Shutdown Interlock Numbering on P&IDs

[khatarnak]

Hi,
Is there a good way to develop Interlock numbering schemes on P&IDs. Should it be done on an equipment by equipment basis ?

Like a high level transmitter in a vessel has the same interlock number as the inlet SDV. The low level transmitter has the same interlock number as outlet SDV.

Please advise if anybody has used a good system and it served the best purpose.

Thanks,

RM

 

[FrancisL]

This scheme works well, I have seen similar:
Use separate logic diagram for the interlocks - there really isn't room on a P&ID to show complete logic.
Then put the logic diagram number in the interlock diamond.
If it is a long number you need only use the last few digits if you have a suitable drawing numbering scheme.


Francis

http://www.controldraw.co.uk

http://www.s88control.blogspot.com

 

[MortenA]

I have seen a system where all interlocked valves are "connted" by line to a special piping item "box". The SI is numbered (tagged) and the box has a text below saying e.g. mechanical interlocking. I think attempting to add info about sequence of interlocking on the p&id will overload the p&id with information.

Best regards Morten