PROCEDURE FOR PRESSURE TESTING? 1

[tcihvacff1]

Hi!
Please help me from i can get the procedure of pressure testing in chilled water pipe lines.....

 

[tcihvacff1]

Hi!
Please help me from where i can get the procedure for pressure testing in chilled water pipe lines...
i am a beginner please help me.....actually i wants to calculate the working pressure of a chilled water system..

 

[jkauwale]

Hi. Sorry for the delay. I typically work on military projects and the following website shows the specifications for the chilled water pressure testing that I specify.

http://wbdg.org/ccb/DOD/UFGS/UFGS 23 64 26.pdf

It involves pumping the piping system up to a specified pressure and inspecting the piping for leaks. Refer to section 3.4.2 Pressure Tests.

Do you want to calculate the pressure at any point in the chilled water system? Or are you trying to determine what pressure your chilled water piping should be rated?



Justin K, P.E.

http://www.engproguides.com

 

[tcihvacff1]

yes I wants to calculate the testing pressure for whole chilled water piping system....
Plz reflect ur experience on this..

 

[jkauwale]

If you want to calculate the pressure throughout the chilled water piping system, then you will need your pump head calculation (friction loss) and pressure at expansion tank. Start at the expansion tank (typically this is at the suction side of your chilled water pump). Let's say your expansion tank is at a pressure of 50 psig. Then move throughout your piping system.

Expansion Tank: 50 psig
Suction side of pump: 50 psig - friction losses between expansion tank to suction side of pump
Discharge side of pump: (Suction side of pump) psig + Pump Head (psig)
1st Piece of Equipment: (Discharge side of pump) - friction losses +/- elevation loses
2nd piece of equipment: (1st Piece of equipment) psig - friction losses +/- elevation losses
N Piece of equipment: (N-1) psig - friction losses +/- elevation losses

Continue going throughout your system until you get back to your expansion tank. You will have the pressure at each piece of equipment throughout your chilled water piping system.

Chilled water systems are typically tested at a pressure of 188 psig for a period of no longer than 2 hours.

Justin K, P.E.

http://www.engproguides.com

 

[tcihvacff1]

Thanks a lot jkauwale!
Really your explanation has given me a clear concept of chilled water pressure calculation...i am familiar with pump head loss calculation but i was not knowing the procedure to calculate the pressure...now i will perform this for my system & will verify it with the already calculated pressure by our senior Designers..And if required i will post you for any assistance....Thanks once again!

 

[tcihvacff1]

one more thing i want to ask u jkauwale that can i get any thumb rules or any shortcuts to calculate the pressure of a Riser pipe serving G+6 Floors building??
Example: as we use 1Tr=400cfm for TR.....any thumb rule similar to this for pressure calculation just by seeing to building height??

 

[jkauwale]

I am not sure of a rule of thumb for calculating total friction loss as function of the number of floors.

Pressure loss due to elevation - 2.31 feet equals 1 PSI.

There is a rule of thumb to estimate friction loss. Typically you take your system length, multiply by 1.5 (for fittings), then multiply by a friction rate of 4 FT of Heat per 100 ft of system length.

Friction Loss Estimate: 1.5 X (System Length [ft]) X (4 FT OF HEAD/100 FT)


Justin K, P.E.

http://www.engproguides.com

 

[tcihvacff1]

Thanks a lot jkauwale!