Defence’s new Infrastructure Engineering Manual: consolidation, not simplification

By Darian Macey, July 16 2026

Defence has replaced six separate infrastructure policy documents with a single 96-page Infrastructure Engineering Manual. The change gives industry a clearer starting point, but it does not reduce the compliance burden. Much of the technical detail now sits in a separate suite of numbered guidelines.

Defence issued Edition 1 of the Infrastructure Engineering Manual, or IEM, on 23 April 2026. It was effective immediately.

The IEM replaces:

• Building Works Manual
• Manual of Fire Protection Engineering
• Manual for Infrastructure Engineering Electrical
• Smart Infrastructure Handbook
• Climate Adaptation Handbook
• Building Energy Performance Guide.

At first glance, replacing six documents with one looks like a major simplification. That is not really what has happened.

The IEM is better understood as the front door to a new technical policy structure. It establishes the common principles, approval processes and headline technical requirements. Much of the detailed material previously contained in the superseded manuals has been moved into separate guidelines covering building certification, fire safety, electrical infrastructure, aeronautical ground lighting and electric vehicle charging.

The biggest mistake project teams could make is to remove the old manuals from their compliance register, insert the IEM and assume the work is complete.

DECNET assessment: The new manual is a consolidation of policy architecture, not a consolidation of every technical requirement.

What the new manual covers

The IEM now brings together:

• general infrastructure policy and whole-of-life principles
• building works and certification
• mechanical services
• fire engineering
• electrical engineering
• aeronautical ground lighting
• electric vehicle charging.

It applies to new construction, refurbishment, alterations and additions, as well as relevant operation and maintenance activities. Its scope also includes leased properties, Public Private Partnership facilities, joint-use facilities and foreign facilities located on Australian Defence establishments.

The manual is not generally retrospective for installations that are not being altered or upgraded. However, that principle is not absolute. Fire safety requirements can apply retrospectively where specified, and existing facilities remain subject to maintenance and fire safety survey requirements. Where the IEM conflicts with other levels of regulation or policy, it says the more stringent requirement is to apply.

How the superseded documents have been treated

Superseded document	Treatment in the IEM	Practical effect
Building Works Manual	The main certification process is retained in Chapter 3. Supporting processes have moved into numbered guidelines.	Building surveyors, approvals, inspections and certificates remain central, but teams must now work across the IEM and supporting guidelines.
Manual of Fire Protection Engineering	The general fire framework is in Chapter 5. Requirements for particular facility types have moved into the 5000-series guidelines.	The main manual is shorter, but fire design is not less detailed. Facility classification and Contribution Factor remain important.
Manual for Infrastructure Engineering Electrical	Core electrical governance and technical principles are in Chapter 6. Detailed subjects have moved into the 6000-series guidelines.	Earlier engagement with the Electrical Operating Authority is required. Clean energy, batteries, cyber security and network integration are much more prominent.
Smart Infrastructure Handbook	Whole-of-life, emissions, resilience and sustainability ratings are incorporated into the IEM.	Sustainability is more closely tied to operational resilience and net zero, but the old checklist regime is not reproduced in the core manual.
Climate Adaptation Handbook	Climate resilience is addressed through whole-of-life principles, the Defence Environment Manual and selected technical requirements.	Climate risk has not disappeared, but much of the detailed process appears to sit outside the IEM.
Building Energy Performance Guide	Energy performance is reflected in sustainability ratings, mechanical design, electrification and clean energy provisions.	The direction is clearer, but the detailed transfer of requirements cannot be confirmed without reviewing the most recent guide.

Building certification remains largely familiar

For architects, engineers, building surveyors and head contractors, much of the former Building Works Manual survives with limited substantive change.

The IEM continues to require:

• the National Construction Code as the minimum building standard
• certification of non-exempt building work
• an appropriately accredited building surveyor
• assessment of designers as competent persons
• a documented building assessment
• a building approval before work starts
• nominated inspections and installation certificates
• approval of variations before inconsistent work proceeds
• a certificate of completion before occupation
• retention of certification records for at least 10 years.

The existing distinction between compliance with legislation and codes and conformance with Defence policy also remains.

There are, however, several useful changes.

