ABB Limited
Please reply to:
Tel: +44(0)1642 372000
Website:
www.abb.comRegistration no:
Registered Office:
Pavilion 9, Byland Way
3780764 England
Daresbury Park
Belasis Hall Business Park
Fax: +44(0)1642 372111
E-mail:
info@gb.abb.comDaresbury, Warrington
Billingham TS23 4EB
VAT Reg No:
Cheshire WA4 4BT
United Kingdom
668 1364 13
United Kingdom
It is clear that the risk assessment in this case should not allow the bypass to be put in place until the
earlier protection layers are reinstated. This information should also be made available to the person
carrying out the SOP, highlighting that a mistake at a critical step is likely to place a demand on the
safety system and potential plant shutdown.
A similar example demonstrates how the same information can be used in the avoidance of plant trips.
In this scenario, the interlock is manual and the alarm is in an active alarm state, but has not been
responded to. Representing the information in this format enables clear visualization that the next
available barrier is the SIF, which if activated will initiate a plant trip. This provides the necessary
decision support to prioritize operator actions, initiate the corrective actions to put the process into the
back into the operating envelope and enable plant production to be maintained.