Scope point 01
The question is fixed first
The report states the design question and the acceptance criteria before any scenario is run, so the output answers a decision rather than filling a folder.
← ServicesFIRE & SMOKE MODELLING · UK
Fire and Smoke Modelling for UK Buildings
Quantified evidence for the design question prescriptive guidance cannot answer.
Scoped
written quotation against a defined modelling question
Documented
inputs, assumptions and limitations recorded
Sensitivity
agreed scenario and sensitivity cases, not a single run
What fire and smoke modelling is, and when it helps
Computational modelling is used when a fire-safety design question cannot be answered clearly by following prescriptive guidance alone. Typical questions concern how smoke moves through a large or connected volume, how long conditions on an escape route remain tenable, whether a smoke-control arrangement performs as intended, and how long occupants realistically take to leave.
A performance-based analysis is carried out within an agreed framework: the question and acceptance criteria are defined first, the design fires and scenarios are justified, the geometry and boundary conditions are built from the information supplied, and sensitivity cases test whether the conclusion survives reasonable changes in assumption. In the UK, performance-based design is commonly framed using BS 7974 and its published documents, with BS 9999 or BS 9991 used where a project follows those routes. These are British Standards and guidance, not legislation.
Modelling supports an argument; it does not replace one. The value of a model depends on whether its inputs are justified and its limitations are stated. Where the information needed to justify an input has not been supplied, that gap is recorded as a limitation rather than assumed.
When this service is useful
Modelling is most useful while the design can still change and before a reviewer's comment becomes a redesign.
Computational modelling of smoke movement, tenability and occupant evacuation for a specific building and a specific design question, delivered as a written technical report with the inputs, assumptions, sensitivity cases and limitations recorded. It supports design development and regulatory review; it does not grant or guarantee approval.
Primary outcome
A written modelling report that states the question, the scenarios examined, the results obtained and the limits of what the results support.
Atria, basements, large-volume or connected spaces
Extended travel distances or a non-standard escape strategy
A decision between natural and mechanical smoke ventilation
A reviewer or approval body has asked for quantitative evidence
A smoke-control or sprinkler interface is being value-engineered
An occupant evacuation assumption needs testing rather than asserting
What you receive
Clear outputs you can act on.
Typical outputs for this service are listed below. The exact format — report, review notes, survey record or technical position — is confirmed in the agreed appointment, and each records the information supplied, the assumptions used and the limitations that apply.
Defined modelling question and acceptance criteria
Scenario matrix with design-fire and ventilation rationale
Computational geometry and boundary-condition record
Smoke, temperature, visibility and tenability outputs
Available and required safe escape time comparison where in scope
Evacuation modelling interface where separately scoped
Written technical report with assumptions and limitations stated
How we scope and coordinate the work
The service is defined before the fee is quoted.
The scope is set from the building facts, drawings, jurisdiction, project stage and the question the written output needs to answer.
Scope point 02
Assumption ledger
Inputs, boundary conditions, design fires and limitations are written down explicitly so the analysis can be reviewed and defended.
Scope point 03
Sensitivity before conclusion
Agreed sensitivity cases test whether the conclusion holds under reasonable changes of assumption instead of resting on a single favourable run.
From enquiry to written report
A clear sequence from information request to issued output.
Every stage records what has been supplied, what remains open and what the report can and cannot conclude.
01
Question framing
We define, in writing, what the modelling must demonstrate and which design or review decision it supports.
02
Scenario matrix
We agree credible fire locations, growth assumptions, ventilation states and occupant assumptions with their rationale.
03
Model build
We build geometry, boundary conditions and outputs from the supplied information and record every assumption made.
04
Simulation and sensitivity
We run the agreed core and sensitivity cases and check outputs for consistency and anomalies.
05
Reported conclusion
We translate the outputs into a written conclusion, stating what the results support and where they stop.
How the evidence becomes a written output
A simplified view of the sequence described above. The actual steps, inputs and outputs are confirmed in the written scope for your project.
