Fire and Explosion Risk Assessment (FERA): Engineering-Grade Consultancy for High-Hazard Facilities

iFluids Engineering delivers fire and explosion risk assessment (FERA) studies for oil and gas, petrochemical, and LNG facilities across the Middle East and South Asia, using DNV PHAST and SAFETI software to produce regulator-ready, consequence-modelled risk reports aligned with IP 15, FERA-211, and API 752/753 standards.

When a hydrocarbon release finds an ignition source, the outcome is not theoretical. It is a jet fire, a vapour cloud explosion, or a pool fire with measurable thermal radiation contours and blast overpressure loads. A fire and explosion risk assessment tells you exactly what those outcomes look like, which assets and personnel are in the hazard zone, and what engineering controls will reduce that risk to ALARP. That is the engineering work. Not a checklist exercise.

At iFluids Engineering, we conduct FERA studies for offshore platforms, onshore refineries, LNG terminals, and petrochemical plants across the Middle East, South Asia, and Southeast Asia. Our studies are built on DNV PHAST and SAFETI consequence modelling, structured against IP 15 and FERA-211 requirements, and delivered as traceable, audit-ready technical documents.

If your project is at FEED, detailed design, or heading into a brownfield modification, this is where the FERA conversation starts.

What Is a Fire and Explosion Risk Assessment?

A fire and explosion risk assessment (FERA) is a structured engineering study that identifies credible fire and explosion hazard scenarios at a facility, quantifies their consequences using consequence modelling software, evaluates risk levels against acceptance criteria, and recommends mitigation measures to reduce risk to ALARP. It is a core input to facility layout, passive and active fire protection design, and regulatory safety cases.

A FERA is not a standalone document. It sits within a broader process safety framework and feeds directly into your Quantitative Risk Assessment (QRA), Escape and Evacuation Risk Assessment (EERA), Temporary Refuge Impact Assessment (TRIA), and Building Risk Assessment (BRA). Get the FERA wrong and every downstream study is built on a compromised foundation.

The study scope covers all credible loss of containment scenarios from process equipment carrying flammable inventory. Releases are modelled across multiple hole sizes. Jet fires, pool fires, flash fires, and vapour cloud explosions (VCEs) are each treated as distinct scenario types with their own consequence profiles. The output is a risk picture: which scenarios are credible, how severe, and how frequently they could occur.

This is not generic safety consulting. It is applied consequence engineering.

FERA vs. Quantitative Risk Assessment: Understanding the Scope

Engineers sometimes use FERA and QRA interchangeably. They are not the same study. A fire and explosion risk assessment focuses specifically on fire and explosion hazard scenarios, characterising consequence severity and spatial extent. A QRA aggregates risk from all major accident hazard sources, including toxic releases, and calculates individual and societal risk metrics against regulatory tolerability criteria.

In practice, a FERA is typically conducted first. Its consequence outputs, thermal radiation zones, overpressure contours, and fire frequency estimates feed directly into the QRA as input data. Conducting both studies under one scope, with a single consistent assumption register, is the most efficient and technically defensible approach.

FERA Purpose

The primary purposes of a FERA study are as follows:

• Identify the fire and explosion hazards on the facility that may pose a risk to personnel, effect the facility equipment and may escalate to other parts of the facility
• Quantification of fire and explosion risks arising from loss of containment
• To determine the acceptability of the calculated fire and explosion risk at the facilities and identification of the key fire and explosion risk contributors. Risk contributors needs to be identified by the source and location
• Assess the benefit of existing and possible inherently safe, prevention, detection, control and mitigation measures for identified fire and explosion scenarios
• Comparing fire and explosion risks of the design options being considered. This helps identifying design options with low risk, and selecting the option which is best from a risk
• For a Brownfield project the purpose of the FERA is to assess the new fire and explosion risks due to plant modification and to arrive at the cumulative risk of the new and existing facilities. In such a project the risk from the new facilities will not be assessed separately, it will be assessed in relation to the existing risk at the facility, and in particular the process facilities adjoining to the new facilities
• To provide clear and unambiguous recommendations for risk reduction where necessary, to ensure that the facilities fire and explosion risks are controlled within acceptable limits.

