Propylene Glycol Industrial Grade (PGI) is often used as an active ingredient in engine coolants and antifreeze, offering benefits including:
- Low freezing point
- The ability to decrease the freezing point of water
- Burst protection
- Low mammalian toxicity
- Low flammability
- Excellent heat transfer properties
- A high boiling point, low vapor pressure
Some types of propylene glycol-based coolants or antifreeze can provide engine protection comparable to ethylene glycol-based systems, most notably in aluminum engines.
When most fluids freeze they expand in volume, which can cause pipes or other containment vessels to rupture. When a water-glycol mixture freezes, 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.