Abstract: The response time of the trigger elements of permanently installed glass barrel sprinkler installations can be shortened by the use of special expanding liquids having a low heat capacity coupled with rapid heat absorption. In particular, lower alkyl homologs of benzene such as, for example, toluene and o-xylene, or halogen derivatives of hydrocarbons such as, for example, tetrachloroethylene, are more suitable for this purpose than the hitherto used expanding liquids based on alcohols. However, aliphatic hydrocarbons of medium chain length, lower cycloaliphatic hydrocarbons, esters of ketocarboxylic acids and simple lower ketones can also be used. The fast response of the glass barrel sprinklers allows fires to be fought at an earlier stage and reduces the water requirement and hence the installation costs.