Attachment welds at openings

[AMinati]

Usually we weld all our openings (nozzles, tubes, fittings, etc.) on vessels by means of full penetration welds even if it is not required or neccessary. We think this way is more stiffer and can withstand much more loads, etc.

Every time our AI require us to calculate and check on vessels the minimum dimension of the weld tw or tc (see UW-16). But if the welding details are according to figg. UW-16.1 sketchs (a), (b), etc. UW-15 (b) write it is not required or not?

Best regards

AMinati

 

[metengr]

Your AI is following the correct approach for their dusties to check calculations.

 

[metengr]

sorry typo - should be duties.

 

[AMinati]

But if these calculations are not required why we have to check this leg dimenions?

Best regards

AMinati

 

[metengr]

AMinati;
Yes, this is required to be validated by the AI.

 

[doct9960]

AMinati,

Here's a National Board article about the AI's responsibility for dimensional inspection...

http://www.nationalboard.org/index.aspx?pageID=164&ID=223

Read the third paragraph under Design Requirement Translation.

 

[AMinati]

Thank you to all

UW-15(b) states that strength calculations are not required if the manufacturer uses certain attachment details. However, each of those attachment details require the manufacturer to make a simple size (not strength) calculation. Even the simplest attachment detail requires the manufacturer to calculate the size of the attaching fillet-weld based upon material thickness. After calculation, the required dimension of the fillet weld is stated on the fabrication

This means that if I put in our drawings for all full penetration welds exempted by the code a 3x3 fillet welds it is Ok and enought or not?

Best Regards

AMinati

 

[AMinati]

I have done confusion beetwen design and drawing (in my language is quite similar)! Now all is clear

Many tanks

AMinati

 

[doct9960]

The simple size calculation for fillet welds means calculating the the weld size based on the material thickness. For example, you need to show how you came up with the value of tc. UW-16(b) shows how you can come up with the minimum value for tc.