Post on 11-Jul-2020
DOCUMENT CONTROL
Document Owner (May also be the Process Owner)
Name: Mark Van Vuuren
Position: Field Practices Coordinator
Date: June 2014
Approved By *
Name: Mark Van Vuuren
Position: Field Practices Coordinator
Date: June 2014
Authorisation ** Process Owner is hereby vested with
authority and responsibility to manage the process end to end.
Name: Lance Roberts
Position: Manager Health and Safety
Date: June 2014
Date Created/Last Updated June 2018
Review Frequency *** Every 3 years
Next Review Date *** June 2021
*
Must be the Process Owner and is the person assigned authority and responsibility for managing the whole process, end-to-end, which may extend across more than one division and/or functions, in order to deliver agreed business results.
** This person will have the power to grant the process owner the authority and responsibility to manage the process from end to end.
*** Frequency period is dependent upon circumstances– maximum is 5 years from last issue, review, or revision whichever is the latest. If left blank, the default will be 1 year unless otherwise specified.
STAKEHOLDERS
The following positions must be consulted if an update or review is required:
NOTIFICATION LIST
The following positions must be notified of any authorised change:
MANAGER SAFETY AND HEALTH MANAGER SAFETY AND HEALTH
MANAGER MICROGRIDS GENERATION MANAGER ENGINEERING & PROJECTS SERVICES
ASSET MANAGER MICROGRIDS GENERATION ASSET MANAGER MICROGRIDS GENERATION
FIELDS PRACTICES COORDINATOR MANAGER MICROGRIDS GENERATION
FIELDS PRACTICES COORDINATOR
REGIONAL MANAGEMENT TEAM (RM, AM, WDC)
OPERATIONAL STAFF
HORIZON POWER
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
INTRODUCTION
This Generation Permit-to-Work Standard (GPTWS) provides the minimum safety
standards for activities related to inspection, testing, commissioning, operation,
maintenance and modification of generation assets. These Standards are written
to assist Horizon Power employees, contractors and other parties involved in
managing risks associated with carrying out the diverse breadth and depth of
these activities in the business.
The standards govern generation asset isolation but do not detail all of the
necessary requirements to carry out activities, but together with other procedures,
operational instructions and manuals will provide a structured safe system of
work.
The GPTWS have been written to support Horizon Power’s overall Safety and
Health Management System and the hierarchy of Acts/Regulations, Codes of
Practice, Organisational Policies, Practices and Procedures.
Hierarchy of Documentation
WA general workplace safety legislation administered by the regulator WorkSafe
WA:
Occupational Safety and Health Act 1984
Occupational Safety and Health Regulations 1996
WA Electrical legislation administered by the regulator EnergySafety WA:
Electricity Act 1945
Electricity Licencing Regulations 1991
Electricity Regulations 1947
In the interest of your own personal safety, and the safety of all Horizon Power
workers and the general public it is essential that you read these standards and
understand how they relate to your work environment.
These Standards will be regularly reviewed, if there are any queries and
suggestions for improvement, then direct your queries to the Field Practices team
via the Continuous Improvement Process.
The following diagram (the next page) outlines the framework into which these
Standards fit.
HORIZON POWER
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
Acts & Regulations
Codes of Practice
AS/ANZ Standards
Guidenace Notes
Horizon Power Safety & Health Management
Systems
Horizon Power Electrical Safety
Standards
Horizon Power Work Instructions
Horizon Power Switching Manuals
Horizon Power published technical
standards & guidelines
Figure 1 –Legislative/ Horizon Power framework
HORIZON POWER
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
CONTENTS
1 PURPOSE .................................................................................................. 1-1
2 SCOPE ....................................................................................................... 2-1
2.1 General ............................................................................................. 2-1 2.2 Isolation and Issuing Permits ............................................................ 2-1
2.3 Training and Authorisation ................................................................ 2-1
3 DEFINITIONS ............................................................................................. 3-1
4 RESPONSIBILITIES .................................................................................. 4-1
4.1 Formal Leaders ................................................................................ 4-1
4.2 Authorised Persons .......................................................................... 4-1 4.3 Permit Issuer .................................................................................... 4-1 4.4 Isolation Officer – Mechanical/Electrical ........................................... 4-2 4.5 Recipient-in-Charge .......................................................................... 4-2
4.6 Recipient........................................................................................... 4-3
5 SAFETY PRINCIPLES ............................................................................... 5-1
5.1 General ............................................................................................. 5-1
5.2 First Aid ............................................................................................ 5-1 5.3 Personal Protective Clothing and Equipment ................................... 5-1
6 ENERGY ISOLATION ................................................................................ 6-1
6.1 General ............................................................................................. 6-1
6.2 Identifying Isolation Points ................................................................ 6-3 6.3 Isolation Procedure ........................................................................... 6-4 6.4 Locking Isolations ............................................................................. 6-4
6.5 Remove Isolation .............................................................................. 6-6 6.6 Removal of Locks ............................................................................. 6-6
6.7 Isolation Tags ................................................................................... 6-7
7 PERMIT TO WORK .................................................................................... 7-1
7.1 General ............................................................................................. 7-1 7.2 Preparation of a Permit-to-Work ....................................................... 7-2
7.3 Isolation ............................................................................................ 7-2 7.4 Issuing a Permit to Work................................................................... 7-3
7.5 Storage of a Permit to Work ............................................................. 7-3 7.6 Working Under a Permit to Work ...................................................... 7-3 7.7 Relinquishing a PTW for a STT ........................................................ 7-4 7.8 Cross Boundary Permit and Lockout Requirements ......................... 7-5 7.9 Transferring Responsibility of a Permit to Work ................................ 7-6
7.10 Relinquishing a Permit to Work ........................................................ 7-6 7.11 Cancelling a Permit to Work ............................................................. 7-7
8 SUPPLEMENTARY PERMITS ................................................................... 8-1
8.1 General ............................................................................................. 8-1 8.2 Hot Work Permit ............................................................................... 8-1 8.3 Confined-Space Entry Permit ........................................................... 8-1
HORIZON POWER
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
8.4 High Voltage (HV) Electrical Access Permit ..................................... 8-2
8.5 Excavation and Trenching Permit ..................................................... 8-2 8.6 Sanction-to-Test (STT) Permit .......................................................... 8-2
8.7 Operating Agreement ....................................................................... 8-3
9 REMOTE SITE PERMIT TO WORK REQUIREMENTS ............................. 9-1
9.1 General ............................................................................................. 9-1 9.2 Preparation of Permit to Work .......................................................... 9-1 9.3 Equipment Preparation – Isolate ...................................................... 9-2
9.4 Issuing a Remote Site Permit to Work .............................................. 9-2 9.5 Working Under a Remote Site Permit to Work ................................. 9-2 9.6 Cancelling a Permit to Work ............................................................. 9-2
10 APPENDIX SECTION .............................................................................. 10-1
10.1 Appendix A – Isolation Philosophy ................................................. 10-1 10.2 Appendix B - Permit to Work Flow Diagram ................................... 10-1 10.3 Appendix C – Associated GPTWS links ......................................... 10-1
HORIZON POWER SECTION 1 Page 1-1
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
1 PURPOSE
This standard encompasses instructions necessary for safe access to Generation
Assets within Horizon Power’s generating systems and fuel facilities to ensure safety of
generation assets and personnel from the dangers related to hazards or unauthorised
operation.
