SI483001_MNL - Gasoline Overfill Protection SIS IMMEAS-SIS1 Design Manual

Immingham Storage Co Ltd – Immingham East Terminal

IME-SIS1 - Safety Instrument System Safety Requirement Specification

P & I Design Ltd

DOCUMENT NO: SI277010_RPT

2 Reed Street, Thornaby, UK, TS17 7AF

ISSUE: G DATE: 31.10.14

Tel: + 44 (0)1642 617444

PAGE 11 OF 13

Fax: + 44 (0)1642 616447

4.2

Interface between the SIS and BPCS

There is no existing control system. In future a control system including PLC control of valve

operation and SCADA display and monitoring may be installed. The SIS will be totally

independent from any future BPCS. The SIS will be designed to provide any future BPCS

with the following to advise status and for external diagnostics of the SIS. They have no

impact on the SIS and are for information and alarm only.

Status of safety relays – volt free contact closed on system healthy.

Valve position – volt free contacts for closed and open status.

There are locally mounted pneumatic switches used for opening and closing the tank-side

actuated valves for the No. 4 East Tanks however, the solenoid valve connected to the Safety

Instrument System allows the air supply to all actuated valves to be vented, on a independent

high high level or on activation of the 4 East Crash stop, regardless of the position of the

locally mounted pneumatic switch.

There is a possibility for future operation of the valves from the BPCS, but this will not

impair the safety function of the valve, nor will it increase the demand rate of the SIF as the

valve will only be operated prior to and at the end of a transfer.