What temperature F does water freeze at 65 PSI ?

1. Dec 12, 2011

gary350

What temperature F does water freeze at 65 PSI ???

I looked this up online but all I find is stuff I already know and lots of advertisements. It makes me mad to clink on a link that forces me to look at an advertisement and when I try to click to leave it will NOT let me leave. All I have learned so far is what I already know, water freezes at 32 deg F, highest density is 39 deg F, only substance know that can exist in all 3 states, gas, liquid, solid. A soft drink will freeze at 29 deg F. Water freezes at 2 bars. Water boils at 70 deg F in a vacuum. Flowing water will not freeze at 32. SO WHAT!!!

What I need to know is how does pressure effect the freezing point of water. There has to be a formula to calculate this?

Water pressure in my house is 65 PSI at what temperature F will water in the pipes freeze?

Last edited: Dec 12, 2011
2. Dec 12, 2011

256bits

Re: What temperature F does water freeze at 65 PSI ???

Here is a site with the pressure/temperature phase diagrams of carbon dioxide, helium and water.
http://www.chem.queensu.ca/people/faculty/mombourquette/Chem221/5_PhaseChanges/PhaseDiagrams.asp

You will notice that all three have what is called a triple point, which is where all three phases ( gas, liquid, solid ) co-exist. Other substances behave similarly. Your statement is not accurate at all.

A litle bit lower than 32 degrees F, but not much. Probably not even 31 degrees F.

3. Dec 12, 2011

nasu

Re: What temperature F does water freeze at 65 PSI ???

Some of the things that you found/know are not quite right or are somehow ambiguous. So is hard to answer the "SO WHAT!!!".

The change in melting point with pressure is very weak. For the pressure you are interested (65 psi) the answer in first approximation will be 0 Celsius (or 32 F). The correction due to the increased pressure (about 4 atm) is of the order of a few hundredths of degree.
Phase diagrams are available in many places, for example here:
http://www.lsbu.ac.uk/water/phase.html

An empiric formula is for example here:
http://en.allexperts.com/q/Physics-1358/2009/1/freeze-point-water-under.htm [Broken]

Last edited by a moderator: May 5, 2017
4. Dec 12, 2011

gary350

Re: What temperature F does water freeze at 65 PSI ???

I have been out of college too long 40 years, I have forgotten more than I ever knew. I clicked the links but I don't see anything about the exact temperature water will freeze under pressure.

There was a TV show a few days ago the guy was talking about winterizing a house. He said turn the heat down low but leave the water on because water under pressure is less likely to freeze.

If I put a soft drink in the freezer for about 1 hour then remove it, it is not frozen but when I open the bottle it will instantly freeze solid.

I remember in college class we put a glass of room temperature water in a vacuum and it boiled. I don't know what the exact temperature the tap water was.

Last edited: Dec 12, 2011