Theoretical Question about water flow. Say I have 3/4 inch water lines in my house. I want to connect a new faucet 15 feet away from these lines. The faucet uses 1/2 inch lines. Does it matter where along that 15 feet that the transition from 3/4 inch to 1/2 inch is made? Will the amount of water output at the faucet change depending on where the transition is made?
2006-12-02 03:04:21 · 6 answers · asked by Karnak 3 in Science & Mathematics ➔ Engineering
Of course it matters! If you transition such that you have only 1 ft of 1/2 line and 14 ft of 3/4 inch line you will have a lower pressure loss than if you transition such that you have 14 ft of 1/2 inch and 1 ft of 3/4 inch. The notion that a smaller pipe diameter results in more pressure is backward.....if you want to get more people through a hallway...you make it bigger not smaller. Also...the hydraulic engineers calcs are wrong.
2006-12-02 09:25:38 · answer #1 · answered by jackwp2000 2 · 0⤊ 1⤋
Although the pressure lost on the 15 feet line will not be critical since line is very short (15 feet only) But much more important is to make connection with the T 3/4 x 3/4 x 3/4 not with T 3/4 x 3/4 x 1/2, make routing as straight as possible using long radius elbows (standard elbow is equivalent to 30 feet of pipe long radius elbow is equivalent to 16 feet of pipe). If it possible do not provide cut off valves valves are equivalent between 70 to 100 feet of line.
Make reducer on the straight run of pipe at least 6 inches from any bend or T.
Follow those rules and you will minimize pressure loss through the pipe and assure maximum discharge from faucets.
2006-12-02 22:51:12 · answer #2 · answered by Anonymous · 1⤊ 0⤋
You want to make the transition as close to the faucet and as far from the source or inlet as possible.
3/4" pipe will have a lot less friction per foot of length than 1/2" pipe. This will mean higher flow.
If you transition to 1/2" further upstream, you are constraining your flow by the higher friction in the 1/2" and the problem only gets worse the more 1/2" pipe you use.
2006-12-02 11:11:59 · answer #3 · answered by www.HaysEngineering.com 4 · 2⤊ 0⤋
Fifteen feet is not a long enough distance to make a noticeable difference in flow. For this question, I will assume that you will be flowing 10 gallons per minute, which is probably on the high side. At 10 gallons per minute, you will lose 4.58 psi through 15' of 1/2" pipe and 1.16 psi through 3/4" pipe. As the flow rate goes down, the pressure loss will also decrease. Since 10 gpm will probably be the upper end of your flow, you will likely be losing less than 3 psi even if you transition immediately from 3/4" to 1/2". Your decision!
2006-12-02 11:20:45 · answer #4 · answered by bw 2 · 1⤊ 1⤋
From my experience I would say that it does not matter where you make the joint - the effect will be the same ie - to increase the pressure of water at the outlet point - like covering half of the hole in a hosepipe to make the water shoot out further. But the actual amount of water flowing out will be restricted somewhat.
2006-12-02 11:09:45 · answer #5 · answered by Anonymous · 0⤊ 1⤋
No,
No.
Practically.
You will loose some flow on smaller diameter pipes, but too little difference on 15 feet.
2006-12-02 11:08:20 · answer #6 · answered by just "JR" 7 · 0⤊ 0⤋