Guidance on marking requirements for combined Ex electrical/non electrical equipment

Background:
Today, the marking of electrical equipment is defined in IEC 60079-0, and the marking of non-electrical equipment is defined in ISO 80079-36.
Due to the fact that combined electrical / non-electrical marking is not defined in 60079-0 or in ISO 80079-36, the electrical part of the equipment has to be marked in accordance with IEC 60079-0 and the non-electrical part has to be marked in accordance with ISO 80079-36.
Therefore, the marking of electrical part and the non-electrical part is described in two different lines:
– Ex db IIA T4 Gb
– Ex h IIA T4 Gb
QUESTION: How shall marking be shown for equipment covered by both the electrical and non-electrical Standards (IEC 60079 and ISO 80079 series)
ANSWER:
After discussion with IEC TC31 Chairmen, SC31M Chairman and IEC TC31 WG22, it is decided to have combined marking for equipment which include an electrical part and a non-electrical part, for example:
– Ex db h IIA T4 Gb
– Ex h tb IIIC T135 °C Db
It will be clearer for the user that the combined risk of the electrical part and the non-electrical part has been assessed for the complete equipment, stating one EPL, one Equipment Group and one Temperature Class for Gas and the same for Dust (but showing a maximum surface temperature instead of a temperature class).
It is also noted that Ex Components are not marked with either a temperature class (Group II) or a maximum surface temperature (Group III)
Original article: http://www.iecex.com/dmsdocument/2163