The exempt building work provisions are now within Chapter 3 rather than a separate annex. Heritage buildings receive explicit treatment, including the relationship between heritage protection and work health and safety. The assessment required when an occupied building remains in use during construction is now called a Construction Zone Safety Strategy, rather than the narrower Construction Zone Fire Safety Strategy used by the former Building Works Manual.

The IEM also adds a substantial section on sustainability rating schemes. Depending on security classification and operational requirements, projects may use schemes such as NABERS, Green Star and Infrastructure Sustainability Council ratings, or Defence’s own Defence Built Environment Sustainability Approach. Buildings in Security Zone 3 or above use the Defence approach, and it also applies to Defence data centres. Approval is required from the Assistant Secretary Environment and Engineering.

More detail has moved out of the main manual

Several former Building Works Manual chapters are no longer reproduced in full. Examples include:

• Contribution Factor assessments
• performance solutions and dispensations
• aircraft hangar assessments
• special structures
• external wall cladding
• detailed building certification templates and processes.

These subjects now depend on guidelines such as Guidelines 2000, 2001, 2002, 3000 and 3001, together with relevant fire guidelines.

That makes document control more important. A design report that cites only “the IEM” is unlikely to define the full design obligation.

Two building certification points need clarification

There are also drafting issues that project teams should not ignore.

The IEM glossary says that a certificate of regularisation is issued under a process in Chapter 3, but Chapter 3 does not clearly reproduce the process previously set out in Chapter 10 of the Building Works Manual.

The former manual also expressly required a separate building approval for each individual building or building part. The new manual does not repeat that exact sentence, although it continues to require a separate certificate of completion for each building.

Neither omission should be treated as permission to relax the previous process. The correct course is to obtain a written position from the building surveyor and, where necessary, the Directorate of Estate Engineering Policy.

Fire engineering has been compressed, not reduced

The former Manual of Fire Protection Engineering contained separate chapters for computing and data facilities, storage buildings, workshops, bushfire-prone construction, aircraft hangars, explosive ordnance buildings, living-in accommodation and buildings for disposal.

The IEM retains the main fire engineering principles in Chapter 5, but moves most facility-specific detail into Guidelines 5003 to 5008 and 5010 to 5013.

The core position has not changed:

• the NCC primarily addresses life safety and adjoining property protection
• Defence may require additional protection for operational capability and assets
• Contribution Factor 1 and 2 facilities attract additional requirements
• competent fire safety practitioners and building surveyors remain necessary
• maintenance and Fire Safety Surveys remain part of the assurance system.

Fire Safety Survey frequencies remain broadly unchanged: CF1 buildings are surveyed annually, while CF2 to CF5 buildings subject to the programme are generally surveyed every three years.

The IEM also formalises the use of a Fire Safety Management Strategy where shortcomings identified through a Fire Safety Survey cannot be rectified immediately. This is not an alternative to eventual compliance. It is a managed, temporary response that requires an agreed strategy and supporting controls.

Firefighting water is now operative policy

One of the clearest changes concerns firefighting water.

Chapter 15 of the supplied 2023 MFPE was marked as being for stakeholder feedback and consideration only. The new IEM contains operative firefighting water requirements.

For CF1 and CF2 facilities, the IEM requires dual water sources, with each source capable of providing the required pressure, flow and duration. At least one source must be a full-capacity static storage tank or an inexhaustible supply. Automatic infill cannot be used to reduce that required storage capacity.

This could have a material effect on site planning, civil works, tank sizing, pump arrangements, water authority consultation and project budgets.

The new wording is not uniformly more prescriptive. Separate firefighting and potable water reticulation is required only where practical and viable for Defence. Even so, the dual-source requirement for critical facilities is a significant design consideration that needs to be resolved before detailed design, not during fire authority review.

Electrical policy now focuses more heavily on authority, resilience and integration

The former electrical manual was a large, highly prescriptive technical document. It contained detailed requirements for master planning, design reports, high-voltage systems, substations, generators, uninterruptible power supplies, hazardous areas, labelling, documentation, commissioning and compliance statements.

The new Chapter 6 is much shorter. Detailed requirements now sit in Guidelines 6000 to 6006.

