1. Home
  2. Benefits
  3. Parameters for substances
  4. Electrical conductivity of liquids

Electrical conductivity of liquids

Contact

Call us
+49 (0) 69 30530012 or write:

This form collects and processes your e-mail address, if you also specify your name and your company. By using this form, you consent to the storage and processing of your data through this website. You have read the privacy policy and agree.

To protect against spam, this form uses simple anti-spam questions.

What is 7+4?

Electrical conductivity of liquids

Liquids and the interior of containers can become dangerously electrostatically charged while they are being filled or emptied of liquids, while liquids are pumped, stirred, mixed and sprayed, and also during sampling and cleaning procedures. (TRGS 727, chapter 4)

Knowledge of the electrical conductivity (reciprocal value of the specific resistance) of the liquid is of decisive importance for correctly assessing the risk of a possible electrostatic discharge of a charged liquid.

According to TRGS 727, a substance or material is classified according to its specific volume resistance ρ as follows:

Conductive: ρ ≤ 104 Ωm

Dissipative: 104 Ωm < ρ <109 Ωm

Insulating: 109 Ωm ≤ ρ

According to TRGS 727, a liquid is classified according to its conductivity κ as follows:

Low conductivity: κ ≤ 50 pS/m*

Average conductivity: 50 pS/m* < κ ≤ 10000 pS/m

High conductivity: 10000 pS/m < κ

Footnote*: 50 pS/m for hydrocarbons or 100 pS/m for other liquids

The determination of the specific resistance of the liquids or the electrical conductivity of the liquid is carried out in accordance with the DIN EN 60079 – 32 – 2 – Electrostatic hazard – test procedure or in accordance with DIN 51412-1.

The Tera Ohmmeter is used to measure contact resistivity. An electrode in accordance with DIN 51412-1 is used as a liquid electrode. This electrode consists of an inner and outer electrode. In the measuring range, both electrodes are separated by a gap filled with the liquid to be measured. A schematic drawing of the electrode is taken from the DIN 51412-1 standard and is shown in Figure 1.

Figure 1: Schematic diagram of the liquid measuring cell (taken from DIN 51412-1)

However, the test can also be applied with the electrode in accordance with DIN EN 60247. A schematic drawing of the electrode is taken from the standard DIN EN 60247 and shown in Figure 2.

Abbildung 2: Schematischer Aufbau der Flüssigkeitsmesszelle (entnommen aus DIN EN 60247)

The measuring voltage of the Tera Ohmmeter TO3 is usually 100 V. The resistivity (or specific resistivity) of the liquid is determined, the temperature of the liquid, the air temperature and humidity are noted. Taking the cell constant into account, the specific resistivity is ρ to ρ = RD · K

The measurements can also be performed at a higher temperature of up to 80 °C.

Parameters for substances
Benefits