Fire safety in buildings involves two broad disciplines that are often confused. Fire risk assessment examines an existing building and its management to identify hazards and evaluate risk. Fire engineering applies scientific and engineering principles to design fire safety into a building - whether at the design stage, during a major alteration, or when an existing building presents problems that standard guidance cannot resolve. Both are important. They are not the same thing, and knowing when you need one rather than the other can save significant time, cost, and frustration.

This article explains what fire engineering is, when an Irish building project or building problem requires a fire engineer, the regulatory framework that governs fire safety design in Ireland, and what qualifications to look for when appointing a fire engineering consultant.

What Fire Engineering Actually Is

Fire engineering is the application of science and engineering to the protection of people, property, and the environment from fire. It draws on physics, chemistry, fluid dynamics, heat transfer, structural engineering, human behaviour, and risk analysis to solve fire safety problems.

In practical terms, a fire engineer analyses how fire behaves in a specific building - how it starts, how it grows, how smoke and heat move through the structure, how long structural elements resist the effects of fire, how people respond and evacuate, and how fire service intervention affects the outcome. Based on that analysis, the fire engineer designs fire safety measures that achieve an acceptable level of safety.

This is different from simply applying the rules in a guidance document. Prescriptive guidance - such as Technical Guidance Document B (TGD-B) - provides standard solutions for standard buildings. Follow the guidance and you have a deemed-to-satisfy solution. But not every building is standard, and not every fire safety problem has a prescriptive answer.

Fire engineering comes into its own where prescriptive guidance does not fit. Large open-plan spaces, atria, complex building geometries, mixed-use developments, buildings with unusual structural systems, heritage buildings where interventions are constrained by conservation requirements, and healthcare buildings where occupants cannot evacuate unaided - these are all situations where fire engineering analysis provides solutions that prescriptive guidance alone cannot.

The Regulatory Framework - Building Control Act 1990 and TGD-B

The Building Control Act 1990 is the primary legislation governing the design and construction of buildings in Ireland. Under the Act and the associated Building Regulations, all buildings must be designed and constructed so that, in the event of fire, the stability of the building is maintained for a reasonable period, the spread of fire within the building and to other buildings is inhibited, there are adequate means of escape, and there are adequate access and facilities for the fire service.

Part B of the Building Regulations deals specifically with fire safety. The Technical Guidance Document B, updated in 2024 (TGD-B 2024), provides guidance on how to satisfy Part B. TGD-B is guidance, not law. It describes approaches that, if followed, will be regarded as evidence of compliance with the Building Regulations. But it is not the only route to compliance.

This distinction matters because TGD-B 2024, like its predecessors, takes a prescriptive approach. It sets out specific requirements for fire resistance periods, compartment sizes, travel distances, escape route widths, fire detection, emergency lighting, and so on. These prescriptive solutions work well for straightforward buildings - a standard office block, a residential development, a single-storey industrial unit. They become problematic for buildings that do not fit the standard patterns.

The alternative is a performance-based approach, which is where fire engineering enters the picture. Instead of applying prescriptive rules, the fire engineer defines the performance objectives (typically life safety, property protection, and environmental protection), establishes acceptance criteria, analyses the fire scenarios that could occur in the specific building, and demonstrates that the proposed design meets the performance objectives. This approach is explicitly recognised in TGD-B and in the Building Regulations themselves.

A fire safety certificate is required under the Building Control Act 1990 for most buildings before construction begins or before a material change of use takes place. The application to the local authority must demonstrate that the building will comply with Part B of the Building Regulations. Where a fire engineering approach is used, the fire safety certificate application must include the fire engineering analysis and report. The local authority's fire officer will review this as part of the certification process.

For a broader understanding of fire risk assessment in existing buildings, see our [complete guide to fire risk assessment in Ireland](/posts/fire-risk-assessment-ireland-complete-guide-2026).

When You Need a Fire Engineer Rather Than a Fire Risk Assessor

The distinction between a fire risk assessor and a fire engineer is not about seniority or expertise level. It is about the nature of the work.

A [fire risk assessment](/fire-risk-assessment-ireland) evaluates an existing building in its current state. The assessor identifies fire hazards, evaluates the risk to occupants, and recommends measures to reduce that risk. The assessment is based on the building as it is - its construction, its layout, its fire safety systems, its management, and its use. Fire risk assessors work to standards such as PAS 79-1:2020, which provides a framework for the assessment process. This is essential ongoing work for any occupied building.