The supplied comparison copy is the 2011 manual with Amendment 3 from 2018, rather than the 2022 edition formally superseded by the IEM. The comparison nevertheless shows a clear change in emphasis.

The Electrical Operating Authority is a project gate

The IEM gives the Defence Electrical Operating Authority a prominent role throughout project development.

Projects modifying or connecting to a Defence electrical distribution system must coordinate with the Electrical Operating Authority through planning, design, construction, commissioning and energisation. The authority can refuse connection or energisation where safety, compliance, documentation, operational integrity or system reliability requirements have not been met.

This means EOA engagement cannot be left until commissioning. For relevant projects, it needs to appear in the design programme, responsibility matrix, hold-point schedule and commissioning plan from the beginning.

Clean energy is now an engineering requirement

The IEM connects clean energy directly to resilience, self-sufficiency and operational capability.

Projects are required to use their best endeavours to avoid power generation technologies that produce greenhouse emissions during normal operation while still maintaining reliability and resilience. They must make reasonable efforts to avoid new diesel generation where practical.

These are not absolute bans. Capability, reliability and operational need remain overriding considerations. Designers should nevertheless expect to demonstrate that lower-emission and hybrid options were properly assessed rather than defaulting to the arrangement used on the previous project.

The IEM also introduces requirements for renewable energy integration planning. A plan is required in circumstances including:

• more than three separate renewable systems above 20 kVA connected to the same internal network
• installed renewable capacity exceeding 20 per cent of the highest recorded peak demand
• a requirement from the distribution network service provider for monitoring or control.

Required studies can include harmonics, load flow, fault levels, protection and control.

Battery energy storage, microgrids and hybrid generation arrangements are also now part of the mainstream Defence electrical policy framework. Their value is considered not simply in terms of electricity cost, but in terms of mission resilience and reduced exposure to liquid-fuel supply disruption.

Cyber security is no longer peripheral

The IEM expressly requires Defence estate engineering networks to withstand cyber attack and prevent unauthorised access, monitoring, interference or control.

That affects power control and monitoring systems, SCADA, renewable energy controllers, building systems and other connected engineering equipment. Cyber requirements need to be included in system architecture, equipment selection, network interfaces, remote access arrangements, testing and handover—not added as a note late in design.

Mechanical services now have their own chapter

The IEM introduces a dedicated mechanical services chapter, giving several requirements more visibility than they had under the former document structure.

Examples include:

• N+1 cooling for data centres
• N+1 cooling for communications rooms supporting CF1 and CF2 facilities
• minimum spare heating and cooling capacity
• benchmark equipment life spans
• requirements for plant access, maintenance and eventual replacement
• separate, occupant-controlled systems for living-in accommodation
• chilled-water systems for offices with more than 1,000 square metres of air-conditioned space.

For critical or long-life facilities, HVAC outdoor design conditions may need to be adjusted for climate change. The manual identifies an indicative increase of between 0.5°C and 2°C to summer dry-bulb and wet-bulb design temperatures for 2030 conditions.

That allowance should not be applied blindly. It should be supported by project life, location, criticality, climate information and the consequence of plant underperformance.

Sustainability has been reframed around resilience and net zero

The former Smart Infrastructure Handbook imposed a structured “if not, why not?” process. It required projects to complete estate planning and design-and-construction checklists and addressed climate adaptation, energy, water, metering, waste, materials, pollution prevention and construction environmental management.

It also contained concrete commercial tests. For example, initiatives achieving a whole-of-life payback within seven years were to be implemented.

The IEM takes a different approach.

It requires whole-of-life decisions to consider:

• cost
• greenhouse emissions
• reliability
• resilience
• capability supported by the asset
• climatic and service conditions
• maintenance support
• survivability after natural disasters.

It also aligns infrastructure decisions with the Defence Net Zero Strategy, clean energy transition and electrification. From 1 July 2028, new gas appliances and connections should be avoided, and end-of-life gas appliances should be replaced with electric alternatives where practical.

The word “should” matters. This is a clear design preference, not an unconditional prohibition. Capability and operational effectiveness remain relevant qualifications.

