CENELEC AND IEC NORMATIVES
THE ROLE OF THE IEC
This is the system developed by the International Electrotechnical Commission (IEC), which was established in 1904 and whose headquarters is in Geneva in Switzerland.
In 1947, with the creation of the International Standards Organization (ISO) by the United Nations, the IEC became responsible for the organization of the electrical division, while still remaining independent.
The IEC has defined three zones of gas and vapor classification:
• Zone 0 : the explosive atmosphere is continuously present.
• Zone 1 : the explosive atmosphere is often present.
• Zone 2 : the explosive atmosphere may accidentally be present.
|Gas and vapor classification
(Tabelle – 1)
Gases are divided into four groups by the CEC and the NEC (with some additional gases).
The IEC also defines different groups of gases and vapors.
The IEC and North American groups are viewed as fundamentally the same, apart from the fact that there are three groups in the IEC and four for North America.
(Tabelle – 1 bis)
The IEC has defined a temperature classification for equipment used in hazardous areas.
Following this, CEC and NEC have also been modified to include a temperature classification.
This temperature table is as follows