Freeze Suppression Applications

The combination of glycol or glycerin with water results in the suppression of the freeze point. Depending on the customer's local climate requirements, concentrations from 30% to 60% are appropriate.

G2 can blend an appropriate mixture, with or without inhibitors to meet system environment conditions to -60F.

Propylene Glycol (PG)

PG is generally the glycol of choice in environments with the potential for human exposure, because of its low toxicity relative to other choices.  At a concentration of greater than 35% propylene glycol with water, there is no expansion of the fluid as it turns to slush in most application environments, freezing solid at approximately -35°F. Higher concentrations of PG will suppress both the temperature of ice crystal formation and ultimate freezing.

Ethylene Glycol (EG)

In applications where exposure to humans and animals is minimal, EG is the best choice for performance and effectiveness.  It suppresses both slush and freeze points several degrees better than PG in the most common concentrations of 30%-50%.


Glycerin is becoming more widely used as a sustainable freeze suppressant as it is a by-product of the manufacturing process for bio-diesel, which continues to grow as a sustainable fuel. Glycerin is not as effective in freeze suppression and a higher concentration is required relative to either PG or EG.  That said, many mainstream antifreeze blends contain a mixture of glycerin and PG as a cost effective product safe for freeze protection in water systems, portable toilets, and oilfield applications.