FERA PROCESS

The FERA Process flowchart is used as a framework for this guideline and to serve as a basis for the minimum requirement for a FERA study undertaken by a FERA specialist.

The FERA process essentially consists of

• Identification of events which could cause fires or explosions
• Analysis of frequencies of these events based on generic failure data
• Modelling of event consequences, in terms of fire size, explosion damage, and subsequent escalation
• Recommending suitable means of preventing, detecting, controlling and mitigating fire and explosion events.

The FERA Methodology: How iFluids Structures Every Fire and Explosion Risk Assessment Study

iFluids Engineering executes fire and explosion risk assessment studies in five structured phases: hazard identification, consequence modelling using DNV PHAST and SAFETI, frequency estimation from recognised failure rate databases, risk evaluation against client and regulatory acceptance criteria, and formal reporting with mitigation recommendations. Every assumption is logged in a traceable assumption register.

Our methodology is sequential and fully traceable. Each phase produces documented outputs that become inputs to the next. There are no black boxes in how we arrive at a risk number.

Phase 1: Hazard Identification

We identify all process equipment carrying flammable or hazardous inventory. Release scenarios are developed using a structured failure case methodology, covering representative hole sizes from small leaks to full-bore ruptures. Isolation system performance is factored into release duration and inventory estimation.

Phase 2: Consequence Modelling 

We run all credible release scenarios through DNV PHAST software. Jet fire, pool fire, flash fire, and VCE scenarios are modelled under site-representative weather conditions. Outputs include thermal radiation contours at 4, 8, 12.5, and 37.5 kW/m² and overpressure contours at 0.02, 0.05, 0.1, and 0.3 barg. Every scenario is mapped spatially against the facility plot plan.

Phase 3: Frequency Estimation

Release frequencies are drawn from recognised industry databases including OGP/IOGP Risk Assessment Data Directory and OREDA. Ignition probabilities are applied based on release location, inventory properties, and site-specific ignition source density.

Phase 4: Risk Evaluation

Individual scenario risks are calculated and plotted against the client’s or regulator’s risk acceptance criteria. We explicitly assess whether risk is tolerable, ALARP, or requires further reduction. Risk ranking matrices and F-N curve outputs are provided where required by the scope.

Phase 5: Reporting and Recommendations

The final FERA report documents all scenarios, assumptions, modelling inputs, results, and risk reduction recommendations in a format that is traceable, repeatable, and auditable. Recommendations are ranked by risk reduction potential and implementation feasibility.

Consequence Modelling and Blast Overpressure Analysis

Consequence modelling is the technical spine of any fire and explosion risk assessment. For explosion scenarios, blast overpressure analysis determines the peak overpressure and impulse loads generated by a vapour cloud explosion, which directly governs the structural design requirements for blast-resistant buildings, control rooms, and occupied modules.

We use PHAST for near-field and mid-field consequence calculations. For confined or semi-confined geometries where congestion significantly affects flame acceleration, a more rigorous CFD-based approach using tools such as FLACS may be warranted. We advise on tool selection based on the specific geometry and regulatory expectation, not on what is cheapest to run.

Blast overpressure results are presented as exceedance frequency curves, showing the probability of exceeding a given overpressure level at a defined location. These are the direct inputs to structural vulnerability assessments and building risk calculations under API 752 and API 753.

Greenfield vs. Brownfield FERA: Scope Differences That Matter

The scope and objective of a fire and explosion risk assessment differ materially between greenfield and brownfield projects. Understanding this difference upfront prevents scope gaps that create problems during regulatory review.

For a greenfield project, the FERA evaluates design options during FEED and detailed engineering. The primary output is design guidance: optimal equipment spacing, passive fire protection requirements, fire and gas detection coverage, and active suppression system specifications. Risk contours are used to validate facility layout before construction is committed.