The instructions explained in this Standard are the minimum required to ensure the
safety of personnel and plant.
This Standard has been prepared to address all of Horizon Power’s generation assets
and has specific inclusions to cater for remote locations where a single person is likely
to be working alone.
The Standard has been developed to cover the following key processes:
Permit to Work
Supplementary Permits
Isolation(s)
Remote Site Authorisation
Where Horizon Power have sites located within the boundaries of other organisations or
where it operates through established Alliance or Joint Venture arrangements the
requirements of this standard shall be applied as the minimum standard.
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HORIZON POWER SECTION 2 Page 2-1
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
2 SCOPE
2.1 General
These standards shall apply to all persons who work on or near Horizon Power’s
generation assets.
This standard applies where inspection, testing, commissioning, operation, maintenance
and modification activities are carried out on generation assets.
This Standard applies to:
generation assets owned and/or controlled by Horizon Power, or
generation assets owned or controlled by contractors or others where the plant is
located on premises owned by Horizon Power
the boundary of the Power Station shall be the output bushings of the step up
transformer or the supply side of a feeder circuit breaker if there is no step up
transformer
This standard does not apply to:
where there is no risk to the safety of person(s) and or generation asset integrity
a construction site that has no potential to be connected to any operational
generation asset(s)
2.2 Isolation and Issuing Permits
The isolation of generation assets and the issue of permits is a restricted duty. Only
Horizon Power authorised persons are allowed to make equipment isolations and issue
permits.
2.3 Training and Authorisation
Persons who are required to work on Horizon Power’s generation assets shall not do so
unless they:
have been appropriately trained for the work they intend to do;
have the appropriate authorisation to perform the work
To maintain authorisation, refresher training in the GPTWS shall be undertaken at
regular intervals (every 2 years). The minimum knowledge and skills necessary to
perform specified activities and tasks will be assessed. Refresher training may be
carried out on the work site.
Field Practices Safety Interaction Audits will be carried out in a scheduled manner to
audit against generation related instructions.
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HORIZON POWER SECTION 3 Page 3-1
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
3 DEFINITIONS
Terminology Definition
Approved Having the appropriate organisation endorsement in
writing for a specific function.
Authorised Person A person with technical knowledge or sufficient experience
who has been approved, or has the delegated authority to
act on behalf of Horizon Power to perform the task
concerned
Circuit Breaker Circuit Breaker shall mean an item of electrical apparatus
designed to de-energize an electrical system under
conditions of load and/or fault.
Control Lock (Blue)
An individually keyed Blue Lock that is attached by an
Authorised Person to further secure a Lockbox and
provide protection for the generation asset and personnel.
Danger Tag
A tag applied in conjunction with a Personal Lock to
identify an individual who is working under the conditions
of a Permit-to-Work.
Only the person whose name appears on the Danger tag
can remove the tag.
Earthed Earthed shall mean electrical apparatus, which has been
electrically connected to earth effectively, ensuring an
immediate and continuous discharge of electrical energy.
Energy Isolation The point at which an energy source (electrical only) is
disconnected or physical blocked and secured from
uncontrolled movement to ensure safety of personnel and
the generation asset.
Formal Leader An individual appointed by Horizon Power who is
accountable for implementing the safety activities
necessary to achieve safety for persons, environment and
the generation asset, within and across defined
boundaries.
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Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
Terminology Definition
Generation Asset For the purpose of this standard means any plant or
equipment used in the production and or generation of
electricity i.e. electrical, electronic, SCADA, control,
mechanical, liquid, gas, instrumentation, and
communication, etc.
High Voltage (HV) Where voltage exceeds 1000 volts alternating or 1500
volts direct current.
Hot Work Means using welding, flame cutting or other fire or spark-
producing power tools.
HV Switching
Officer A person authorised to carry out HV switching operations
within their limits of authority on generation assets.
HV Switching
Operation Any physical operation required to energise, de-energise,
or earth HV apparatus or any other device used in
accordance with an authorised Switching Programme.
HV Isolation Lock
(Black)
An individually keyed Black that is attached by a HV
Switching Officer to secure a Lock-out on HV equipment.
Isolation Lock
(Yellow)
An individually keyed Yellow lock that is attached by an
Isolating Officer to secure a Lock-out (other than HV
isolation) e.g. Mechanical isolation or Low Voltage (LV)
electrical isolation.
Isolation Officer A person authorised to isolate generation assets (other
than HV unless authorised) to be worked on under a
Permit-to-Work.
Isolation Tag
A tag installed by the Isolating Officer/HV Switching Officer
that contains Permit to Work information.
HORIZON POWER SECTION 3 Page 3-3
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
Terminology Definition
Job Risk
Assessment (JRA)
(DM# 3104177)
Before any work starts, a JRA is carried out to identify any
hazards and ensure their associated risks are either
eliminated or suitably controlled in accordance with
Horizon Powers minimum standards.
Lockbox
A safety device used to contain the keys of Isolation Locks
associated with a Permit-to-Work. Lockboxes shall have
the means of being able to be secured by Control (Blue),
Isolation (Yellow) and Personal Locks (Red).
Lock-out A device placed as a means of physically securing and
identifying isolation and/or control measure placed for
safety. A Lock-out generally consists of a keyed lock and
Isolation Tag or Danger Tag.
Lockout Hasp
To be used in conjunction with an Isolation Lock to allow
the fitting of multiple locks.
Mechanical
Isolation The point at which an energy source (Gas, Fuel, etc) is
disconnected or physical blocked and secured from
uncontrolled movement to ensure safety of personnel and
the generation asset.
Operating
Agreement (OA) An “OA” is a statement outlining the condition of
generation asset(s) that shall be used between operating
authorities across operational boundaries to confirm asset
conditions and isolations to support an access authority or
other operational requirements.
This statement covers only the state of the generation
asset(s) specified and does not by itself authorise work on
the electrical apparatus or plant.
Operational Area Any generation store warehouse, compound, power
station, workshop, switchyard, switch room or enclosure.
