FIRE PROTECTION OF STEEL STRUCTURES ... - CISC-ICCA

called Fire Dynamics Simulator, which was developed by the
National Institute of Standards and Technology in the United
States and is categorized as a computational fluid dynamics field
model. The model also represents the compartment’s associated
physical properties such as geometry, ventilation, finish, etc.
Output from the model simulations provide relevant information
such as ceiling jet temperatures, fuel burning rates, heat flux on
enclosure boundaries and sprinkler activation times. The data
was used in traditional heat calculation methods to determine the
structural response of the exposed structural steel assemblies.
The Fire Protection Engineer involved in a PBD of a building’s fire
protection can use a range of computer models. A useful website
with an international survey conducted on a range of computer
models for fire and smoke is www.firemodelsurvey.com. The
site lists 168 computer fire and smoke models in six categories:
fire endurance, egress, detector response, zone, field
and miscellaneous.
There has also been a development in a set of sophisticated C
codes of practice for the fire design of structures, namely
M
Eurocodes. Eurocodes apply to the common building materials
Y
of concrete, steel, composite steel-concrete, timber, masonry
CM
and aluminum. For steel structures, the code is EN 1993-1-
2:2005, Eurocode 3: Design of Steel Structures, Part 1-2: MY
General rules -- Structural Fire Design. The provisions in
CY
Eurocode 3 for steel structures and fire deal with the complexity
CMY
of internal forces induced by thermal expansion, strength
K
reduction due to elevated temperatures, the associated
amplified deflections and other design factors (the document’s
technical content is over 80 pages). Similar engineering
guidance in North America has recently been published by
both AISC and CSA, i.e., ANSI/AISC 360-05’s Appendix 4
and CSA S16-09’s Annex K, entitled Structural Design For Fire
Conditions, which provide an aid for structural engineers to
develop PBD fire safety for buildings designed with structural
steel. The provisions in ANSI/AISC 360-05 and CSA S16-09
FiRE PROtEctiON
“There are many examples where a PBD approach has led to steel components
in the building structure being designed to be unprotected or with a significant
reduction in fire protection materials”
appendix/annex are general introductory guidelines (about
10 pages) to orient a structural engineer in performance-based
fire engineering, a skill that, for the most part, is unfamiliar
territory for the profession. This is an exciting advance because
it opens the door to new design possibilities once the team has
demonstrated that the alternative meets the fire safety levels
required by the Code without adopting all of the prescriptive
Code provisions.
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