For a brownfield project, the FERA assesses the risk impact of a proposed plant modification against the existing risk baseline at the facility. The new risk is not evaluated in isolation. It is evaluated in the context of the cumulative risk profile of the adjacent existing plant. This is a more complex analysis and requires careful scoping of the existing facility boundaries and the interfaces between old and new systems.

One of the most common brownfield FERA mistakes we see is assessing the new modification as if it were a standalone greenfield unit. Regulators and operators who understand the methodology will immediately identify this as a scope failure. The modification risk must always be assessed against the existing facility risk baseline. If your FERA consultant does not raise this distinction upfront, that is a signal worth noting.

FERA Methodology

The FERA considers accidental releases from equipment’s carrying flammable & hazardous inventory. Normal design operation of the isolation system is assumed when determining the duration and characteristics of releases. Dust release rates and durations shall calculate based on normal operating pressures and process conditions.

The consequence analysis determines the size and duration of releases and predicts hazard zones for releases in terms of radiant heat. FERA evaluates the adequacy of fire protection system and recommends risk reduction measures based on the consequence results.

FERA Compliance and Standards: IP 15, FERA-211, and API 752/753

Fire and explosion risk assessment studies in the oil and gas industry are governed by IP Model Code of Safe Practice Part 15 (IP 15), Energy Institute FERA-211 guidance, API RP 752 and 753 for occupied building risk, and NFPA codes for specific facility types. Offshore facilities in UK-regulated waters additionally require compliance with the PFEER regulations and the Safety Case Regulations.

iFluids Engineering aligns every FERA study with the applicable regulatory and industry standard framework from the outset of scoping. The choice of acceptance criteria, consequence modelling methodology, and risk evaluation approach are all standard-dependent decisions. Getting this right at the start avoids costly rework when the report reaches regulatory review.

The key standards governing our fire and explosion risk assessment methodology are:

IP 15 (Energy Institute Model Code of Safe Practice Part 15): The primary industry reference for fire and explosion hazard management in the petroleum industry. Governs hazardous area classification, ignition source control, and risk assessment methodology.

FERA-211 (Energy Institute Guidance): Specific guidance on the conduct of fire and explosion risk assessments, covering scope definition, consequence modelling requirements, frequency estimation, and risk evaluation criteria. Our FERA study structure directly maps to FERA-211 requirements.

API RP 752 and 753: Risk-based approach to evaluating occupied building siting in process plant environments. FERA blast overpressure outputs feed directly into API 752/753 building risk calculations.

NFPA Codes: NFPA 30 for flammable and combustible liquids, NFPA 59A for LNG facilities, and NFPA 72 for fire alarm systems where applicable to the facility type.

OISD Guidelines (India): For Indian refinery, pipeline, and terminal projects, OISD standards govern fire safety assessment methodology and are incorporated into our study framework for Indian clients.

FERA-211 requires that the assumption register be formally issued as part of the study deliverables, not treated as internal working documentation. If your existing FERA report does not include a standalone assumption register, the study may not be fully compliant with current Energy Institute guidance. This matters during regulatory audits and insurance reviews.

Industries and Facilities We Assess

iFluids Engineering conducts fire and explosion risk assessments for offshore oil and gas platforms, FPSOs, onshore refineries, LNG import and export terminals, petrochemical plants, gas processing facilities, and pipeline infrastructure across the Middle East, India, Southeast Asia, and North Africa. Our consultants have delivered FERA studies for major operators including projects at Ras Laffan Industrial City in Qatar.

We work where the process hazard is greatest. Our client base spans national oil companies, international operators, and EPC contractors who need a FERA that stands up to regulatory scrutiny and genuinely informs engineering decisions.

