Sensitivity Study on Using Different Formulae for Calculating the Temperature of Insulated Steel Members in Natural Fires

Zhang, Chao; Li, Guo Qiang; Wang, Yongchang

doi:10.1007/s10694-011-0225-x

Cited by 22 publications

(9 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Here, the simplifications and assumptions for calculation in post-flashover fires [8,[18][19] were applied to calculate the temperature of a circular CFT column fully engulfed in a localized fire,…”

Section: Temperature Of Circular Cft Columnsmentioning

confidence: 99%

Simple Approach for Performance-Based Fire Safety Design of Circular CFT Columns in Lage Enclosure

Wang¹,

Zhang²,

Li³

2016

Volume 12 Number 1

Self Cite

View full text Add to dashboard Cite

ABSTRACT:The usage of concrete filled steel tubular (CFT) columns in large space buildings is increasing. Flashover is unlikely to happen in a large enclosure and the localized fire model is preferable to model the fire environment in a large enclosure fire. This paper proposed a simple approach to evaluate the fire resistance of circular CFT columns in localized fires. Simple model was provided to calculate the column temperatures in a localized fire. The concept of equivalent fire severity or time equivalent was used to correlate the localized fires with the standard fire. The simple model used in the Chinese code was used to calculate the load capacity of the circular CFT columns subjected to the equivalent standard fire exposure. The proposed approach, by correlating real fires with the standard fire, only includes heat transfer analysis and avoids the complex structural analysis, which provides an easy and efficient way for performance-based fire safety design. A case study is also provided to demonstrate the application of the approach. INTRODUCTIONConcrete-filled steel tubular (CFT) columns have many advantages, including high load carrying capacity, fast construction, small cross-section, and high fire resistance. These attractions have enabled CFT columns to be used in many large space, and high-rise buildings [1].Traditionally, the fire resistance of CFT columns is determined by a standard fire resistance test conducted on an isolated member subjected to a specified heating such as ASTM E119, ISO834. The standard fire resistance test is time consuming and expensive, and the dimension of the test specimen is limited by the size of the furnace. As an alternative to the test method, calculation approaches are also developed to assess the fire resistance of CFT columns [1][2][3][4][5]. Lie and Chabot [2] developed a mathematical model to calculate the temperatures and fire resistance of circular CFT columns. In the model, the cross-section area of the column was subdivided into a number of concentric layers to calculate the column temperatures, and a finite difference method was applied to solve the heat transfer equations. The strength and stiffness was calculated by subdividing the cross-section area into a number of annular elements. The representative temperature of an element was taken as the average temperature of the layer in which the element was located. In the Eurocode EC4-1-2 [3], a simple model is provided in the Annex H to calculate the fire resistance of CFT columns by subdividing the cross-section area into several elements and respectively calculate the strength and stiffness accordingly. Kodur [4] proposed a simplified equation based on the results of parameter studies supported by an experimental program on circular and square CFT columns under fire. The equation is widely used in North America, and it directly provides the fire

show abstract

Section: Temperature Of Circular Cft Columnsmentioning

confidence: 99%

Simple Approach for Performance-Based Fire Safety Design of Circular CFT Columns in Lage Enclosure

Wang¹,

Zhang²,

Li³

2016

Volume 12 Number 1

Self Cite

View full text Add to dashboard Cite

show abstract

“…Equivalent Thermal Resistance of Intumescent Coatings Figure 2 shows the one-dimensional (1D) heat transfer model used for calculating the temperature of steel members insulated by coatings [21,22]. Due to its high conductivity, the temperature gradient within the steel section has been ignored in the model.…”

Section: Thermal Conductivity Of the Charmentioning

confidence: 99%

“…Ignoring the heat absorbed by the insulation materials, by energy balance the steel temperature can be calculated by [21] 534 Fire Technology 2012…”

Section: Equivalent Thermal Resistancementioning

confidence: 99%

“…ECCS [19], CECS [20]. Those simple formulae are, however, only applicable to situations where the properties of the insulation materials are or can be treated as constant or temperatureindependent [21]. This paper intends to develop a simple procedure to determine the equivalent constant thermal resistance of intumescent coatings for calculating the limiting temperatures by simple formulae.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Assess the Fire Resistance of Intumescent Coatings by Equivalent Constant Thermal Resistance

