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Part B - Fire Safety


Part B - Fire Safety applies to non-domestic buildings over 15m high, as well as hospitals, schools, warehouses, factories and shopping centres of any height.

Part B - Fire Safety is about protecting lives. It:

• Provides guidance on the use of building materials with differing levels of fire performance

• Contains the requirements of Building Act Regulations and guidance on compliance

Part B applies to England and Wales. Its five sections deal with:

• B1: Means of warning and escape

• B2: Internal fire spread (linings)

• B3: Internal fire spread (structure) Part B - Fire Safety

• B4: External fire spread

• B5: Access and facilities for fire services

For Scotland, see Section 2 of the Scottish Building Regulations.



Class 0 Compliance

British Standards refer to Class 0 compliance. Class 0 is the spread of fire across the surface of a building material – what’s known as the surface spread of flame – and the non-combustibility of that surface.

Reaction to Fire

The reaction-to-fire classification covers the potential for flashover, the spontaneous ignition of hot smoke, gases, and fuel that can cause a fire to spread uncontrollably.
Two other hazards encountered in fires, and therefore subject to risk assessment, are classified by s (for smoke production) and d (for flaming droplets). They relate to the quantity of smoke produced (s1 is the least; s3 is the most) and the potential for flaming droplets to fall (d0 means no droplets; d3, many droplets).

Euroclass Harmonisation

The Euroclass classification of building products harmonises standards of fire safety across Europe, including England, Scotland and Wales. The intention is that it will replace the British Standards. The classes A1, A2, B, C, D, E, and F rank a product’s reaction to fire. The safest products are A1, the most dangerous are E. F is not classified.