Fire engineering and fire risk assessment are often discussed as if they are the same service. They are not. A fire risk assessment looks at an existing building, how it is used, and how fire risk is being managed. Fire engineering is design work. It uses fire science, building behaviour, evacuation analysis and engineering judgement to show how a building can meet its fire safety objectives.

The distinction matters. If you appoint the wrong person for the wrong task, you can lose time, spend money in the wrong place, or end up with a report that does not answer the question being asked by the fire authority, building control authority, client or insurer.

This article explains when a fire engineer is needed in Ireland, how fire engineering fits with Building Regulations and fire safety certificates, and how to decide whether you need engineering design input or a fire risk assessment.

What Fire Engineering Means

Fire engineering is the application of engineering principles to fire safety design. It considers how a fire may start, grow and spread; how smoke and heat may move through a building; how people are expected to respond; how long escape or evacuation may take; how the structure will behave; and how active and passive fire protection measures work together.

A fire engineer does not simply list defects. They develop or assess a fire safety strategy. That may involve means of escape, compartmentation, smoke control, structural fire resistance, fire detection and alarm, emergency lighting, sprinkler protection, firefighting access, fire service facilities and management procedures.

In straightforward buildings, the design may follow prescriptive guidance closely. In more complex buildings, or where the guidance does not fit, a fire engineer may need to justify an alternative approach using calculations, modelling, comparative analysis or a structured fire safety argument.

The Irish Regulatory Context

In Ireland, the legal fire safety requirements for new building work sit mainly in the Building Regulations, particularly Part B. Part B deals with means of warning and escape, internal fire spread, external fire spread, structural fire resistance and access and facilities for the fire service.

Technical Guidance Documents are published to show how the requirements of the Building Regulations can be met in practice. The current Technical Guidance Document B for buildings other than dwelling houses is TGD B 2024, with a January 2026 reprint incorporating corrections. TGD B Volume 2 remains the relevant document for dwelling houses.

TGD B is guidance. It is not the regulation itself. Following it is treated as evidence of compliance, but it is not the only possible route. This is where fire engineering becomes important. If a design does not follow the guidance in a particular respect, the designer still has to show that the legal requirements of Part B are met.

A Fire Safety Certificate is required for many non-domestic projects, including new buildings, extensions, material alterations and certain changes of use, subject to the exemptions and rules in the Building Control Regulations. The application has to show that the works or building will comply with Part B. Where the design relies on an engineered solution, the fire engineering argument should be clear enough for the building control authority to review.

When A Fire Engineer Is Needed

You should consider appointing a fire engineer when the project cannot be dealt with confidently by standard guidance alone. That does not mean every building needs a full performance-based fire engineering study. It means the level of engineering input should match the problem.

Common triggers include excessive travel distances, large compartments, atria, complex smoke movement, basements, mixed-use developments, shopping centres, large assembly buildings, high-rise or multi-storey buildings, unusual structures, complex residential layouts, buildings with vulnerable occupants, and projects where a change of use creates a higher fire risk than the original use.

A fire engineer is also useful where the design team proposes compensatory measures. For example, a project may rely on sprinklers, enhanced detection, smoke control, additional compartmentation, staff management procedures or a revised evacuation strategy to justify a departure from the prescriptive guidance. Those measures need to be linked to the fire safety objective, not added as a vague trade-off.

The earlier the fire engineer is appointed, the better. Late fire engineering often becomes damage control. Early fire engineering can influence layout, stair provision, compartment lines, riser positions, door strategy, plant room locations and fire service access before the design becomes expensive to change.

When A Fire Risk Assessment Is Enough

A fire risk assessment is normally the correct service where an occupied building needs a review of existing fire precautions, management procedures, staff training, escape routes, fire doors, alarm systems, emergency lighting and maintenance records. It is a management and risk review, not a design submission for new work.

A competent assessor can identify hazards, prioritise actions and advise on practical controls. If the assessment uncovers a design issue that cannot be resolved by ordinary remedial work, a fire engineer may then be needed. Examples include inadequate compartmentation in a care facility, excessive travel distances in a heritage building, or a proposed management solution that needs technical justification.

The two services should work together. The fire risk assessment identifies the problem. The fire engineer may be needed to design or justify the solution.

