Chilled Water Piping Sizing

[SRBKDW]

What is a typical value that is used for sizing chilled water piping. I've heard that 10'head loss/100' of pipe is a good rule of thumb. Any advice is appreciated. Thanks.

 

[remp]

Use 300-450 pa/m.

 

[ChasBean1]

ASHRAE 2001 Fundamentals, Ch. 35:

1-4 ft friction loss per 100 ft of pipe; 2.5 ft as mean. For noise, keep velocity less than 4 feet per second (fps) for 2&quot; dia. and smaller pipes. For greater than 2&quot; dia., keep PD <4 ft per 100 ft pipe. If you reduce air and turbulence, you can exceed the 4 ft limit.

There are also tables in Ch. 35 that indicate:

4-10 fps for general service
3-7 fps for city water (per Crane & Carrier)
2-5 fps for city water (per Grinnell)
6-15 fps for boiler feed
4-7 fps for pump suction & drain lines

And max. water velocity to minimize erosion is 10-15 fps range, depending on hours of operation during the year.

 

[imok2]

SRBKDW, Get a hold of a Bell and Gosset system syzer calculator The normally used design range is 100 to 500 mil inches/ft of pipe

 

[ChasBean1]

mil inches/ft?

 

[TD2K]

I think the term 'mil inches/ft' is a pressure drop term in terms of head, head being the mil inches.

mil inches of water per foot of pipe essentially.

0.25 mil inches/ft is about 1 psi/100' (if I'm right).

 

[quark]

If I am correct, mil inches seems to be a redundant term.
1 mil = 1/1000 th of an inch.(generally used to figure out corrosion, mils/year)

100 mils = 0.1 inch and 500 mils = 0.5 inch
so for 100 ft, it is 10 to 50 inches which is 0.83 to 4.2ft/100ft. So the values given by Imok seems to be ok.

Regards,


Believe it or not : Eratosthenes, a 3rd century BC true philologist, calculated circumference of earth with the help of a stick and it's shadow. The error was just 4% to the present day calcuated value.

 

[imok2]

YOU guys need to get B&G system syzer I'm not talking about thickness

 

[imok2]

This is friction loss