An aqueous fire sprinkler fluid containing a C4 or greater carboxylate salt for freezing point depression is described. The salts may be used in conjunction with glycols. The salts decrease the combustibility and give lower viscosity than higher glycol fluids, both benefitting fire sprinkler systems. These salt solutions are friendly to metal and CPVC pipes and are thus useful for fire sprinkler systems by not causing environmental stress cracking of the CPVC components and not being corrosive to the metal parts.