PVC pipe dimensions - did I just screw up?!

[Shirak]

Found this interesting chart the other day for deciding drain size ID based on flow. https://hy-techroofdrains.com/water-flow-through-a-pipe/

How Much Water Can Flow Through A Pipe (GPM/GPH)?​

We regularly get asked about the water flow capacity of different pipe sizes, and which is the best roof drain for a specific pipe size. Unfortunately, recommendations aren't that straightforward because you also need to account for water pressure, material friction and more.
That said, we put together the following tables to serve as general guides for estimating a pipe's water flow capacity through a pipe or roof drain.

Water Flow (GPM/GPH) based on Pipe Size and Inside/Outside Diameters​

			Assume Gravity to Low Pressure. About 6 f/s flow velocity, also suction side of pump	Assume Average Pressure (20-100PSI). About 12 f/s flow velocity	Assume "High Pressure" PEAK flow. About 18 f/s flow velocity
Pipe Size (Sch. 40)	I.D. (range)	O.D.	GPM (w/ min. PSI loss & noise)	GPH (w/ min. PSI loss & noise)	GPM (w/ min. PSI loss & noise)	GPH (w/ min. PSI loss & noise)	GPM (w/ min. PSI loss & noise)	GPH (w/ min. PSI loss & noise)
1/2"	0.5 - 0.6"	0.85"	7	420	14	840	21	1,260
3/4"	0.75 - 0.85"	1.06"	11	660	23	1,410	36	2,160
1"	1 - 1.03"	1.33"	16	960	37	2,200	58	3,480
1-1/4"	1.25 - 1.36"	1.67"	25	1,500	62	3,750	100	6,000
1-1/2"	1.5 - 1.6"	1.9"	35	2,100	81	4,830	126	7,560
2"	1.95 - 2.05"	2.38"	55	3,300	127	7,650	200	12,000
2-1/2"	2.35 - 2.45"	2.89"	80	4,800	190	11,400	300	18,000
3"	2.9 - 3.05"	3.5"	140	8,400	273	16,350	425	25,500
4"	3.85 - 3.95"	4.5"	240	14,400	480	28,800	700	42,000
5"	4.95" - 5.05"	5.563"	380	22,800	750	45,000	1,100	66,000
6"	5.85 - 5.95"	6.61"	550	33,000	1100	66,000	1700	102,000
8"	7.96"	8.625"	950	57,000	1900	114,000	2800	168,000

 

[Shirak]

Have not compared it to other charts but based on the information a 3/4" ID pipe with gravity flow would be good for 660 GPH

 

[kilnakorr]

Have not compared it to other charts but based on the information a 3/4" ID pipe with gravity flow would be good for 660 GPH

Yes, I've seen this chart and I should be fine with my 3/4" pipes.
It seems the stores here are mixing sch 40 and and sch 80, without giving such info.
I'm just glad I noticed it, before I glued the hosetail to the rest of the pipes

 

[Stigigemla]

The reason why we use outer diameter as measurement in Europe is that elbows and other connections always fit on a 25 mm tube . If it has thin walls for 6 bar or thicker for 10 or 16 doesnt matter. It just fits. Most usual is tubes for 10 bar max pressure. Called PN6, PN 10 or PN16.
A 25 mm PN16 should have 1,9 mm thick walls so it should be 21,2 mm inside. Tubes for higher pressure is very rare.

 

[kilnakorr]

The reason why we use outer diameter as measurement in Europe is that elbows and other connections always fit on a 25 mm tube

Yes. And it makes great sense.
I just wished that stores would list the wall thickness, or at least keep same thickness throughout the fittings.
When ordering online one would assume all fittings in the same diameter category, would have same wall thickness and inner diameter.
Especially when there is just one option.

I cannot order a 25mm bend and 25 mm tee and expect to get same inner diameter.

So, I have to contact each store and ask for inner diameter of each fitting and then order pieces from several stores. That is what I find really frustrating.

 

[Stigigemla]

In Denmark You should have European standard fittings. Many times called GF. Then a bend or a tee or a tank connector should all have the same 25mm inner diameter.
On the outside they are many times different. Most (nearly all) connectors are PN16 but it also exists PN10 connectors with thinner plastics. But inside they fit 25mm tubing.
There are a few aquarium stores having American dimensions in stock but they are usually not called mm but inch.

 

[kilnakorr]

In Denmark You should have European standard fittings. Many times called GF. Then a bend or a tee or a tank connector should all have the same 25mm inner diameter.

They SHOULD have same inner diameter, but they don't and do not list it.
Only info is outer diameter.
Example of the one store within 30 min drive from my place:

PVC slangestuds

PVC slangestuds og anden godt grej

www.akvariebutikken.dk

Info translated
Hosetail 25 mm - fits 25 mm hose.

Inner diameter is just 16 mm.

 

[Stigigemla]

There are a few exceptions.
Some 25mm connectors are made to fit inside other 25 mm connectors.
A 25mm hose connector is made to fit inside a 25mm connector. To fit it to a 25 mm tube You need a Samlemuffe Ø25 (or an elbow or T)
Other are reductions. A short reduction 32/25 will fit inside a 32mm connector and outside a 25 mm tube.
Its very very strange if the person in the store dont know this.

 

[kilnakorr]

Its very very strange if the person in the store dont know this.

Discussion is getting rather long
I believe the main issue is that very few people are doing this kind of stuff, which is why only few aquarium stores even sell pvc pipes and fittings, and just small selection.

 

[Dabcrusher]

I still find it a bit confusing, since I was under the impression that the inner diameter was true to dimension while the outer diameter increased for higher pressures and thicker walls. While checking dimensions for my earlier response, I noticed that the PVC Schedules have the same outer diameter while the inner diameter gets slightly smaller with the thicker walls of Schedule 80 pipe.

I guess the answer is to always confirm the specific dimensions of each item and make sure they match other plumbing parts.

They do that so you can use 80 and 40 schedule together anything over avout an inch of scedule 80 isnt easy to cut with hand shears .recomebd if you dont have electric pipe cutters to use a circular saw.