A fire engineer works at the design level. They are involved when the building itself is being designed or modified, when the fire safety strategy needs to be developed from first principles, or when the existing building presents a problem that requires an engineering solution.

You need a fire engineer in the following situations.

New construction is the most common trigger. Any building that goes beyond the standard solutions in TGD-B 2024 will benefit from fire engineering input. For complex buildings - healthcare facilities, large commercial developments, high-rise residential, mixed-use schemes, buildings with atria or large open spaces - fire engineering is not optional. It is the only way to develop a fire safety strategy that works for the specific building.

Change of use is another frequent trigger. Converting a warehouse to apartments, a church to a restaurant, or an office to a nursing home changes the fire safety requirements fundamentally. The existing structure may not meet the prescriptive requirements for the new use. A fire engineer can assess the existing building, identify the gaps, and design solutions that achieve compliance without requiring demolition and reconstruction.

Departures from TGD-B arise regularly on building projects. The architect designs a building with travel distances that exceed the prescriptive limit, or with a compartment that is larger than TGD-B permits, or with a structural system that does not have a standard fire resistance rating. In each case, a fire engineer can analyse the specific situation and demonstrate that the proposed design achieves the required level of safety through alternative means - additional detection, sprinkler protection, smoke ventilation, or other compensatory measures.

Fire safety certificate applications require a demonstration of compliance with Part B. For straightforward buildings, this can be shown by reference to TGD-B. For anything complex, the local authority will expect a fire engineering report. Some local authorities will specifically request fire engineering analysis where the building type or the departure from guidance warrants it.

Disabled access certificates interact with fire safety where the design must accommodate the evacuation of people with disabilities. Fire engineering input is needed to develop an evacuation strategy that works for all building users, including the design of refuges, evacuation lifts, communication systems, and management procedures.

Existing buildings with fire safety deficiencies sometimes present problems that cannot be resolved by standard measures. A fire engineer can assess the building, quantify the actual risk, and design a proportionate solution. This is particularly relevant for buildings where retrospective compliance with current standards would be physically or economically impractical.

Fire Engineering in Healthcare Settings

Healthcare buildings present some of the most demanding fire safety challenges. Nursing homes, hospitals, and residential care facilities house occupants who may be unable to evacuate without assistance, who may be bedridden, who may have cognitive impairments, or who may be dependent on medical equipment. The standard evacuation model - alert, evacuate, assemble - does not work in these buildings. Instead, healthcare buildings rely on a defend-in-place strategy, where occupants are protected in situ and evacuated progressively only if necessary.

Making this strategy work requires careful fire engineering. The building must be divided into fire compartments that contain a fire long enough for staff to manage the situation. Sub-compartments within each storey allow horizontal evacuation - moving residents to a place of relative safety on the same floor without needing to use stairs. The compartment walls, floors, and doors must achieve the required fire resistance. Fire detection must be early and reliable, with appropriate integration with building management systems. Smoke ventilation or control may be needed to maintain tenable conditions during progressive evacuation.

For nursing homes in Ireland, compliance with HIQA standards adds another layer. Regulation 28 of S.I. 415/2013, as amended by S.I. 1/2025, requires adequate precautions against the risk of fire. HIQA inspectors assess the physical fire safety measures in the building as well as the management systems - training, fire drills, documentation. Where a nursing home has fire safety design deficiencies, a fire engineer can assess the building and develop a proportionate remediation strategy. Our [nursing home fire safety compliance service](/nursing-home-fire-safety-compliance) and [healthcare fire safety consultancy](/healthcare-fire-safety-consultancy) work alongside our fire engineering team to address these specific challenges.

The fire alarm system in a healthcare building must comply with IS 3218:2024, which sets out requirements for fire detection and alarm systems in Ireland. The system design in a healthcare setting is more complex than in a standard commercial building - it must accommodate staged alarm sequences, staff alert systems, and integration with other building systems. Our [IS 3218 fire alarm audit service](/is-3218-fire-alarm-audits) can assess whether your existing system meets the current standard. You can also read about the changes in the latest standard in our article on [what changed in IS 3218:2024](/posts/is-3218-2024-whats-changed-fire-detection-alarm-standard).

Emergency lighting must comply with IS 3217:2023 and is assessed as part of the fire engineering strategy. Our [IS 3217 emergency lighting assessment service](/is-3217-emergency-lighting-assessments) covers testing and compliance verification.

