SDR calculation

[mcgearailt]

How do you calculate the SDR of a pipe for a pipe network? I presume there are charts available but I dont know how to get these.

 

[bimr]

try Unibell:

http://www.uni-bell.org/

http://www.uni-bell.org/faq.html#q4

 

[Ussuri]

Look in any technical catalogue from a supplier.

The SDR is:

SDR=(Pipe Outside Diameter/Pipe Wall Thickness)

The pipe wall thickness is calculated from a pipe wall stress analysis. The approach below is from the Wavin technical catalogue:

Hoop Stress = (P/2)*(SDR-1)

Where P is maximum pressure.

An allowable pressure (PFA) can be calculated as follows:

PFA = (2*MRS)/(alpha*(SDR-1))

Alpha is a design factor. Wavin use 1.25.
MRS is minimum required strength. PE80 is 8MPa and PE100 is 10MPa at 20 celsius for a 50 year design life.

http://www.wavinpdfs.co.uk/pdfType.asp?id=6

 

[mcgearailt]

How do you know which SDR relates to which pressure capacity or stiffness? Is there a chart that can allow you to find the relevant SDR (independant of pipe size) for each pressure? It possible that the above formula for MRS and PFA can be manipulated in order that an SDR be calculated so I presume i have my answers!

Thanking you both kindly. Appreciated.