Gas, Vapour and Liquid Explosion Properties Testing

The handling of gases, liquids and selected substances may constitute risks for explosions. Knowing the properties related to the risk of these materials, such as the ignition and explosion characteristics, is therefore essential.  By being aware of the properties of materials handled in your plant or used in your products, it allows the necessary safety precautions to be taken to prevent explosions or reduce their consequences.

Gexcon performs tests to determine the explosion characteristics of gases, vapours and liquids. All our tests are performed following internationally recognised standards.



Determination of the auto-ignition temperature of gases and vapours

The auto-ignition temperature of a substance is used to assess the ignition hazards of gases and vapours. The test is performed in a heated vessel into which the test sample is introduced. The temperature and sample concentration is varied until the threshold of ignition is determined. The test is performed according to EN 14522: ‘Determination of the autoignition temperature of gases and vapours.’


Conductivity of liquids

This test measures the conductivity of liquids, which allows the evaluation of their electrostatic charging properties.

The conductivity of a liquid is an important measure to determine electrostatic ignition hazards. Low-conductivity liquids obtain charges. For example, during pouring or stirring operations—liquids with conductivities < 5×10-11 S m-1 are low enough that electrostatic hazards must be carefully guarded. However, for liquids with extremely low conductivity, i.e. conductivities < 10-13 S m-1, charge buildup occurs to a lesser extent and is not considered hazardous. These low-conductive liquids may be subject to incendive brush discharges. Liquids with high conductivity may be involved in static electrification accidents if they are placed inside insulated vessels or in the form of an aerosol.


Explosion limits

Gexcon applies the bomb method as described in EN  1839: a quiescent mixture in a closed vessel (bomb) is subjected to an ignition source. The overpressure is measured. The amount of test substances in the mixture is varied until no significant overpressure is seen, thus determining the lower and upper explosion limits.


Maximum explosion overpressure and maximum rate of pressure rise

Gexcon determines the maximum explosion overpressure and rate of pressure rise in a closed test vessel (bomb) as described in EN 15967. Explosive mixtures of the substance and air are prepared in the vessel at atmospheric conditions and ignited in the centre. The pressure-time history is measured. From the pressure-time histories the highest rate of pressure rise (dt/dt)m is calculated, and the highest pressure determined. This is performed over a large range of substance-air concentrations until the maximum values of both parameters have been obtained.


Laminar burning velocity

Gexcon applies the bomb (closed vessel) method to determine the laminar burning velocity. Mixtures of the substance to be investigated and the air are prepared in the closed vessel using the partial pressure method. Ignition in the center yields a pressure-time history. Burning velocities are extracted from the pressure-time history. This is repeated over a large range of substance-air concentrations until the maximum value of the burning velocity is obtained.


We believe in an individual approach because we believe each client has a different test preference. We offer:

  • Detailed price transparency
  • Customised testing
  • Detailed testing report



The cost and the preparation that should be made depends on many factors, such as the type of gas, liquid or vapour that is to be tested. Please let us know your preference by sending a quotation request via the enquiry form below.

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