Operational Work Any construction, testing and commissioning, inspection,
maintenance (e.g. cleaning), fault finding, operating activity
or decommissioning on or near generation assets
including HV Switching.
SECTION 3 HORIZON POWER Page 3-4
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
Terminology Definition
Permit Board A board where the Permit-to-Work and any Supplementary
Permits are prominently displayed whilst permits are open.
Permit Issuer An Authorised Person appointed to prepare, issue, transfer
and close a Permit-to-Work, Supplementary Permits or
other authority to work and all associated documentation
Permit Requestor Any person wishing to schedule or perform work that
requires a Permit-to-Work to be issued prior to the
commencement of the work.
Permit-to-Work
(PTW)
A formal written authorisation which allows access to, work
on or near, or testing of generation assets. It details the
isolation(s) and control(s) implemented to make the
generation asset safe.
Permit-to-Work
Register A register that contains a sequence of PTW numbers for
all issued, cancelled and future permits.
Personal Lock
(Red)
An individually keyed Red Lock that is attached as an
additional Lock-out by the Recipient-in-Charge and
Recipient(s) to further secure Lockouts made in the
preparation of the Permit-to-Work.
Remote Site Horizon Power sites that are operated and maintained by
single person.
Remote Site
Authorisation The issuing of a Permit-to-Work by the Permit Issuer to an
Authorised Person completing work in a Remote Site
location.
Recipient A person or group of persons performing work under a
Permit-to-Work.
Recipient-in-Charge An Authorised Person who accepts the conditions of a
Permit-to-Work and is responsible for the work being
carried out by a Recipient under the Permit-to-Work.
Safety Document Any safety related document such as Permit-to-Work,
JRA, Safety Case, Safety Management Plan, Procedure,
Work Instruction, etc.
HORIZON POWER SECTION 3 Page 3-5
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
Terminology Definition
Single Point
Isolation
An activity that is performed where a single isolation
protects or supplies generation asset.
Standard Isolation Generation site specific pre-defined isolation procedure for
generation assets.
Supplementary
Permits
Additional permits used to support a Permit-to-Work. They
are used for activities such as Confined Space Entry,
Excavation, Hot work, HV Access, Sanction-to-Test and
other high risk activities.
SECTION 3 HORIZON POWER Page 3-6
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HORIZON POWER SECTION 4 Page 4-1
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
4 RESPONSIBILITIES
The following responsibilities are set for Horizon Power and Contractors working on
Horizon Power Assets. Horizon Power personnel and contractors have a requirement to
ensure they are trained, have read, understood and comprehend the Horizon Power
GPTWS requirements at the time of their induction.
Once training is completed it is the responsibilities of all personnel to be appropriately
authorised (see section 2.3).
4.1 Formal Leaders
It is the responsibility of the Formal Leader to ensure:
that the GPTWS are applied without compromise to ensure the safety of all
personnel working on Horizon Power’s generation assets
the instructions and procedures contained in this standard are read, understood
and complied with
employees are trained and authorised to perform the assigned tasks.
they correct the behaviour of employees who fail to follow the instructions and
procedures contained in this standard
4.2 Authorised Persons
It is the responsibility of the Authorised Person to:
comply with the instructions and procedures contained in this standard
practice safe behaviour
perform Job Risk Assessment(s) (JRA) for each new task or as jobs change
actively work with the Formal Leader to support implementation of safety
programmes
Authorised Persons will ensure the GPTWS and all related procedures are applied
without compromise to ensure the safety of personnel from hazards.
4.3 Permit Issuer
It is the responsibility of the Permit Issuer to:
comply with the instructions and procedures contained in this standard
define the isolation and/or control measure(s) of the Permit-to-Work (PTW) in
accordance with the instructions and procedures contained in this standard
ensure that Recipient-in-Charge acknowledges the PTW conditions and the
isolation and control measure(s) before the issuing the PTW
SECTION 4 HORIZON POWER Page 4-2
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
correct the behaviour of a Recipient-in-Charge who fails to comply with the
conditions contained within the PTW
4.4 Isolation Officer – Mechanical/Electrical
It is the responsibility of the Isolation Officer to:
undertake isolations of generation assets (only if authorised) in accordance with
the instructions and procedures contained in this standard
perform JRA(s) for each new task or as jobs change
4.4.1 Mechanical and Low Voltage (LV) Switching Officer
It is the responsibility of the Mechanical/LV Switching Officer to:
only undertake mechanical isolations within their limits of authority on generation
assets
only undertake LV switching operation within their limits of authority on
generation assets
4.4.2 High Voltage (HV) Switching Officer
It is the responsibility of the HV Switching Officer to:
undertake HV switching operations within their limits of authority on generation
assets
4.5 Recipient-in-Charge
It is the responsibility of the Recipient-in-Charge to:
accept responsibility as the person in charge of the work.
comply with the instructions and procedures contained in this standard.
agree to the conditions of the PTW.
ensure the Recipient(s) complies with the conditions contained within the PTW.
ensure that all Recipient(s) sign on and off the Permit-to-Work as required.
correct the behaviour of a Recipient who fails to comply with the conditions
contained within the PTW.
ensure a Job Risk Assessment is completed with each permit or as jobs change.
ensure that when transferring a PTW the incoming Recipient-in-Charge
acknowledges the PTW conditions and the isolation and control measure(s) of
the PTW.
HORIZON POWER SECTION 4 Page 4-3
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
4.6 Recipient
It is the responsibility of the Recipient to make sure that they:
comply with the instructions and procedures contained in this standard.
do not commence any work on any generation asset without a PTW issued by a
Permit Issuer.
comply with the conditions of the PTW.
do not interfere with any control, HV isolation, Isolation or Personal lock(s) or
safety isolation and control device placed in association with a PTW.
practice safe behaviour.
are involved in Job Risk Assessment for each task or as work conditions change.
actively work with their Formal Leader to support the implementation of safety
programmes.
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HORIZON POWER SECTION 5 Page 5-1
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
5 SAFETY PRINCIPLES
5.1 General
All generation assets shall be regarded as operational until isolated.
A PTW shall be issued before any work starts on any generation asset.
All relevant instructions, procedures and conditions contained in a PTW shall be
complied with when carrying out any work activity in any operational area.
Hazards shall be identified and the associated risks assessed and controlled
prior to working on any generation assets.
The GPTWS shall be regularly audited to ensure compliance.
All incidents which has or could have caused personal injury or damage to
property shall be reported to the Recipient-in-Charge and the Formal Leader
immediately.
The safe approach distances to electrical apparatus for persons, vehicles and
plant shall be adhered to at all times.
5.2 First Aid
All personnel who work in Operational Areas or undertake Operational Work
must be trained in First Aid.
