Pro/Forums - View Single Post - Would it be bad to use a T connector on it's side?

bobkoure · 01-24-2005, 09:24 AM

I just did a web search and the closest answer I can find is in this plumbers handbook.
If you look on page 35
HEAD LOSS (H) = A x (Q/N)(squared)
A = fitting loss factor (see table)
Q = flow rate in liters/sec
N =calculation factor for DN100B

Now, guessing a bit about the ID/OD relationship of "nominal" metric copper tubing sizes - I would guess that nominal DN15 is actually about 1/2" ID. (Speaking of guessing - I'm also guessing you're using 1/2" ID)

Look on page 36 for 'N' values for DN15. There are several types of copper tubing - you're not using copper tubing, so the best we're going to get is a guesstimate. I'd use 0.1

Now look at page 37, "Fitting loss factors - A"
Under DN15 / 'T's , there's
Branch (turn the corner) 0.122
Flow (straight through) 0.046

You didn't mention what pump you were using. pHaestus did a pump comparison which might have your pump listed.

I'm going to guess 1GPM (or about 0.063 L/sec)

So, you've got
headloss = A x (Q/N)(squared)
Branch 0.122 x (0.063 / 0.1)(sq) or .122 x 39.69 or 4.8
Flow 0.046 x (0.063 / 0.1)(sq) or .046 x 39.69 or 1.8

So using the branch offers about 2.7 times the head loss as straight through (pretty much the same as the relationship in 'A' values) but your flow will go down as resistance goes up, which means your head loss goes down.

I'm pretty sure head loss is in meters, so, refer back to pHaestus' table see what 4.8M head loss will do to your flow.

Erm... pretty bad, isn't it. Maybe it's really head loss in cm. Maybe I did something else wrong. Maybe it really is pretty bad.
Anyone else?
Feel free to call me an idiot/moron/sloppy thinker/missed something important

Bob
PS: Apropos plumbing, I just got a call from our commonhouse (like a clubhouse - I live in a cohousing community) that there's the sound of running water and a big puddle in the furnace room. I'm off to go deal with US sized pipes...

01-24-2005, 09:24 AM	#2
bobkoure Cooling Savant Join Date: Feb 2003 Location: USA - Boston area Posts: 798	I just did a web search and the closest answer I can find is in this plumbers handbook. If you look on page 35 HEAD LOSS (H) = A x (Q/N)(squared) A = fitting loss factor (see table) Q = flow rate in liters/sec N =calculation factor for DN100B Now, guessing a bit about the ID/OD relationship of "nominal" metric copper tubing sizes - I would guess that nominal DN15 is actually about 1/2" ID. (Speaking of guessing - I'm also guessing you're using 1/2" ID) Look on page 36 for 'N' values for DN15. There are several types of copper tubing - you're not using copper tubing, so the best we're going to get is a guesstimate. I'd use 0.1 Now look at page 37, "Fitting loss factors - A" Under DN15 / 'T's , there's Branch (turn the corner) 0.122 Flow (straight through) 0.046 You didn't mention what pump you were using. pHaestus did a pump comparison which might have your pump listed. I'm going to guess 1GPM (or about 0.063 L/sec) So, you've got headloss = A x (Q/N)(squared) Branch 0.122 x (0.063 / 0.1)(sq) or .122 x 39.69 or 4.8 Flow 0.046 x (0.063 / 0.1)(sq) or .046 x 39.69 or 1.8 So using the branch offers about 2.7 times the head loss as straight through (pretty much the same as the relationship in 'A' values) but your flow will go down as resistance goes up, which means your head loss goes down. I'm pretty sure head loss is in meters, so, refer back to pHaestus' table see what 4.8M head loss will do to your flow. Erm... pretty bad, isn't it. Maybe it's really head loss in cm. Maybe I did something else wrong. Maybe it really is pretty bad. Anyone else? Feel free to call me an idiot/moron/sloppy thinker/missed something important Bob PS: Apropos plumbing, I just got a call from our commonhouse (like a clubhouse - I live in a cohousing community) that there's the sound of running water and a big puddle in the furnace room. I'm off to go deal with US sized pipes...