Blog | Fauske and Associates, LLC

New Hartmann Tube for Combustible Dust Screening!

Written by AnnMarie Fauske | Apr 24, 2015 3:11:04 PM

  This is a combustible dust cloud explosion pre-screening test. This test is performed based on procedures from VDI 2263, Part 1 (Section 2.1.1), “Dust fires and dust explosions; hazards, assessment, protective measures”, using a Modified Hartmann Apparatus with a 10 J AC electric arc. The material tested here is a fine metallic powder which was determined to have an Explosion Severity ratio of 0.4 – based on subsequent testing. The pre-screening test in the Modified Hartmann Apparatus is a precursor to the standard explosion screening test conducted per ASTM E1226 Section 13. Both tests, when used in conjunction, can be used as a tool to ascertain if a given sample of dust poses an explosion risk if suspended into a cloud in air in the presence of an ignition source.

In response to frequent requests, Fauske & Associates,LLC (FAI) announces the availability of a portable Hartmann Dust Testing apparatus that can be used on-site at a client’s facility. The practicality of this device is its simplicity to test and determine if dusts in question are classified as combustible; it uses a very small sample size (0.3 - 3.0 grams). The portability aspect is appealing as the device can be brought onto the plant site and local samples can be tested in a very short time, providing an instant identification of combustible materials. Applications include, but are not limited, to combustible testing of: floor and process samples per NFPA 654/OSHA CPL 03-00-008, R&D, process development, and commercial scale-up of starting materials, isolated intermediates and final products, including final packaged forms with excipients. The data can be used internally or shared using Material Safety Data Sheets. The device conforms to EU and UN test requirements. We can send an engineer with the device or we can train plant personnel to use it.

The modified Hartmann apparatus consists of a dispersion cup, a PTFE tube holder and a glass tube with a volume of 1.0 liter. By means of pressurized air a quantity of the powder sample is suspended in the presence of an ignition source. The ignition source used for the tests is a continuous spark generated by a high voltage transformer between two standardized electrodes placed near the bottom of the cylindrical tube. The energy content of the spark corresponds to an equivalent energy of about 10 Joule of a discharge spark.

Powder concentrations in air are between 30 mg - 3000 mg/liter (30 - 2500 g/m3). A powder is considered to be explosible if dust fires or explosions are observed during the tests. If no dust fires or explosions are observed in three-series of tests for any concentration, the powder is considered to be not explosible at the conditions of the test.

If the process that you suspect could contain combustible dust, it would be prudent to contact us for dust screening advice or if you would like more information on this portable equipment, please contact us at