Sven Erik Magnusson

Fire Safety Design Based on Calculations. Uncertainty Analysis and Safety Verification

Abstract Evacuation life safety in a one-room public assembly building has been analysed with regard to uncertainty and risk. Limit state equations have been defined, using response surface approximations of output from computer programmes. A number of uncertainty analysis procedures have been employed and compared: the analytical first-order second-moment (FOSM) method, two numerical random sampling procedures (simple random sampling and Latin hypercube sampling) and standard PRA method. Eight scenarios have been analysed in isolation as well as aggregated into an event tree, with branches denoting functioning/failing protection system (alarm, sprinkler and emergency door). Input parameter distributions have been subjectively quantified and classified with respect to category: knowledge or stochastic uncertainty. Risk assessment results comprise probability of failure p f , reliability index β and CCDF (complementary cumulative distribution function) for evacuation time-margin deficit. Of special interest is the calculation of confidence intervals for the distribution of CCDFs obtained by the two-phase Monte Carlo sampling procedure, allowing a distinction between knowledge and stochastic uncertainty. The importance analysis carried out analytically gives data of fundamental significance for an understanding of the practical design problem. Partial coefficients have been treated only by calculating values implicit or inherent in a few existing sample design configurations. Future studies, preferrably using optimization procedures, are needed to produce generally valid values.

Rational Design Methodology for Fire Exposed Load Bearing Structures

The state-of-art of reliability studies in the area of fire-exposed structures or structural members is illustrated, taking examples from published papers concerning load-bearing building structures of steel, reinforced concrete, and wood. In parallel, trends are described in the present development of rational structural fire design methods, principally adapted to modern loading and safety philosophy for the non-fire state. Statistically derived results are presented for fire-exposed, insulated steel structures in office buildings, giving the breakdown of the total variance in maximum steel temperature and load-bearing capacity into component variances as a function of the insulation characteristics. The safety index and probability of failure are compared numerically for different fire design procedures. The data presented are examples of the information which is required as input in a qualified systems analysis of fire exposed load-bearing structures.

Detemination Of Safety Factors In Design Based On Performance

A pilot study on a very limited scale has been carried out in the application of the FOSMmethodology for fire safety engineering design. The methodology is based on using the mean and standard deviation from distributions in a first order approximation of a limit or failure equation. In this way it is possible to establish an expression for the safety index P both for linear and non-linear limit equations. This paper exemplifies the methodology for a practical scenario deriving the safety index P for a small shopping centre.

Risk Based Decision Making: Three Examples of Practical Application Tools

The paper discusses three ongoing or recently finalised projects carried out at the Lund University Centre for Risk Analysis and Management (LUCRAM). The first section discusses decision making situations involving extreme or catastrophic events and the application of a newly developed decision analysis method. The second chapter discusses the framework and the methodological aspects of a computer based decision analysis tool for assessing and managing local or municipal vulnerability. The third part of the paper, finally, presents a comparative uncertainty analysis of a risk study of an ammonia storage facility employing a number of methods: Monte Carlo analysis, Interval analysis, Fuzzy arithmetic and Probability bounds theory.

FREIA—an expert system for fires and explosions in the process industry

FREIA is a simple tool for evaluating industrial fire safety. It considers fires and the accidental release of hazardous substances both inside and outside buildings. It gives a rough estimate on whether certain components within a room will be damaged or not. The system has been used for evaluating fire safety in both the process industry and at power plants for several years, and an example of an evaluation is presented in this paper. The system has been found to be valuable in finding weak links in the fire safety system.

University training of senior fire brigade officers. The new approach in Sweden

In Sweden a fundamental development has recently taken place in the training of future senior fire brigade officers. There are two main changes: the training period has been substantially increased and the theoretical part upgraded to university curriculum level with final requirements corresponding to a university undergraduate degree. The new educational system reflects the changing and expanding role of fire brigades and the need for a professionally improved leadership. To put the new training system into a proper context, the varied and dissimilar responsibilities of a Swedish fire brigade officer should be touched upon. Four main sectors are identified: business administration, fire prevention, training of employed staff and rescue service operations. The main structure of the training system and the university curriculum are discussed. (Less)