Pipe Freezing 1

[lci]

I am looking for data on pipe freeze protection without heat tracing. I would like to find references on how to calculate the minimum flowrate through a 8" water line that will prevent the pipe from freezing at ambient temperatures less than -20F.

Thank you,

 

[aviat]

It would depend on the material pipe is made of, whether pipe is insulated, temperature and purity of water,or if heaters will be used on the pipe.
The site below has some formulas and calculators that may help or you may contact them for more info.

http://www.thermomegatech.com/freezepro.html

Go to bottom of page and click on application profile #3.

 

[MANHOLE]

u need to use a copper tube type k .040 guage, i hope it will help

 

[TBP]

From the "Handbook Of Data Sheets For Solution Of Mechanical Systems Problems" (I'm not making that title up, either) that has just shows the solution to just such a problem, and the example (believe it or not) is the minimum flow required to protect an 8" water line at -20*F. It says the minimum flow rate needs to be 5 USGPM for every 100 feet of pipe. This is with a 40*F water temperature. The example is for 250 feet of line, so the required flow is 12.5 GPM. If the line is insulated, the bleed flow can be cut about in half to 6.25 GPM. If there are sustained winds of over 15 MPH, it suggests doubling the bleed flow to 25 GPM.

 

[kyong]

TBP,
It's difficult for me to understand how come the flow rate should depend on pipe length. Oh, I see. The water cools down along the pipe! Then water temperature 40 deg F should mean start temperature, I think. And required flow rate should directly depend on start temperture. This is an interesting problem sometime I could also confront with. In that regards, I am going to write down the name of the handbook.

Thanks, ici and TBP.

kyong