Fire engineering calculators
12 calculators for UK fire strategy work, built on the same validated engine as our AI product. Every one shows its working, cites the clause it came from, and prints as a record you can put in a file.
Means of escape
Travel distance, occupancy, exit and stair width: the numbers a reviewer will measure off your drawings.
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.
Open the calculatorOccupancy 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.
Open the calculatorEscape and stair 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.
Open the calculatorRegulation
Higher-risk building status, the second staircase threshold, Gateway 2 readiness and which standard governs.
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.
Open the calculatorHigher-risk building 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.
Open the calculatorGateway 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.
Open the calculatorWhich fire 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.
Open the calculatorExternal walls
PAS 9980 triage and BR 187 space separation, for the part of the market that is busiest right now.
Structure and compartmentation
Fire resistance periods and the door ratings that follow from them.
Fire engineering
ASET, RSET and the evidence a performance-based design has to carry.
Practice
Fees, effort and programme.
Why these are free
Because a calculator is the easy part. The hard part is a fire strategy that survives a Gateway 2 review: every requirement covered, every departure justified, every drawing consistent with the report, and all of it traceable to a clause. That is what FireStrategy.ai does, and it is what we charge for.
These calculators use the same numerical engine, validated against the published equations to machine precision. Use them on their own for as long as you like.