Fire Safety Engineering & the Performance of Structural Steel in Fires

Main 9/11 Links Page 

"Recently reported fire tests have demonstrated that structural steel columns under a sustained load of about 70% of their cold strength collapse when heated to 250° C." –Zdenek Bazant, Discussion of “Mechanics of Progressive Collapse: Learning from World Trade Center and Building Demolitions


"The local building department is taking a great deal of interest in the burning of the building of Post & McCord in the recent Greenpoint fire. This building was supposed to be absolutely fireproof, being constructed of steel and cement in its entirety except the window frames, which were of wood. It contained valuable patterns [blueprints: Post & McCord was a structural steel engineering and fabrication firm], and for that reason no pains were spared to make its burning impossible." –The Brooklyn Daily Eagle, April 22, 1900

"The iron and steel in the structure was warped and twisted by the heat and the fireproofing material served no better purpose than paper. In a short time this costly building was nothing but a pile of twisted steel." –The Brooklyn Daily Eagle, April 9, 1900.

Excerpts from Building Construction for the Fire Service by Francis Brannigan
The fact that steel is non-combustible leads to unwarranted confidence in its "fireproofness" and suitability for all applications where fire is a problem. "I never would have believed it," is a common reaction by otherwise well-informed people when they see the ruins of an unprotected, steel building.

...It is very likely that the most important use of water in some fires is to remove the heat from the steel so that the structural integrity is maintained.

...It is often difficult, even for technically trained people, to understand how fast steel can be destroyed. Pictures of steel damage might be convincing. The distortion of steel due to fire may alter the structure of the building so that it will not be able to carry the superimposed loads or unexpected stresses, particularly torsional, that may be created due to buckling.

...The potential for fire damage to steel buildings is not clearly understood. Often, unwarranted confidence is placed on the fact that the steel is non-combustible. A major insurance carrier found it necessary to conduct demonstrations of actual fires for plant managers in which the only fuel was the hydraulic oil in the presses. (pp. 257, 260, 275)

A few examples of structural steel failing in building fires
(I've excluded the very common examples of lightweight steel bar joist floors and roofs failing, often in a few minutes, in fires.)

Large multistory steel-framed factory buildings quickly collapse due to fire Go

2008: 13-story steel-framed section of Delft University of Technology's Architecture Building collapses due to fire (video). Go

WTC building 5 heavy steel columns buckle due to fire (floor 8 of 9, not hit by plane). Go

Unprotected steel fails in Madrid's Windsor Building fire, concrete core stands. Go

Collapse mechanism of the Madrid Windsor Building Go........BBC Report: Windsor building fire Go

Unprotected heavy steel truss roof quickly fails in fire at McCormick Place, Chicago Go

Fire damage to protected steel in One Meridian Plaza, Philadelphia (PDF) Go

Noises in steel buildings during fire equals danger! Go

JREF, Unfit4Command: Examples of steel destroyed by fire Go

Steel fails in paper factory fire Go

A building fire and structural failure (Steel buildings collapse due to fire) Go

Loss of fireproofing on steel leads to collapse (PDF) Go

NIST and FEMA Experiments, Studies, and Reports

NCSTAR 1-1 Design, Construction, and Maintenance of Structural and Life Safety Systems
NCSTAR 1-4 Active Fire Protection Systems
NCSTAR 1-5 Reconstruction of the Fires in the World Trade Center Towers
NCSTAR 1-6 Structural Fire Response and Probable Collapse Sequence of the World Trade Center Towers
NCSTAR 1-7 Occupant Behavior, Egress, and Emergency Communication
NCSTAR 1-8 The Emergency Response Operations

FEMA 403 Appendix A: Overview of Fire Protection in Buildings (pdf) Go

NIST: Fire Protection of Structural Steel in High-Rise buildings (white paper) Go

Underwriters Labs post-9/11 WTC fire testing, ASTM E119 standard Go

NIST early WTC fire simulation experiments and photos Go

Report of WTC fire code compliance--1993 (pdf Released via FOIA request) Go

NIST's Safety of Threatened Buildings Research Projects

NIST: 2-D Analysis of a Building Frame Under Gravity Load and Fire.

