Intrinsic Safety Options for Zone 2
Zone 2 hazardous areas previously used energy limiting ignition protection type Ex nL. The new Ex ic intrinsic safety standard will replace the existing Ex nL rules in 2011.
The new Ex ic standard applies solely to circuits in Zone 2 and must be used for new plants and major upgrades. Zone 2 installations employing Ex ic must conform to the demands of intrinsic safety:
- Separation of intrinsically safe and other circuits by 50 mm clearance
- Ex ic circuits must be marked. If marked by color, a light blue cable must be used
- Validation of intrinsic safety Ex ic through entity parameters
The demands are similar to those for Zone 1 with the exception that Ex ic does not consider fault conditions. It still allows work on a live circuit. Also, EPCs and end users will arrive at safe and cost-effective solutions for many greenfield installations in Zone 2. This applies not only to Remote I/O but other Ex ic certified equipment as well.