An exploratory investigation into moisture content and wind impact on the fire behaviour of modular living walls

Abstract

Vertical greenery systems (VGS) consist of vegetation biomass and organic materials as well as plastics or metal elements in supporting systems. In this work, we investigate fire properties of live and dead plants as part of complete VGS systems (living walls, LW). Small-scale tests using a cone calorimeter and medium-scale tests using the SBI method were used to determine reaction to fire properties. Full-scale experiments were carried out to approximate the flame spread with and without wind along a living wall. Highly moist plants lead to slower spread of the fire, but have not prevented spreading the fire on the plastic potting, which in all cases was eventually involved in the fire and burned down to a collapse. On dry vegetation and without wind, the vertical flame spread velocity was up to 90 cm/s, and horizontal up to 2.7 cm/s. Wind conditions have changed the living wall fire performance, accelerating the fire spread on the vegetation and the fire of plastic potting as well. For moist samples in PN-B 02867 test the test duration (until full destruction of the facade) was 2100 s without and 1150 s with wind. For dry samples, this was 1350 s and 590 s, respectively.