Petroleum Development Oman L.L.C.
Temporary Overriding of Safeguarding Systems
Document ID
PR-1001c
Document Type
Procedure
Security
Discipline
Owner
Issue Date
Revision
Unrestricted
Engineering and Operations
Functional Production Manager - UOP
October 2014
6.2
Copyright: This document is the property of Petroleum Development Oman, LLC. Neither the whole nor
any part of this document may be disclosed to others or reproduced, stored in a retrieval system, or
transmitted in any form by any means (electronic, mechanical, reprographic recording or otherwise)
without prior written consent of the owner.
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i
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Document Authorisation
Authorised For Issue – July 2014
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ii Revision History
The following is a brief summary of the 4 most recent revisions to this document. Details of all
revisions prior to these are held on file by the issuing department.
Revision
No.
6.2
Date
Author
Scope / Remarks
Oct-14
Philip Hatherton UOP61
Revisions to incorporate Minor
Amendments
6.1
Aug-14
Philip Hatherton UOP61
Revisions to incorporate Minor
Amendments
6.0
Jul-14
Philip Hatherton UOP61
Revisions to incorporate Audit findings
5.0
Apr-13
Robin Norman UOP61
Reviewed and updated to address the
MoC Application and Web based forms
iii Related Business Processes
Code
Business Process (EPBM 4.0)
EP.71
Produce Hydrocarbons
EP.72
Maintain and Assure Facilities Integrity
iv Related Corporate Management Frame Work (CMF)
Documents
The related CMF Documents can be retrieved from the CMF Business Control Portal.
See also Appendix 4
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Petroleum Development Oman LLC
TABLE OF CONTENTS
i
Document Authorisation.................................................................................................. 3
ii
Revision History............................................................................................................... 4
iii
Related Business Processes........................................................................................... 4
iv
Related Corporate Management Frame Work (CMF) Documents...................................4
1
Introduction...................................................................................................................... 6
1.1
Background
6
1.2
Purpose
6
1.3
Scope 6
1.4
Distribution / Target Audience
6
1.5
Changes to the Document
6
1.6
Variance Approval
6
2
Roles and Responsibilities.............................................................................................. 7
3
Temporary Override of Safeguarding Systems..............................................................10
3.1
Authorisation for Temporary Override Risk Assessment 10
3.2
Process Overrides Request Form
3.3
Validity of Temporary Process Override 14
3.4
Temporary Process Override Auditing
3.5
Retention of Completed Process Override Requests
11
15
15
Appendix 1 – Worked Example of the Process Override Request.............................................16
Appendix 2 – Approved Override Type......................................................................................28
Appendix 3 – Abbreviations........................................................................................................ 29
Appendix 4 – Reference Material............................................................................................... 30
Appendix 5 – Temporary Overrides of Safeguarding and E-MoC audit......................................31
Appendix 6 – User Feedback Page............................................................................................ 33
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Introduction
1.1 Background
IMPORTANT: OVERRIDING OF SAFETY CRITICAL SYSTEMS IS ONE OF THE LIFE
SAVING RULES
Definition: An override can be considered as a device which when initiated will defeat
the safeguarding action. The device will be returned to normal condition at the original
set point(s) once the override is removed.
NOTE: An override can also be considered as any method where a protective function
is defeated either temporarily or permanently
During the Operations Phase it sometimes becomes necessary to apply overrides on
Safeguarding Systems. This operation requires to be strictly controlled and monitored.
In addition the action of applying overrides requires to be risk Assessed to ensure that
all necessary controls are in place to reduce any induced risks to As low As Reasonably
Practicable (ALARP).
1.2 Purpose
The purpose of the procedure shall be to ensure that Safeguarding System
Temporary Overrides are authorised, applied, monitored and removed in a correct
and controlled manner
1.3 Scope
The scope of this procedure will be the management of Safeguarding System
Temporary Overrides.
NOTE: The procedure does not apply to devices are specifically provided for start-up.
1.4 Distribution / Target Audience
The following personnel shall have knowledge and / or awareness of this procedure and
its intent:

Operations Teams (North, South, Gas and Infrastructure)

