CE808: Structural Fire Engineering – Research Project Impact of Design Fires on Performance of Steel Beams Under Fire Conditions CE808: Structural Fire Engineering – Research Project Megan Vivian April 18th, 2008

History of ASTM E119 What you might not know… ASTM E119 Swedish Curves Comparison SAFIR Analysis Conclusions What you might not know… American Society for Testing and Materials First published in 1918 To specify a standard time-temperature curve for pass/fail criteria for structural elements Designed to provide a comparative measure between structural members and building construction assemblies Provide one factor in assessing fire performance We’ve studied it and used it a lot this semester … but …

ASTM E119 Fire Curve The Good The Bad Easily reproduced ASTM E119 Swedish Curves Comparison SAFIR Analysis Conclusions The Good Easily reproduced Used as a standard for comparison Provides good relation to building contents, materials of construction, and ventilation conditions The Bad Could be un-conservative for engineering design Represents an intense fully developed fire within a building Not always the scenario Does not accurately model every fully developed fire The development, growth, and decay of the fire depend upon the building contents, materials of construction, and ventilation conditions Very simple and easy too use But is it too simple?? Not well enough defined for specific cases? Should only be used for comparison not as the only factor to determine fire performance (which is typically the case)

ASTM E119 Fire Curve The Good The Bad Easily reproduced ASTM E119 Swedish Curves Comparison SAFIR Analysis Conclusions The Good Easily reproduced Used as a standard for comparison Provides good relation to building contents, materials of construction, and ventilation conditions The Bad Could be un-conservative for engineering design Represents an intense fully developed fire within a building Not always the scenario Does not accurately model every fully developed fire The development, growth, and decay of the fire depend upon the building contents, materials of construction, and ventilation conditions Very simple and easy too use But is it too simple?? Not well enough defined for specific cases? Should only be used for comparison

Design Fire Curves Swedish Design Fire Curves ASTM E119 Swedish Curves Comparison SAFIR Analysis Conclusions Swedish Design Fire Curves Published in 1970 by P. Jumppanen Modeled to represent real fire curves Derived from heat balance calculations Use Kawagoe’s equation for burning rate of ventilation-controlled fires Curves reflect the effects of changing fuel load and ventilation during the course of a real fire Varying fuel loads and ventilation factors available Scenarios Model fires that reach post flashover and use all combustibles Model fires that consider a slower fire with a longer duration Model fires that follow a hydrocarbon fire (much hotter!!)

The Fire Curves ASTM E119 Swedish Curves Comparison SAFIR Analysis Conclusions Shown here is the standard ASTM curve The few curves that reach post flashover The curves that are slow growing and maintain lower temperatures The curves that have short duration and quick cooling rates The hydrocarbon fire curve

Thermal Analysis ASTM E119 Curve FV02100 Design Curve ASTM E119 Swedish Curves Comparison SAFIR Analysis Conclusions Used the same 2-hour rated protected steel beam for analysis with varying fire curves ASTM E119 Curve FV02100 Design Curve

Temperature Domain Failure ASTM E119 Swedish Curves Comparison SAFIR Analysis Conclusions For presentation only discuss temperature domain failures – did study the deflection criteria as well with structural analysis Temperature at 2 hours in the lower flange of steel beam If our temperature domain criteria is used at about 530°C … two curves fail the protected steel beam ASTM is the fourth worst case scenario One fire curve doesn’t even reach 120°C!

Maximum Temperatures Scenario Temperature (C) Hydrocarbon 559.5 ASTM E119 Swedish Curves Comparison SAFIR Analysis Conclusions Scenario Temperature (C) Hydrocarbon 559.5 FV08800 533.5 FV12900 505.3 ASTM E119 469.2 FV08400 379.6 FV04200 318.8 FV02100 235.7 FV12225 167.7 FV08100 114.0 NIST WTC Workshop, Szoke

Conclusions ASTM E119 Swedish Curves Comparison SAFIR Analysis Conclusions ASTM E119 is useful for comparing performance between structural members and construction assemblies To determine actual fire performance for a specific member or fire scenario, design fires should be considered Can be completed with computer modeling (furnace testing would be very expensive) Using most applicable curves - could run multiple tests to determine worse case scenarios Even design fires cannot exactly match real fires Difficulties measuring combustible content of assemblies and precise type or quantity of building contents If the fire curve could be more properly modeled… Safety factors could be improved upon Huge impact on design and industry standards How to make better fire curves… Possibly use a heat-flux time curve to make a better model