ASME B31.1 reinforcement areas

[19750412]

Hi All.

Before i get a questions, small introduction to subject. Now I’m working in some project of main steam pipelines which are designed and manufactured according to European standard EN 13480. Due to fact that this standard dose not allow to design straight tees in creep range my subcontractor used to design of them ASME B31.1, what is allowed in EN 13480. The materials used to construction of complete pipelines fulfill requirements of adequate European material standards for different products as pipes and forgings and it is X10CrMoVNb9-1 what is comparable with ASME SA 182 F91 for forgings, (material for tee). The strength calculations according to ASME B31.1 has been proceeded based on ASME material to fulfill requirements of standard.

And now i have two questions.

1. Dose red marked area on attached sketch can be considered as reinforcement area A4 as is defined in point G.6.3 or on sketch (c) in fig. 104.3.1(G)?
2. Is it allowed to use such designed tee for pipeline which must work 200 000 h, as required EN 13480, having on mind that ASME give allowable stresses in creep range based on lifetime 100 000 h.

Thanks for help.

Arti

 

[DSB123]

Answers are : -

1. If the area is within the reinforcement zone then it can be considered.
2. Does 100 000hr = 200 000hr ? Answer is no. Therefore 200 000hr stresses must be used. However where in branch reinforcement calcs does the stress come in ? Answer - it doesn't it's an area replacement approach.

 

[19750412]

Thanks DSB123 for answer.

Regarding answer to question 1, no doubts.

Regarding question 2, it is true that in reinforcement calculation allowable stresses are not necessary, but they are used to determine minimum wall thickness of pipe and branch, what have direct influence to reinforcement calculation. And base on this, my question has been raised.

Arti

 

[ColonelSanders83]

I have a question rather than an answer.

I notice the fitting has listed an SIF of 1 on the drawing. I assume that this SIF refers to the SIF of the Tee junction itself. This seems a little low, but if it has been tested and proven than it should be fine. However I notice that this fitting contains three tapers transitions from the thick tee material to the pipie wall thickness.

Is the tapered transition SIF being taken into acount at each of the fitting to piping joints (per B31.1 this could e as high as 1.9)?

A question properly stated is a problem half solved.

Always remember, free advice is worth exactly what you pay for it!

http://www.ap-dynamics.ab.ca/