Whats the difference between 4" schedual 80 & 40?

Date 02-25-2008 19:36

Prairiedawg,
I am sorry but I can only give you the answer in millimetres.
The OD stays the same regardless of schedule.
The ID is reduced as you move up from Schedule 5 to 10, 20,40,60 80 etc.
The wall thickness of 4" Sch 40 is 6.04 mm and Sch 80 is 8.56 mm
Hope that helps,
Regards,
Shane

By aevald

Date 02-25-2008 19:44

Hello PrairieDawg, I believe you will find that the schedule will refer to the nominal wall thickness, Pipe will remain sized according to it's O.D. dimension and as the schedule changes, so will the I.D. and the nominal wall thickness. One other note, even though it is referred to as 4" pipe, it is not really 4" O.D., instead it is measured as 4 1/2." I have a pocket pipe chart from Tri Tool Inc. There are many others available through a lot of different sources, if you can, see about getting one of these and it will answer many of the questions that you may have about this. Also, I believe you will find a large difference when you are comparing pipe to round tubing, tubing is referred to by it's O.D. directly when called out for size, example: 4" round tube will measure 4" O.D., the other dimensions related to tubing will be called out according to wall thickness and associated I.D. Hope this helps somewhat. Best regards, aevald

By CWI555

Date 02-25-2008 19:58

Prairiedawg,

Here is a site with a chart of pipe schedules, There are multiple others out there.
http://www.crestwoodtubulars.com/pipe_schedule.html

Regards,
Gerald

By PrairieDawg (*)

Date 02-25-2008 20:36

so according to shane and that chart the only difference should be the wall thickness right?

By Kix

Date 02-25-2008 20:53

Yes, wall thickness and ID will be different.

By NDTIII

Date 02-26-2008 03:29

On a standard pipe chart, the diameter for a pipe up to 12" is the ID measurement. After that it is the OD measurement. So with 4" Sch. 80 & 40 the only difference will be the wall thickness. The ID is the same the OD will be difference due to the wall tickness.

By aevald

Date 02-26-2008 03:40

Hello NDTIII, I believe you may have stated your information incorrectly. For verification look at the chart that is linked to Gerald's post. Respectfully, aevald

By James Corbin (**)

Date 02-26-2008 03:52

Refer to the web chart CWI555 recommended.
When Pipe is noted its measured by nominal ID so the OD remains the same and can be threaded. (For pipe thread plumbing connections, which has been around way longer than welding it)
When Tube is noted its OD actual size by wall thickness unless otherwise noted.

By NDTIII

Date 02-26-2008 05:34

Thanks aevald. I stand corrected. I've been bass ackwards all this time. You see old dogs can learn new tricks.

By js55

Date 02-26-2008 14:37

The key to the confusion is in the idea of 'nominal'. As James stated.

By swnorris (****)

Date 02-27-2008 14:17

Nominal is just a fancy word for "so called". Also, since the o.d. stays the same and the wall thickness increases, the weight increases as well.

By PrairieDawg (*)

Date 02-27-2008 19:28

okay this question is screwy then. Because with 4" schedule 40 and 80, as the wall thickness increases the ID decreases. Is that correct?

But with the question is gives you the options, OD, ID and wall thickness.

By aevald

Date 02-27-2008 19:48

Hello again PrairieDawg, one of the other posters called it out the best and most understandably, I believe. Since a lot of pipe is threaded, the O.D. needs to remain constant and is listed according to most pipe charts with the actual O.D. being slightly larger than diameter that is called out(4" pipe is measured at 4.5" and so on and so forth). As the schedule number increases, 5, 10, 40, 80, 160, etc. the wall thickness increases and the I.D. decreases and as someone else stated the weight of the pipe increases as well. Hope the confusion isn't still present. Best regards, Allan

By js55

Date 02-27-2008 20:09

NDT III had it partially correct. Up to 12" the diameter is nominal. 14" and up the diameter is actual (within ASMT spec tolerances of course). But the wall thickness in either case comes off the ID.

By aevald

Date 02-27-2008 23:22

Hello Gerald, I believe a part of the confusion over this comes from perspective. Pipe sizes from 1/8" to 12" are not sized on the O.D. to match the size they are called out as. 14" and up they are called out on the O.D. according to the size they are called out at. Examples: 1/2" pipe actually measures .840 on the O.D., 3" pipe actually measures 3 1/2" on the O.D., 14" pipe measures 14" on the O.D., sizes including 14" and greater, measure the same on their O.D. as the diameter that they are called out as. In all instances however, the O.D. of the pipe remains the same as the schedule of the pipe increases(sch. 5 being the thinnest, sch. 10, sch. 40, progressing upwards, indicating thicker wall pipe), the wall thickness will increase, this is not to say that the sch. # is specific with regard to thickness, for different diameters of pipe sch. #'s there can be different thickness values. Thus different wall thicknesses for different sizes of pipe will indicate smaller I.D. dimensions as the schedule numbers increase, the O.D. however, will remain the same. Don't mean to beat a dead horse so to speak, but I guess I haven't been able to let this one rest. Best regards, Allan

By dbigkahunna (****)

Date 02-28-2008 00:24

Sch 40 0.237
Sch 80 0.337
or 0.100 inch