Wouldn't just plain logic prevail and cause you to use non-toxic food grade anti-freeze such as Propylene Glycol . . . . even without regulations dictating it ?
The procedures are another thing. I once had a plumbing company winterize the house, and instead of draining and plowing out the pipes . . . . they pumped all of them full of that same non-toxic anti-freeze, which dissolved 100 years of mineral deposits.
It left me with a house that took about 4 days of continuous running of water through the system before it would run clear enough for a water test to be submitted. The water was a thick opaque liquid like chocolate milk for days . . . . I thought it would never end. Now I always check to make sure nobody makes that mistake again.
Dale C. Hittle of GOLDEN RULE PROPERTIES in Glover, Vermont
Where We're Always Striving To Put Together "THE FAIR DEAL"