Se. Magnusson et al., FIRE SAFETY DESIGN BASED ON CALCULATIONS - UNCERTAINTY ANALYSIS AND SAFETY VERIFICATION, Fire safety journal, 27(4), 1996, pp. 305-334
Evacuation life safety in a one-room public assembly building has been
analysed with regard to uncertainty and risk. Limit state equations h
ave 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 s
ystem (alarm, sprinkler and emergency door). Input parameter distribut
ions 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 beta and CCDF
(complementary cumulative distribution function) for evaluation time-
margin deficit. Of special interest is the calculation of confidence i
ntervals for the distribution of CCDFs obtained by the two-phase Monte
Carlo sampling procedure, allowing a distinction between knowledge an
d stochastic uncertainty. The importance analysis carried out analytic
ally gives data of fundamental significance for an understanding of th
e practical design problem. Partial coefficients have been treated onl
y 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. (C) 1997 Els
evier Science Ltd.