Solutions: Explosion-protection

WILL & HAHNENSTEIN has been building equipment for explosion-endangered environments for over 30 years. Take advantage of this wealth of experience! We would be pleased to advise you on any aspect of explosion protection

We are open for your questions about explosion protection.

Our range of explosion-proof devices:

• warming ovens
• drum heaters
• flask heaters
• sheet-metal hoods
• heating containers
• melting tanks
• offtake sysstems for the workplace
• custom heaters

Please provide us with the following information when you place your request:

Do you need explosion protection against gases or dust particles?

• If gas, please provide required temperature class
• If dust, please provide zone required (21 or 22) and the maximum allowable surface temperature

Zone Classification
In working places the explosion-endangered areas at the most belong to the zones 1, 2, 21 or 22. The zones 0 and 20 are normally reserved for the interieur of technological facilities or very small areas in working places.
At WILL & HAHNENSTEIN the construction of warming ovens / drum heaters concerning gas explosion risk normaly fits the requirements for zone 1. With this the zone 2 is also covered. You get the best possible gas explosion protection, cause a warming oven for zone 0 is nearly not realisable. Concernign the dust explosion protection you can choose between zone 21 and 22. Here also a protection accomplishing zone 20 is nearly unrealisable.

General information
In all environments where combustibles (for example combustible gases, liquids or dust) can come into contact with oxidised matter (for example atmospheric oxygen) there is the potential for explosion.

Explosive combinations can, for example, be set off by the following:

• high surface temperatures
• sparks (that arise, for example from a break in an electrical current / electrostatic discharge)
• sparks from hammering or chafing mechanisms

Primary Explosion Protection
Primary explosion protection seeks to either displace or reduce combustible matter or atmospheric oxygen to such an extent that no explosive compound can form. This can be achieved, for example, through an increase in air supply. The compound concentration can be monitored with a gas detector. If the composite reaches the minimum level for explosion potential, the detector sets off a warning signal and shuts down the entire machine.

Secondary Explosion Protection
Machines are designed so that ignition sources, such as high surface temperatures, electrical sparks and sparks that arise through chafing and hammering mechanisms are contained separately from electrical equipment.
What measures are undertaken depends on the conditions in which the equipment will be put to use. These can be assessed based on the zone, explosion group and temperature class of each application.


Explosion Group: (gases and vapours only)
Combustible gases and vapours are divided into three explosion groups: IIA, IIB, and IIC. Environmental conditions that are rated as IIC are most highly explosive, group IIA is least explosive. Will & Hahnenstein's warming ovens and drum heaters are designed to meet the requirements for the most explosive environments, rated as IIC. In this way, our products also meet the requirements of groups IIB and IIA.

Temperature Class: (gases and vapours only)
Every gas/air blend has a different point of ignition. A piece of equpment's temperature class shows its maximum surface temperature. The maximum surface temperature has to be set according to the ignition point of the gas/air blend; that is, if a compound ignites at around 280°C, the facility's maximum permissible surface temperature is 200°C, which is temperature class T3.