This Published Document provides guidance on evaluating fire growth and/or size within the enclosure of fire origin, as well as enclosures to which the fire has subsequently spread. Guidance is also provided for “special cases” which include malicious fires, racked/stacked storage of goods and fires external to the
building.
The characteristics of the design fire for any particular scenario are influenced by a number of factors, including building design, environmental influences, potential ignition sources and location, types of combustible materials, distribution and arrangement of combustible materials, ventilation conditions and other events occurring during the fire.
The determination of the characteristics of the design fire from ignition through to decay is used by other Sub-systems as inputs into calculations of events such as time of fire spread from enclosure [PD 7974-3 (Sub-system 3)] and time to activation of suppression systems [PD 7974-4 (Sub-system 4)].