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Atmosphere Cl 86.1

Verification of the atmosphere at the workplace

The general provisions on monitoring the atmosphere at workplaces that are liable to be contaminated by substances or products which present a risk to health are specified in Instruction CL 86.1 issued by the ITM.
Only the verification agencies authorised by the latest ministerial regulation of the Minister of Labour and Employment are authorised to perform this verification. The operator of the workplaces must assess these risks. He must:

  • produce a survey of all dangerous substances and preparations present in the establishment;
  • keep a register of the safety notes applicable to these substances and preparations;
  • look into the possibility of replacing dangerous substances by less dangerous alternatives.

Risk monitoring must be assured. The measured values must be compared with the limit exposure values. The analyses must be repeated at intervals defined in the light of the extent to which limit values are exceeded. 

The analysis reports must be written in precise terms and must contain defined headings.
A register of the analysis reports is to be kept by the operator for at least 30 years.

Ventilation Cl 53.1

Ventilation and air conditioning systems

The general provisions on safety, health and convenience of all ventilation and air conditioning systems are specified in the Instructions CL 53.1 issued by the ITM.
European standards are applied as and when they are adopted. The working atmosphere and environment are characterised by parameters for which reference values have been defined in these provisions:

  • Introduction of new air and evacuation of waste air: 20 to 40 m3 per hour and per worker for persons working in a seated posture.
  • The recommendation is that the relative atmospheric humidity should not be less than 30% if artificial ventilation is provided. Maximum values are also defined in light of the ambient temperature (values never reached in offices).
  • The minimum temperature for an office must be 20°C and this temperature must be reached before work is resumed each day.
  • The maximum temperature of the working premises must not normally exceed 26°C.

The supplier must provide a guide explaining the use of his installations.
There are provisions concerning the maintenance of air conditioning and heating appliances, ducts, air filters, humidifiers…
Maintenance must be effected by qualified personnel in strict compliance with the rules on occupational safety.
Workers who intervene on the installations must be properly trained and informed.
Access to the installations must be confined to authorised persons.


Lighting Cl 55.2

Workplace lighting

The general provisions on safety, health, hygiene and convenience concerning the lighting at workplaces are specified in Instruction CL 55.2 issued by ITM.
European standards apply as and when they are adopted and replace the various national standards.

Natural lighting

Workplaces must have adequate natural lighting to allow workers to move around and work under good conditions of safety and health.

  • A view onto the outside surroundings must be guaranteed.
  • The minimum glazed surface must be 1.25 m2 (depth of the premises <5m) or 1.50 m2 (depth of the premises > 5m).
  • The minimum height of the glazed surface must be 1.25 m.
  • The minimum width of the glazed surface must be 0.80m.
  • The glazed surface must cover at least 1/10th of the floor area for premises with a floor space of up to 600 m2.
  • The windows and top lighting must not create a risk to workers and must be kept properly clean.

Artificial lighting

  • The installations must not present an accident risk to workers and must be installed in such a way as to prevent all dazzle.
  • Proper diffusion of light must be ensured and shadow zones avoided.
  • Good visibility of surfaces and colours must be ensured, especially in the case of what are known as safety colours.
  • The general lighting must not be too weak in relation to the local lighting

The lighting intensity must be measured during activities at the same workplace. There are tables of recommended light intensity, depending on the particular type of activity pursued; in general, however, a nominal light intensity of at least 500 Lux is recommended for workplaces which are permanently occupied and situated indoors.