Production Strategy and Support Teams

Maintenance Strategy and Support Teams

Systems and Operations Field Support Team

Engineering and Maintenance Contractors
1.5 Changes to the Document
Responsibility for the upkeep of the Document shall be with the Functional Production
Manager UOP, the Owner. Changes to this document shall only be authorised and
approved by the Owner.
Users of the Document who identify inaccuracy or ambiguity can notify the Custodian or
his/her delegate and request changes be initiated. The Requests shall be forwarded to
the Custodian using the “User Feedback Page” provided in this Document.
The Document Owner and the Document Custodian should ensure review and reverification of this procedure every 3 years.
1.6 Variance Approval
Variance is not applicable to this procedure.
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Roles and Responsibilities
The following table lists the Roles and Responsibilities for the Key Personnel.
All affected personnel shall read this procedure. If they do not understand something within
the procedure they shall ask their line supervisor or The Operating Integrity Coordinator
(Interior) to explain it. It is the line Supervisor’s Responsibility to ensure that all his
subordinates have read and understood this procedure. When the procedure is read and
understood they shall sign the Record of Procedure Understanding Form.
Role
Responsible for:
Permit Holder / Permit
Applicant
 Request of the overrides to be applied when necessary.
 Request override to be removed upon completion of the Job.
 With guidance from Control Room Operator / Production
Operator (in case dual role) when necessary:
 Initiates the Form from the Application and completes
the key details. Act as Originator.
 Completes override related Risk Assessment and
supporting documentation if required and attaches to
the form (electronically embedded).
 On completion of the request nominates the reviewer.
 Requests extensions of the Override prior its overdue
Control Room Operator /
Production Operator (in
case dual role)
 Identification of suitable point of application of the override.
 Initiates the Form from the Application and completes the key
details and act as Originator when required.
 Completes override related Risk Assessment and supporting
documentation if required and attaches to the form
(electronically embedded) when necessary.
 On completion of the request nominates the reviewer when
necessary.
 Application and removal of override
 Updating and maintaining override register, E-MoC, E-Log,
isolation certificates and/or hard copy MoC form if applicable.
 Ensuring all overrides are duly logged in the E-log and
discussed at handover
 Ensuring/confirming application and removal of override as
intended to Permit Holder.
 Act as Implementer in the E-MoC system.
 Requests extensions of the Override prior to being overdue
when necessary.
 Carry out a weekly audit of all system Overrides. See
Appendix 5
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Control and Automation
(Instrument)
Engineer/Technician
Production Supervisor /
Instrument Supervisor
Production Coordinator
Delivery Team Leader
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 Identification of suitable point of application of override when
necessary
 Application and removal and registration of override under
direction of Control Room Operator / Production Operator (in
case dual role) when necessary.
 As part of IPF testing ensure clear understanding of which
override is to be applied for test
 Ensure that a SAP notification is raised for the defect causing
the need for application.
 Adherence to this procedure on shift
 Review the Originators submission and the Risk Assessment
and/or Supporting Documentation
 Ensuring the right disciplines review the intended use of
overrides.
 Nominates the Risk Assessment Approver, the Technical
Approver (if required) and the Final Approver
 Carry out a monthly audit of all system Overrides using standard
form. See Appendix 5
 Ensure all technicians under his supervision read and
understand the procedures and sign the Record of Procedure
Understanding Form
 Responsible for ensuring his / her subordinates are aware of this
procedure and compliant to it
 Approve the implementation of the Temporary Safeguarding
Override and authorize extensions forSIL-1 and SIL-a Classification
of the Safeguarding device. Act as Final Approver.
 Review and approve the Risk Assessment if no SIL level
available based on a Low Residual Risk if authority to do so has
been formally delegated by the DTL using the e-MoC process (see
3.1.1).
 Carry out a monthly audit of all system Overrides using standard
form. See Appendix 5
 Act as a Risk Assessment reviewer
 Ensure that the Record of Procedure Understanding Form is
correctly completed and retained in a central location within each
area.
 Approve the implementation of the Temporary Safeguarding
Override and authorize extensions for, SIL-2 Classification of
the Safeguarding device. Act as Final Approver.
 Review and approve the Risk Assessment if no SIL level
available based a Low Residual Risk
 Accountable for compliance to this Procedure within his / her
area of Authority
Operations Manager
 Approve the implementation of the Temporary Safeguarding
Override and authorize extensions for SIL-3 Classification of
the Safeguarding device. Act as Final Approver.
Review and approve the Risk Assessment based on the
Medium Residual Risk
Technical Director
 Review and approve the Risk Assessment based on the
High/Serious Residual Risk
Technical Approver
(Process Engineer /
Integrity Engineer /
 If nominated shall review the Override at a technical level to
ensure that it has no implications regarding the operating
envelope of the system/equipment or process in general
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Process Safety Engineer)
Operating Integrity Coordinator (interior)
 Carry out a monthly audit of all system Overrides using
standard form. See Appendix 5
Maintenance Staff

