Determination of steel emissivity for the temperature prediction of structural steel members in fire

H. Sadiq, M. B. Wong, J. Tashan, R. Al-Mahaidi, X. L. Zhao

Research output: Journal article publicationJournal articleAcademic researchpeer-review

33 Citations (Scopus)


A numerical method, with which experimental results were processed, was adopted to measure the total emissivity of mild steel specimens at high temperatures. This method is derived from considering the transient thermal energy equilibrium between a steel specimen and its surrounding heating environment. As a first step to validate this method, the results obtained at a low temperature were compared with those using infrared thermographic techniques, and a good correlation of 87% was achieved. The numerical model was then extended to high temperatures to investigate the variation of emissivity of steel with temperatures. The convective heat transfer coefficient used in the numerical model was examined in great detail using results obtained from transient high temperature tests. The emissivity of steel obtained from this study shows that steel emissivity varies over a range of temperatures and the variation becomes more abrupt between 400 and 500°C. Formulation for the emissivity of steel at rising temperatures is recommended for steel design in fire.

Original languageEnglish
Pages (from-to)167-173
Number of pages7
JournalJournal of Materials in Civil Engineering
Issue number2
Publication statusPublished - 2013
Externally publishedYes


  • Convection
  • Emissivity
  • Heat transfer
  • Radiation
  • Steel
  • Temperature

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Materials Science(all)
  • Mechanics of Materials


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