Key points at a glance
A paint store must be secured in such a way as to minimise the risk of fire and explosion. Specific requirements apply in terms of environmental, fire and occupational safety, as highly flammable and potentially hazardous substances are often stored there. In companies that work with paints, varnishes, hardeners or solvents, paint and solvent storage areas are a key part of operational processes and should be secured accordingly.
Paints and varnishes consist of binders, pigments, additives and solvents. Solvents generally consist of volatile organic compounds (VOCs), which evaporate at certain temperatures. When the flash point is reached, flammable vapours are formed. When combined with atmospheric oxygen, this can lead to explosive mixtures. These vapours can, in turn, cause an explosion when combined with an ignition source (e.g. sparks, flames, hot surfaces).
The risk of explosion depends on the physical properties, known as the explosion limits (LEL, UEL as specified in section 9 of the safety data sheet). These describe the concentrations at which a substance forms an explosive mixture with air.
This information forms an important basis for the classification of Ex zones.
The GHS (Globally Harmonised System) classifies and labels chemicals. In the EU, this is implemented through the CLP (Classification, Labelling and Packaging) Regulation. Since the switch to this system, the pictogram (GHS 02) alone no longer indicates how hazardous a substance or mixture actually is, as the same symbol is always used. The following substance properties are therefore crucial for a correct assessment:
The following apply to paint storage areas and other areas at risk of explosion:
A risk assessment must be carried out and protective measures defined in accordance with the requirements. This specific risk assessment is also referred to as an explosion protection document. The relevant inspections (in accordance with the BetrSichV) must also be specified therein.
A key step in explosion protection is the division into zones, whereby the hazardous area is classified into three zones for gaseous substances, depending on the occurrence of hazardous explosive atmospheres:
| Zone | Occurrence of an explosive atmosphere |
|---|---|
| Zone 0 | an explosive atmosphere that is present continuously or for a long period (e.g. inside containers) |
| Zone 1 | occasional explosive atmospheres (e.g. near mixing tanks, when cleaning spray guns) |
| Zone 2 | Explosive atmospheres occur rarely and, when they do, only for a short time (passive storage) |
We assess substances and work areas on site and classify the zones in a transparent manner.
The most important technical measures include ventilation systems, explosion-proof electrical equipment or work equipment, and adequate equipotential bonding. Detailed descriptions of the individual measures can be found below.
All staff working in or near the paint store must receive appropriate training. This includes recognising potential hazards and malfunctions, being familiar with the safety precautions, and thus knowing how to act correctly in an emergency. This should be set out in a set of operating instructions.
Adequate ventilation is crucial for keeping the concentration of flammable vapours below the explosion limit. A distinction is made between forced and natural ventilation. For paint storage facilities, forced ventilation is generally required to replace the air at regular intervals. Outdoors, where storage is purely passive, natural ventilation via ventilation slots may sometimes be sufficient. However, paints may usually only be stored within defined temperature ranges. It is also important to ensure that solvent vapours are captured close to the floor, as they are heavier than air.
All electrical equipment used in a potentially explosive atmosphere must comply with explosion protection requirements (ATEX approval). This means that they are designed in such a way that they do not generate sparks or hot surfaces that could trigger an explosion. This depends on the relevant zone classification.
The movement of liquids can give rise to static electricity. This can act as a spark and become a source of ignition. It is therefore essential that all metal parts in the paint store are earthed and interconnected, and that plastic components are electrically conductive. Flexible cables with terminals attached to containers are therefore important. The floor must also be conductive (grating or conductive coating).
Frank Schüle
Graduate Engineer (FH) Head of the Environment, Health and Safety / Fire Safety Department