Introduction to Flameproof (Ex d) #
Flameproof protection is one of the original methods of explosion protection developed for use in mining industry. It has a wide range of applications, typically junction boxes, lighting fittings, electric motors etc.
The letter ‘d’ comes from the German word ‘druckfeste’ (kapselung) which means ‘pressure tight’ (enclosure).
When properly installed, flameproof equipment enables components which arc or spark (e.g. switches, contractors and relays) to be safety used in hazardous areas.
Flameproof is an explosion protection method in which an explosion is permitted.
However, the explosion must be contained within the strongly constructed flameproof enclosure. The hot products of combustion are cooled as they escape from the enclosure via the various flamepaths, and will have insufficient thermal energy to ignite the surrounding atmosphere.
Standards #
| Current constructional standard | |
| IEC 60079-1: 2014 BS EN60079-1: 2014 | Explosive atmospheres – Part 1: Equipment protection by flameproof enclosures ‘d’ |
| Codes of Practise | |
| IEC 60079-14: 2013 BS EN60079-14: 2014 | Explosive atmospheres: Part 14 Electrical installations design, selection & erection |
| IEC 60079-17: 2013 BS EN60079-17: 2014 | Explosive atmospheres: Part 17 Electrical installations inspection and maintenance |
Definition #
The construction standard IEC 60079-1 defines flameproof as:
‘An enclosure in which the parts which can ignite an explosive atmosphere are placed and which can withstand the pressure developed during an internal explosion of an explosive mixture, and which prevents the transmission of the explosion to the explosive atmosphere surrounding the enclosure’
