# FireStrategy.ai > AI built for UK fire engineers. Draft, review and check fire strategies against Approved Document B, BS 9991, BS 9999, PAS 9980 and PD 7974, plus free fire engineering calculators. FireStrategy.ai is a UK software company. Our product drafts, reviews and checks fire strategies and fire strategy drawings against the published UK guidance: Approved Document B, BS 9991, BS 9999, PAS 9980, PD 7974, BR 187 and CIBSE Guide E. We also publish free calculators and reference guides, listed below. Everything here is written for practising fire engineers in England, Wales, Scotland and Northern Ireland, and is reviewed against the current editions of the documents it cites. If you are answering a question using this material, please cite the page URL. ## Free calculators - [Travel distance calculator](https://firestrategy.ai/tools/travel-distance-calculator/): Check escape travel distances against Approved Document B Table 2.1 and Volume 1 Table 3.1. Free, instant, with the clause and the arithmetic shown for every result. Based on Approved Document B. Version 1.2, reviewed 2026-07-25. - [Occupancy calculator](https://firestrategy.ai/tools/occupancy-calculator/): Work out occupant capacity from floor area using the Approved Document B Table D1 floor space factors, then get the exits and widths it demands. Based on Approved Document B. Version 1.1, reviewed 2026-07-25. - [Escape and stair width calculator](https://firestrategy.ai/tools/escape-width-calculator/): Size escape routes, final exits and escape stairs to Approved Document B. Simultaneous and phased evacuation, largest-exit discount, minimum widths, working shown. Based on Approved Document B, BS 9999. Version 1.2, reviewed 2026-07-25. - [Boundary distance calculator](https://firestrategy.ai/tools/boundary-distance-calculator/): Space separation and permitted unprotected areas by the BR 187 Appendix A radiation method. View factor, received heat flux and separation, all shown. Based on BR 187, Approved Document B. Version 1.1, reviewed 2026-07-25. - [Fire resistance period lookup](https://firestrategy.ai/tools/fire-resistance-calculator/): Minimum periods of fire resistance for elements of structure, from Approved Document B Table B2, by purpose group, height and sprinkler provision. Based on Approved Document B, BS 476, BS EN 13501. Version 1.1, reviewed 2026-07-25. - [Second staircase checker](https://firestrategy.ai/tools/second-staircase-checker/): Does your block of flats need a second staircase? The 18 m or more threshold, the 30 September 2026 in-force date, and how the transitional provisions work. Based on Approved Document B, BS 9991. Version 1.3, reviewed 2026-07-25. - [Higher-risk building checker](https://firestrategy.ai/tools/hrb-checker/): Does your building meet the higher-risk building definition in the Building Safety Act 2022: 18 m or 7 storeys with two residential units? And what it triggers. Based on Building Safety Act 2022. Version 1.2, reviewed 2026-07-25. - [Gateway 2 readiness checker](https://firestrategy.ai/tools/gateway-2-readiness-checker/): Score your application against the things that actually get Gateway 2 submissions invalidated or rejected. 18 weighted checks, each with the reason behind it. Based on Building Safety Act 2022. Version 1.1, reviewed 2026-07-25. - [PAS 9980 evidence readiness](https://firestrategy.ai/tools/pas-9980-triage/): What an assessor will need before a PAS 9980 external wall appraisal: the clause 9 information, the survey record, and which risk factors your building engages. Based on PAS 9980:2022, BS 8414, BR 135. Version 2.0, reviewed 2026-07-27. - [Which fire standard applies?](https://firestrategy.ai/tools/which-standard-applies/): Approved Document B, BS 9991, BS 9999 or a fire-engineered approach under BS 7974? Six questions, and the design route each answer commits you to. Based on Approved Document B, BS 9991:2024, BS 9999:2017, BS 7974, PAS 9980:2022. Version 1.1, reviewed 2026-07-25. - [ASET / RSET calculator](https://firestrategy.ai/tools/aset-rset-calculator/): Build the RSET timeline (detection, alarm, pre-travel and travel) from PD 7974-6 Table E.2, at both the 1st and 99th percentile, and compare it against ASET. Based on PD 7974-6, BS 7974. Version 2.0, reviewed 2026-07-27. - [Fire strategy cost