5.3 Personal Protective Clothing and Equipment
All personnel who work in Operational Areas or undertake Operational Work shall
wear approved personal protective clothing and equipment in accordance with
Horizon Power Minimum Personal Protective Clothing and Footwear Standard
and the appropriate Safety field instruction in the Horizonpower Instruction
Manual (HIM).
Approved Personal Protective Equipment (PPE) specified for the task or work
area shall be worn.
SECTION 5 HORIZON POWER Page 5-2
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HORIZON POWER SECTION 6 Page 6-1
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
6 ENERGY ISOLATION
This section describes, what energy isolations are, how to prepare generation assets,
use locks, other control measures and tags to ensure the isolation(s), once made, are
adequately identified, de-energised, flow stopped, locked and/or physically restrained to
prevent inadvertent operation of the generation asset(s).
6.1 General
Isolations and/or controls are required where the work is to be carried out on generation
assets where personal and/or generation asset protection is required. Additionally,
isolation and/or control measures are required where stipulated in any other work
instruction, procedure or manufacturer requirement (e.g. Permit-to-Work, JRA, Safety
Case, Safety Management Plan, Non-routine Procedure, etc.).
All isolations shall only to be carried out by an authorised Isolation Officer or HV
Switching Officer.
All isolation and control measures placed as part of PTW shall be arranged and
managed by the relevant Permit Issuer responsible for approving the isolation(s) and
issuing a PTW.
All persons on site are responsible for complying with the requirements of all PTW
conditions, as unauthorised removal of any Lockout or safety device may result in
serious injury or death, equipment or environmental damage.
An Electronic Control System (e.g. Programmable Logic Controller, SCADA System) or
emergency stop/off switches shall not be used as the isolation and/or control point.
Horizon Power’s PTW isolation and/or control process is included at Appendix A.
6.1.1 Type of Energy isolations
Energy Isolation can be classed into two main categories, that being:
Mechanical Energy Isolation and
Electrical Energy Isolation.
SECTION 6 HORIZON POWER Page 6-2
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
Mechanical Energy Isolation
Mechanical energy can be in the form of Liquids, Gases and Vapours. There are many
way in which mechanical energy can be isolated, such as:
close a block valve to prevent flow and venting, draining or depressurising the
isolated section,
fix a blanking device to a pipe to prevent flow
disconnect a pipe to prevent flow, and
open a bleed valve to vent gas or drain liquid
Blanking devices (blinds, spades & caps) shall be designed and rated for the system. All
valves used as isolation and/or controls are required to be secured and locked and
tagged.
Where the energy source is a liquid or gas that may enter a confined space, it is
recommended to remove a pipe spool between the source and Confined Space then
blank off the energy source prior to entry.
Electrical Energy Isolation
There are two main reasons for electrical energy isolations, that being, 1) Isolation to
allow access to the driven machinery for non-electrical work and 2) Isolation to allow
access to the normally energised plant for electrical work.
Electrical energy will be classified as either Low Voltage (LV) or High Voltage (HV). LV
is where voltage exceeds 50 volts (alternating Current) and less than 1000 volts
(alternating current). For direct current the limits are between 120 volts and 1500 volts.
High voltage is where voltage exceeds 1000 volts alternating current (a.c.) or 1500 volts
direct current (d.c.).
Isolation of equipment for electrical work is to be carried out by an authorised electrical
person or authorised licensed electrical worker.
Note:
Single block, double block and bleed valves shall not be relied upon as a form of isolation for Confined Space entry.
Additional tags shall be attached to access covers removed to provide entry and ventilation to ensure they stay removed.
HORIZON POWER SECTION 6 Page 6-3
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
6.2 Identifying Isolation Points
The Permit Issuer is responsible for identifying isolations that are necessary to access
generation assets to undertake work activities. Isolation and/or control points for a
particular generation asset or part thereof can be identified by the following means:
review of the appropriate piping and instrumentation diagram (P&ID)
review the appropriate electrical schematics
review of the appropriate operating or manufacturers instruction manual
review with the Operator
performing system walk downs/visual observations
In all cases, verify that the drawings and information used for the purpose of identifying
isolations accurately reflect the current configuration of the generation assets.
Checks shall also be undertaken to identify potential back feeds, reverse flows and
interaction with adjacent equipment.
Should cross boundary isolations be identified by an Isolation Officer or HV Switching
Officer, the owner of the relevant equipment shall be contacted so that the interfacing
isolations can be arranged and managed using an Operating Agreement.
Where standard isolation procedures exist these should be carefully checked each time
they are used to verify their accuracy prior to use. Where HV electrical isolations have
been identified, a HV Switching Programme shall be completed.
A HV Switching Programme is a logical sequence of events which shall be followed to
isolate the HV electrical system and shall be used to make specific electrical
apparatus:-
de-energised prior to work commencing
energised following completion of work
supplied by different incomers and/or distribution feeders
Note:
Switching programmes for known situations which have been checked and
approved by a HV Switching Officer must be verified by a second authorised
person on each occasion prior to use to ensure that conditions regarding the
equipment and drawings have not changed.
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Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
6.3 Isolation Procedure Requirements
To effectively isolate, control or restrain generation assets or block access to an
operational area the Isolation Officer and/or HV Switching Officer shall, by using
approved safe methods, ensure that:
the equipment is shut down or de-energized
all sources of energy are isolated
the isolation is tested and proved.
isolation and/or controls are secured with Isolation Locks and tags.
Release the potential stored energy of springs when applicable.
identify and isolate automatic operation of the generation asset(s).
6.4 Locking Isolations
Where generation assets are isolated, the isolation and/or control measure shall
physically restrain from movement, locked out and identified.
All keys to Isolation Locks shall be placed in a Lockbox and secured with a Control
Lock.
A Personal Lock shall be applied to the Lockbox by the Recipient-in-Charge and
Recipient(s) to provide additional security and prevent access to the Isolation Keys.
All Personal Locks shall also be fitted with a personal Danger Tag to identify the owner
of the lock.
HORIZON POWER SECTION 6 Page 6-5
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
Isolation
Lock Keys
Lockbox 1
Isolation
Lock Keys
Lockbox 2
Isolation
Lock Keys
Lockbox 3
PTW 1
PTW 2PTW 4
PTW 3
FactoryIsolate Lock & Tag
Equipment/System
Permit Board
Figure 2 – Cascade Isolation Arrangement
The Permit Issuer may waive the use of a Lockbox for Single Point Isolations. In this
case a multi lock hasp shall be used to facilitate the application of the Recipient-in-
Charge and Recipient(s) personal Locks on the same single isolation and/or control
point. (Refer to Figure 3). The Permit Issuer shall retain the isolation lock key.