The former Smart Infrastructure Handbook’s detailed provisions for water, waste, materials, metering and pollution prevention are not reproduced in the core IEM. It would be unsafe to conclude that these obligations have been abolished. They may now sit in the Defence Environment Manual, associated guidance, project briefs or contract documents.

Electric vehicle charging is now an explicit project consideration

Electric vehicle charging has its own chapter.

The IEM requires EV charging infrastructure to be considered in estate planning and infrastructure projects. Where a project includes car parking or an electrical upgrade relevant to parking, it may need to provide the enabling civil and electrical infrastructure from project funding.

Every Defence charger must connect to charging management software and comply with the Defence hardware specification. Charging an EV from a general-purpose outlet is expressly prohibited on the Defence estate.

For designers, this introduces issues around load growth, spare capacity, switchboard provision, communications, parking layouts, fire safety and future expansion. For builders, it means charger selection and substitution cannot be separated from the Defence management platform and network requirements.

What designers should do now

First, build a project-specific policy register. It should identify the applicable IEM edition, every relevant numbered guideline, the NCC edition, referenced standards, Defence environmental policy, the contract hierarchy and any project-specific brief requirements. Record the actual document versions, not just their titles.

Second, establish the authority map early. Identify the building surveyor, Electrical Operating Authority, Defence fire policy contacts, responding fire service, sustainability decision-maker and any specialist technical authorities. Put their submissions and decisions into the design programme.

Third, redesign the basis-of-design process. Reports should now expressly address whole-of-life cost, emissions, resilience, climate conditions, maintainability, cyber security, clean energy, EV charging and future expansion where relevant.

Fourth, resolve departures before detailed design. Performance solutions, Defence dispensations, electrical alternative conformance solutions and compliance by specific design are separate pathways. They are not interchangeable, and none provides relief from legislation or mandatory codes.

Fifth, pass the policy requirements into every package. A general note requiring compliance with the IEM is not enough. Relevant guideline clauses, approvals, certification, inspections, commissioning and handover requirements need to appear in consultant and subcontractor scopes.

What builders should do now

Confirm the approved baseline before mobilisation. Check the building approval, approved drawings, specifications, applicable policy versions, fire safety schedule, dispensations and performance solutions.

Turn approval conditions into construction hold points. Required inspections, witness testing, concealed work inspections and installation certificates need to be visible in the inspection and test plans.

Treat design changes as approval events. A technically reasonable site substitution may still breach a Defence policy, performance solution, fire strategy, electrical standardisation requirement or cyber requirement.

Plan energisation and commissioning backwards. EOA acceptance, fire system testing, electrical safety certificates, control-system integration, charger commissioning, training, as-built records and operating information can prevent handover even where the physical work is complete.

Preserve evidence as the work proceeds. Photographs, test results, calibration records, installation certificates, product evidence and marked-up drawings are much cheaper to collect during construction than to reconstruct at completion.

The transition risk is contractual

The IEM was issued effective immediately, but it does not provide a detailed transition regime for projects already under contract, in design or holding an earlier building approval.

That does not mean every existing project automatically changes to the new requirements. Nor does it mean teams can continue using superseded policy without review.

The applicable position may depend on:

• the contract and its document hierarchy
• the policy versions identified in the building approval
• the stage of design or construction
• variations made after the IEM’s issue
• written directions from the delivery authority
• decisions of the building surveyor, EOA or DEEP.

The correct response is a documented applicability assessment. Unilaterally substituting the IEM for documents named in an existing contract creates scope, price, certification and professional liability risks.

The bottom line

The IEM is a worthwhile improvement in structure. It brings building, fire, mechanical, electrical, clean energy, aeronautical lighting and EV charging policy into a common framework. It also reflects current Defence priorities more clearly, particularly resilience, electrification, emissions reduction and connected infrastructure.

But it is not a lighter compliance regime.

The new system places more importance on early coordination, authority engagement, whole-of-life reasoning, digital and cyber interfaces, and disciplined use of supporting guidelines.

The firms most exposed are those that reuse the previous project’s compliance schedule and assume that an old Defence solution remains acceptable. The firms best placed are those that identify the complete policy stack early, assign each obligation to a responsible discipline, and maintain evidence from design through to handover.