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Network StandardNETWORKNW000-S0034NW000-S0034For Official use onlyDocument No: NW000-S0034Amendment No: 4Approved By: Head of AEP&SApproval Date: 03/11/2017Minor Amendment Approved on 11/11/2021NS189 OIL CONTAINMENT FOR MAJOR SUBSTATIONSUNCONTROLLED IF PRINTEDPage 1 of 45

NS189 Oil Containment for Major SubstationsAmendment No 4ISSUEFor issue to all Ausgrid and Accredited Service Providers’ staff involved with the design of oil containment systems at majorsubstations, and is for reference by field, technical and engineering staff.Ausgrid maintains a copy of this and other Network Standards together with updates and amendments on www.ausgrid.com.au.Where this standard is issued as a controlled document replacing an earlier edition, remove and destroy the superseded documentDISCLAIMERAs Ausgrid’s standards are subject to ongoing review, the information contained in this document may be amended by Ausgrid at anytime. It is possible that conflict may exist between standard documents. In this event, the most recent standard shall prevail.This document has been developed using information available from field and other sources and is suitable for most situationsencountered in Ausgrid. Particular conditions, projects or localities may require special or different practices. It is the responsibility ofthe local manager, supervisor, assured quality contractor and the individuals involved to make sure that a safe system of work isemployed and that statutory requirements are met.Ausgrid disclaims any and all liability to any person or persons for any procedure, process or any other thing done or not done, as aresult of this Standard.All design work, and the associated supply of materials and equipment, must be undertaken in accordance with and consideration ofrelevant legislative and regulatory requirements, latest revision of Ausgrid’s Network Standards and specifications and AustralianStandards. Designs submitted shall be declared as fit for purpose. Where the designer wishes to include a variation to a networkstandard or an alternative material or equipment to that currently approved the designer must obtain authorisation from the NetworkStandard owner before incorporating a variation to a Network Standard in a design.External designers including those authorised as Accredited Service Providers will seek approval through the approved process asoutlined in NS181 Approval of Materials and Equipment and Network Standard Variations. Seeking approval will ensure NetworkStandards are appropriately updated and that a consistent interpretation of the legislative framework is employed.Notes: 1. Compliance with this Network Standard does not automatically satisfy the requirements of a Designer Safety Report. Thedesigner must comply with the provisions of the Workplace Health and Safety Regulation 2011 (NSW - Part 6.2 Duties of designer ofstructure and person who commissions construction work) which requires the designer to provide a written safety report to the personwho commissioned the design. This report must be provided to Ausgrid in all instances, including where the design was commissionedby or on behalf of a person who proposes to connect premises to Ausgrid’s network, and will form part of the Designer Safety Reportwhich must also be presented to Ausgrid. Further information is provided in Network Standard (NS) 212 Integrated SupportRequirements for Ausgrid Network Assets.2. Where the procedural requirements of this document conflict with contestable project procedures, the contestable projectprocedures shall take precedent for the whole project or part thereof which is classified as contestable. Any external contact withAusgrid for contestable works projects is to be made via the Ausgrid officer responsible for facilitating the contestable project. TheContestable Ausgrid officer will liaise with Ausgrid internal departments and specialists as necessary to fulfil the requirements of thisstandard. All other technical aspects of this document which are not procedural in nature shall apply to contestable works projects.INTERPRETATIONIn the event that any user of this Standard considers that any of its provisions is uncertain, ambiguous or otherwise in need ofinterpretation, the user should request Ausgrid to clarify the provision. Ausgrid’s interpretation shall then apply as though it wasincluded in the Standard, and is final and binding. No correspondence will be entered into with any person disputing the meaning ofthe provision published in the Standard or the accuracy of Ausgrid’s interpretation.KEYPOINTSThis standard has a summary of content labelled “KEYPOINTS FOR THIS STANDARD”. The inclusion or omission of items in thissummary does not signify any specific importance or criticality to the items described. It is meant to simply provide the reader with aquick assessment of some of the major issues addressed by the standard. To fully appreciate the content and the requirements ofthe standard it must be read in its entirety.AMENDMENTS TO THIS STANDARDWhere there are changes to this standard from the previously approved version, any previous shading is removed and the newlyaffected paragraphs are shaded with a grey background. Where the document changes exceed 25% of the document content, anygrey background in the document is to be removed and the following words should be shown below the title block on the right handside of the page in bold and italic, for example, Supersedes – document details (for example, “Supersedes Document Type (Category)Document No. Amendment No.”).NW000-S0034For Official use onlyUNCONTROLLED IF PRINTEDPage 2 of 45

