ATEX Area Classification

The method

• Identification of every source of release and its grade
• Release rate from hole size, pressure, and fluid state
• Ventilation degree and availability, indoors and outdoors
• Zone type and extent, derived rather than assumed
• Temperature class from the ignition temperature of the substances present

Substance data

The quality of a classification depends entirely on the substance data behind it. Techso has developed an internal calculation engine for area classification to IEC 60079-10-1, with a database of 129 substances, so that the properties used are consistent, traceable and the same on every project.

• Flammability limits, flash point and vapour density
• Explosion group and temperature class
• Mixtures and the properties that govern them

Equipment selection and installation

• Equipment protection level required by each zone
• Types of protection and their suitability for the application
• Cable entries, glands and enclosure integrity
• Earthing, bonding and static electricity control
• Verification and inspection of existing installations

Documentation

In Italy the classification is not a stand-alone deliverable: it feeds the explosion protection document required by the workplace safety legislation, and it has to be consistent with the risk assessment that sits alongside it.

• Classification drawings, in plan and elevation
• Schedule of sources of release with the calculation behind each
• Equipment register with protection level and marking
• Input to the explosion protection document