FactoryIsolate Lock & Tag
Equipment/System
Figure 3 – Single Point Isolation
SECTION 6 HORIZON POWER Page 6-6
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
6.5 Remove Isolation
Before Lockouts are removed from isolation and/or control points to enable energy to be
restored to the generation assets, the following sequence shall apply:
inspect the area to ensure that non-essential items have been removed, the
equipment components are intact and the generation asset(s) is operationally
ready.
check the work area to ensure all personnel are clear
ensure PTW and Supplementary Permits issued for the work have been signed
off and cancelled.
remove all Isolation Locks from the isolation and/or control points and return the
generation asset to its normal operating status.
record the isolation and/or control removal on the relevant Permit-to-Work
6.6 Removal of Locks
All locks placed shall be unlocked with the dedicated key for that lock.
6.6.1 Person or Key Missing
Where the person or dedicated Personal or Isolation Lock key cannot be found and the
Isolation Lock is required to be removed, the lock can only be removed by the Formal
Leader once the following steps have been taken:
all personnel protected by that lock are identified and notified.
the environment protected by the lock is proved safe.
the asset protected by the lock is proved safe.
the missing person is notified and not expected to return to site.
search for the dedicated key is unsuccessful.
Note:
It is recommended that the de-isolation is done in reverse order to prevent introducing a
hazard prior to the completion of the de-isolation.
HORIZON POWER SECTION 6 Page 6-7
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
6.6.2 Emergency
Where an emergency requires the overriding of any lock, the relevant lock may only be
removed by the Formal leader once the following steps have been taken:
all personnel protected by that lock are identified and notified, and
the environment protected by the lock is proved safe, and
the asset protected by the lock is proved safe.
In all cases where a lock is removed by force, the “Emergency Lock Removal” form
shall be completed and filed with the PTW.
6.7 Isolation Tags
The Isolation Officer shall place an Isolation Tag on all isolation and/or control points
and identify and record the necessary PTW or Supplementary Permit details on the tag.
As a minimum each Isolation Tag shall list PTW number (if applicable), equipment ID
and/or brief equipment description, Isolation Officer name and contact details, date and
time of isolation.
SECTION 6 HORIZON POWER Page 6-8
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HORIZON POWER SECTION 7 Page 7-1
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
7 PERMIT TO WORK
This section describes how to prepare issue, accept, work under, transfer, suspend,
relinquish cancellation and close a PTW and Supplementary Permits. The PTW flow
diagram are shown in Appendix B.
A Permit-to-Work is not required for:
Routine testing, inspection or fault finding work that does not require Isolation
and/or Control.
People undertaking ground maintenance activities in a non-hazardous location of
Horizon Power generation site.
Some supplementary permit(s) may still be required to comply with the Safety and
Health Management System.
7.1 General
A PTW is an authorisation to do work. An integral function of the PTW process is to
record all isolations and other controls that are required to perform the work safely. A
PTW is required at all times where:
isolation and/or control of a generation asset are required to carry out a work
activity.
operational work is carried near a generation asset, i.e. excavation work.
where work is to be performed of a hazardous nature or in a hazardous location.
when stipulated in any other Horizon Power document. (Safety Case, Safety
Management Plan, JRA, Non-routine Procedure, etc.)
A person working under the authority of a PTW shall be responsible to carry out that
work under the conditions contained in the work permit.
In addition to a PTW, Supplementary Permits are also required for specific high risk
activities or specific activities in hazardous locations. Supplementary Permits are used
for the following:
Confined Space Entry.
Hot Work in hazardous areas.
Excavation and Trenching.
Sanction-to-Test.
HV Electrical Access.
Operating Agreement (OA).
SECTION 7 HORIZON POWER Page 7-2
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
7.2 Preparation of a Permit-to-Work
A PTW including Supplementary Permits may only be completed and issued by a
Permit Issuer.
On request for a PTW, the Permit Issuer shall prepare the PTW, Supplementary
Permits (where required) and organise for an Isolation Officer and/or HV Switching
Officer to undertake the necessary isolations and provide any special controls.
The generation asset(s) to be worked on and the scope of work are to be recorded on
the PTW. No work outside of the defined PTW scope of work will be allowed.
Identify the isolations required to safely perform the work in accordance with the
Isolation requirements described in Section 6 of this procedure.
Record the identified isolation and/or controls (with generation asset item description
and tag number whenever possible), the number of the Lockouts used and the safe
position of each point of isolation in section 3 of the Permit-to-Work. Where there is
insufficient space an Isolation Continuation Sheet shall be completed and attached to
the Permit-to-Work and indicate this on the PTW. (An Isolation Continuation Sheet is an
extension of Section 3 of a Permit-to-Work).
7.3 Isolation
The Isolation Officer or HV Switching Operator shall carry out the isolations and update
the relevant column in section 3 of the Permit-to-Work for that isolation to indicate that it
has been applied.
Where HV isolations are required, a HV Switching Operator must complete a HV
Switching Programme. These HV isolations shall be indicated in Section 3 of the PTW.
A copy of the HV Switching Programme shall be attached to the PTW.
Where Supplementary Permits are required to facilitate additional safe conditions,
update Section 4 of the PTW as the circumstance requires, identifying the type of
Supplementary Permit and its number.
The Isolation Officer or HV Switching Operator shall apply the Blue Control lock with an
Isolation Tag to the associated Lockbox. (Note: Except for a single person remote site
the Isolation Officer and HV Switching Operator can also be the Permit Issuer)
The Permit Issuer shall verify that all of the required isolation and/or control measure(s)
have been established in the field and recorded on the specific permit. After the permit
conditions have been verified the Permit-to-Work is ready for issue.
HORIZON POWER SECTION 7 Page 7-3
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
7.4 Issuing a Permit to Work
The Permit Issuer shall always ensure that Recipient-in-Charge acknowledges the PTW
conditions and the isolation and/or control measure(s) before issuing the PTW.
The Isolation officer/HV switching officer shall:
Place the keys for all HV and/or Isolation Locks in the relevant Lock Box and lock
the Lockbox with a Control Lock.
And record the following in Section 5 of the PTW:
the date and time the PTW was issued
the date and time to which the PTW can remain valid
Issuer Name, sign and date the PTW.
The Recipient-in-Charge shall sign the Permit Acceptance section of the
Permit to Work.
The PTW, Supplementary Permits and associated paperwork shall be handed over to
the Recipient-in-Charge for ongoing control until relinquished for Cancellation back to a
Permit Issuer.
7.5 Storage of a Permit to Work
The Recipient-in-Charge shall place all documentation on the Permit Board located
adjacent to the associated Lock Box.