Fire Engineering for Heritage Buildings

Ireland has thousands of buildings of architectural and historical significance that must comply with fire safety legislation while preserving their heritage value. Churches, courthouses, country houses, institutional buildings, commercial premises in historic town centres - all present the same fundamental tension between safety and conservation.

Prescriptive fire safety guidance is often incompatible with heritage buildings. TGD-B 2024 may require fire resistance upgrades that would destroy original plaster ceilings, historic joinery, or significant interior finishes. It may require compartmentation that conflicts with the architectural significance of open plan spaces. It may require fire doors in openings where the existing doors are of conservation value.

A fire engineer approaches these problems differently. Rather than applying prescriptive rules and accepting the conservation damage, the fire engineer assesses the actual fire risk in the specific building, considers the contribution of existing features to fire safety (thick masonry walls, for example, provide considerable fire resistance even without modern fire-rated linings), and designs a bespoke fire safety strategy that achieves an acceptable level of safety with minimum intervention.

This might involve enhanced fire detection rather than physical compartmentation, a sprinkler system designed to be visually unobtrusive, an active smoke ventilation system rather than passive smoke reservoirs, or a management-based approach with trained fire wardens and rigorous procedures. The fire engineer must quantify the effectiveness of these measures and demonstrate that the overall package achieves the required level of safety.

Fire engineering reports for heritage buildings often form part of planning applications as well as fire safety certificate applications, and the fire engineer may need to engage with both the local authority fire officer and the conservation officer.

The Prescriptive vs Performance-Based Debate

In practice, most fire safety designs in Ireland use a combination of prescriptive and performance-based approaches. The prescriptive elements of TGD-B 2024 are applied where they fit, and fire engineering analysis is used to address specific aspects where they do not.

A purely prescriptive approach works for simple, standard buildings. It is quick, well understood by all parties, and does not require specialist analysis. Its limitation is that it can be over-conservative for some situations and entirely inadequate for others. A standard office building fits the prescriptive framework well. A 12-storey mixed-use building with residential, retail, and commercial elements, a double-height entrance atrium, underground car parking, and a rooftop restaurant does not.

A purely performance-based approach starts from first principles for every aspect of fire safety. It is theoretically the most refined approach, but it is also the most expensive and time-consuming, and it requires a very high level of expertise from both the fire engineer and the reviewing authority. It is rarely used in its pure form in Ireland.

The pragmatic middle ground is to follow TGD-B where it applies, use fire engineering analysis for the aspects where it does not, and document the approach clearly in the fire safety certificate application. A good fire engineer knows when prescriptive guidance is sufficient and when engineering analysis adds genuine value. Performing complex fire modelling to justify a standard corridor width is a waste of time and money. Performing it to justify a non-standard atrium smoke ventilation strategy is essential.

Fire Door Inspections and Fire Engineering

Fire doors are a critical component of the compartmentation strategy that fire engineering relies upon. A fire compartment is only as effective as its weakest element, and fire doors are often that weak element - subject to damage, propping open, incorrect maintenance, or deterioration over time.

BS 8214:2026 provides the standard for fire door assemblies, covering selection, installation, maintenance, and management. Where a fire engineering strategy relies on specific fire resistance periods for compartment boundaries, the fire doors within those boundaries must achieve the corresponding fire resistance rating and must be maintained in a condition that preserves that rating.

Our [fire door inspection service](/fire-door-inspections-ireland) assesses fire doors against the applicable standards, identifies deficiencies, and provides a prioritised programme of remedial work. Where fire engineering analysis has been undertaken for a building, the fire door inspections should be informed by the fire engineering strategy - the doors in critical compartment boundaries receive the highest priority.

Qualifications - What to Look for in a Fire Engineer

Fire engineering in Ireland is not a regulated profession in the sense that anyone can call themselves a fire engineer. However, the complexity of the work means that qualifications and experience matter enormously.

A BEng in Fire Engineering or equivalent degree provides the technical foundation. This is a specialist degree programme that covers fire science, fire dynamics, structural fire engineering, human behaviour in fire, fire risk analysis, and fire safety design. It is distinct from a general engineering degree, though some fire engineers come from structural, mechanical, or building services engineering backgrounds and specialise through postgraduate study or professional development.

Chartered engineer status with Engineers Ireland demonstrates that the individual has met defined standards of education, training, and professional competence. While not a legal requirement, it is a mark of professional standing that local authorities and clients increasingly expect.

Membership of relevant professional bodies provides access to peer review and continuing professional development. In Ireland, Engineers Ireland is the primary body. Internationally, the Institution of Fire Engineers and the Society of Fire Protection Engineers are the main professional organisations.

