The development of automatic fire protection methods for computing and telecommunications areas
With highly accelerated developments in computing and communications technology, society's overall dependence on this equipment is becoming increasingly acute. In areas such as critical electronic data processing centres and telecommunication hubs, one of the main protection objectives is to achieve minimum operational disruption, as downtime resulting from a fire condition could lead to huge financial losses. Minimising negative impact on an organization and the need for a sound basis in the decision making process are the fundamental reasons why companies implement fire risk management for their essential information technology systems. For many years a key element used to protect these critical assets was the installation of a fixed Halon 1301 gas extinguishing system. Often, the mere presence of a computer was sufficient justification to install such a system and little thought was given to any systematic fire risk assessment of the installation. This led to the use of Halon 1301 where other fire extinguishing systems and protection techniques could have been applied with equal effectiveness and at comparable costs. The cessation of production of halon as a result of the Montreal Protocol gave fresh impetus to the development of suitable alternative fire extinguishing agents. It also offered fire protection engineers an opportunity to re-evaluate existing loss control techniques and to examine alternative fire protection strategies. However, it is argued in this study, that an appropriate level of automatic fire protection can only be determined by the use of a suitable quantitative risk assessment and a number of such methodologies are critically examined. There are a significant number of contributing factors that must be considered when deciding which fire suppression system to select for a new installation or whether to retrofit fire suppression on a legacy platform. Consequently, it is necessary to develop a methodology to quantify any fire suppression technology by its life cycle cost and then to apply informed technical opinion into this system. The results of this assessment procedure offer a number of possible fire engineering solutions including a quite diverse range of automatic fire extinguishing techniques and these are discussed and evaluated in detail. Inevitably, a high proportion of such critical risks will require the installation of an automatic fire suppression system. The main halocarbon and inert replacement extinguishing agents are therefore critically compared and contrasted for their suitability in protecting these facilities. A complete review of these extinguishing agents was conducted which focused on suppression mechanisms; quantification of their performance and qualities; interaction with a fire and potential damage to electrical equipment from the release of a given agent. It is shown that all the post-halon extinguishing agents are deficient in some important areas. Major issues such as the formation of thermal decomposition products, the protection of continuously energized electrical circuits and the adequacy of the specified design and extinguishing concentrations have generally not been adequately addressed. Unfortunately, some of these issues are not even resolved in the current gaseous fire extinguishing standards which offer minimal advice from either a design or installation standpoint. This study demonstrates that existing international design standards are deficient in some fundamental areas and that, in a number of circumstances, systems installed to these standards are inadequate to fully protect the hazard in question. A number of recommendations are presented to address some of these deficiencies. Finally, a semi-quantitative risk assessment methodology for the selection of suitable extinguishing agents is proposed. Initially, this attempts to synthesize the results derived from the critical extinguishing agent review and then applies an application weighting factor based on expert consensus to provide a final score for a particular suppression mechanisms suitability to protect a given application.
Networked Digital Library of Theses and Dissertations