7.6 Working Under a Permit to Work
Where a single person signs as the Recipient-in-Charge of a PTW, they will accept
responsibility for the PTW and will not work outside of the conditions and the isolation
and/or control measure(s) of the PTW.
Where a person signs as the Recipient-in-Charge of a PTW in a work group of
Recipients, they accept the responsibility as the person in charge of the work.
Note:
Without signatures in the Permit Issue and Permit Acceptance sections, the PTW
is invalid.
SECTION 7 HORIZON POWER Page 7-4
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
The Recipient-in-Charge shall be responsible for:
Ensuring that all Recipient(s) are fully aware of the conditions, the isolation
and/or control measure(s) of the PTW, and
All members sign onto the PTW.
The Recipient-in-Charge shall actively monitor the Recipient(s) activities to manage
overall safety.
Additional isolations are permitted to be added to the PTW only after agreement
between the Recipient-in-Charge, the Permit Issuer and Isolation Officer.
Where additional isolations are agreed, the details of the additional isolations must be
recorded on the PTW and any working copy. All Recipient(s) must be informed of the
additional isolation(s).
All Recipient(s) who have signed onto a PTW shall attach a Personal Lock to the
Lockout Hasp on the Lockbox associated with their PTW.
Personal Locks shall only be placed in accordance with the provisions of the PTW
Isolation Procedure in Section 6 of this standard.
Persons who are required to permanently leave the work site cannot do so without firstly
signing off the PTW and removing their Personal Lock and Danger Tag from the
Lockbox. This is to ensure that if the work is completed in their absence the PTW can
be signed off as complete and cancelled.
Any person, who leaves the site without signing off a PTW or without removing their
Personal Lock, will be required to return to the site to do so.
Where such persons cannot be found or brought back to site, the Emergency Lock
Removal steps outlined in Section 6.6.1 of this standard are to be followed.
7.7 Relinquishing a PTW for a STT
The STT shall be initiated by the Recipient-in-Charge and in conjunction with a Permit
Issuer. Although the STT Recipient-in-Charge is generally in charge of the test, the
Permit Issuer is responsible for ensuring the equipment being tested is in an adequate
state prior to issuing a STT Permit.
This adequate state prior to the issuing of the STT Permit, the Permit Issuer shall
ensure that:
All plant and equipment is clear of the Worksite,
All supplementary permits have been relinquished.
All person(s) working under the PTW have been withdrawn and signed off the
PTW
HORIZON POWER SECTION 7 Page 7-5
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
All necessary guards and protective devices have been replaced where possible.
The generation asset or part thereof is ready for testing or adjustment, and
The Isolation Officer shall record all Isolation and/or Control measures that have
been removed on the PTW.
Permit Issuer issues the STT Permit to the Recipient-in-Charge.
If work under the PTW needs to continue on completion of the test(s) or adjustments,
Section 8 of the STT Permit form shall be completed and the Permit Issuer shall
arrange for the Isolating Officer to have all isolations re-instated, recorded on the PTW
and verified to comply with the PTW.
The Permit Issuer will reissue the PTW and all Recipient(s) are to re-sign the PTW.
If the test or adjustment is completed and the job is complete, the STT Permit and the
PTW may be signed off as cancelled and closed together, with the Generation Asset(s)
being returned to service.
7.8 Cross Boundary Permit and Lockout Requirements
Where an external operator has requested isolations within the generation boundary the
following shall apply:
The Permit Issuer shall prepare the Operating Agreement (OA) and arrange for
an Isolation Officer or HV Switching Operator to undertake the isolations and/or
controls.
The Isolation Officer shall undertake the required isolations in accordance with
the GPTWS standard.
The Issuing Officer shall issue an OA to the external operator’s Recipient-in-
Charge.
The external operator OA Acceptor shall check all isolations prior to accepting
the OA.
The external operator’s OA Acceptor shall place their Personal Lock to the
Lockbox to provide additional security and prevent access to the Isolation Keys.
Note:
If the test or adjustment involves HV isolations, then only an Authorised HV
Switching Officer may perform the task under the STT Permit.
SECTION 7 HORIZON POWER Page 7-6
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
On completion of the task the OA shall be cancelled in accordance with the GPTWS
standard.
The external operator’s OA Acceptor shall remove their Personal Lock in accordance
with the GPTWS standard.
7.9 Transferring Responsibility of a Permit to Work
The PTW may be transferred to another Recipient-in-Charge by completing Section 10
of the PTW.
The departing Recipient-in-Charge must notify the Permit Issuer of the change
before transferring the PTW.
The departing Recipient-in-Charge shall always ensure that the incoming
Recipient-in-Charge acknowledges the PTW conditions and the isolation and/or
control measure(s) before transferring the PTW.
The departing Recipient-in-Charge must remove their Personal Lock and Danger
Tag from the Lockbox.
If the permit transfer section is not fully completed, the PTW is invalid.
7.10 Relinquishing a Permit to Work
The Recipient-in-Charge is responsible for ensuring that all Recipient(s) have exited the
work area, that the work has been completed and that the generation asset is ready to
be placed back into service.
All Recipient(s) are required to have signed off the PTW and any Supplementary
Permits, and then remove their Personal Locks from the Lockbox. (This includes the
Recipient-in-Charge removing their lock(s) if placed).
The PTW and any Supplementary Permits may be relinquished by the Recipient-in-
Charge by signing the appropriate section of the Supplementary Permit(s) and Section
7 of the PTW.
The PTW and Supplementary Permits shall be removed from the Permit Board and
returned to the Permit Issuer for closure and record keeping.
HORIZON POWER SECTION 7 Page 7-7
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
7.11 Cancelling a Permit to Work
The Permit Issuer must ensure that the PTW and any Supplementary Permit(s) have
been completed in accordance with this GPTWS standard.
The Permit Issuer shall instruct an Isolating Officer to remove the isolation and/or
control measure(s) placed in association with that PTW.
The Isolating Officer shall initial/sign the “Remove” column in Section 3 of the PTW to
confirm that the isolation and/or control measure(s) have been removed.
The Isolating Officer shall return the PTW form and associated Supplementary Permits
including all Isolation Tags to the Permit Issuer.
The Permit Issuer may then sign the permit cancellation section of the PTW, and file all
documentation for record keeping and auditing.
SECTION 7 HORIZON POWER Page 7-8
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HORIZON POWER SECTION 8 Page 8-1
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
8 SUPPLEMENTARY PERMITS
8.1 General
Supplementary Permits (7.2 – 7.7) are an authorisation to do specific activities and are
used to record the additional controls specific to the high risk tasks they are associated
with. Refer to other Horizon Power procedures for additional instruction for the high risk
activity the Supplementary Permits are provided for.
Where Supplementary Permits are required they shall be issued, accepted, relinquished
and cancelled using the same process as a PTW.