Practical experience is at least as important as academic qualification. Fire engineering is an applied discipline, and the quality of fire engineering advice depends heavily on the engineer's experience of real buildings, real fire scenarios, and real construction processes. An engineer who has only performed theoretical analysis without site experience will miss practical issues that affect the viability of their designs.

Registration on the National Fire and Risk Assessment Register (NFRAR) is relevant for fire risk assessors in Ireland. For fire engineers specifically, the relevant credentials are the engineering qualifications and professional body memberships described above, but NFRAR registration indicates a commitment to professional standards in the broader fire safety field.

Phoenix STS provides [fire engineering consultancy](/fire-engineering-consultancy) through BEng-qualified engineers with practical experience across healthcare, commercial, and residential sectors. We are ISO 9001 and ISO 45001 dual certified and NFRAR registered. Our fire engineering work is informed by our hands-on experience of fire risk assessment, fire system design, and fire safety management in over 290 client organisations.

Whether your project is in [Dublin](/fire-safety-dublin), [Galway](/fire-safety-galway), or elsewhere in Ireland, our fire engineering team can advise on the approach that fits your building and your budget. Call 043 334 9611 or visit our [contact page](/contact-us) to discuss your project.

Frequently Asked Questions

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

A [fire risk assessment](/fire-risk-assessment-ireland) evaluates an existing building in its current state to identify hazards and assess risk to occupants. Fire engineering applies scientific and engineering principles to design fire safety measures for a building, typically at the design stage or during major alteration. A fire risk assessment tells you what the current risk is and how to manage it. Fire engineering designs the building to achieve a defined level of fire safety.

When is a fire engineering report required for a fire safety certificate?

A fire safety certificate application must demonstrate compliance with Part B of the Building Regulations. Where the building follows the prescriptive guidance in TGD-B 2024, a report referencing TGD-B may suffice. Where the building departs from TGD-B - through non-standard travel distances, compartment sizes, structural solutions, or other design aspects - a fire engineering report is needed to demonstrate that the proposed design achieves an equivalent or better level of safety.

Can a fire engineer help with an existing building that has fire safety problems?

Yes. Fire engineering is not limited to new construction. Where an existing building has fire safety deficiencies - for example, inadequate compartmentation, excessive travel distances, or non-compliant structural fire resistance - a fire engineer can assess the building, quantify the actual risk, and design proportionate solutions. This is particularly valuable for heritage buildings and healthcare facilities where full retrospective compliance with current prescriptive standards may not be practicable.

What qualifications should a fire engineer have?

A BEng in Fire Engineering or equivalent specialist degree is the standard academic qualification. Chartered engineer status with Engineers Ireland demonstrates professional competence. Practical experience in fire safety design and construction is essential. Membership of professional bodies such as the Institution of Fire Engineers or the Society of Fire Protection Engineers indicates ongoing professional development.

Is TGD-B 2024 mandatory?

TGD-B 2024 is guidance, not law. The Building Regulations (Part B) are the legal requirement. TGD-B provides one way of demonstrating compliance with Part B. A building can comply with Part B without following TGD-B, provided the designer can demonstrate through fire engineering analysis that the alternative approach achieves the required level of safety.

Do nursing homes need fire engineering input?

Most nursing homes benefit from fire engineering input, particularly at the design stage or when undergoing significant alteration. The defend-in-place evacuation strategy used in healthcare buildings requires carefully designed compartmentation, fire detection, smoke control, and evacuation procedures. A fire engineer ensures these elements work together as a coherent system. Where an existing nursing home has fire safety deficiencies identified by HIQA or through a fire risk assessment, a fire engineer can develop a remediation strategy.

How much does fire engineering consultancy cost?

The cost depends on the complexity and scale of the project. A fire engineering report for a straightforward change of use will cost significantly less than a full performance-based design for a complex multi-storey development. Phoenix STS provides fixed fee quotations for fire engineering work after an initial assessment of the project scope. Contact us on 043 334 9611 for a quotation.

What is the difference between prescriptive and performance-based fire safety design?

Prescriptive design follows the specific rules set out in TGD-B 2024 - defined fire resistance periods, maximum travel distances, minimum escape route widths, and so on. Performance-based design uses fire engineering analysis to demonstrate that a non-standard approach achieves an acceptable level of safety. Most real projects use a combination of both, applying prescriptive guidance where it fits and fire engineering analysis where it does not.

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