EFFICIENCY FOR PENSTOCKS WELDED JOINTS

[Heyner]

Hi everybody!

Would you help me define the efficiency to be applied when calculating wall thicknesses for a 1800mm dia penstock?

Which codes govern this kind of construction? Is E according to RT examination and weld detail as in ASME?

thanks a lot.

Heyner

 

[chicopee]

Check AWS code and ANSI piping code for welding joint efficiencies. Efficiency will be based on type of welded
joints w/ or w.o./ reinforcements and if joints were examined by X-ray and other methods.
ASME codes will base their efficiencies on the ANSI piping and AWS codes. Structural engineers will primarily use AWS code.
Joint efficiencies have pretty much beem standardized and will be as high as 100% for full penetration welds w.o. reinforcement to 75% for joints that did not under N.D. examinations.

 

[Bushbaby]

There are a couple fo standards relating to penstock design. If you are in Europe there is the CECT reccomendations. However, most companies use the ASCE report on engineering practice No. 79 'Steel Penstocks'. In the ASCE No. 79 table 3-3 there is a list of weld joint reduction values (similar to ASME VIII).

Hope this helps..