Fire behavior of regular and latent heat storage gypsum boards D. A. Kontogeorgos* ,† , I. D. Mandilaras and M. A. Founti National Technical University of Athens, School of Mechanical Engineering, Laboratory of Heterogeneous Mixtures and Combustion Systems, Heroon Polytechniou 9, Zografou Campus, Athens 15780, Greece SUMMARY This paper investigates the fire behavior of a regular and an energy storage gypsum board with latent heat storage characteristics when exposed to fire temperatures. Gypsum board samples, with and without a microencapsulated paraffin mixture phase change material, are studied at material and board level. At the material level, measurements of the physical properties, that is, mass and effective thermal conductivity, as a function of temperature, as well as differential scanning calorimetry experiments, in inert and oxidized environments, are performed. At the board level, specimens are inserted into a preheated oven, and the tem- perature evolution at preselected board locations is recorded. Both experimental procedures reveal signifi- cant information concerning the evolution of the various thermochemical processes taking place inside the gypsum boards during their heating. Results indicated the different fire behavior of the samples at differ- ent temperature ranges. At temperatures up to 300°C, the materials act as a fire retardant because of the dehydration of the free and chemically bound water contained in the gypsum boards. On the other hand, at temperatures higher than 300°C, the temperature rise within the samples is enhanced and accelerated because of the oxidation of the phase change material and their external finishing. Copyright © 2014 John Wiley & Sons, Ltd. Received 26 July 2013; Revised 13 February 2014; Accepted 27 February 2014 KEY WORDS: gypsum board; phase change materials; fire temperatures; small-scale experiment; differential scanning calorimetry 1. INTRODUCTION Gypsum boards (GBs) are building materials, which are widely used as facing materials for building walls and ceilings because of their very good mechanical and thermal properties, as well as their fire endurance. The latter is owed to the endothermic dehydration process that takes place at fire temperatures [1–4], which is capable of slowing down the fire spread through GB-based systems [5–7]. This phenomenon can be of great importance from the fire safety point of view providing sufficient building evacuation times. Conventional GBs consist of a gypsum-based core material that is covered on both sides with a thin layer of paper or other protective material that enhances the stability and the integrity of the core. The gypsum-based core is a porous material that consists mainly of calcium sulphate dihydrate (CaSO 4 · 2H 2 O) (>65 wt %), which contains up to 21% by weight chemically bound water and a small amount of absorbed free water (≤4 wt %) [5,8, 9]. In some cases, the GB core may also contain calcium carbonate (CaCO 3 ) and/or magnesium carbonate (MgCO 3 ) [10, 11]. *Correspondence to: D. A. Kontogeorgos, Laboratory of Heterogeneous Mixtures and Combustion Systems, Thermal Engineering Section, School of Mechanical Engineering, National Technical University of Athens, Heroon Polytechniou 9, Polytechnioupoli Zografou, Athens 15780, Greece. † E-mail: dimkon@central.ntua.gr Copyright © 2014 John Wiley & Sons, Ltd. FIRE AND MATERIALS Fire Mater. (2014) Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/fam.2246