Fire Safety Certificates And Design Changes

A Fire Safety Certificate application normally includes drawings and a technical report explaining how the design complies with Part B. For a simple project, that report may follow TGD B closely. For a complex project, it may need a fire engineering strategy, calculations or supporting analysis.

A fire engineer should be involved where there is a material departure from TGD B, where the project relies on a non-standard evacuation strategy, where smoke control is central to the design, or where the reviewing authority has raised questions that require technical analysis.

A revised Fire Safety Certificate may be needed where a design already granted a certificate is significantly changed. A 7 Day Notice may be used where works are intended to start before the Fire Safety Certificate is granted. Where work has started or been completed without the necessary certificate or 7 Day Notice, regularisation may be required. These are procedural issues, but the technical fire safety case still has to be sound.

Healthcare And Designated Centres

Healthcare buildings are one of the clearest examples of where fire engineering judgement can matter. Nursing homes, hospitals and designated centres may include people who cannot evacuate unaided. A simple alarm and total evacuation model is often unsuitable.

The fire safety strategy may depend on progressive horizontal evacuation, compartmentation, sub-compartmentation, staff response, early warning, fire-resisting doors, smoke control, evacuation aids and reliable fire alarm information. These measures have to work as a system. If one element is weak, the overall strategy may fail.

For designated centres, fire engineering input should be read alongside HIQA Regulation 28 duties, the centre's fire risk assessment, fire drills, staff training and documentation. Phoenix STS provides nursing home fire safety compliance and healthcare fire safety consultancy for these settings.

Fire detection and alarm design should also be considered against I.S. 3218:2024. Where an existing system is in question, an I.S. 3218 fire alarm audit can help establish whether the system supports the evacuation strategy.

Heritage And Existing Buildings

Ireland has many older and protected buildings where a standard prescriptive approach can be difficult. Thick masonry walls may perform well in fire, but timber stairs, hidden voids, old doors, unprotected openings and limited escape routes can create serious challenges.

A fire engineer can help avoid crude solutions. Instead of assuming that every modern measure must be inserted regardless of damage to the building, the engineer can assess the actual risk and propose a balanced strategy. That might involve earlier detection, discreet compartmentation, upgraded doors, management controls, suppression, smoke control or limits on occupancy.

This does not mean heritage value overrides life safety. It means the solution should protect people while being honest about the building's constraints. The report should explain the assumptions, the residual risk and the measures needed to manage that risk over time.

Prescriptive And Performance-Based Design

Most real projects use a mixed approach. The design follows TGD B where the guidance fits, and uses fire engineering for the parts that need a different solution. This is usually more practical than trying to engineer every part of the building from first principles.

Performance-based design is useful when a design must show that a different arrangement still achieves an acceptable level of safety. It may involve smoke modelling, evacuation analysis, structural fire analysis, comparative assessment or qualitative engineering judgement. The method should be proportionate to the risk.

Not every issue needs a complex model. A good fire engineer should know when a simple, well-evidenced argument is enough. Over-engineering can be as unhelpful as under-engineering.

What A Fire Engineering Report Should Include

A useful fire engineering report should be clear about the building, the proposed use, the fire safety objectives, the relevant guidance, the departures from guidance, the assumptions, the design fire scenarios, the acceptance criteria and the proposed fire safety measures.

It should also explain limitations. For example, a smoke control analysis may depend on doors closing, fans operating, sprinklers being maintained or staff following a defined procedure. If those assumptions are not realistic, the design is weak.

The report should be usable by the design team, the building control authority and the person who will manage the building after completion. A clever report that cannot be translated into drawings, specifications, commissioning records and management procedures is of limited value.

Choosing A Fire Engineer

Look for relevant fire engineering qualifications, practical experience, professional indemnity insurance and a track record with similar buildings. A BEng in Fire Engineering or a related specialist qualification is a strong indicator, but experience matters. The engineer should understand construction, approval processes, fire safety systems and how buildings are managed after handover.

Chartered status, Engineers Ireland membership, Institution of Fire Engineers membership or equivalent professional standing can help demonstrate competence. For fire risk assessment work, NFRAR registration is relevant. For fire engineering design, the key question is whether the person has the right engineering competence for the specific project.