Zhang

Lou

et al. 2011

Fire Technol

Self Cite

View full text Add to dashboard Cite

Intumescent coatings are now the dominant passive fire protection materials used for steel construction. Intumescent coatings will react at high temperatures and the thermal properties of intumescent coatings can not be measured directly by the current standard test methods which are originally designed for the traditional inert fireproofing materials. This paper proposed a simple procedure to assess the fire resistance of intumescent coatings by using the concept of equivalent constant thermal resistance. The procedure is based on the approximate formula for predicting the limiting temperatures of protected steel members subjected to the standard fire. Test data from investigations on both small-scale samples and full-scale steel members are used to calculate the equivalent constant thermal resistance. Using the equivalent constant thermal resistance of intumescent coatings, the calculated steel temperatures agree well with the test data in the range of the limiting temperatures from 400°C to 600°C. The procedure needs no complex computation and is recommended for practical usage. The equivalent constant thermal resistance could be used to quantify the insulation capacity of intumescent coatings.

show abstract

“…Correspondingly, the temperature of exposed members can be easily determined by interpreting the homogenous gas temperature as the effective black body radiation temperature and as the same gas temperature for convection calculation. At present, various formulae are provided by fire codes in different countries for calculating the temperature of steel members in post-flashover fires [2][3][4]. However, for pre-flashover or localized fires, the distribution of gas temperature is spatially non-uniform.…”

Section: Introductionmentioning

confidence: 99%

Fire Dynamic Simulation on Thermal Actions in Localized Fires in Large Enclosure

Zhang

Li²

2012

Volume 8 Number 2

Self Cite

View full text Add to dashboard Cite

ABSTRACT:Large enclosures commonly exist in many buildings like atria, open car parks and airport terminals. There is an international trend to prompt performance-based method (PBM) for fire resistance design. By PBM, the temperatures of structures in design fires should be determined. Localized fires are always adopted as design fires in large spaces. Currently, no agreed calculation method is available for the calculation of the heat flux from a localized fire to a vertical column. This paper aims at providing a feasible way of calculating the thermal actions in localized fires. Particularly, gas temperatures in localized fires and heat transfer from localized fires to steel vertical columns have been numerically investigated. The popular CFD code FDS is adopted as the numerical tool. A design fire scenario and four real localized fire tests are simulated in FDS. The effects of input parameters, including grid size and number of solid angles, on the accuracies of the numerical results have been investigated. Numerical results are compared with correlations and test data, which shows good agreement. INTRODUCTIONA compartment fire will generally undergo six stages which include ignition, growth, flashover, full fire development or steady burning, decay and extinguishment. Flashover is the rapid transition between the primary fire which is essentially localized around the item first ignited, and the general conflagration within the compartment when all fuel surfaces are burning [1]. Depending on whether flashover will happen or not, the real fires are usually divided into pre-and post-flashover fires. For small and middle scaled compartments with sufficient fuel and ventilation, the potential fires will develop to flashover and be characterized as post-flashover fires. For large scale enclosures or where sprinklers work effectively, flashover is unlikely to occur and the fires are characterized as pre-flashover fires. Post-flashover fires provide the worst case scenarios which are usually considered in fire resistance design. However, localized heating of key elements of structure in pre-flashover fires must be also considered.For post-flashover fires, the gas properties within the compartment are approximately uniform that temperature-time curves are usually adopted to represent the fire environments. Correspondingly, the temperature of exposed members can be easily determined by interpreting the homogenous gas temperature as the effective black body radiation temperature and as the same gas temperature for convection calculation. At present, various formulae are provided by fire codes in different countries for calculating the temperature of steel members in post-flashover fires [2][3][4]. However, for pre-flashover or localized fires, the distribution of gas temperature is spatially non-uniform.

show abstract

Sensitivity Study on Using Different Formulae for Calculating the Temperature of Insulated Steel Members in Natural Fires

Cited by 22 publications

References 12 publications

Simple Approach for Performance-Based Fire Safety Design of Circular CFT Columns in Lage Enclosure

Simple Approach for Performance-Based Fire Safety Design of Circular CFT Columns in Lage Enclosure

Assess the Fire Resistance of Intumescent Coatings by Equivalent Constant Thermal Resistance

Fire Dynamic Simulation on Thermal Actions in Localized Fires in Large Enclosure

Contact Info

Product

Resources

About