Fire Protection Engineering: "The future of fire simulation at NIST" (PDF)

NIST Gallery of WTC Fire Experiment #6

NIST project 6 structural fire response & collapse analysis

NIST Collected Publications Related to the Use of Elevators During Fires

Fire Protection Engineering Magazine on Computer Modeling / NIST

NIST fire tests: steel residential floor assemblies last 4 mins.

Similar test to above: steel lasts 4.5 minutes, wood, 9 minutes.

Some comments on Fire Testing and Modeling in the NIST WTC 1&2 report


Ryan Mackey on NIST recovered steel and fire models Go

JREF Ktesbios on NIST workstation actual tests Go

JREF RWGuinn on testing models to failure Go

Ryan Mackey on NIST fuel load estimates Go

Building Code Changes and Recommendations Resulting from WTC Collapses

Sally Regenhard Calls for New High-Rise Codes and Code Group Composition (Fire Engineering Mag. 4/02)

Engineering News-Record: Skyscrapers' Supporters Infuriated By Fire Fearmongers (response to Regenhard &


City Reshaping Building Codes To U.S. Model (NYT May 17, 2004)

9/11 Has Spurred Only Modest Changes in New York City and National Building Codes (NYT 9/9/06)

First Comprehensive Set of Model Code Changes Adopted Based on Recommendations from Commerce’s NIST World Trade Center Investigation (June, 2007)

NYC Building Code – Fire Protection

UK reached same NIST conclusions 3 years earlier: ARUP, New Civil Engineer Plus Go

NYC Dept. of Buildings WTC Task Force recommendations report Go

The AIA's Response to NIST's Draft Report and Recommendations (PDF)

The World Trade Center Collapse and its Implications for International Standards – W. Gene Corley ISO Focus, January 2004 (PDF)

"Reexamining Premises for High-Rise Design" Security Management magazine (PDF)
In this article from Security Management magazine, Dr. Gene Corley discusses lessons from the World Trade Center investigation and how they might affect future building design.

NIBS Building Code Experts: Translating WTC Recommendations into Model Building Codes

''If I say, 'That product passed the test,' you as John Q. Public may be happy,'' said Dr. James G. Quintiere, a professor in fire protection engineering at the University of Maryland. ''But if we say, 'It passed the test, but we don't know how it will function in your house,' you would not be happy.''

Federal investigators studying the collapse of the twin towers on Sept. 11, 2001, say they now believe that the Port Authority of New York and New Jersey, the government agency that built the towers, never performed the fundamental tests needed to determine how their innovative structures would perform in a fire

Papers and articles about fire vs. structural steel, specific to the WTC

The behavior of lightweight composite floor trusses in fire Go

Did the Ban on Asbestos Lead to Loss of Life? (Guy Tozzoli, 707, PA discontinued asbestos use before required to do so. $ NYT 9/18/01)

Asbestos Use in the Construction of the World Trade Center

Faulty Fireproofing Is Reviewed as Factor in Trade Center Collapse (Frederick Mowrer, Alan REiss, Roger Morse. $ NYT Dec 13, 2001)

Comparing 2 Sets Of Twin Towers; Malaysian Buildings Offered as Model (Charles Thornton on Petronas Towers / High-strength concrete / Robertson / Nordenson NYT Oct. 23, 2002)

Some interesting thoughts on WTC fire protection, steel vs. concrete, redundancy, new materials Go

Charles H. Thornton, a structural engineer who is co-chairman of the Thornton-Tomasetti Group and also a member of the investigation's advisory committee, said the work would go a long way toward putting the field on a par with research on weaponry and space travel, which also require precise calculation of the effects of heat and blast on structures. ''It's never been done before in the building industry,'' said Mr. Thornton, who collaborated in the design of the Petronas Towers in Kuala Lumpur, Malaysia, currently the world's tallest structures. Especially puzzling is that the analysis of hazards posed by earthquakes and high winds has far outstripped similar work on fires. But just as earthquake engineering lurched forward after the major California quakes of 1971, 1989 and 1994, fire science is advancing after the events of Sept. 11, 2001. Reliving 9/11, With Fire as Teacher (NYT Jan 6, 2004)

Role of Fire Resistance Issues in the Collapse of the Twin Towers (PDF. Institute for Research in Construction, Canada)

Some papers and articles about fire vs. structural steel, not specific to the WTC

Fire Protection of Structural Steel in High-Rise Buildings – Civil Engineering Research Foundation, 2004 (PDF)

Restrained fire resistance ratings in structural steel buildings Go

Structural Fire Engineering: Database: Cardington Fire Test Data Go

JREF: Dave_46 on the Cardington Lab Tests

Determination of fire induced collapse mechanisms of multi-story steel framed structures Go

A New Approach to Multi-Storey Steel Framed Buildings Fire and Steel Construction.