KEY POINTS OF THIS STANDARDScope and Risks AddressedThis standard details general designrequirements for oil containment for majorsubstations with the limitations as listed belowand the associated risks as indicated: Applies to new and existing majorsubstations with primary voltages of33kV, 66kV and 132kV.Controls apply to both normal operationsand during emergency situationsMaintenance and operation of oilcontainment facilities is specifiedseparately in NS190 Oil ContainmentOperational Requirements for MajorSubstationsConsideration given to different types ofoil containment plant for varioussituations found in major substations.All materials and equipment used inconstruction of Ausgrid assets must beasbestos free.Three main risks to be addressed: Catastrophic failure causingprolonged fire Catastrophic failure large amountsoil spreading off-site Minimise oil pollution during normaloperationDesign Principles, Site andRegulatory RequirementsThis section lists the basic design assumptionsand principles used to design oil containmentsystems within Ausgrid: Basic design assumptions listed in Cl. 6.1New and existing systems reviewed in Cl.6.2For existing major substations, all areaswith any oil-filled equipment containingmore than 1000 litres of oil will require oilcontainment facilitiesFor equipment less than 1000 litres or inareas designated low risk containmentmay not be necessary.For new substation sites all oil-filledequipment will be bunded unless indicatedotherwise.Due consideration to minimisecontamination of stormwater.Principles for addressing three main risksSelection criteria for oil containmentsystems based on Life Cycle Cost.Criteria for preferred designs indicated forgreenfield sites.For brownfield retrofit sites the preferredoil containment system is a closeddrainage PPS system.Drainage design philosophy for closedsystems and gravity drainage reviewed.Some existing and temporary sites mayadopt an alternative approach.Designer Safety Report required.Site selection criteria to limit impact of oilloss.Oil containment discharge to Stormwaterand Sewer may have RegulatoryrequirementsTypical Layouts, Bunding andDrainageSpecific design requirements are addressed aslisted:Specific design requirements are addressedas listed: Typical oil containment layouts given forCBD and suburban major substationsBunding areas designed to minimise entryof clean stormwaterBunding designed to prevent burning fuelspreading fire to adjoining equipment.Spray screens may be required if bundunable to contain spray discharge.Transformer roadways may have bundingrequirementsBunding design requirements identifiedSecondary containment requirementsdetermined by Ausgrid risk managementassessment.Oil spill kits to be available for every majorsubstationSection 12 identifies requirements for oilwater separators and oil containmenttanksSection 13 identifies requirements fordrainage and associated structuresincluding pits, pipework, flame traps,valves, and pumps For CBD and other major indoorsubstations fire-fighting watercontainment capacity shall be made forup to 90 minutes of expelled fire-fightingwaterFor both non-rural and rural sites, theminimum containment storage for nonfixed firefighting is 20 minutes of onehose with foam at 4 l/sThe required minimum storage can beinclusive of volume available in bundedareas plus any secondary storage oroverflow areas.Burn down rates can be included incalculations for provisions of storagewhere a full bund oil fire occurs.Capacitors have specific containmentprovisions.After an emergency, oil containment andcontainment tanks must be emptied andremediation work undertaken.Clean up should comply withenvironmental guidelines and legislationRequirements for decommissioning tanksare provided.Where to for more information?Section 14, 15, 16, 17Where to for more information?Where to for more information?Where to for more information?Section 1, 2, 5, 7Section 6, 7, 8, 9Section 10, 11 12, 13NW000-S0034Fire Fighting & Clean upUNCONTROLLED IF PRINTEDTools and FormsAnnexures A, B and CPage 3 of 45

NS189 Oil Containment for Major SubstationsAmendment No 4Network StandardNS189Oil Containment for Major SubstationsContentsPURPOSE . 7SCOPE . 7RELATED DOCUMENTS . 7General. 7Ausgrid documents . 7Other standards and documents . 8Acts and regulations . 8Literature . 8DEFINITIONS . 9ASBESTOS . 10INTRODUCTION . 11General. 11Typical oil containment systems . 12Alternative oil-water separation systems . 12OIL CONTAINMENT PRINCIPLES . 12Where is oil containment required? . 12Selection criteria for oil containment systems . 14Drainage design philosophy . 15Existing or temporary major substations . 15Structural and other design considerations . 15Designer safety reports . 15SITE SELECTION CRITERIA . 16REGULATORY REQUIREMENTS . 16Sewer . 16Stormwater . 16Local council requirements . 16TYPICAL OIL CONTAINMENT LAYOUT FOR NEW SUBSTATIONS . 17CBD major substation with high velocity water spray . 17Suburban major substation . 1810.2.1 General . 1810.2.2 Closed drainage PPS system . 1810.2.3 Gravity drainage system with oil containment tank . 19OIL CONTAINMENT BUNDING . 20General. 20Transformer bunding . 20Spray screens . 20Transformer roadways . 20Bunding design requirements . 20NW000-S0034UNCONTROLLED IF PRINTEDPage 4 of 45