ISA TR67.04.09-2005
Graded Approaches To Setpoint Determination

Standard No.

ISA TR67.04.09-2005

Release Date

2005

Published By

ISA - International Society of Automation

Latest

ISA TR67.04.09-2005

Scope

This Technical Report provides guidance on a graded approach for calculating and documenting channel and indication uncertainties as well as for documenting uncertainty-adjusted interlock values@ setpoints@ test acceptance criteria@ and action points for permanently installed nuclear plant instrumentation. Purpose This Technical Report supplements the information provided in ISA-67.04.01 and ISA-RP67.04.02 for the determination of instrument channel uncertainty@ instrument indication uncertainty@ and instrument setpoints. Specifically@ the topic addressed in this technical report is the use of a graded approach as mentioned in the Recommended Practice@ where issues of higher safety significance are treated with greater rigor and issues of lower safety significance are treated with less rigor. Branch Technical Position HICB-12 allows such variations in rigor based on the safety significance of the instrument function. Uncertainties for measurement and test equipment@ laboratory instrumentation@ and other nonpermanently installed or non-process instrumentation such a meteorological instrumentation are outside the scope of this document. Other guidance and requirements exist for determining instrument uncertainties for other applications. Specifically@ ASME sets forth requirements for In Service Testing instrumentation. Such alternate guidance is beyond the scope of this document. Descriptions of and requirements for a full setpoint control program are beyond the scope of this document.

ISA TR67.04.09-2005 history

• 2005 ISA TR67.04.09-2005 Graded Approaches To Setpoint Determination