Supplementary Permits shall only be issued in conjunction with and referenced on the
PTW. If a PTW is cancelled in accordance with 6.10, the Supplementary Permit must be
cancelled at the same time.
8.2 Hot Work Permit
A Hot Work Permit is required where hot work is to be carried out on or near any
generation asset(s) in hazardous zones or where identified by the Permit Issuer.
Hot work may include but is not limited to:
Use of mobile phone, cameras, power tools and other non-intrinsically safe
equipment.
Use of all forms of electric/gas welding and cutting processes.
Operating plant and machinery driven by a combustion engine.
Use of tools that generate a spark during impact or use.
Any vehicle and equipment that may generate an ignition source.
8.3 Confined-Space Entry Permit
A Confined-Space Entry Permit is required where persons are required to enter into any
declared Confined Space.
The definition of a Confined Space in AS 2865 is any enclosed or partially enclosed
space that is not intended or designed primarily for human occupancy, within which
there is a risk of one or more of the following:
An oxygen concentration outside the safe oxygen range.
A concentration of airborne contaminant that may cause impairment, loss of
consciousness or asphyxiation.
A concentration of flammable airborne contaminant that may cause injury from
fire or explosion.
Engulfment in a stored free-flowing solid or rising level of liquid that may cause
suffocation or drowning.
SECTION 8 HORIZON POWER Page 8-2
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
8.4 High Voltage (HV) Electrical Access Permit
The HV Electrical Access Permit is designed to be used by personnel who are required
to access HV Electrical Generation Assets.
No Horizon Power employee or authorised contractor shall work on HV electrical
apparatus which is energised or is capable of being energised.
Access is permitted only after the electrical generation assets have been isolated,
proved de-energised, earthed by approved methods, locked where practicable and
danger or isolation labels fitted.
8.5 Excavation and Trenching Permit
The Excavation Permit is designed to be used by personnel who are required to carry
out excavations or trenching where there is a risk of damage to underground generation
assets.
A site survey must be undertaken to identify if there are any buried services prior to any
excavation work being undertaken.
All buried generation asset(s) shall be identified, located, proved and where possible
isolated.
Where generation asset(s) have been identified an Excavation and Trenching Permit
will be required.
All buried Generation Asset(s) and their controls shall be recorded on the Excavation
and Trenching Permit.
An excavation or trench by virtue of other hazards may also be classified as a Confined
Space. This is generally as a result of atmospheric contamination, engulfment, flooding
etc.
Where the excavation or trench is classified as a confined space, a Confined Space
Entry Permit will be required by personnel required to enter these excavations.
8.6 Sanction-to-Test (STT) Permit
The STT Permit is designed to be used by personnel who are required to test new,
reconditioned or existing generation assets on which tests are to be conducted.
A STT is required when, in order to complete the work described in the PTW, the
release of one or more isolation and/or control measures by an Isolating Officer is
required so that energy supplies can be used to complete the test or adjustment.
The STT allows access to generation assets for the fitting, operating and removal of test
devices.
HORIZON POWER SECTION 8 Page 8-3
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
Any alterations to the manner in which the generation assets have been isolated are
permitted only with the knowledge and approval of the Permit Issuer, who may give
written instructions on the STT.
The STT cannot be issued in conjunction with an HV Electrical Access Permit for the
same apparatus, as the testing procedure may require a voltage to be applied.
8.7 Operating Agreement
An Operating Agreement (OA) is an agreement between two Operating Authorities, for
example, Horizon Power as a generator and Horizon Power as a network operator or an
Independent Power Producer (IPP) as a generator and Horizon Power as a network
operator.
It is used to confirm that an electrical apparatus operational state will be held in an
agreed state until the OA is cancelled. An OA is used when one party needs to work on
an item of plant or electrical apparatus which requires isolation and/or earthing from an
adjacent Operating Authority.
The Operating Agreement recipient shall verify the isolations and earthing points stated
on the Agreement, and may apply additional locks and tags. An OA is not a work permit.
It does not authorise work to be undertaken. A work permit must be issued to allow work
to take place. The conditions stated on the work permit must reference the OA. An OA
is issued by a switching operator.
For standard outages, the outage requestor will write the associated switching program,
unless otherwise agreed. For the commissioning of other Operating Authority
apparatus, Horizon Power will usually write the switching program. The issue and
relinquishment of Operating Agreement must be recorded as steps in the switching
program.
Note:
Only the minimum number of Isolation Locks and / or HV Isolation Locks shall be removed to conduct the required test or adjustment.
SECTION 8 HORIZON POWER Page 8-4
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HORIZON POWER SECTION 9 Page 9-1
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
9 REMOTE SITE PERMIT TO WORK REQUIREMENTS
9.1 General
Typically Horizon Powers’ generation assets at remote sites are maintained by single
person operators thus making the issue and receipt of Permits difficult. To cater for sites
that are operated and maintained by a single person, the PTW will be issued and
authorised from a Horizon Power representative.
The Horizon Power representative issuing a PTW from the District (not at Generation
site) shall be a Permit Issuer.
A PTW can be issued and authorised by phone (refer to Section 5 of the PTW form).
All isolations at the remote sites are to be carried out in accordance with this GPTW
standard.
Persons accepting a PTW, preparing equipment and undertaking isolations and/or
control measures at remote sites shall be trained and authorised to undertake isolations
and HV switching operations.
9.2 Preparation of Permit to Work
The remote site operator shall complete Sections 1, 2 and 4 of the PTW form listing all the required isolations as identified in the site specific standard isolation procedures.
Once the PTW has been prepared, the remote site operator is required to contact the Horizon Power representative by telephone, fax or email to have the PTW checked and approved by a Permit Issuer.
Prior to approving a PTW the Horizon Power representative Permit Issuer shall verify the accuracy of the proposed isolations or controls to be applied by checking the information against the current drawings, and isolation procedures for the nominated remote site.
If the Horizon Power representative Permit Issuer is of the opinion the remote site operator has identified the appropriate isolations and controls to complete the works, the Horizon Power representative Permit Issuer shall log the scope of work & date in the Permit to Work Register and issue a permit number for the remote site operator to use on the PTW form.
Note:
The remote site operator may also be required to undertake non-standard isolations by completing Sections 1 to 4 of the PTW.
SECTION 9 HORIZON POWER Page 9-2
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
9.3 Equipment Preparation – Isolate
Isolations shall be applied at a remote site in accordance with the requirements of this standard. Only an authorised Isolation Officer/HV Switching Officer can isolate the equipment.
9.4 Issuing a Remote Site Permit to Work
On completion of the isolations the remote site operator will contact the Horizon Power representative Permit Issuer to advise that all PTW isolation and/or control measures have been completed.
