Flameproof enclosue Ex d

About the test  

Flameproof protection Ex d is based on the principle that enclosure of the equipment will contain the explosion inside and not transmit the explosion outside the enclosure. 

To pass the test enclosure needs to: 

1. withstand the pressure developed during an internal explosion of an explosive mixture 
2. prevent the transmission of the explosion to the explosive atmosphere surrounding the enclosure 
3. not have external surface temperature that is capable of igniting the surrounding explosive atmosphere.  

Standard requirements and compliance  

The design requirements for flameproof enclosures are specified in the International Standard IEC 60079-1 or Australian/New Zealand Standard AS/NZS 60079.1, when read in conjunction with the General Requirements standard IEC 60079-0 or AS/NZS 60079.0 respectively. 

Electrical equipment used in the mining, oil and gas, and petro-chemical industries, such as luminaries, metering devices, motors, generators, brakes, valve actuators, plugs and sockets, are assessed and tested for compliance with the flameproof Standards. 

Manufacturer's documents for flameproof enclosures must provide details of all flame paths, which may be a flange, thread, cylindrical, labyrinth, serrated or multi-step. The Standard sets down the minimum requirements for specific flame paths of each gas group against internal free volumes of the enclosures. 

Gas groupings  

This type of protection is applicable to the following Gas Groups, which are based on Maximum Experimental Safety Gap characteristic of flammable gases: 

1. Group I:  a typical gas is methane 
2. Group IIA: a typical gas is propane 
3. Group IIB: a typical gas is ethylene 
4. Group IIC: typical gases are hydrogen and acetylene.  

Protection levels  

Type of protection Ex d may have three levels of protection: 

1. ‘da’ for Equipment Protection Level EPL Ma or EPL Ga 
2. ‘db’ for Equipment Protection Level EPL Mb of EPL Gb 
3. ‘dc’ for Equipment Protection Level EPL Gc. 

Test types  

Here are some tests that may be applicable depending on the construction and material of the equipment and these may include but are not limited to:  

• temperature rise test 
• thermal endurance to heat and to cold 
• impact tests 
• verification of flame-proof joints 
• sealing test 
• determination of explosion pressure (reference pressure) test 
• overpressure test 
• test of erosion by flame 
• test for non-transmission test of internal ignition. 

Getting the test results

The results of our testing are presented in a test report that is endorsed by our local Australian laboratory accreditation body, NATA (National Association of Testing Authorities, Australia).

When product sample testing, design assessment (Ex test report) and quality assessment (quality assessment report) are successfully completed, an Ex Certificate of Conformity (IECEx or ANZEx) is issued by TestSafe.

Help and support

Complete our online enquiry form.

Call: +61 (2) 4724 4900

Email: testsafe@safework.nsw.gov.au

Mail us at: PO Box 592, Richmond, NSW 2753 Australia.