Flame Heights and Heat Transfer in Façade System Ventilation Cavities

Research output: Contribution to journalArticle


The design of buildings using multilayer constructions poses a challenge for fire safety and needs to be understood. Narrow air gaps and cavities are common in many constructions, e.g. ventilated façade systems. In these construction systems flames can enter the cavities and fire can spread on the interior surfaces of the cavities. An experimental program was performed to investigate the influence of the cavity width on the flame heights, the fire driven upward flow and the incident heat fluxes to the inner surfaces of the cavity. The experimental setup consisted of two parallel facing non-combustible plates (0.8 × 1.8 m) and a propane gas burner placed at one of the inner surfaces. The cavity width between the plates ranged from 0.02 m to 0.1 m and the burner heat release rate was varied from 16.5 kW to 40.4 kW per m of the burner length. At least three repeated tests were performed for each scenario. In addition, tests with a single plate were performed. The flame heights did not significantly change for Q′/W < 300 kW/m2 (where Q′ is the heat release rate per unit length of the burner and W is the cavity width). For higher Q′/W ratios flame extensions up to 2.2 times were observed. When the distance between the plates was reduced or the heat release rate was increased, the incident heat fluxes to the inner surface increased along the entire height of the test setup. The results can be used for analysing methodologies for predicting heat transfer and fire spread in narrow air cavities.


External organisations
  • Danish Institute of Fire and Security Technology
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Other Civil Engineering


  • Flame height, Flow velocity, Heat flux, Ventilated façade
Original languageEnglish
Pages (from-to)689-713
JournalFire Technology
Issue number3
Early online date2018 Feb 5
Publication statusPublished - 2018
Publication categoryResearch

Related research output

Karlis Livkiss, 2020 Feb 28, Division of Fire Safety Engineering, Lund University. 133 p.

Research output: ThesisDoctoral Thesis (compilation)

View all (1)