PD 7974-4:2003 - Page 2

This Published Document provides guidance on the development, design and application of fire detection systems, and the activation of fire alarm and fire control systems to fulfil a role in the fire safety engineered design for a building. Scientific and engineering principles are used as part of a structured approach. The key elements covered are:

• detection: information is provided on the various types of fire detection system and their application for a given set of circumstances, as derived from a qualitative design review, risk assessment and the results of formulae provided by other Sub-systems;
• activation and control: once the fire detection system has detected a fire, it activates a series of measures designed to fulfil the requirements of the fire safety engineered design. These measures may include operation of fire warning systems, the remote signalling to emergency services, and the operation of fire alarm, fire suppression and fire control systems. Guidance is given on the methodology and formulae required in ensuring that the appropriate systems are activated in an appropriate manner and within given criteria.

In the context of this document, fire control includes:

• fire suppression systems: active systems designed to suppress a fire, temporarily (i.e. control) or permanently (i.e. extinguish). Examples include automatic water sprinkler systems;
• fire barrier systems: active systems designed to contain a fire within a given area or separate a fire from another area. Such systems may be regarded as offering similar benefits to passive fire compartments or separations for the duration of their operation. Examples include fire damper systems and door release mechanisms;
• smoke/heat control systems: active systems designed to positively control the movement and build up of fire effluents such as smoke, heat and toxic gases. Examples include smoke venting systems and air pressurization systems.