Phoenix STS provides fire engineering consultancy across Ireland. Our work is supported by BEng-qualified fire engineers, professional indemnity insurance, ISO 9001 and ISO 45001 certification, and practical experience in healthcare, commercial, residential and existing building fire safety.

Common Mistakes To Avoid

The first mistake is appointing a fire engineer too late. If the design is already fixed, the engineer may only be able to identify problems rather than shape good solutions.

The second mistake is treating compensatory measures as simple swaps. A sprinkler system does not automatically justify every departure. A smoke vent does not solve every escape problem. A management procedure is not a substitute for a building measure unless it is realistic, trained and maintained.

The third mistake is forgetting handover. Fire engineering assumptions must become operating instructions, maintenance tasks, drawings, commissioning records and staff procedures. Otherwise, the building may only be safe on paper.

When You Probably Do Not Need A Fire Engineer

Not every fire safety question needs fire engineering. A routine fire alarm service, emergency lighting test, extinguisher service, staff training session or ordinary fire drill does not normally need a fire engineer. Those tasks need competent contractors and a clear management system.

A straightforward fit-out that follows the granted Fire Safety Certificate, keeps the approved compartmentation, does not alter escape routes, and does not change the use or risk profile may not need a new fire engineering study. It may still need competent review to confirm that the works stay within the approved design.

Likewise, many fire risk assessment findings can be dealt with by ordinary remedial work. Missing seals, faulty closers, blocked escape routes, poor housekeeping, out-of-date training records or missing alarm tests are usually management or maintenance issues. Calling them fire engineering problems can slow down action that should be simple.

The dividing line is whether the proposed solution changes the fire safety strategy or needs technical justification. If the answer is yes, involve a fire engineer. If the answer is no, deal with the defect promptly through the normal fire safety management process.

Keeping The Strategy Alive After Handover

A fire engineering strategy only works if the building is built, commissioned and managed in line with the assumptions in the report. This is where many projects lose control. A drawing changes, a door hold-open device is added, a tenant fit-out blocks a smoke reservoir, or a plant room becomes a storage room. The original calculation may still exist, but the building has moved away from it.

The person managing the building should receive the fire strategy, relevant drawings, commissioning records, cause-and-effect information, maintenance requirements and any management assumptions. If the strategy relies on trained staff, phased evacuation, smoke control, sprinklers or particular door arrangements, those points need to be visible in the fire safety file.

Future alterations should be checked against the strategy before work starts. This is especially important in shopping centres, healthcare facilities, apartment blocks, hotels and multi-tenant offices, where small changes by one occupier can affect the fire safety assumptions for others.

Good fire engineering is therefore not just a report for approval. It is a thread that should run from design, through construction and commissioning, into day-to-day management of the building and its occupants properly and safely over time.

Frequently Asked Questions

What is the difference between fire engineering and fire risk assessment?

A fire risk assessment reviews an existing building and its management. Fire engineering designs or justifies fire safety measures, usually for new work, alterations, change of use or complex existing building problems.

Is TGD B mandatory?

TGD B is guidance, not the regulation itself. Following it is evidence of compliance with Part B, but an alternative approach can be used where compliance with Part B is demonstrated in another way.

When do I need a fire engineering report?

You may need one where a project departs from TGD B, involves a complex building, relies on smoke control or compensatory measures, changes use, or raises questions that cannot be answered by prescriptive guidance alone.

Do existing buildings need fire engineering?

Sometimes. Routine occupied-building reviews usually need a fire risk assessment. Fire engineering may be needed where the solution involves design judgement, complex compartmentation, smoke control, structural fire resistance or a non-standard evacuation strategy.

Do nursing homes need fire engineering input?

Many nursing homes benefit from fire engineering input, particularly during design, extension, refurbishment, change of use or remediation of fire safety deficiencies. The need depends on the building and the evacuation strategy.

Contact Us

For fire engineering consultancy, fire risk assessment or healthcare fire safety support, contact Phoenix STS on 043 334 9611 or visit our contact page.

This article is for general information only and is not legal or professional advice. Fire engineering requirements should be assessed for the specific building, project, fire strategy and approval route by a competent person.