chilled water pipes recommended velocilty

[etchyHA]

hi all

i need to know the velocitiy range of ch. water recommended for horizontal vertical pipes , risers & headers at a (sch.40)steel pipe.
thanks

 

[bman289]

etchyHA,

I assume you mean both horizontal and vertical pipes. If you have access to the Carrier System Design Manual, look in Part 3, Chapter 2 for basic design rates. My ROT was to design small pipes at max 5 ft/sec and large pipes at 10ft/100ft of friction loss. Also, get a copy of Cameron Hydraulic Data, great resource for pumping, piping. If your piping is inside, over a suspended ceiling, be careful of your velocities for noise reasons, if your in an industrial plant or where noise is not a primary concern you can run the velocity a little higher. Have you done your head loss calculation, do you have a max head your limited too?

bman289

 

[etchyHA]

hi bman

i look at ch.2 water piping i used to use a max.velocity of 8 fps the table recommend a velocity reaches 15 fps at header design.. i feel confused .
no, i didnt do the i didnt design the net yet what do u mean by a limited head loss?
head loss is the frcition head

thanx again
etchy,,

 

[Engineer6512]

I typically would use a max velocity of about 6 feet/sec but it depends on numerous factors... can you tell us a bit more about your design?

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[HVAC68]

Recommended Water Velocity
--------------------------

Pump discharge - 8 to 12 fps
Pump suction - 4 to 7 fps
Header - 4 to 15 fps
Riser - 3 to 10 fps

Maximum water velocity to minimize erosion based on normal operation in hours / year
---------------------------

1500 hrs/year - 15 fps
2000 hrs/year - 14 fps
3000 hrs/year - 13 fps
4000 hrs/year - 12 fps
6000 hrs/year - 10 fps
8000 hrs/year - 8 fps

Velocity is only one part of the selection. Also check the friction loss in feet of water per 100 feet. I normally use in the range of 1.5 to 6.




HVAC68

 

[cme]

pipes less than 6" .... 100-500 millinches/ft of pipe ... B&G system sizer

6" and larger .... 6 fps max

also correct for glycol percentages

 

[etchyHA]

hi again

steam guy,
my project consists of a 4 stores villa, chillers are on roof c.l= 8o T.R. i used 2 carrier chiller each 4o T.R.

hvac,
the recommended velocity for pump discharge and suction u mean the velocity at headers attached to the pump or the supply & return pipe after ?

 

[AEBuck]

Speaking for HVAC68, who provided a very good response, he/she meant suction and discharge piping connected directly to each pump. Stay closer to 4 on the suction side if you can.

In addition, for piping that passes near to acoustically-sensitive areas, I would not exceed 7 FPS.