SDR-7 Dimensions 1

[zdas04]

I'm working on my first project where I actually have to know something about SDR-7 poly pipe and information seems to be a bit sketchy. I'm trying to model a complex gathering system that is almost all SDR-7 and I haven't been able to determine the ID of the pipe.

I've found the formula's for wall thickness required to meet the pressure-containing capacity of SDR-7, but it assumes you know an SMYS of the brand you're looking at. I haven't been able to find any SMYS data.

Does anyone have a link that would allow someone to determine inside diameter (or a table of a specific manufacturer's pipe dimensions)?

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

The harder I work, the luckier I seem

 

[vzeos]

NPS for Windows v2.2 has a comprehensive listing of pipe of various materials.
Download NPS for Windows v2.2 from the following webpage.

http://www.herne.com/down.htm

Also, the following webpage has much info on plastic pipe and fittings. I recommend ordering Performance Pipe (Plexcalc) CD-ROM (it's free), the engineering manual is very good.

http://www.herne.com/down.htm

 

[EGT01]

Have you tried any of the polyethylene pipe manufacturer's websites?

http://www.cpchem.com/enu/performance_pipe_engineering_manual.asp

 

[ApC2Kp]

zdas04,

There is table of pipe dimensions for HDPE by KWH Pipe,

http://www.kwhgroup.com/_FileRoot/322114.pdf

on page 3.

 

[ApC2Kp]

zdas04,

More tables for HDPE pipe dimensions,

http://www.isco-pipe.com/pdf/ips.pdf

http://www.isco-pipe.com/pdf/dips.pdf

 

[SlideRuleEra]

The short answer: here is a link to a typical manufacturer's catalog for IPS polyethylene pipe

http://www.vylonpipe.com/brochures/HDPEBrochure.pdf

The long answer: SDR (Standard Dimensional Ratio) defines the nominal pipe wall thickness as a ratio to the "exact" pipe outside diameter. For example, a 4" IPS polyethylene pipe has an outside diameter of 4.500". For SDR 7, the wall thickness is 4.500 / 7 = 0.643".

In this example, the shortcut to calculate the inside diameter is to multiply the outside diameter (4.500") by (5/7) = 3.21".

This works for any IPS Polyethylene Pipe & any SDR (if using SDR 21, multiply the OD by 19/21 to obtain the ID).

http://www.SlideRuleEra.net

 

[SlideRuleEra]

P.S. If using Hazen-Williams to design for water flow in a long pipeline with fused joints, don't believe that C = 150. The laboratory test method used to obtain this value appears to ignore the fact that fused lengths of pipe have a bead on both the inside & outside at each fusing location (the inside bead can be bored out, but this rarely done in the field). Based on my experience, a single length of pipe MAY have C = 150, but for a pipeline (with many fused joints) C = 130 to 140 (depending on pipe diameter) is a better number.

http://www.SlideRuleEra.net

 

[zdas04]

SlideRuleEra,
It's that simple?? I've dug through several hundred pages of murky nonsense and nothing I looked at came close to explaining it in a way that I could actually use to calculate an ID. I'm using the AGA equation in a pipeline model and in the calibration step I'll see if the weld bead is giving me any permanant reduction in efficency.

Everyone else,
Thanks for the links, there was a bunch of good information (not ID for the Imperial pipe dimensions I'm looking at, but a lot of really good information).

David

 

[SlideRuleEra]

zdas04 - It really is that simple & the SDR calcs apply regardless of units (see Figure 3 in the Wavin Polyethylene Water Systems Technical Guide)

http://www.wavin.co.uk/main/content...<>ast_id=1408474395253915&bmUID=1124840393792

If you are using any mitered fittings (especially Tees) be sure to take into consideration that they are MUCH weaker (withstand less internal pressure) than the pipe itself.

Please let us know the results your investigation of internal fusing bead effects.

Best Wishes

http://www.SlideRuleEra.net