I have been advised, that I can put salt into a trap to prevent the water from freezing in building I do not use much during tough part of the winter. I know I need to remove all water from pipes where possible, but I would like to avoid manually sucking the water from traps, especially from toilets.
My questions:
-
can I use road salt, or is it safer to use the salt used for human consumtion? In other words – is something wrong in road salt that could damage the pipes?
-
what is correct dosage of road salt (for sink, toilet) if I do expect about -20 degress celsius as the lowest outdoor temperature possible (small building).
Best Answer
Your plan is OK except that -20C is about the lowest you are going to get protection with NaCl (i.e. common salt). Here is a graph of freeze point vs. concentration. You really cannot get a higher concentration than about 23% since excess salt precipitates out.
I think you'll be better off using an anti-freeze product.