average radon levels measured earlier exceed the reference level of 300 Bq/m³.
The Radiation and Nuclear Safety Authority (STUK) maintains a list of these areas:
- In workplaces located on ridges or other highly air-permeable gravel or sand formations in all parts of the country.
- In institutions supplying household water where the water does not come exclusively from a body of surface water and comes into contact with indoor air.
The easiest way to control radon is during the construction of a building, but high radon levels in indoor air can also be reduced with a radon extractor, for example. Radon measurements can be ordered from an operator that uses a measurement method approved by the Radiation and Nuclear Safety Authority.(opens in a new window, you will be directed to another service)
Safety in the use of radiation
The Radiation and Nuclear Safety Authority (STUK) monitors the use of radiation. Monitoring of radiation exposure includes monitoring of exposure conditions and individual monitoring of workers. Monitoring the exposure conditions ensures that the working environment is safe. Individual monitoring measures and determines the individual radiation dose of an individual
worker. Individual monitoring must be based on individual measurements conducted by an approved dose measurement service.
Radiation workers are classified into two categories (A or B). The basis for this classification is an estimate of the exposure and potential exposure caused by the work. Individual monitoring must always be arranged for category A workers, and often it is also appropriate for category B workers. More detailed instructions on the classification of radiation workers into different categories are laid down in the Government Decree on Ionizing Radiation. All workers’ radiation doses are recorded in the dose register maintained by STUK. STUK also carries out inspections at places where radiation is used.