Wednesday 15 August 2012

Loop checks standard!

New ISA Standard on Loop Checks Approved by ANSI

An ISA standard, ANSI/ISA-62382-2012 (IEC 62382 Modified), Automation Systems in the Process Industry—Electrical and Instrumentation Loop Check, has been approved by the American National Standards Institute (ANSI) and is now available.

This standard defines procedures and specifications for loop checks, which comprise the activities between the completion of the loop construction (including installation and point-to-point checks) and the start-up of cold commissioning. It is applicable to the construction of new plants and to expansion/retrofits (i.e. revamping) of E&I (electrical & instrument) installations in existing plants (including PLC, DCS, panel-mounted and field instrumentation).

The standard is a US-modified adoption by the ISA105 standards committee of IEC 62382 Edition 1. While the content is largely the same as IEC 62382, this adoption includes such changes as:

- The addition of both the increasing and decreasing directions to tests in order to identify any hysteresis issues.
- The addition of a category of “standard loops” for completeness.
- The replacement of various input/output check forms with a single loop check form that can be used for all loops, including indicating and control. This significantly reduces the number of check forms needed and at the same time reinforces the “loop” concept in the loop check activity.
- Expanded examples of loop checks. Specific loop checks must be established by the user depending on the specific hardware/software to be verified on the project.

• This adoption follows the adoption by ISA105 and publication in late 2011 of the following: ANSI/ISA-62381-2011 (IEC 62381 Modified), Automation Systems in the Process Industry—Factory Acceptance Test (FAT), Site Acceptance Test (SAT) and Site Integration Test (SIT).

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