Structural fire engineering

Increasing innovation in design, construction and usage of modern buildings has created a  situation where it is sometimes difficult to satisfy the functional requirements of the Building Regulations by use of the provisions given in the Approved Documents and Technical Handbooks.  Recognition of this, and also increased knowledge of how real buildings react in fire and of how real fires behave, made possible by a wide ranging and intensive and programme of research and development world-wide, has led many authorities to acknowledge that improvements in fire safety may now be possible in many instances by adopting analytical approaches. Thus Approved Document B states that:

“Fire safety engineering can provide an alternative approach to fire safety. It may be the only practical way to achieve a satisfactory standard of safety in some large and complex buildings and in buildings containing different uses.”

Fire safety engineering can be seen as an integrated package of measures designed to achieve the maximum benefit from the available methods of preventing, controlling or limiting the consequences of fire. The Institution of Structural Engineers defines it as a process

“…aimed at adopting a rational scientific approach which ensures that fire resistance/protection is provided where it is needed rather than accepting universal provisions  which may over or under estimate the level of risk.”

The move from prescriptive to functional requirements in the Building Regulations in the United Kingdom provided a huge boost to the development of fire engineering and this country can now lay claim to many of the leading consultancies in this field in the world. As a consequence, the majority of tall and complex buildings now benefit from a fire engineering approach rather than relying on the blanket provisions of the Approved Documents or similar. This has proved extremely beneficial to the construction industry as a whole.

BS7974(33) contains guidance on the procedures for carrying out a fire engineering analysis.

The introduction describes its purpose as being to provide a framework for developing a rational methodology for the design of buildings using a fire safety engineering approach based on the application of scientific and engineering principles to the protection of people, property and the environment from fire.

The code is accompanied by a series of published documents giving detailed guidance on the principles of fire engineering, fire development, spread of smoke, structural response, fire detection, fire service intervention, evacuation and risk assessment.

Fire engineering can deliver value across the five areas of activity in the provision of fire precautions in buildings. These are:

• means of warning and escape
• internal fire spread
• structural response
• external fire spread
• access and facilities for the fire service.

The following web pages concentrate on the third of these, Structural response.