Comply with this procedure
 Ensure the procedures are read and understood and they
sign the Record of Procedure Understanding Form
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Temporary Override of Safeguarding Systems
Temporary Overrides of Safeguarding Systems (including Fire and Gas) are / or may be
provided to facilitate repairs, function testing and calibration whilst the facility / plant is
operational.
WARNING: THE USE OR PROVISION OF TEMPORARY OVERRIDES CAN BE
POTENTIALLY HAZARDOUS AND MUST BE STRICTLY CONTROLLED AND
DOCUMENTED.
IMPORTANT: In accordance with Matrix of Permitted Operations (MOPO) overrides on
safeguarding systems are permitted for short durations only, are subject to risk
assessment and only to be used when the facility / station is manned. Additionally all
other safeguarding instrumentation on equipment shall be functional. High priority shall
be given to any repairs required to normalise the system.
PDO uses the following Temporary Override devices in their operations:

Maintenance Override Switch (MOS) : Installed by design for the purpose of
testing and maintenance

Start up bypass override: Installed by design for purpose of operational Start
up.

Force : An imposed healthy signal within an Instrumented Protective System
(e.g., Prosafe) – software, or use of “CAL” or “SCAN OFF” function within the
DCS

Mechanical (Hardware force) : A physical override, e.g., wire bridge,
pneumatic bypass, physical removal of protective device (e.g. Minimum Stop)

