Explosion-Protected Equipment: Applications and Requirements

In a hazardous environment, even a small spark can cause severe damage to people, equipment and property. Using suitable explosion-protected equipment is an important part of workplace safety. Selection, installation and maintenance require an understanding of the applicable requirements.

What Is Explosion-Protected Equipment?

For flameproof equipment, the enclosure is designed to contain an internal explosion and prevent ignition from propagating to the surrounding atmosphere. It must withstand the explosion and prevent flames or hot gases from escaping in a way that could ignite the external atmosphere.

How It Works

If an explosion occurs inside an enclosure, pressurized gases seek a path out. Flameproof equipment uses a robust enclosure and engineered flamepaths to cool escaping gases before they reach the surrounding atmosphere. High-quality, appropriately certified equipment is essential to reducing fire and explosion risks.

Uses and Requirements in China

Explosion-protected equipment is used in locations where flammable dusts, liquids, gases, vapours or fibres may create an explosive atmosphere. Typical industries include oil and gas, mining, chemical processing and pharmaceutical manufacturing. Appropriate preventive measures are required to reduce the associated risks.

Follow Applicable Guidance

International standards: select equipment that complies with the relevant IEC standards and other standards applicable to the installation.

Local rules: understand and comply with the laws and regulations of the country or region where the equipment is used.

Certification and testing: verify that the equipment has been tested and certified for the required type of protection and hazardous-area rating, normally by an appropriate third party.

Installation and maintenance: follow the manufacturer’s instructions, including correct wiring, inspection and scheduled maintenance.

Training: train personnel in correct use, safe operating procedures and emergency response.

Periodic review: reassess equipment in service to confirm continued suitability and arrange updates or replacement when needed.

Emergency planning: implement plans for preventing and responding to fires or explosions.

Following these practices helps maintain equipment effectiveness and protect workers and facilities.

Hazardous-Area Classification

Two common approaches are the Class/Division system, used mainly in the United States and Canada, and the Zone system, used in many other regions. Zones describe how likely an explosive gas or dust atmosphere is to occur and how long it may be present.

Zone 0: an explosive gas or vapour atmosphere is present continuously or for long periods.

Zone 1: an explosive gas or vapour atmosphere is likely to occur in normal operation.

Zone 2: an explosive gas or vapour atmosphere is unlikely in normal operation and, if it occurs, persists only briefly.

Zone 20: a combustible-dust atmosphere is present continuously or for long periods.

Zone 21: a combustible-dust atmosphere is likely to occur in normal operation.

Zone 22: a combustible-dust atmosphere is unlikely in normal operation and, if it occurs, persists only briefly.