The Horizon Power representative Permit Issuer shall advise the remote site operator that the PTW has been approved.
On notification of approval the remote site operator shall record the name of the Permit Issuer in Section 5 of the PTW and then sign Section 6 on the PTW as the Recipient-in-Charge.
The Horizon Power representative Permit Issuer shall record the PTW details in the Permit to Work Register.
9.5 Working Under a Remote Site Permit to Work
Work may only commence under a PTW once the remote site operator has signed Sections 5 - Statement for Issue by Telephone on behalf of the Permit Issuer and Section 6 – Permit Acceptance of the PTW as the Recipient-in-Charge.
9.6 Cancelling a Permit to Work
On completion of the works, the remote site Isolation Officer/HV Switching Officer shall check that it is safe to remove all isolation and/or control measures.
Once all isolation and/or control measures are removed, the remote site Isolation Officer/HV Switching Officer shall complete Section 7 (cancellation) of the PTW and advise the Horizon Power representative Permit Issuer that the PTW has been cancelled.
The Horizon Power representative Permit Issuer shall record the cancellation in the Permit to Work Register. The PTW is now closed.
The remote site Isolation Officer/HV Switching Officer shall attach the now closed PTW to any other paperwork associated with the works along with all Isolation Tags and retain on file at the remote site for auditing purposes.
Note:
Copies of the PTW shall be retained on file at the remote site.
HORIZON POWER SECTION 10 Page 10-1
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
10 APPENDIX SECTION
10.1 Appendix A – Isolation Philosophy
Where a double block and bleed is required the vent shall be appropriately sized and
located to ensure the isolation can be adequately proven.
Note: Neither a Single block or Double Block and bleed valve(s) shall be relied upon as
an Isolation and/or Control measure for confined space entry.
Where an automated actuated valve is being used as an energy Isolation and/or
Control, the driving mechanism must be capable of being locked in the isolated position
and its motive force (e.g. electricity, air) must be capable of being positively isolated.
In the following table the box marked “E” is the equipment being isolated.
System Description Major Work
(includes any confined space entry)
Gas (e.g. gas turbine fuel supply and gas metering and conditioning)
Double block and bleed plus a spade/blind (Note 1).
Chemical Injection Points on vessels that require entry (e.g. water treatment chemicals
in storage tank)
Single block and removable spool with cap supplied for disconnected joints
Other water systems (e.g. water treatment plant)
Single leak tight closed valve + Blind (Note 1)
Nitrogen
- Heat Recovery Steam Generator required for entry to steam drum
Single block and removable spool/flexible connection
(single block and spade is acceptable for larger pipe sizes)
Compressed Air
- control valve actuators
Single leak tight closed valve
E
E
E
E
E
E
SECTION 10 HORIZON POWER Page 10-2
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
System Description Major Work
(includes any confined space entry)
CO2 and other inert atmosphere fire protection systems
- fire protection systems
Electrical and mechanical isolation as required by Horizon Power Generation isolation instructions
and procedures
Electrical As per Horizon Power Generation electrical isolation instructions and procedures
.
Note 1:
In order to limit the number of potential leak points it is acceptable to locate spectacle blinds / spades at valve/equipment flanges.
HORIZON POWER SECTION 10 Page 10-1
Generation Permit To Work Standards © Horizon Power DM# 10253285 Reviewed Date: June 2018
10.2 Appendix B - Permit to Work Flow Diagram
Permit to Work Flow Diagram
Re
qu
est
Pla
n &
Pre
pa
reIm
ple
me
nt
Re
vie
w &
Ve
rify
Issu
e &
Acce
pt
Ca
rryo
ut W
ork
sC
an
ce
l/C
lose
Permit IssuerIsolation officer Permit Acceptor Work PartyPermit Requestor
Define scope of work, identify equipment
and complete JRA for the workReview and validate the scope of work
Permit
required?
Work to proceed in accordance with
agreed procedures andJRANo
Review and accept scope of work, arrange
and prepare Permit requirements including
any Supplementary Permit requirements
Yes
In consultation with Permit Issuer review
scope of work and develop required
Permit Controls eg. Isolations
Implements the Permit controls (isolations etc)
and places Isolation Lock keys in Lockbox
Review and validates the Permit controls with
the Equipment Preparer and places Control
Lock on Lockbox
Articulates the Permit controls
to the Permit Acceptor
Reviews Permit conditions and controls
and acknowledges understanding of same
Dual verification of
documentation
and controls
Issues Permit to Permit Acceptor
retains copy on file for record
Accepts Permit conditions and controls and
places Personal Lock on related Lockbox
Permit conditions explained and controls
demonstrated to Work Party
Reviews and accepts Permit conditions and
controls – signs onto Permit and places
Personal Lock on associated Lockbox
Commence workMaintains Permit controls
Conditions
change
Review condition change and discuss
with Permit to Work IssuerYes
Stop Work
Complete work
Sign off Permit and
remove Personal Locks
No
Verifies the safety of Work Party, ensures the site
is safe and relinquishes control of the Permit
Validates the completion of
work and cancels the Permit
Removes the Permit controls
as requiredPermit Closed
Do the changes
introduce a hazard
not controlled in the
Permit?
Yes
Verifies the safety of Work Party,
Personal Locks removed and
relinquishes control of the Permit
NO
Yes
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HORIZON POWER SECTION 10 Page 10-1
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10.3 Appendix C – Associated GPTWS links
The following section outlines the links for all related documents:
http://dm.horizonpower.com.au/otcs/llisapi.dll/open/1893654 - Permit-to-Work permit
register
http://dm.horizonpower.com.au/otcs/llisapi.dll/open/10186760 - Permit-to-Work permit
http://dm.horizonpower.com.au/otcs/llisapi.dll/open/10189422 - Sanction-to-Test permit
http://dm.horizonpower.com.au/otcs/llisapi.dll/open/10189888 - Excavation and
trenching permit
http://dm.horizonpower.com.au/otcs/llisapi.dll/open/10196628 - High Voltage (HV)
Electrical Access permit
http://dm.horizonpower.com.au/otcs/llisapi.dll/open/10191030 - Emergency Lock
Removal form
http://dm.horizonpower.com.au/otcs/llisapi.dll/open/10191043 - Generation Permit-to-
Work Standard (GPTWS) Operating Agreement
http://dm.horizonpower.com.au/otcs/llisapi.dll/open/10191701 - High Voltage (HV)
Switching Schedule form
http://dm.horizonpower.com.au/otcs/llisapi.dll/open/3227438 - Confined-Space Entry
Permit
http://dm.horizonpower.com.au/otcs/llisapi.dll/open/3230109 - Hot Work Permit