Rein et all, Multi-Story Fire Analysis for High Rise Buildings, 11th Interflam, London, September 2007

Performance of unprotected steel and composite steel frames exposed to fire (Master's Thesis) Go
Effect of Support Conditions on Steel Beams Exposed of Fire (Master's Thesis) Go
Fire safety engineering forum (numerous papers) Go

Recent advances in fire–structure analysis. Fire Safety Journal, In Press, Corrected Proof, Available online 20 August 2007, Dat Duthinh, Kevin McGrattan and Abed Khaskia

Coupled fire dynamics and thermal response of complex building structures. Proceedings of the Combustion Institute, Volume 30, Issue 2, January 2005, Pages 2255-2262 Kuldeep Prasad and Howard R. Baum

"Cabling in commercial buildings is frequently in close proximity to structural steel beams – which can lose structural integrity at fire temperatures as low as 800 degrees centigrade. Combustible cabling can burn at temperatures as high as 1,000 degrees centigrade — sufficient to cause the collapse of tall buildings under certain conditions.

The average ten-story commercial building with 100 office workstations per floor can contain more than 1 million feet of combustible "exception" cabling in concealed spaces; equivalent to the fuel load of 1,500 gallons of gasoline."

Zeng, J. L., Tan, K. H., and Huang, Z. F. �2003�. “Primary creep buckling of steel columns in fire.” Journal of Constructional Steel Research, 59�8�, 951–970.

Huang, Z. F., Tan, K.-H., and Ting, S.-K. �2006�. “Heating rate and boundary restraint effects on fire resistance of steel columns with creep.” Eng. Struct., 28�6�, 805–817.

Kang-Hai Tan, Wee-Siang Toh, Zhan-Fei Huang, Guan-Hwee Phng 2007. "Structural responses of restrained steel columns at elevated temperatures. Part 1: Experiments"  Engineering Structures, 29-8, 1641-1652

Wei-Yong Wang, Guo-Qiang Li, "Behavior of steel columns in a fire with partial damage to fire protection" Journal of Constructional Steel Research, February 2009

Y.B. Yang, T.J. Lin, L.J. Leu, C.W. Huang, "Inelastic postbuckling response of steel trusses under thermal loadings" Journal of Constructional Steel Research, Volume 64, Issue 12, December 2008, Pages 1394-1407

Jiro Takagi, Gregory G. Deierlein 2007. "Strength design criteria for steel members at elevated temperatures" Journal of Constructional Steel Research, 63-8, 1036-1050

Joaquim C. Valente and I. Cabrita Neves 1999 "Fire resistance of steel columns with elastically restrained axial elongation and bending" Journal of Constructional Steel Research, 52-3, 319-331

Faris Ali and David O’Connor 2001 "Structural performance of rotationally restrained steel columns in fire" Fire Safety Journal, 36-7, 679-691

Achim Rubert and peter Schaumann 1988 "Critical Temperatures of Steel Columns Exposed to Fire" Fire Safety Journal, 13-1, Pages 39-44

Kuo-Chen Yang, Hung-Hsin Lee and Olan Chan  2006. "Performance of steel H columns loaded under uniform temperature" Journal of Constructional Steel Research, 62-3, 262-270

Ju Chen, Ben Young 2008. "Design of high strength steel columns at elevated temperatures" Journal of Constructional Steel Research, 64-6, 689-703

C. G. Bailey, "Membrane action of slab/beam composite floor systems in fire" Engineering Structures, Volume 26, Issue 12, October 2004, Pages 1691-1703

I.W. Burgess, A.O. Olawale and R.J. Plank 1991. "Failure of steel columns in fire" Fire Safety Journal, 18-2, 183-201

K.H. Tan, W.F. Yuan 2008. "Buckling of elastically restrained steel columns under longitudinal non-uniform temperature distribution" Journal of Constructional Steel Research, 64-1, 51-61