Wire jumper
More detail is provided on each of the above in Appendix 2 and Appendix 3.
3.1 Authorisation for Temporary Override Risk Assessment
Authorisation for the use of overrides on safeguarding systems shall be in accordance
with Table 1.
The table is considered the most appropriate method to simplify authorisation levels for
use of overrides on safeguarding systems. The SIL / IPF classification process will have
ensured the safeguarding system has been fully risk assessed.
Table 1 – Guide to Authorisation Levels
SIL
Classification
IPF
Classification
Required Authorisation Level
VI
Ops Manager or Delegate
V
Ops Manager or Delegate
2
IV
DTL or Delegate
1
III
Prod. Coordinator or Delegate
II
Prod. Coordinator or Delegate
I
Prod. Coordinator or Delegate
3
a
Table 1 was adapted from EP200607206661
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Table 1 above provides the Authorisation Level for the proposed Temporary Override.
Where a SIL/IPF classification is not in place the authorisation level required will be
decided from the Residual Risk of the supporting RAM.
The use of the override will require being Risk Assessed using the PDO RAM. The
RAM will be attached to the Web based override request and sent with the request for
review and authorisation. The Risk Assessment Approver will be determined by the
residual risk i.e. Low = DTL or Delegate; Medium = Operations Manager; High/Serious
= Technical Director.
3.1.1
DTL Delegation of Signing Authority
To allow for periods when the DTL is not available due to leave, illness etc. and to
facilitate the application of overrides following an unplanned event there may be a
requirement for him to delegate his signing authority to the Production Coordinator.
The delegation of such authority shall be given using the E-MoC process for
Organizational Change with a validity period not exceeding 1 month
The authority shall not be delegated for planned events outwith this period
IMPORTANT: Routine work that is covered by an approved procedure and has already
been risk assessed, via IPF or SIL Classification, can use the original risk assessment
provided that the risks assessed have not changed and no changes have been made to
the way the work is conducted. All other types of safeguarding override i.e. multiple,
long term, process startup and stabilisation and non-routine activities shall require the
risks to be assessed using the standard RAM.
3.2 Process Overrides Request Form
The Process Overrides Request Form is accessed from the Applications/Management
of Change (MOC).
Accessing Management of Change (MOC) will open up the Home Page
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From the management of Change list in green select Process Overrides. This will open
the access screen.
The access screen contains information on all process overrides that have been raised
and the status of each. To open a new request use ‘Add new item’ at the foot of the
screen.
The basic form that is opened will be completed by the requester. It is important to
remember that all items on the form that have a * or which are highlighted I red are
required and must be completed for the form to be processed.
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The Requested by box is automatically generated and will be the same as the logged
on person using the computer. Appendix 1 displays an actual Form that has been
completed and implemented and shall serve as a guidance template to completing the
request Form fully.
Displayed above is the portion of the form that is completed by the requester. There are
a number of multi choice ‘dropdown’ boxes indicated by
highlighting the choice and clicking the mouse.
the selection is made by
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To select the reviewer enter the persons company number and click on the man/tick
icon or the browse icon and select using the person’s name, highlight and then OK
Attachments shall be a Risk Assessment to support the use of the override (refer to
Section 3.1) and any other document i.e. Method Statement, that is considered relevant
to assisting the reviewers and approvers in understanding the Request. The
attachments are selected from the computer and automatically embedded in the form.
They accompany the Form throughout its life cycle.
Once the Request is completed it is electronically processed and sent to the Reviewer.
This action is accomplished by clicking
The process is described in detailed using a worked example in Appendix 1.
3.3 Validity of Temporary Process Override
Where the Temporary Process Override is linked with a PTW it shall be removed at the
end of the working day when the PTW is suspended unless it is required to remain in
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place for operational reasons. When the PTW is validated the next day the necessary
Temporary Process Override shall be re-applied. Application and removal of the
Overrides should be recorded by “ON” / “OFF” E-MoC function to provide evidence and
reflect real status of the Overrides in the Register (E-MoC)
The PTW has a validity of 14 days after which it is closed out or extended. In
conjunction with the PTW the Temporary Process Override can be extended. A total of
three extensions, normally authorised by the production Coordinator are allowed after
which the Process Override request shall be closed out. If after this period the override
is still required, an example being if waiting for spares, a new E-MoC shall be raised
with the PTW number being ‘Operations’. The justification for the override will be
updated with the expected return to service as will the risk assessment.
If the override is expected to be in place for over 12 months then a FCP (Facilities
Change Proposal) should be made to engineer out the requirement for the override.
NOTE: If the Temporary Override is required to be maintained when, in the case of an
unmanned station, the station is vacated then approval shall be obtained from the
Production Coordinator. When leaving Temporary Overrides in place a Risk
Assessment shall be required to ensure all risks are mitigated to ALARP and it can be
demonstrated the area control room is able to monitor the process effectively and
initiate any remote actions required. Failure to satisfy this requirement shall mean
manning or shutting down the station during the night hours.
See PR-1172 – Permit to Work Section 7 for details on PTW validity and isolations.
3.4 Temporary Process Override Auditing
The temporary process override is recorded in the Operational Override Log. Each
facility shall demonstrate a methodology whereby the temporary overrides can be
audited on a monthly basis. Overrides that have a Risk Assessment conducted during
authorisation shall require having that Risk Assessment checked to ensure that there
are no changes in the hazards and residual risk.
Temporary Process Overrides that are not required shall be removed and the Process
Override Request Closed Out. The status of all Process Overrides Requests can be
checked on-line from the reports Section of the Management of Change – Process
Overrides. To be carried out as per the Roles and Responsibilities Matrix at the front of
this document
