Scope of Radiogrpahy

[ak1965]

100 % RT on a A333Gr.6 piping weld joints with hazardous service of NGL at low temp. -30 deg.C & 40 kg/cm.2, is justifiable or not?

Some standards support it and some not !

For better reliability and safety involved, we have carried out 100% Radiogrpahy of weld joints

Whats is your opinion

 

[TomBarsh]

Design Codes specify the minimum level of inspection and quality assurance. They do not, and should not, restrict the level of construction quality.

So, you can certainly justify any construction/inspection as being "above Code", indicating (in most cases) a better quality product (applies to any product manufactured under some governing code).

As to whether the particular design code(s) applicable to your situation requires full RT or not, that is another issue.

 

[ak1965]

Thank you TomBarsh.....you are right it is minimum level....

in our case, we have given more emphasis ro safety and reliability an upper edge over the standard,which in my opinion is a guideline and not always a mandatory requirment.

 

[moltenmetal]

I've seen people spec 100% RT on services less hazardous than the one you've mentioned. I've also seen people spec random spot RT at 5% including 1 shot min per welder (ie. code minimum per B31.3) for services more hazardous than yours. It's an owner's judgment call fundamentally based on experience. Do you routinely see a lot of bad quality welding? Is this a new or suspect shop doing the work? Had serious accidents related to weld failures? Then spec more RT.

Just don't think that 100% RT is going to come at zero additional cost. There will be false positives and unnecessary re-work. But with 100% RT, the welders will definitely know that someone is watching...

 

[ak1965]

Thank you Moltenmetal,

Knowing that RT is in QAP, welders do get more attentive and the repair rate eventually has fallen.

 

[Mr168]

On our questionable jobs, we will start out at 100% RT, and if we see that all is going well, we will tailor it back some.

Given your use and service temperatures, I can't see anyone making a particularly strong argument against what you're doing.