In the present paper, the performance of an innovative thermal insulation rigid board is evaluated in terms of fire behaviour and fungal resistance. The board is based on vegetal pith and a natural gum (corn pith and sodium alginate) and it is completely compostable. This new composite was developed in previous work. Here boric acid, aluminium hydroxide and ammonium polyphosphate are used as fire retardants and montan wax, acetic acid and lactic acid are used as water repellent and fungicides respectively. Interactions between these different treatments is investigated. Both flaming and smouldering combustion processes of the different formulations are evaluated by small-scale techniques which include pyrolysis microcalorimetry and thermogravimetric analysis. A medium-scale device is also designed in order to study the impact of the different additives to the smouldering kinetics. Fire behaviour tests show that good improvement is obtained, both in flaming and smouldering combustion when boric acid is added. Although smouldering is not avoided in any case, the addition of 8% of boric acid or aluminium hydroxide slows down the speed of combustion propagation. The effect of the different additives on the moisture content and mould growth at 97% RH and 27 °C is analysed. Under such severe conditions none of the additives is able to prevent mould growth, with the exception of boric acid. None or marginal mould growth was observed on samples containing 8% of boric acid although moisture content was higher than the other cases.Peer ReviewedPreprin

The building sector is one of the highest energy consumers representing around 30% of total energy use. One of the recommendations of the IEA (International Energy Agency) to reduce energy consumption in buildings is to enhance the thermal performance of building envelopes. In the present study, PCM (Phase Change Material) gypsum materials have been manufactured using three different PCM inclusion methods and a thin layer of gypsum without PCM is added as external layer with the aim of improving the fire reaction behaviour. By performing a detailed physical, mechanical and thermal characterization, the suitability of the materials to be implemented in the building envelope as inner coating is demonstrated. Results show that also the thermal properties are improved in the three cases by the addition of PCM. Moreover, the negative effect of adding paraffin wax PCM into gypsum against flame can be easily reduced by the addition of a thin gypsum layer, which is a low tech and cheap solution without extra environmental impact.Peer ReviewedPreprin

Rammed earth is considered a very sustainable construction system due to its low embodied energy, long service life and high recyclability. However, authors found that there is a lack of experimental results at real scale regarding rammed earth thermal behaviour. For this reason, this paper is first focused on the characterization of two different types of earth in order to check the suitability of being used in rammed earth walls. After the characterization, two experimental cubicle-shape buildings were built in Barcelona and Puigverd de Lleida (Spain) in order to test the thermal behaviour of their walls in two different climatic conditions. Temperature profiles inside walls have been monitored using thermocouples and temperature profile of southern walls was analysed in free floating conditions during summer and winter periods of 2013. Results show that thermal amplitude from outside to inside temperatures are decreased by rammed earth walls, achieving constant temperatures in inner surface of southern walls.