Experimental study on vertical fire spread along a wooden façade

Abstract

The main purpose of these tests is to get some information on fire spread along a combustible façade in order to assess the ability of numerical codes [1] to simulate flame propagation. Many authors have already studied compartment fire with external flames for non-combustible façades [2][3][4] and also combustible façades [5,6]. Studies on non-combustible façade allow to describe flames (flame depth, flame height, thermal actions, etc.) and to explain the influence of geometrical parameters (opening dimensions, "U" configuration, etc.) on flame shape and flame behaviour. These studies highlight the importance of some of these parameters on vertical spread and correlations are issued from these experimental studies. If many researches on combustible façades exist, it is difficult to find academic configurations with a large instrumentation and generally, these studies focus on a facade system involving complex combustible materials (insulation or composite). That's why it was decided to perform some large scale tests to study fire spread along a vertical wood wall. EXPERIMENTAL SET-UPA principle drawing of the experimental set-up is presented in Fig. 1. The fire room is made of lightweight concrete. As a façade, a fire resistant board is set on a steel frame structure. The total area of the façade is 2.5 m × 4.9 m. The compartment is 1.5 m on a side and 1.15 m high. One side of the compartment is completely open on the façade in order to ensure well-ventilated condition inside the compartment. This test rig is really similar to the British standard façade test which is a real fire propagation test. But in the present test there is no side wall along the façade. As you can see in Table 1, three different tests are carried out. The first test is made without any combustible cladding on the calcium silicate board in order to measure the temperature and the calorific on inert façade. In the second and third tests a cladding of 18 mm thick plywood is mounted directly onto the calcium silicate board, i.e. no ventilation cavity behind plywood. In these two tests, two different type of wood are used, respectively Birch wood and Okoumé (African wood), in order to observe the influence of the essence of the wood on flame propagation and on calorific values. This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.