Verification of an operator-initiated SIF

The verification of the operator-initiated SiF shouid consider the potentiai for operator error using user-approved criteria or anaiysis techniques. This assessment shouid inciude the human interface design and operating procedures. [Pg.52]

Most automated SiFs are designed as de-energize to trip. As a result, the PFDavg calculation for these SIFs generally does not take into consideration any utility systems. Operator action inherently requires support systems to compiete the safety function. Display/alarms require power to actuate the light and/or horn for operator response. Therefore, the reliability of the electrical power system directly affects the PFDavg of the credited operator action. [Pg.52]

No reproduction or networtdrrg permitted without license from IHS [Pg.52]

Copyright International Society of Automation Provided by IMS under license with ISA [Pg.53]

No reproduction or networking permitted without license from IMS [Pg.53]

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