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Tank Overfill Safety Instrument System
Modification Sheet
P & I Design Ltd
DOCUMENT NO: SI297014.RPT
2 Reed Street, Thornaby, UK, TS17 7AF
ISSUE: A DATE: 15/11/10
Tel: + 44 (0)1642 617444
PAGE 2 OF 2
Fax: + 44 (0)1642 616447
www.pidesign.co.ukFrom the Standard BS EN 61511, and following the requirement for a modification of the
SIS have the following been considered and implemented:
Description of the modification – See Below
Reason for the modification - See Below
Identified hazards which may be affected – See Below
Analysis of the impact of the modification – See Below
Approval for the modification
Has all documentation affected by the modification been revised - Yes
Has the modification been fully proof tested - Yes
Has a detailed modification sheet been completed – See below
SIS Modification Sheet
Describe The Proposed Change & Objective
Slops Tanks 11, 12 & 13 removed permanently from Safety
Instrument System.
Note
What is it you are proposing to modify?
What is the objective of the modification?
What are the benefits of the modification?
If temporary change, how long will it be in effect
for?
Reason for the modification
Following the implementation of facilitate blending of ethanol with
gasoline. The existing slops tanks 11,12 & 13 were modified to store
ethanol.
Tanks 11, 12 & 13 will now be filled from road tankers and as such
are outside the PSLG guidelines and have been permanently removed
for the site gasoline Safety Instrument System.
Note
Why is the modification being proposed?
Options Available & Risks
The new risks will be the possible overflow of tanks 11, 12 & 13 and
release of ethanol. The tanks will have their own independent overfill
protection system. There will be a separate Safety system to prevent
overfill of tanks 12, 12 & 13 by shutting down the Road Tanker
Offloading Pump in the event of an activation of any of the high high
level switches in tanks 11, 12 & 13. There is no impact on the
existing Safety Instrument System with the removal of the three tanks
11, 12 & 13 apart form that stated above
Note
What options are there to make the change?
What are the risks of not doing the change, what
new risks does the change potentially introduce
and how are these risks to be managed?
Outline Plan To Introduce Change
The existing SIS Monitoring panel will be modified to incorporate
the logic for the removal of the tanks. The SIS design and Lifecycle
documentation has been modified to exclude the three tanks.
Note
Identify the requirements to introduce and manage
the change
Any suggestions to improve the proposed change?
Has all documentation affected by the modification been revised
SIS Designer:__________________________
Approvals (Note: Signature Indicates Acceptance Of
Modification With Actions/Comments Noted)
Sign
Date
Approved by Conoco Phillips