The effects of high ambient temperatures on gypsum plasters

Abstract

Gypsum plasterboard, widely used for internal partitions in building structures, has been shown to suffer rapid dehydration when heated between 60° to 125°C in the laboratory, under humidity conditions representative of those found in normal buildings ($\text{≏13}$ mm Hg water vapour pressure).

This dehydration could have important consequences for the use of gypsum in some building situations, since loss of water leads to cracking, powdering and loss of fire resistance.