Gases & Vapours
IEC 600790-11 - Intrinsic Safety "Ex i"
Products and designs sent for assessment and testing to 'intrinsic safety' type of explosion protection are examined to the requirements of AS/NZS 60079.11, when read together with AS/NZS 60079.0, or equivalent Standards.
The circuit design is examined by reviewing the circuit schematics, interconnections diagrams, circuit board layouts, and most of this work is done on the desk using the knowledge of experts who have a design background and a complete knowledge of the intrinsic safety Standards.
As and when required, the circuit, or an equivalent one made up in our laboratory, is then tested on the Spark Test Apparatus. Explosive gases are mixed and piped into this apparatus, and wires from the circuit under test are connected to an arrangement of tungsten wires being brought intermittently into contact with a cadmium disk. The purpose is to 'make and break' the circuit 1600 times inside an explosive atmosphere to check if the energy in the circuit may cause an ignition.
To measure the maximum temperature rise on the surface of the components, and to confirm that the temperature is less than that at which the explosive gas could ignite, power is applied to the components under test, and the temperature is measured.
To measure the critical spacing distances on the electronic printed wiring board, a sample, or layout drawings, are examined for the places where spacing is critical. The distances are then measured on an Optical Profile Projector and compliance is thus determined.
To test that the internal circuits are adequately insulated from any metallic parts that may not be grounded, a high voltage test is applied between the metallic enclosure and the internal circuit.
There are several other tests that may be applicable - Drop test, IP test, impact test on piezo-electric devices, battery short circuit test, small component ignition test etc., and these are conducted using documented procedures using calibrated equipment.
In the end, a compliance test report is prepared, with a complete listing of all the safety components, and how compliance was determined.
Certification of the product is based on the test report and an audit of the manufacturing facility where the product is produced.
For information that should be addressed prior to submission for Certification, please check through General Requirements IEC 60079-0.
- For more information regarding certification of equipment, please click here.
- Please click here for application form.
We will also consider test requirements to other standards or similar tests as required, please use the enquiry form.
