# Hydraulic Head Loss (minor) loss coefficient References?

1. Jul 13, 2018

### Oleg Fomin

Hi all,
Quick question:

What do you guys use as your reference for minor head loss coefficients (k).

I'm sure those with more experience have their own database/excels of k values found over the years. I have been personally using a combination of my Hydraulic Engineering Textbook and Google. However I have recently come across something which stumped me. I cannot seem to find the loss coefficient for a cross pipe fitting anywhere (I looked at three different textbooks).

I can understand why this is such a rare tidbit of information, as I've personally haven't seen a cross fitting in actual use until now, but still... someone somewhere must have run a head loss test. :)

2. Jul 13, 2018

### Staff: Mentor

Do you mean a tee?

3. Jul 13, 2018

### Oleg Fomin

No, It is an actual cross fitting (not sure of a better term for it) with the flow turning 90°

I'm attaching the picture of what I'm talking about, the flow is outlined in yellow, and the other two branches are stopped with valves.

4. Jul 13, 2018

### Staff: Mentor

So it’s basically an elbow?

5. Jul 13, 2018

### Oleg Fomin

At the moment, that's how I'm treating it in my calculations, but the actual fitting has four 8" pipes entering it at right angles, so I wasn't sure, if that would affect flow more so than just a rounded elbow.

Surely there will be more turbulence/vorticity around the other two unused openings, but perhaps their effect is negligible.
This leads me to a related question, what will have a bigger impact: flow direction change or the internal geometry of the fitting?

6. Jul 13, 2018

### Staff: Mentor

Maybe adapt the result for a tee, since the flow in each half of the tee looks something like what you have? At least compare the equivalent results for a tee and an elbow. How accurate does this thing have to be (since it’s probably only a small part of the total network)?

7. Jul 13, 2018

### Oleg Fomin

You're right, the loss for this particular fitting is not as important to the total losses, especially so because the flow tends to slow down by this point.
I guess I was just looking for confirmation from other people that this is indeed something rare, and not something I was misreading or overlooking and also if there were perhaps a more reliable reference for these values than textbooks (something more along the lines of Steel/concrete manuals for structural design, but for hydraulics).