Operating plants or areas where inflammable substances in sufficient quantity get in contact to oxygen (air) become a hazardous area. In this case, measures are necessary in order to exclude the danger of ignition by electric or mechanical operating equipment (devices, tools, machines or vehicles).

In order to exclude the danger of explosion by ignition sources, you have to use operating equipment with explosion protection, if required.

Types of Protection:

"Types of Protection" for operating equipment according to the the standardisation work are e.g. "Flame-proof Enclosure", "Increased Safety", "Powder Filling" or "Restricted Breathing Enclosure" which offer the same protection against the danger of ignition amongst themselves.

Classification of Areas:

Hazardous regions are classified in areas. Depending on the extent of explosive atmosphere, these are for gases, vapours, mists:

Explosion Groups:

Explosive gases and steams are classified in explosion groups:

Temperature Classes:

Depending on the ignition temperature, inflammable gases and vapours are classified in temperature classes.
The maximum surface temperature of an electric operating material has always to be lower than the respective ignition temperature.

Share of Responsibility of the Owner:

The responsible co-operation of the planner, the plant constructor and the owner is essential for the successful explosion protection. This includes a careful selection of the operating equipment and its application for a specific purpose as well as the careful assembly, installation and commissioning. By repeated inspections of the operating equipment and the plant, the proper condition of the explosion protection can be maintained.

Heater Connection Casing:

The connection casing of the heater consists of two components with different types of protection:

	casing with connections of the heating elements as well as switching devices or temperature sensors for temperature monitoring, type of protection "flame-proof enclosure" EEx d
	connecting box for the connection of the power and control cables, type of protection "increased safety" EEx e

Temperature Monitoring

In order to keep the temperature class, the surface temperature of the heating bundle has to be monitored.

	for air and gas heating, temperature probe effective on heater surface temperature
	for heating of liquids, Temperature probe effective on medium temperature

	Temperature limiter accord. to PTB-attestation with manual reset function, adjusted in accordance with the respective temperature class.
	Temperature controller, individually adjustable below the limiter adjustment, for an approximate regulation of medium temperature normally prevents the release of the limiter.

Type-examination certificates accord. to the regulation 94/9/EC - ATEX - are available for all heaters.

We will be glad to provide further information on request.