When work is considered work under cold stress
The conditions for protecting employees are laid down by Government Decree No. 361/2007 Coll..
At an indoor workplace, cold stress is assessed according to the operative or resultant temperature. For outdoor workplaces, the air temperature corrected for the effect of air movement is used.
At a technologically cooled workplace, the temperature may deliberately be lower than the usual minimum temperatures laid down for the work environment. Typical examples are cold stores, freezer rooms and some food or pharmaceutical operations.
The Government Decree permits exposure to cold at such an indoor workplace for work corresponding to an energy expenditure of 106 W/m² and higher, i.e. from work class IIb.
Are you dealing with cold stress because of the KHS or job categorisation? Send us a description of the workplace, the work operations, the time spent there and any KHS requirement. Send documents for a measurement proposal
Cold stores, freezer rooms and unheated halls are assessed differently
In a cold store or freezer room, the low temperature is a technological requirement. The employer must therefore set up a protective regime according to the actual temperature and the length of time the employee spends there.
For an unheated production or storage hall, the measured microclimatic conditions are first compared with the minimum values laid down for the individual work classes.
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| Work class | Energy expenditure | Minimum operative or resultant temperature |
|---|---|---|
| I | up to 80 W/m² | 20 °C |
| IIa | 81–105 W/m² | 18 °C |
| IIb | 106–130 W/m² | 14 °C |
| IIIa | 131–160 W/m² | 10 °C |
| IIIb | 161–200 W/m² | 10 °C |
| IVa | 201–250 W/m² | 10 °C |
| IVb | 251–300 W/m² | 10 °C |
| V | 301 W/m² and more | 10 °C |
The values are based on Annex No. 1 to Government Decree No. 361/2007 Coll. and apply to indoor workplaces without maintained temperature. For their assessment, suitable work clothing with a thermal resistance of 1.0 clo is assumed.
A warehouse worker who moves intensively during the shift is therefore subject to different requirements than a worker sitting at a computer for several hours in the same hall.
Specific obligations arise at temperatures below 10 °C
If the operative, resultant or corrected temperature at the workplace falls below 10 °C, the employer must provide work clothing with sufficient thermal insulation properties.
At a temperature of 4 °C and lower, the employee must also be equipped with gloves and work footwear that protect against cold.
To determine the required thermal insulation of clothing and the maximum permissible exposure to cold, procedures under the relevant technical standards for the assessment of the thermal environment and the IREQ index are used.
How long can an employee work in the cold
The Government Decree sets the maximum duration of continuous work according to the ambient temperature.
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| Temperature at the workplace | Maximum continuous work duration |
|---|---|
| 13 to 4.1 °C | 3 hours |
| 4 to −10 °C | 2 hours |
| −10.1 to −20 °C | 1 hour |
| −20.1 to −30 °C | 30 minutes |
If an employee works for more than 2 hours per shift at a temperature of 4 °C or lower, he or she is entitled to a safety break in a warm-up room. The break must last at least 10 minutes and the warm-up room must be equipped with a facility for warming the hands.
For outdoor work at a corrected temperature lower than −30 °C, work must be organised so that the employee does not perform it under normal conditions. Exceptions concern in particular urgent repairs and emergencies. At a temperature of −30 °C and lower, unprotected skin must not be exposed for longer than 10 minutes.
Alternation between a cold store and a warm space is part of the assessment
In many operations, the employee does not stay in the cold continuously. A typical example is a warehouse worker who repeatedly enters a freezer room, picks up material and returns to a temperature-controlled warehouse.
For the assessment, it is therefore necessary to know the actual work cycle.
What may be decisive is, for example, 15 entries into the freezer room of ten minutes each, rather than merely the fact that the employee works an eight-hour shift in the warehouse.
The alternation between time spent in warm and cold conditions is also expressly taken into account by job categorisation under Decree No. 432/2003 Coll..
When work is classified into the second or third category
The current Decree sets separate criteria for the cold stress factor.
The second category includes, among others, work involving alternation between time spent in warm and cold conditions, for example in cold stores and freezer rooms. The second category also applies to specified work in an environment with a technologically maintained temperature not lower than +4 °C.
Work is classified into the third category if it is performed for longer than 4 hours per shift in a technologically cooled space or at an outdoor workplace in a characteristic shift, where the temperature is lower than +4 °C.
This is particularly important for employees who work most of the shift in cold stores, freezer rooms and deep-cooled warehouses.
