Hazardous Area Classifications & Protections
In industries dealing with hazardous materials, such as the Oil and Gas industry, understanding hazardous area classifications and equipment protection is crucial. Here are important details about Equipment Protection Level (EPL), zones, marking, and certifications:
Equipment Protection Level and Zones:
Electrical and electronic equipment installed in hazardous (classified) locations must comply with the requirements of IEC 60079-14. When EPLs are identified in the area classification documentation, the selection of equipment should follow the corresponding requirements.
Equipment Protection Levels and Assigned Zones:
- Zone 0: "Ga"
- Zone 1: "Ga" or "Gb"
- Zone 2: "Ga", "Gb", or "Gc"
- Zone 20: "Da"
- Zone 21: "Da" or "Db"
- Zone 22: "Da", "Db", or "Dc"
Exceptions and Restrictions for Equipment Protection Techniques:
a) Zone 1 Areas:
i. Medium Voltage (MV) motors (601-15,000 V range) and sparking equipment (equipment with contact) such as switchgear and control gear should have type of protection "d".
ii. "de" type MV motors (flameproof motor with increased safety terminals) can be used.
iii. Increased safety "e" type MV motors are not permitted.
b) Zone 2 Areas:
i. Motors and non-sparking equipment should have a minimum type of protection "n".
ii. Sparking equipment (equipment with contact) should have type of protection "d".
iii. MV motors with voltage exceeding 4.8 kV and driving centrifugal/screw hydrocarbon or hydrogen compressors should have type of protection as in "Zone 1" or "p". Type of protection "n" or "e" is not permitted.
c) Single-phase motors located in hazardous locations (Zone 1 and Zone 2) should be of the totally enclosed flame-proof Ex-d or Ex-de type as per IEC 60079-1.
Approval for Zone and Properties:
a) Approval for "Zone and Properties" should comply with the requirements of IEC 60079 Series. Equipment should be identified not only for the zone of location but also for the explosive, combustible, or ignitable properties of the specific gas, vapor, dust, or fibers/flyings present.
b) Zone 0, 1, and 2 equipment should not have any exposed surface operating at a temperature exceeding the auto-ignition temperature of the specific gas or vapor.
Marking and Certification:
a) Equipment should be marked according to the requirements of IEC 60079-0.
b) Equipment and materials installed in hazardous areas should have markings as per IEC standards and should be listed, labeled, or certified by recognized Testing Laboratories.
Note: The equipment is certified for specific ambient temperatures indicated on the certification. Exposing it to higher temperatures may exceed the stated T-Class temperature, potentially leading to unsafe conditions.
c) Assembled equipment and materials in hazardous areas, such as switch-racks, control and distribution panels, should be certified and labeled as complete units in addition to each component having the required certification for the installation area.
Understanding the requirements and certifications for equipment in hazardous areas ensures compliance and promotes safety in these environments.