As a minimum a monthly physical audit of the status shall be conducted
Minimum requirements are:
 All fields in register, E-MoC filled in correctly
 Risk assessments adequate
 Mitigations adequate and in place if override is current
 Authority levels / Approvals correct
 Override use within expiry date
 Current overrides logged in end of shift reports and E-Log.
3.5 Retention of Completed Process Override Requests
The completed (implemented) Process Override Request form can be printed from the
web and attached to the PTW. The hard copy form will then be filed with the PTW on
completion of the work. The completed PTW is retained for a period of 6 months.
The Safeguarding System Temporary Overriding Request Form will be attached to and
filed. The focal points for the retention of the PTW are the permit Coordinator in the
North and the Permit to Work Focal Point in the South and Gas.
The web based requests shall be closed out and will be retained (archived) indefinitely.
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Appendix 1 – Worked Example of the Process Override Request
A completed Process Overrides Request with explanatory text and covering the full process is
detailed on the following pages.
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Appendix 2 – Approved Override Type
Maintenance Override Switch (MOS)
Maintenance override switches are used to override safeguarding initiators to enable
maintenance or on-line functional testing. It shall be considered during the basis of
design (BfD) phase whether MOS's are required in those cases where spare process
units or equipment are available.
Maintenance override facilities may be provided only for those safeguarding initiators
where a second or back-up indication and an associated means to stop the process are
available to the operator. Furthermore, the process dynamics shall be such that the
operator has time to act.
All maintenance override keys shall be removed from their locks when not in service
and be kept in a separate key box controlled by the Production Supervisor, or his / her
delegate.
IPS-PLC Software Overrides (Forces in PLC systems)
Software overrides can be provided on input and output channels of IPS-PLCS to
override trip commands for repairs, equipment calibration and functional testing.
Wherever possible the override shall be provided on the input channels as these are
inherently less hazardous than overrides on the outlet channel. The implementation
shall be enabled and disabled by means of a key lock and / or password facility.
NOTE: The method of implementation shall be discussed with and approved by the
Instrument Supervisor and the Production supervisor prior to use.
All 'forced enable/disable' keys shall be removed from their locks when not in service
and kept in a separate key box controlled by the Production Supervisor, or his / her
delegate.
Jumpers
Jumpers shall be used only when MOS or IPS-PLC Software Overrides are not
available. Their use shall be strictly controlled, logged and monitored as they entail the
physical bridging (frigging) of trip contacts.
The use of ‘Jumpers’ must be approved by the Production Coordinator and the location
and method of implementation agreed prior to their use. The use of jumpers must be
entered on the Operational Override Log Sheet.
Mechanical Overrides
Usually associated with automatic valves these are temporary mechanical means to
prevent valve travel for repair and tests purposes. Use of this type of override should be
avoided, as they are overrides on IPF final (output) elements and by nature more
hazardous than overrides on IPF initiators (inputs).
The use of ‘mechanical overrides’ must approved by the Instrument and Production
Supervisor and the location and method of implementation agreed prior to their use.
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Appendix 3 – Abbreviations
The following abbreviations have been used in this procedure:
ALARP
As Low As Reasonably Practicable
CAL
(Yokogawa), calibration, can be used to freeze a process variable in the DCS
and disable alarming to allow maintenance and testing. This overrides the
function, including alarms, of associated control and/or calculation. If the function
has executive action then CAL is classed as an override.
EORD
Engineering and Operations Reference Document
EPI
Extended Period Isolation
FCP
Field Change Proposal
IPF
Instrumented Protection Function
IPS
Instrumented Protection System
MoC
Management of Change
MOPO
Matrix of Permitted Operations
MOS
Maintenance Override Switch
PLC
Programmable Logic Controller
PTW
Permit to Work
RAM
Risk Assessment Matrix
SAP
Systems, Applications and Products
Scan off
(Honeywell), the technique used to stop an Experion server reading data from
controller/point parameters, such as PV, SP and OP. This overrides the function,
including alarms, calculation, and associated control. If the function has executive
action then scan off is classed as and override.
SIL
Safety Integrity Level
TA
Technical Authority
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Appendix 4 – Reference Material
PDO Related Documents
The following PDO procedures have interface with this specification.
CP-114 – Maintenance and integrity Management Code of Practice
CP-115 - Operate Surface Product Flow Assets - CoP
PR-1001a – Field Change Proposal
PR-1001x - Operations Variance and Change Management
PR-1073 - Gas Freeing, Purging & Leak Testing of Process Equipment (Excluding Tanks)
PR-1076 - Isolation of Process Equipment Procedure
PR-1077 - Preparation of Static Equipment for Internal Maintenance and Inspection
PR-1079 - Gas Freeing and Purging of Tanks Procedure
PR-1094 - Instrumented Protective Functions Test Procedure
PR-1100 – Operator Routine Functions
PR-1148 - Entry into a Confined Space Procedure
PR-1172 – Permit to Work
GU-437 - Guideline on SIL Assessments and Implementation Guideline
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Petroleum Development Oman LLC
Revision: 6.2
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Appendix 5 – Temporary Overrides of Safeguarding and E-MoC
audit
LINK TO AUDIT FORM
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Systems
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Petroleum Development Oman LLC
Revision: 6.2
Effective: Oct-14
Printed 25/03/22
PR-1001c - Temporary Overriding of Safeguarding
Systems
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Revision: 6.2
Effective: Oct-14
Petroleum Development Oman LLC
Appendix 6 – User Feedback Page
PR-1001c - Temporary Overriding of Safeguarding Systems User
Feedback Page
Any user who identifies an inaccuracy, error or ambiguity is requested to notify
the custodian so that appropriate action can be taken. The user is requested
to return this page fully completed, indicating precisely the amendment(s)
recommended.
Name:
Ref ID
Page Ref:
Date:
Brief Description of Change Required and Reasons
Surface Operations and Integrity Team Leader (UOP6):
Date:
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PR-1001c - Temporary Overriding of Safeguarding
Systems
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The controlled version of this CMF Document resides online in Livelink®. Printed copies are UNCONTROLLED.