I see it as a serious Flaw in your and Contractor's working style, while designing
piping/pipeline, Stress calculations are carried out to determine where and how many supports
are required, from the pictures provided, it appears that designing phase is bypassed.
Anyway since you wanted to know about Design of supports, please find as described below:-
*For Pipeline:- ASME B31.4 clause 404.9.1, if pipeline is operated above 20% of SMYS (specified
metal yield strength) then support must be attached to full encircle reinforcement (ATTACH NOT
Welded)
*For Pipeline:- ASME B31.8 clause 834.5, if hoop stress is greater than 50% then support must
be welded to full encirclement reinforcement (Welded to 2 180deg RF PAD)
*For Piping:- ASME B31.3 allows to weld support with RF PAD.
*For Pipeline:- AS2885 states that if pipeline is operated above 50% of SMYS, a support and
clamp shall completely encircle the pipe, when it is necessary to provide positive attachment,
the pipe may be welded only to encircling member,support shall be encircling member not
directly to pipe.
To conclude, Support welding to pipeline/piping is prohibited, greater %of Yield strength is
reserved exclusively for hoop stress utilization, so no introduction of additional stresses by
rigid welded to the pipe restraint is welcome.
Another factor to consider is that for pipelines, a non-metallic PTFE pad are provided in
between of encircling member and pipeline,it is placed to avoid corrosion of pipeline with
direct contact.
Regards
Manpreet Singh
On Fri, 10 Feb 2012 15:47:25 +0530 wrote
>Dear All,
Need your suggestions on both the cases as given in these photos.
My contractor has done these, his stand is that if welding of theses are to be avoided, then
there will be problems during installation & will result in leakage during Hydrotest.
Request you all to provide your suggestions to avoid these in future.
Regards,
Vimal Kumar.
--
>
To post to this group, send email to materials-welding@googlegroups.com
>
To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
>
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
>
The views expressed/exchnaged in this group are members personel views and meant for
educational purposes only, Users must take their own decisions w.r.t. applicable
code/standard/contract documents.
>
 |
| Follow Rediff Deal ho jaye! to get exciting offers in your city everyday. |
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
No comments:
Post a Comment