IE3: Feed of liquids

Hazards: Chargeable liquid charges as it is agitated during the filling process. If it comes into close proximity to a conductive earthed object, a discharge can ignite an explosive atmosphere.

Protective measures: Feed the conductive paint before adding the solvent when adjusting the viscosity. Reduce the agitation speed when using non-conductive coating systems.

When coating materials are being mixed and adjusted, a liquid of low conductivity can become charged. There is a fundamental possibility of liquids becoming charged during agitation procedures, even in the case of liquids of moderate conductivity, though this material group can be regarded as of secondary importance in the context of liquid coating applications because of the low agitation speeds and the vessel geometry in the case of earthed vessels. An ignition-capable charge accumulation is unlikely for materials of moderate conductivity because of the negligible surface areas and the proximity to the earthed vessel wall.

Low conductivity		κ ≤ 5 * 10-11  S/mc
Moderate conductivity	5 * 10-11 S/m <	κ ≤ 10 -9 S/m
High conductivity	10 -9 S/m <	κ

Table: Classification of liquids by their conductivity

Coating systems are not generally classified as liquids of low conductivity.

When adjusting the viscosity, on the other hand, aromatic compounds such as xylene or toluene, which have a low viscosity, are also used. In such cases, the conductive coating component must always be fed first when mixing. Where the coating system is also based on aromatic solvents, supplementary measures, such as reducing the agitation speed, may also have to be taken.

Table: Organic solvents of low conductivity

Solvent name	Conductivity range [S/m]
Paraffins	10-14 to 10-11
Aromatic compounds (e.g. toluene, xylene)	10-13 to 10-11
Kerosene	10-13 to 5*10-11
Gasolines (depending on sulphur content)	10-13 to 10-10
White oils	10-13 to 10-10
Ether	10-13 to 10-10
Aromatic solvent mixtures	10-12 to 10-9