Replacing Glycerin with Propylene Glycol 1

[FFP1]

I have a steel pipe antifreeze system which currently is filled with glycerin, but the concentration (& freeze temperature) is too low. Can anyone confirm for sure whether or not we can drain the glycerin and replace the antifreeze solution with a proper mixture of propylene glycol (approved for fire protection systems of course). I am a little concerned about the residual amounts of glycerin which will still be in the system piping after we drain as much as possible from the system piping. Both are glycerin based, but I am simply not sure if this might create a problem of some sort. Thanks.

 

[stookeyfpe]

You are substituting one glycol creating material for another. They both have approximately the same mole weight and are only different based on the number of alkyl alcohols. You should be fine.

 

[chevy4x4trucks]

Just be sure their is no cpvc on the non-antifreeze portion of the system (if their is a non-antifreeze portion) as glycol is not compatible with cpvc.