SEMINARIE BRANDBEVEILIGHEID Alles over brandblussers WELKOM

1
The role of fire risk analysis in fire
engineeringFields Shopping Centre
CopenhagenProf David Charters, CEng
FIFireEArup Fire, Leeds, UK
22 04 2005
2
Fields Shopping Centre
3
Overview

• Introduction
• Fields Copenhagen
• The Building
• The Fire Strategy
• Quantified fire risk assessment
• Results
• Future Developments
• References

4
Introduction
Fire engineering can be defined as The
application of scientific and engineering
principles to the protection of people,
property and the environment from fire.
British Standard BS 7974 Code on the
Application of Fire Safety Engineering Principles
to the Design of Buildings is supported by 8
Published Documents (PDs). PD 0 General
principles PD 1 Initiation and development of
fire within the enclosure of origin PD 2 Spread
of smoke and toxic gases within and beyond the
enclosure of origin PD 3 Spread of fire beyond
the enclosure of origin PD 4 Detection of fire
and activation of fire protection systems PD
5 Fire service intervention PD 6 Evacuation PD
8 Probabilistic risk assessment
5
The Building
A 280 000m² multi-purpose retail/leisure complex
in Denmark. The podium is approximately 200m by
150m with a high-rise hotel above and linked
adjacent blocks (see figures 1 and 2). Can be
divided into the following functional
areas car park retail levels offices
leisure facilities conference centre
cinema complex hotel building A shopping and
leisure complex such as Fields is not
specifically addressed in the Danish Building
Regulations so a performance-based fire
engineering approach has been adopted.
6
Figure 1 General view of the development
including transport links
Figure 2 Internal view of an upper mall and
general mall layouts
7
The Fire Strategy
A performance-based fire engineering approach and
incorporating international practice for shopping
centres and the Danish Building Regulations.
Some of the fire safety objectives for the
project were Safe and efficient evacuation of
large populations Minimise property loss and
business interruption Maintain open routes and
shop fronts and Provide flexibility for varied
tenant use. Measures were designed to provide an
integrated package. With fire safety systems,
such as sprinklers, smoke control to protect the
mall, automatic fire detection and a voice alarm
system, the mall forms an evacuation route
through which people can escape from the fire
(see Figure 3). Own fire/smoke compartment,
will share escape routes, including stairs.
Evacuation will be phased, evacuating each
functional area individually. Sub-divided into a
number of evacuation zones. The fire strategy
was developed and agreed with the local
authorities Will also be used for the future
development and management of the centre.
8
All openings in mall roof to close automatically
on operation of the smoke control system
Extract system (e.g. fans and ducts) from smoke
reservoir
Smoke retardant construction to protect leisure
areas adjacent to mall
Clear layer under smoke to protect occupants
Downstands to limit plume width.
Smoke spreads from fire in shop, flows under
balcony, to be contained and extracted from smoke
reservoir above mall
Figure 3 Typical section showing smoke control
9

• Due to the provision of automatic sprinklers,
  smoke control to protect the malls and large
  shops, automatic fire detection and a voice alarm
  system, which allows for the alternative design
  to incorporate
• Extended travel distances within malls
• Travel distances in shops to be measured to the
  exit to the mall.
• Shops not fire separated from the mall.
• Fire resistance levels will be reduced in
  specific areas
• Open stairs at the main entry/exit point from the
  mall areas will be used for egress direct to
  the outside

10
Quantified fire risk assessment
Figure 4 Typical quantified fire risk
assessment process
11

• The quantified fire risk assessment was
  undertaken using SAFiRE
• (Simplified Analytical Fire Risk Evaluation).
• SAFiRE combines consequence and frequency
  analysis
• Frequency analysis is based on statistical
  analysis, simple fault and event trees and
  Monte-Carlo analysis of highly variable
  parameters.
• Consequence analysis is based on statistical
  analysis and simplified models for time to
  untenability and time for evacuation.
• This method is well suited to use in the design
  process because it about a tenth of the time of
  traditional quantitative risk assessment (see
  Figure 4).
• SAFiRE takes into account the regulatory
  paradigm. That is, it addresses the same fire
  safety objectives as Building Regulations and
  assesses adequacy using the same variables, eg.
  Exit width, travel distance, number of people,
  compartment sizeetc.
• The method is also consistent with the principles
  of traditional quantitative risk assessment.

12
Figure 5 Typical output from SAFiRE

• Shows a general example of an F-n curve for life
  safety (not specific to the Fields project).
• The further to the upper right the higher the
  risk and the further to the lower left the lower
  the risk. The individual curves show relatively
  high frequency/low consequence fire events on the
  upper left and relatively low frequency/high
  consequence events on the lower right.
• The risk analysis showed that the overall risk to
  occupants satisfied the acceptance criteria and
  is the same or less than that for a department
  store or similar public building designed to meet
  the Danish Building Regulations 1995.

13
Results
The quantified fire risk assessment also showed
that, for certain parts of the development,
relatively simple changes to the design could
significantly improve life safety. This
powerful combination of deterministic fire
engineering and probabilistic risk assessment
provided a more rounded view of fire safety in
the development and may be a taste of things to
come in countries with risk-informed functional
fire safety regulations.
14
Future Developments
Fire engineering has come a long way in the last
few decades Is now recognised a distinct
engineering discipline has not yet reached a
maturity similar to that of other engineering
disciplines. As with other engineering
disciplines, there is need for more scientific
knowledge, before even greater benefits to
society can be unlocked. In particular, more
research is needed into the more stochastic
aspects of fire safety, such as The prevention
of fires Fire growth and flame spread The
formation and movement of smoke The detection of
fire by people The efficacy of fire
suppression The behaviour of people in
fires The response of structures to fires There
is a significant body of existing knowledge, but
as recent events have shown there is much work to
be done.
15
References
Approved Document to Part B of the Building
Regulations 1991, 2000 Edition, Department of
Environment, Transport and Regions. BS 7974
Code on the application of fire safety
engineering principles to the design of
buildings, PD7 Probabilistic risk assessment,
British Standards Institute, 2003. The SFPE
Handbook on Fire Protection Engineering, 3rd
Edition, SFPE/NFPA 2002 Charters D, Paveley J
and Steffensen F-B, Quantitative fire risk
assessment in the design of a major
multi-occupancy building, Proceedings of
Interflam 2001, Interscience Communications,
2001. Charters D and McGrail D, Assessment of
the environmental sustainability of different
performance based fire safety designs
Proceedings of the 4th International Conference
on Performance Based Codes and Fire Safety
Design Methods, SFPE Melbourne, 2002. Charters D
A, Holborn P and Townsend N, Analysis of the
number of occupants, detection times and
pre-movement times, Proceedings of the 2nd
International Symposium on Human Behaviour in
Fire, Interscience Communications, Boston, 2001.