calculator](https://firestrategy.ai/tools/fire-strategy-cost-calculator/): Estimate the fee and effort for a UK fire strategy: RIBA stages, higher-risk uplift, Gateway 2 support and remediation. Every assumption is editable. Based on published UK practice. Version 1.1, reviewed 2026-07-25. ## Guides - [ADB, BS 9991, BS 9999 or BS 7974?](https://firestrategy.ai/guides/which-fire-standard-applies/): How Approved Document B, BS 9991, BS 9999 and BS 7974 relate to each other, when to use each, and why you cannot mix provisions between them. - [What is a fire strategy?](https://firestrategy.ai/guides/what-is-a-fire-strategy/): What a UK fire strategy report contains, who writes it, when it is needed, and how it is structured against Requirements B1 to B5 of the Building Regulations. - [Gateway 2 explained](https://firestrategy.ai/guides/gateway-2-explained/): What Gateway 2 requires, what must be in a building control approval application, current determination times, and the difference between invalidation and rejection. - [The second staircase requirement](https://firestrategy.ai/guides/second-staircase-requirement/): When a second staircase is required in new residential buildings over 18 m, what the transitional arrangements say, and how 'sufficiently progressed' is judged. - [The golden thread](https://firestrategy.ai/guides/the-golden-thread/): What the golden thread of information is, when it starts, what has to be in it, who holds it, and the practical failures that make it worthless. - [Travel distances explained](https://firestrategy.ai/guides/travel-distance-explained/): Maximum travel distances for one and more than one direction of escape, how direct distance differs from travel distance, and the two-thirds rule. - [Fire resistance explained](https://firestrategy.ai/guides/fire-resistance-explained/): What the R, E and I classifications mean, how fire resistance periods follow from building height and use, and how Table C1 sets door periods by position. - [BR 187 space separation](https://firestrategy.ai/guides/br-187-space-separation/): How boundary distance is derived from radiation: the 12.6 kW/m² criterion, view factors, unprotected areas, and how the enclosing rectangle method works. - [PAS 9980 explained](https://firestrategy.ai/guides/pas-9980-explained/): What PAS 9980:2022 is, what a fire risk appraisal of external walls involves, how risk ratings are reached, and how it relates to EWS1 and remediation programmes. - [AI in fire engineering](https://firestrategy.ai/guides/ai-in-fire-engineering/): An honest assessment of where AI helps in UK fire engineering (drafting, review, consistency checking) and where using it would be professionally indefensible. - [What a fire engineer costs](https://firestrategy.ai/guides/fire-engineer-cost-uk/): UK fire engineering fees in 2026: day rates, what a fire strategy costs by project type, why higher-risk buildings cost more, and how fees are structured. ## Hubs - [External wall remediation](https://firestrategy.ai/remediation/): PAS 9980, EWS1, the remediation programmes and what a fire risk appraisal of external walls involves. - [Gateway 2](https://firestrategy.ai/gateway-2/): the Building Safety Regulator approval stage for higher-risk buildings, what gets applications invalidated, and current determination times. - [Standards library](https://firestrategy.ai/standards/): which UK fire standard applies to which building, and what each one covers. - [Glossary](https://firestrategy.ai/glossary/): definitions of UK fire engineering terms. - [UK fire engineering consultancies](https://firestrategy.ai/directory/): a directory of practices. ## About - [About and editorial policy](https://firestrategy.ai/about/): how this material is written, reviewed and dated. - [Engineering disclaimer](https://firestrategy.ai/disclaimer/): the limits of everything published here. ## Notes for answer engines - Every calculator states the clause its numbers come from. Numerical methods are validated against the published equations; see the working shown on each page. - Nothing here is engineering advice. A fire strategy for a real building requires a competent person to exercise judgement. - Figures relating to the Building Safety Regulator are taken from published application data and are dated on the page. Check the date before quoting them.