Design Methodologies For Smoke And Heat Exhaust Ventilation

This guide summarizes the advice available from the Fire Research Station, to designers of Smoke and Heat Exhaust Ventilation Systems (SHEVS) for atria and other buildings. It builds upon currently available published advice (especially BRE Report Design approaches for smoke control in atrium buildings[13], but also BRE Report Design principles for smoke ventilation in enclosed shopping centres[24]), by including more guidance on the use of the methods given, and by including the results of research carried out since the publication of ref. [13] in 1994. In particular, the use of a design fire size is considered in more detail, including: a discussion of growing fires; formulae and calculation methods to determine the deflection of smoke curtains in fire situations so that the specification of smoke curtains can become part of the SHEVS design; the effects due to airflow on the efficiency of natural smoke exhaust ventilators and on the stability of smoke layers. This guide does not consider the scenario where a fire in a room connecting to an atrium causes a flame plume to rise into the atrium. In this context, any large space adjoining the fire room may be considered to be an atrium, eg malls in shopping complexes. A discussion is included of the factors which need to be considered when specifying the hardware (ventilators, smoke curtains, etc.) required to implement the design in a building. Some advice is also included on: factors to be considered in installing the system in buildings; how to test the functioning of the equipment separately and as a complete system once it has been installed; and 'good practice' measures involving the management and maintenance of the system when the building is in everyday use. The purpose of this book therefore is to provide practical guidance on the design of smoke-control systems. It reflects current knowledge and is based on the results of research where available, including as yet unpublished results of experiments. In addition, it draws on the authors' cumulative experience of design features required for regulatory purposes in many individual smoke-control applications. Many of these design features have evolved over several years by consensus between regulatory authorities, developers and fire scientists, rather than by specific research. The methodology underpinning the book is explicitly empirical in approach and can easily be extended to most buildings. Where guidance is necessary to address practical design issues but there are gaps in the established knowledge-base, the authors have exercised their professional judgement in offering conservative, pragmatic advice. When guidance is offered in these circumstances any potential weaknesses are made explicit. Related to this is the continuance of the philosophy used in the book's predecessor BRE Reports[13,24] that even where a document is difficult to obtain, or even verbal private communication is the source of advice, it is listed as a reference.