Natural ventilation calculation report
A natural ventilation report records the design intent, required airflow, proposed air paths, opening assumptions, control strategy, calculation or simulation method, constraints and evidence that the strategy can work in use.
A natural ventilation report records the design intent, required airflow, proposed air paths, opening assumptions, control strategy, calculation or simulation method, constraints and evidence that the strategy can work in use.
What this report needs to prove.
The page targets “natural ventilation report” while keeping the report-template query on its own page.
Not one opening-area sum
A useful report connects air-quality and heat-removal requirements to openings, pressure drivers, internal flow paths, controls and real site constraints.
Design stage matters
Early reports may test feasibility and strategy. Later issues should record coordinated free areas, actuator logic, acoustic limits, weather protection and commissioning requirements.
Thermal comfort link
Natural ventilation performance should be reviewed alongside overheating, internal gains and thermal modelling rather than treated as an isolated airflow calculation.
How to prepare the assessment and report.
Use controlled source information, keep each modelling decision traceable and obtain competent-person review before issue.
Define the ventilation purpose
Separate fresh-air, purge, heat-removal and night-cooling requirements for each space and operating mode.
Map the airflow paths
Record inlets, outlets, transfer paths, opening heights, free areas, obstructions and the intended single-sided, cross-flow or stack strategy.
Choose the design method
Use an appropriate envelope-flow model, dynamic thermal model, CFD study or staged combination for the project risk and design stage.
Test constraints and controls
Include noise, security, rain, pollution, wind, occupant access, fire strategy, actuators, sensors and fallback modes.
Document verification
Set out commissioning tests, control checks, seasonal tuning, handover information and post-occupancy review.
Information to gather before you start.
Missing inputs should remain visible as review items. They should not be replaced with convenient assumptions without approval.
| Input group | Source information | Why it matters |
|---|---|---|
| Room requirements | Occupancy, fresh-air rates, extract needs, heat gains and operating hours | Defines required airflow |
| Opening schedule | Type, dimensions, aerodynamic free area, height, location and control | Defines available airflow paths |
| Building context | Façade exposure, wind, stack height, internal doors and obstructions | Defines pressure drivers and resistance |
| External constraints | Noise, air quality, security, rain, insects and local microclimate | Tests whether openings are usable |
| Control sequence | Temperature, CO2, weather and user overrides with safe states | Defines real operation |
| Model and test outputs | Airflow, temperature, comfort, sensitivity and commissioning evidence | Supports the report conclusion |
What the issued report should contain.
Use the separate template page when the search task is to find the report layout rather than understand the assessment.
| Section | Required coverage |
|---|---|
| Executive summary | Ventilation concept, design duties, governing constraints and key actions. |
| Design criteria | Air quality, comfort, purge, heat-removal, occupancy and operating requirements. |
| System and airflow paths | Opening types, locations, free areas, transfer routes, zones and operating modes. |
| Calculation and modelling method | Pressure assumptions, weather, envelope-flow or simulation method, inputs, cases and QA. |
| Results and constraints | Room duties, achieved airflows, temperature results, acoustic and security limits, and sensitivity findings. |
| Controls, commissioning and risk | Sequences, fail-safe states, test requirements, seasonal tuning, user information and residual risks. |
Standards and guidance to check.
The project team must confirm the current edition, jurisdiction, contractual requirements and authorised access to each publication.
- CIBSE AM10 Natural Ventilation in Non-Domestic Buildings (2026)The current manual covers strategy, components, controls, design tools, envelope-flow methods and worked examples.
- CIBSE AM11 Building Performance ModellingAM11 covers quality assurance and appropriate modelling approaches for ventilation and thermal performance.
Prepare the report in Adelphos Chat.
Collect the inputs, identify missing evidence and build the report structure now. Report Studio templates are being prepared for release.
Natural ventilation calculation report questions
What should a natural ventilation report include?
It should include the design criteria, airflow paths, opening data, calculation or simulation method, controls, constraints, results, commissioning plan and residual risks.
Is natural ventilation calculated using ACH?
Air changes per hour can be one design expression, but a complete strategy also needs source requirements, pressure drivers, opening characteristics, controls and use conditions.
When is dynamic thermal modelling needed?
It is commonly used where thermal comfort, overheating, controls, night cooling or time-varying weather materially affect the design decision. The design team should choose a method proportionate to risk.
Can Adelphos size openings automatically?
Adelphos can help structure declared inputs and calculation evidence. The engineer remains responsible for the chosen method, opening data, constraints and coordinated design.
Continue with the evidence.
Move between the technical guide, the report structure and the calculation tools without mixing their search intent.
Adelphos structures declared evidence and report content. A competent person remains responsible for the model, calculations, standards, assumptions, interpretation, coordination and issued conclusion.