Propylene Glycol as an Antifreeze

[Ian_Edwards]

If I use Propylene Glycol as an antifreeze, which I think, has a very low toxicity and isn't as damaging to the environment.
Do I use it neat (out of the container) or do I premix with water?
If it is premixed with water, what ratio do I use to give frost protection to say -20 deg C? The Marina got down to -17 deg C last winter!
Can I use Propylene Glycol in my freshwater system as well as the heads and domestic waist pipes?
I assuming that if I do use it in the freshwater system and I flush the tanks well before use next season, there won't be any side effects, is this correct?

 

[VicS]

Propylene glycol is used where a low toxicity is required.

I think you will probably find it in caravan/RV places for protecting the domestic water systems. Freeze Ban comes to mind. A little investigation suggests that a 35% solution will protect to -20 C and 50% to -33C. Further investigation needed though

PG engine antifreezes may not be all that readily available in the UK.
You would have to ensure that it contains an inhibitor package suitable for the target engine if you intend using it as an all year engine coolant rather than just for winterisation.

I feel the most practical at the moment is to stick to an ethylene glycol antifreeze for the engine but use a PG antifreeze for the domestic water system.

Maybe someone knows of suitable PG engine coolants which are readily available in the UK

 

[JumbleDuck]

If I use Propylene Glycol as an antifreeze, which I think, has a very low toxicity and isn't as damaging to the environment.

Ethylene glycol isn't terribly nice stuff to swallow, but environmentally it's not too bad. See www.who.int/ipcs/publications/cicad/en/cicad22.pdf‎ for the WHO's official view of it.

 

[Ian_Edwards]

I did some more searching on Propylene Glycol

I found this:

"For many heat-transfer applications it is necessary to use a heat-transfer fluid with lower freezing point than water. The most common antifreeze fluid -ethylene glycol - must not be used where there is the slightest chance of leakage to potable water or food processing systems.

In food processing systems the common heat-transfer fluid is based on propylene glycol."

So it looks like Propylene Glycol is the correct stuff to use for a potable water system.

I also found a reference to being added to ice cream.

29% by volume give protection to -14 deg C and 40% by volume protection to -22 deg C

So I've just ordered a 5L container of "food grade" Propylene Glycol container to give it a try.

 

[JumbleDuck]

In food processing systems the common heat-transfer fluid is based on propylene glycol."

So it looks like Propylene Glycol is the correct stuff to use for a potable water system.

Yes. Ethylene glycol is fine for engines, though, and does little harm if it escapes.

 

[Angele]

LeeFreeze non toxic antifreeze

LeeFreeze is a non toxic antifreeze for fresh water systems installed in boats, RVs and caravans.
It will protect the system down to -15°C, is safe, odourless & tasteless.
5 litres of LeeFreeze mixed with 5 litres of water (to make 10 litres of solution) is sufficient to treat the freshwater system on an average boat with 2 sinks, a shower and calorifier.
The solution should be added to an empty water tank and pumped around the entire system.
The system should be flushed thoroughly with fresh water when re-commissioned.
Leefreeze can also be used at full strength for boat engine winterisation.