Apparatus Marking

I.S. concept is an instrument loop arrangement with 3 parts to the loop design.

  1. There is equipment installed in the hazardous area (Process Plant).

  2. Cabling which connects the hazardous area apparatus to the non-hazardous area (e.g. Control Room).

  3. Energy limiting apparatus is installed in the non-hazardous area.

Equipment installed in the hazardous area will be marked ia, ib or ic. Equipment installed in the non-hazardous area will be marked Ex[ia], Ex[ib] or Ex[ic].

NOTE

Please Note: [ ] indicates that the apparatus is an ASSOCIATED piece of apparatus.

It is a component part of an I.S. system and must be installed in the non-hazardous area.