Permanent attachment to another permanent attachment distance

[Syahar1975]

Dear Experts,

For material group IV and above, API 650 para 5.8.1.1 does not cover the distance between permanent attachment to another permanent attachment nearby.

For example, fillet weld the anchor chair's pad and and fillet weld pad plate for vertical ladder are welded to the shell plate both. But API 650 does not address the minimum distance of these 2 fillet weld.

Any comment ?

Syah

 

[IFRs]

The standard says permanent attachment welds should be 6" from a reinforcing-plate fillet weld. It would be safe to use this guidance and keep the fillet welds around adjacent permanent attachments 6" from each other.

 

[Syahar1975]

Dear IFRs,

Thanks for the response.

But by the code it is not mandatory isn't it ?

I mean we can keep as it is without relocating the orientation and elevation of the permanent attachments to maintain 6" rule.

Syah

 

[IFRs]

When the standard is silent on an issue, you have to use good engineering judgment. Your (and your customer's) appetite for risk need to be evaluated. If any risk is unacceptable be conservative. If both of the weldments were high stress items or with large temperature differences, I would feel different than if they were both low stress attachments. In your case one is high stress during a potentially unlikely event and the other is a nothing. Unless your heat affected zones overlap and the metalurgy of the anchor attachment is negatively affected it may be OK. If there is any question, move the ladder support to meet the more restrictive condition included in the standard. If you can't move it you can improve your comfort level by doing some additional NDE, perhaps hardness testing to identify the heat affected zones, MT or PT to detect small surface cracks, UT or RT to detect internal discontinuities, etc. Sometimes we move things like this just so there is no question from a future inspector or owner. You have a large, expensive piece of equipment whose cost of failure is so far greater than the near zero cost of moving the ladder pad. I'd just move it and be done with it.

 

[Syahar1975]

Dear IFRs,

Thanks for your reply.

Syah