Steel Framed Buildings & Fire Regulations
UK Building Regulations require steel framed buildings to maintain structural stability when exposed to fire.
Regulations vary between UK Countries but generally a steel framed building is required to retain its load bearing capacity for a reasonable time to allow occupants of the building to escape.
The regulations vary depending on the size of the building, the use of the building and its position in relation to the property boundary but it is also important that fire cannot easily spread to neighbouring properties.
Full details of the regulations applying to England & Wales are set out in Approved Document B which can be downloaded from the Government’s Planning Portal.
Fire Protection Solutions for Steel Framed Buildings
Significant research has been carried out into the effect of fire on steel over the past 20 years and fire protection solutions for steel frames are now widely available.
Hot rolled steel frames can be treated with intumescent paint either at the factory or on site. Board fire protection systems and sprays can also be used.
Cold rolled steel frames tend to be more lightweight than their hot rolled counterparts and react differently in a fire. Fire protection boards are frequently used which can provide a fire resistance of up to 1.5 hours (based on double thickness with staggared joints).
Fire Resistance Classification of Building Walls
Insulated cladding with fire resistant cores have been developed to help the spread of fire in a steel building.
Building walls are required to contain a fire inside a building and are assessed on their ability to meet the following :-
- Stability – the ability of the wall to remain in place during a fire
- Integrity – resistance to flame and hot gases
- Insulation – resistance to heat transmission
If the cladding used in the building walls is able to meet these criteria for 1 hour it is classed as having 1 hour fire resistance.
Class 0 Classification
This is the best possible classification used for wall or ceiling material that does not help the spread of fire and meets tests set out in Building Regulations Approved Document B.
Class FAA/SAA Classifications
These classifications are used for material that does not allow fire to penetrate a roof or spread across a roof if burning material falls from an adjacent burning building. A surface is classed as FAA (flat) or SAA (sloping) if it has no spread of flame and resists fire penetration for at least one hour.
Windows and areas of wall which do not provide fire resistance are classed as unprotected areas. Building Regulations allow more unprotected areas as the building is located further from the property boundary.
Fire Resistance of the Building Roof
The roof of the building envelope does not generally require fire resistance, however, building owners may be required to include fire resistant panels which conform to Factory Mutual (FM) or Property and Business Protection – Loss Prevention Certification Board (LPCB) standards to obtain insurance cover.
Want to find out more? Email us or call Miracle Span’s expert consultants on 01507 358 974 for more information.