A. Heidarpour, M.A. Bradford 2008. "Local buckling and slenderness limits for steel webs under combined bending, compression and shear at elevated temperatures"
Thin-Walled Structures, 46-2, 128-146

J.R. Sharples, R.J. Plank, D.A. Nethercot 1994. "Load-temperature-deformation behaviour of partially protected steel columns in fires" Engineering Structures, 16-8, 637-643

J.Y. Richard Liew 2008. "Survivability of steel frame structures subject to blast and fire" Journal of Constructional Steel Research, 64, Issues 7-8, 854-866

Jun Ding, Guo-Qiang Li, Y. Sakumoto 2004. "Parametric studies on fire resistance of fire-resistant steel members" Journal of Constructional Steel Research, 60-7, 1007-1027

Y. C. Wang 1997. "Effects of structural continuity on fire resistant design of steel columns in non-sway multi-storey frames" Fire Safety Journal, 28-2, 101-116

J. Janss, R. Minne 1981-1982, "Buckling of steel columns in fire conditions"
Fire Safety Journal, 4-4, 227-235

Jelle Witteveen, Leen Twilt 1981-1982. "A critical view on the results of standard fire resistance tests on steel columns" Fire Safety Journal, 4-4, 259-270

Skyscraper fire protection in practice after 9/11, innovations, proposals

The discipline of structural fire protection after 9/11 Go

Arup: Innovative Structural Engineering for Tall builings in Fire (2005, PDF) Go

Arup Fire – Fire engineers present latest tall building structural response in severe fire studies (2005) Go

Structural fire engineering: Free advice from structural fire group in Manchester University. Go

Fire and Structures: The Implications of the World Trade Center (PDF) Go

Scientific American: New Thinking to Make Skyscrapers Safer Go

A Midtown Skyscraper Quietly Adds Armor (Citigroup Center NYT Aug 15, 2002)

Report Sees Lower Towers That Can Empty Faster (NYT March 28, 2002)

9/11 Prompts New Caution In Design of U.S. Skyscrapers (300 Mad., NYT Bldg, AOL Time Warner. NYT Sept. 9, 2002)

Structural Fire Engineering, World Trade Center Incident (9-11) & Fire Serviceability Limit States

Interact Fire Solutions--Passive Fire Protection using cast epoxy intumescent

Scientific American: New thinking to make skyscrapers safer

Interesting approach to protecting steel using fluid in channels

Cables hold promise in protecting existing buildings from bombs, researchers find

ARCHITECTURE; High Anxiety (Freedom Tower. NYT March 14, 2004)

The Fire Next Time: Skyscraper safety: the push for NY's high-rises to learn not to burn (VV July 5, 2005)

Increasing use of concrete in skyscrapers.

Astaneh recommends concrete shear walls

Lloyd's commissions study: King Concrete - 08 December 2001 - New Scientist

Concrete: Changing Uses Post-9/11 (New York Construction News May, 2003)

Public Issues and the World Trade Center Disaster (Masonry Contractors Association)

Features of the new WTC 7

Video: New WTC 7: safety and structural features

Fire engineering history, general publications

Dr. James Quintiere presentation on the history of fire science, fire science & education (PDF)

Eurocode: Introduction to Structural Fire Engineering (Powerpoint presentation) Go

Fire Engineering archives (subscription) and FDNY Chief Hayden podcasts (free)

Structural Fire Engineering One Stop Shop

Publications of the Fire Safety Association

Book: Collapse of Burning Buildings : A Guide to Fireground Safety – Vincent Dunn

Links to several fire studies from Peter, an architect with experience in designing high-rises

Publications of the University of Sheffield Fire Engineering Research Program Go

Arup Fire on Tall Buildings and the Events of 9/11 Go

Determination of Fire Induced Collapse Mechanisms of Multi-Storey Steel Framed Structures Go

Miscellaneous related links

AIA Building Security Through Design

Where does black smoke come from? (dark vs. light smoke explanation)

Oil rig destroyed in two hours by fire.

Elevator shaft smoke explosion Boston Go

Physicist Manuel Garcia Jr.: The Thermodynamics of 9/11 Go

Chris Marrion of ARUP USA Go

Book: Why Buildings Fall Down (great for the layman)