Recorded basis
A scoped, documented modelling process
The design question, acceptance criteria, scenarios and information supplied are recorded in writing before a fee is quoted.
Question and acceptance criteria agreed first
Design-fire and ventilation assumptions justified in the report
Sensitivity cases agreed rather than added afterwards
Result
The output records the scenarios examined, the results obtained from the information supplied, and the limitations that bound them. Approval and regulatory determination remain with the relevant authorities.
Related project records
Explore the scope recorded for each project.
Prepare your project brief
What we need from you to scope the work.
Fire and Smoke Modelling for UK Buildings
Use this as a checklist before you ask for a quotation. Tick what you hold; unknown items can be listed as unknown. Nothing here is saved.
Scope boundaries
What this service does not include.
- Modelling supports a design argument; it is not a building-control or Building Safety Regulator approval and does not guarantee approval.
- The modelling approach, software and mesh strategy are confirmed per project in the written scope; no specific tool is promised in advance.
- Results are only valid for the geometry, scenarios and assumptions recorded in the report.
- Where the information needed to justify an input is not supplied, it is recorded as a limitation, not assumed.
- A modelling report is not a fire risk assessment, a fire strategy, a fire-door inspection or an installation certificate unless separately scoped.
- Structural fire analysis, evacuation modelling and external fire spread work are included only where separately scoped.
- Fees and programme are confirmed in a written quotation after the modelling question and scope are agreed.
Suitable scope examples
Buildings and uses this service scope suits.
These are examples of building types, uses and project contexts for which this service scope is suitable. They are scope examples, not a client list or a record of completed instructions.
- Atria and multi-storey connected volumes
- Basements and below-ground occupied space
- Large retail, leisure and assembly spaces
- Transport and interchange environments
- Industrial and warehouse volumes
- Mixed-use developments with shared escape routes
- Refurbishments where prescriptive guidance cannot be met directly
Client needs
How this service supports project and building teams.
- Architects
- Quantified evidence for a defined design question where prescriptive guidance does not resolve the issue.
- Developers
- A documented analysis that supports an informed design decision without promising approval or savings.
- Building engineers and surveyors
- Transparent scenarios, assumptions and sensitivity results for technical coordination and review.
Questions about this service
Is modelling always required?
No. It is most useful when prescriptive guidance cannot answer the design question clearly, or when a reviewer has asked for quantitative evidence. Where prescriptive guidance answers the question, modelling adds cost without adding certainty.
Which software do you use?
The modelling approach and software are confirmed for each project in the written scope, based on the question being answered, and are stated in the report alongside the version used.
What makes a modelling report credible?
A clearly stated question, justified inputs, agreed sensitivity cases, transparent limitations, and conclusions tied directly to the decision the report supports.
Can modelling reduce cost?
It can, where evidence shows a simpler or better-targeted arrangement still meets the agreed criteria. It can also show the opposite. No saving is promised in advance.
Does a model guarantee approval?
No. Building control, the Building Safety Regulator or the relevant approval body decides the outcome. The report provides evidence for that decision; it does not make it.
Request a written scope
Send the drawings and the design question. We will scope the modelling.
Provide the drawings, the building use, the jurisdiction, the project stage and the specific question or reviewer comment the modelling must address. We will respond with the scope required for a written quotation.
Related services
Other scoped services often considered with Fire & Smoke Modelling.
Use these links when the building question also involves design strategy, operational risk, regulatory route mapping or evidence coordination.
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Fire strategy reports for new builds, refurbishments and changes of use across the UK. Send drawings and project details for a scoped quotation.
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Fire-safety regulatory route mapping for UK projects: applicable duties, evidence gaps and dutyholder responsibilities. Send the project details for a scoped review.
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Risk Assessment
Fire risk assessments for commercial, residential and mixed-use buildings in London and across the UK. Send the building details for a scoped quotation.
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