Fires Stair Specification Requirements

Fire stair compliance is governed by two main code sections; B-Stability and D-Access. They need to provide safe egress from the building in the event of fire or other emergency and there are a number of criteria that need to be met to ensure this. These can vary depending on the use of the building and density of occupancy.


Here are some quick pointers to get you started on fire stair compliance. It might be worth noting that there is potential for these to change over time as average body size is increasing and specifications will eventually change to reflect this. Calculations still work around buildings being exited within 2.5 minutes. Larger body sizes limit pedestrian flow and will have slower evacuation rates.

stair rail cross section


  • Surfaces need to be slip resistant under all conditions
  • Stair treads must have uniform rise within each flight and across consecutive flights ( a (5mm difference can make stairs unsafe)
  • Tread depth must provide adequate footing and be a minimum of 280mm
  • Tread width must be a minimum of 1200mm
  • Rises of a maximum of 190mm
  • Nosings shall be rounded and should be between 15 mm - 25 mm
  • Maximum pitch is 37 degrees
  • Closed risers are required for indoors only.


  • Landings must be a minimum length of 900mm including mid flight landings
  • Clearance must be a minimum of 900mm allowing for handrails
  • Landings must be at appropriate intervals along a stair or ramp to prevent undue fatigue, not exceeding 2500mm between landings
  • Doors must not block access or themselves be blocked
landing detail


  • Handrails shall be provided on both sides of accessible stairs and steps including landings
  • Minimum width between handrails on stairs shall be 900mm
  • Handrails shall be continuous with no obstructions to the movement of the hand along its length
  • Handrails shall not have projecting ends that will create a hazard.
  • The height of a handrail above the nosings of the tread shall be between 900mm and 1000mm above
  • Handrails shall not project into any other path of travel except when a centre handrail projects into a landing by the distance of the stair going
  • Handrails shall be securely fixed and rigid. A handrail shall be able to support a weight of 110kg at any point.
  • The clear space between a handrail and the adjacent wall surface shall be 50 - 60 mm at the sides and 100mm above

There are many factors to consider. Need some help? Contact your expert team and we can help you from planning and design to manufacture and installation. Phone us on 0800 658 637 or email us and one of our team will get back to you.

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