Temperature measurement can be a hot issue

Companies that use temperature measurement products - including thermocouples and RTDs - that are installed in potentially explosive atmospheres need to ensure that the sensor assembly (sensor, enclosure and terminal glands) meets the overall area classification requirements for each installation. In Europe, this is covered by the ATEX Directives, including the ATEX harmonised standards.

Directive 94/9/EC covers equipment that is intended for use in potentially explosive atmospheres. The CE mark on equipment such as this represents the manufacturer’s declaration of compliance to this directive and to the EN standards that are harmonised to it. All equipment should be supplied with a declaration of conformity, stating compliance with these standards and with product certification provided by a notified body, such as BASEEFA or SIRA in the UK.

If the chosen certification classification is Exia for use in zone 0, 1 or 2, there is no need for product certification in the case of thermocouples or RTD sensors, but care must be taken to ensure the correct installation with an appropriate barrier, that the IP rating of the termination is correct and that there is appropriate terminal clearance.