Classification is made according to the actual exposure during the characteristic shift, not merely according to the lowest temperature recorded in the space.
Warm protective drink
Under cold stress, an obligation to provide a protective drink also arises under specified conditions.
At an indoor workplace, it is provided where the technologically maintained operative or resultant temperature is lower than 4 °C. For an outdoor workplace, the decisive factor is a corrected air temperature lower than 4 °C.
The protective drink must be warm and is provided in a quantity of at least 0.5 litre per eight-hour shift.
Handling cold products
A specific situation arises when working with material or a product at a temperature of 10 °C and lower.
If the technological procedure does not allow the use of gloves against cold and the employee must touch the cold material with an unprotected hand, he or she must, after finishing this work, be allowed a safety break to warm the hands of at least 5 minutes.
This requirement may be relevant, for example, for manual handling of food, laboratory samples or products removed from cooling technology.
What is determined when measuring cold stress
The scope of measurement is chosen according to the type of workplace. For indoor spaces, the operative or resultant temperature is essential. At the same time, the work activity, energy expenditure, clothing used, length of exposure and the worker's movement between individual locations are assessed.
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| Input | Significance for the assessment |
|---|---|
| Temperature at individual workplaces | Determines the level of exposure to cold |
| Air movement | Significantly influences the cooling of the employee |
| Work class | Determines the energy expenditure and permissible microclimatic conditions |
| Time spent | Determines the work regime and categorisation |
| Work clothing | Influences the employee's thermal insulation |
| Alternation of spaces | Makes it possible to determine the actual exposure per shift |
| Temperature of handled materials | Important for hand protection |
| Shift length | Enters into the overall assessment of working conditions |
It is advisable to schedule the measurement for a period when conditions are representative of the least favourable part of the year. For an unheated hall, a summer or autumn measurement may therefore be unusable for assessing winter cold stress.
What the KHS may require
During an inspection or when assessing job categorisation, the regional public health authority may require evidence of the actual working conditions and the measures taken.
The employer should have available in particular:
- a report on the measurement of microclimatic conditions, a description of work operations, the exposure time and documents for determining the work class,
- job categorisation and a description of the regime of safety breaks, rotation of employees and use of the warm-up room,
- documents on the work clothing, footwear, gloves and protective drinks provided.
If the measurement is used as a basis for job categorisation or to demonstrate compliance with the requirements of the public health protection authority, it must be performed by an entity with appropriate accreditation or authorisation under Act No. 258/2000 Coll., on the Protection of Public Health.
An unheated hall can be a problem even without freezer technology
In logistics and production halls, a drop in temperature during the winter months is a common problem. The cause may be insufficient heating, frequent opening of doors, intensive air exchange or the large volume of the space.
The assessment is based on the class of work performed and the minimum temperatures given in the Government Decree. For example, for class IIb work the minimum is 14 °C, whereas for class IIIa it is 10 °C.
If, at a workplace intended for permanent work, doors are repeatedly opened directly to the outdoors in winter, protection against the ingress of cold outdoor air must also be addressed.
In practice, for example, air curtains, high-speed doors, vestibules or suitable organisation of handling are used.
What to prepare before measurement
The best results come from measurement planned according to the actual course of the shift. Before the technician's visit, it is advisable to determine the job positions, the work operations and the exact times spent in the individual temperature conditions.
Information on employees who move during the shift between the ordinary warehouse, the cold store, the freezer room and the outdoor area is particularly important.
If the aim is also to update job categorisation, it is advisable to review the other work environment factors in advance. In cold-storage and production operations, noise, physical load, working posture or manual handling of loads may be relevant at the same time.
What you can send us and what we will verify
For a measurement proposal, you can send us:
- a description of job positions, the shift length, the individual operations and the time employees spend in the cold store, freezer room, hall or outdoor area,
- photographs of the workplace, the work clothing used, the entrances to cooled spaces, doors and any warm-up room,
- the existing job categorisation, previous measurement reports or a requirement of the regional public health authority.
Based on the documents, we will determine suitable measurement points and a measurement date. We will evaluate the cold stress, the work regime and the link to job categorisation, and point out any requirements for protective clothing, safety breaks or protective drinks.
You will find more information on the page Heat and cold stress measurement – NATURCHEM.
Related legislation
Government Decree No. 361/2007 Coll., laying down conditions for the protection of health at work
Decree No. 432/2003 Coll., on the conditions for classifying work into categories