Offshore Platforms and FPSOs

Offshore fire and explosion risk assessment presents the most demanding technical environment. Congested topsides geometry, limited escape routes, high-pressure hydrocarbon inventories, and the proximity of the Temporary Refuge to process areas all combine to make the consequence modelling and risk evaluation highly site-specific.

We model jet fire and VCE scenarios against the actual topsides geometry, assess blast loads on the TR and safety-critical equipment supports, and produce outputs that feed directly into EERA and TRIA studies. Our offshore FERA work covers fixed steel platforms, jack-ups, semi-submersibles, and FPSOs.

Onshore Refineries, LNG Terminals, and Petrochemical Plants

Onshore facility fire and explosion risk assessment involves larger plot areas, more complex dispersion behaviour due to atmospheric effects and terrain, and typically a wider range of inventory types including LNG, hydrogen, and high-vapour-pressure liquids.

For LNG terminals, our FERA scope covers cryogenic spill scenarios, rollover events, and rapid phase transition in addition to standard vapour cloud and jet fire scenarios. For refineries, we address distillation unit fire scenarios, crude tank farm pool fire events, and hydrogen unit explosion risk. Each facility type brings distinct hazard profiles that require specific modelling approaches, not a generic template.

Our blast analysis consultancy services across the GCC region, including Bahrain, Oman, UAE, and Qatar, deliver site-specific consequence modelling that accounts for local regulatory requirements and operator risk acceptance criteria.

FERA Study Deliverables: What You Receive from iFluids

A completed iFluids fire and explosion risk assessment study delivers a formal FERA report including: a scoping document, hazard identification register, consequence modelling results with spatial contour maps, frequency estimation worksheets, risk evaluation outputs, a traceable assumption register, and a prioritised risk reduction recommendation schedule. All deliverables are formatted for regulatory submission.

We do not deliver a report and step back. The deliverable package is structured so that your engineering team, HSE manager, and regulator can each find exactly what they need without needing to call us to explain the methodology.

The standard iFluids FERA deliverable package includes:

Study Scope Document: Confirms facility boundaries, scenario selection criteria, modelling tool selection rationale, applicable standards, and acceptance criteria. Issued for client approval before modelling begins.

Hazard Identification Register: Full inventory of credible release scenarios, equipment items, hole size selections, inventory data, and isolation assumptions.

Consequence Modelling Results: Scenario-by-scenario output tables and spatial contour maps for thermal radiation and overpressure, plotted against the facility layout. Generated using DNV PHAST and SAFETI.

Frequency Estimation Worksheets: Release frequency data, ignition probability assignments, and event tree outputs for each scenario category.

Risk Evaluation Summary: Scenario risk rankings, individual risk contours where required, F-N curves for societal risk where required, and explicit ALARP demonstration.

Assumption Register: Formal, numbered register of all key assumptions made during the study. Issued as a standalone deliverable per FERA-211 requirements.

Risk Reduction Recommendation Schedule: Ranked recommendations with technical basis, risk reduction rationale, and indicative implementation priority. Not a generic list: each recommendation is tied to a specific scenario and consequence result.

Typical FERA study duration for a medium-complexity onshore facility runs eight to sixteen weeks from data receipt to final report issue, depending on the number of release scenarios, the complexity of the consequence modelling, and client review cycles.

Work With iFluids Engineering on Your Next FERA Study

A fire and explosion risk assessment is an engineering commitment, not a compliance formality. The quality of the consequence modelling, the rigour of the frequency estimation, and the traceability of the assumption register determine whether the study genuinely reduces risk or simply produces a document that sits on a shelf until the next audit.

iFluids Engineering has conducted fire and explosion risk assessment studies across Qatar, UAE, India, Oman, Bahrain, and Southeast Asia. Our team works across the full scope of process safety studies, and we structure FERA consultancy engagements so that your study integrates cleanly with your QRA, EERA, and TRIA work, whether we are conducting those studies or another team is.

If your project requires a FERA scope review, a study for regulatory submission, or a revalidation of an existing report, contact our process safety team to discuss scope and timeline