In engine coolants, propylene glycol is mainly used to reduce the freezing point of the liquid, thus preventing the cooling system and the engine from corrosion, overheating and freezing.
In burst protection liquids, propylene glycol, with its inherently high boiling point, lowers vapour pressure. When fluids freeze they expand in volume, which can cause pipes or other containment vessels to rupture. When a water-glycol mixture becomes colder, it retains its flow ability and does not create added pressure in pipes or vessels. This makes it an ideal solution for burst protection in pipe and containment systems.