Influence of Horizontal and Vertical Barriers on Fire Development for Ventilated Façades

Abstract

Although using various innovative materials for ventilated facade systems positively contribute to the energy efficiency of buildings, the application of such materials can also pose a certain risk of fire propagation through the fac¸ade. In the last decade, medium and large-scale tests, as well as numerical analysis have been performed to assess the impact of fire barriers on fire propagation through ventilated fac¸ades. However, the number of fire barriers and their specific positions can also have an effect on the fire safety of facades, which has not been studied. Consequently, the question arises whether real fire exposure on a fac¸ade can be adequately simulated and analysed in sufficient detail, by using large-scale testing methods. This paper aims to conduct a parametric analysis on a broader range of large-scale samples by using the procedure given in the standard BS 8414-1:2015 + A1:2017. To understand better the impact of the number and position of cavity barriers for different types of insulation materials (stone wool/PIR/phenolic foam) used in modern fac¸ade systems with non-combustible cladding (ACM-A2). Seven tests were carried out in Croatia between October 2017 and April 2018. In the case of combustible insulation, two horizontal barriers were insufficient in preventing fire propagation. Temperatures accumulated above 600°C, reaching 840°C in PIR insulation and 979°C in phenolic foam insulation. For the same sample designed with non-combustible insulation, the maximum temperature measured was 133°C. Facades with combustible insulation passed the test only when four horizontal barriers were used. The existence of vertical barriers had a positive impact on preventing the fire propagation because the insulation on the left side of the chamber, behind the vertical barrier, remained undamaged. Vertical barriers on the right side of the chamber delayed the horizontal fire propagation from the main wall to the wing wall depending on the type of insulation. The results from these tests can serve as a basis for future research on the effects of fire barriers on fire propagation.

A Critical Appraisal of the UK’s Regulatory Regime for Combustible Façades

“…In the tests commissioned by MHCLG at BRE, the publicly available test reports, show notable differences between the early fire growth rates from the wooden cribs with faster fire growth occurring consistently on test wall 2. A similar effect was reported from the RISE/Zagreb tests [26,32], when run outside on days with different wind speeds. Table 2 shows significant variation in the time taken from t s for the temperature to reach 300°C at level 2.…”

“…The UK government reports do not include air velocity data. The fourth and fifth columns of Table 2 show the time taken for the temperature to reach 300°C in the tests undertaken by RISE in Zagreb [26,32]. The test wall was located outside, with the first three tests being conducted in spring, with a wind speed between 2 m s -1 and 5 m s -1 and the last three tests in summer, with Table 2 Time to Reach 300°C in UK Government Tests [31] and in RISE Tests [26] Test number a wind speed varying between 0 m s -1 and 2 m s -1 .…”

Fire risk of apparel manufacturing buildings in Sri Lanka

“…Chang and Huang (2005) have discussed about the rate of fire growth based on the exponential growth, which explains the effect of the fire growth coefficient of burning material. Accordingly, Čolić and Pečur (2020) have found that fires spread both horizontally and vertically within the building. Common reasons for horizontal fire spread are open of fire doors, breakdown of compartment walls, extinction, ventilation conditions and to balance of fuel supply.…”

Flame behaviour, fire hazard and fire testing approach for lightweight composite claddings – a review

“…Due to the sudden fire growth, it leaves the cavity barrier ineffective in most cases (Building Regulations, 2010). The use of non-combustible insulation materials especially horizontal fire barrier with 300 mm and reducing the air cavity in the cladding system can delay the fire spread effectively (McKenna et al , 2019; Peng et al , 2013; Zhou et al , 2016) (Čolić and Pečur, 2020; Chen et al , 2019a). Besides, the use of mineral wool as a non-combustible fire barrier in each storey is an effective measure that can slow down the fire spread in real-time (Xin et al , 2013; Zhou et al , 2016; Zehfuß et al , 2018; Hofmann et al , 2018).…”