calculating actual min thickness as an inspector

Inspection is to ensure proper performance under all expected circumstances. This means you will always have to consider external forces as well as the function of the system. If the part the pipe connects to can sway in the wind, you will need to make sure your pipe can deal with this. If not the consequences can be extremely expensive so it pays for itself.

For data on pipes please go and google it yourself. You need a lot more info than what you have given here.

I guess when the vessel is inspected by a ASME inspector ,they just check it (THICKNESS)for pressure calculations,since external loadings doesnt fall under code purview.

Similarly wind,seismic analysis and nozzle loadings are not as per any ASME codes(B31.3-piping or VIII-1 Boiler and pressure vessel) and varies from place to place,and therefore it shall be the responsibilty of the designer to consider all the loads while arriving at a suitable thickness considering all the loading types.

In the realm of most piping carrying gas, oil, or hazardous liquids (as opposed to water, etc) , it is important to differentiate between the responsibilities of an inspector and the engineers responsible for the operation thereof.

The inspector should be familiar with both the Codes and the prints/specs that are applicable to what is being inspected ... and should be given an idea as to what the "pass/fail" criteria will be prior to initiating the inspection. That way, if he begins to see measurements that are closely-approaching the "fail" criteria, he knows that he must interrogate that area more diligently (closer-grid) so as to not MISS the absolute minimum measurement that exists there.

For API pipelines, w/t spec for brand new pipe is typically +/- 6% of the standard tabulated values. For P/L's operating near their Maximum Allowable Operating Pressure, concerns are usually elevated when remaining w/t reaches -12.5%.

Unless you are taking degreed engineers and forcing THEM to do 'double-duty' as field-inspectors, it is NOT the inspector who needs to take into account any external loading factors ... (though during the inspection, the inspectors SHOULD be verifying the existence of hangars, supports, etc., per the prints) ... It is the engineer who takes loading factors into account, and interprets the results of the inspector's data.

Previous 2 replies are wrong!

If the design states certain conditions which pre describes a safety factor of any given value, it is most definitely up to the inspector to ensure these "assumed" conditions are correct. If it blatantly is not, and he or she failed to conclude as such, the inspector will be held responsible for the failure if such occurs. This makes it, albeit indirectly, necessary for the inspector to take external condition in to account to a degree.

If however you are talking about the non destructive engineers who are given a table of wall thicknesses to check, then it is NOT up to them to take external forces in to account as they are told to check to the spec sheet. I would NOT CALL this guy the inspector. He or she is just doing the measuring. The inspector is the person responsible for the certification of the system and as such he or she is much more responsible.

I agree this question leaves some room for interpretation but given the seriousness of the possible results I would always like to state the SAFEST reply reflecting the worst case scenario.

Oh...? Would you please be so kind as to break them down, line-by-line, and explain your justification for stating "Wrong!"...? To begin with, the original post leaves a bit to the imagination, insofar as who the inspector is, and exactly what it is that he wants to do.

If you're saying that it is NOT necessary to differentiate between the responsibilities of an inspector versus an Engineer-in-charge of pipeline operation, then I'd sure like to review the Certification Schema for inspection personnel in your locale...!

However, I can see in your paragraph (italicized below) that you DO place some kind of emphasis on this:

"If however you are talking about the non destructive engineers who are given a table of wall thicknesses to check, then it is NOT up to them to take external forces in to account as they are told to check to the spec sheet. I would NOT CALL this guy the inspector. He or she is just doing the measuring. The inspector is the person responsible for the certification of the system and as such he or she is much more responsible."

In this statement, you have seemingly clarified that on your side of the big pond, the guys to whom WE refer as "Inspectors" are actually (in your tongue) the "Engineers", and the person to whom you refer as the "inspector" is what we would call an Engineer.

You are certainly welcome to "disagree" ~ don't get me wrong. However, based on the ambiguity in the original post, I think that if you would sit down with an English major and dissect the 2 posts which you so vehemently denounce, you will find that there are most certainly some worthy validities therein contained.

Regards ~

Sorry about that, I meant to say previous post number 2 is wrong.

Your post is correct and I do appologise. The other one got me in a knot and I responded from the hip.

You correctly pointed out, as I did, the differentiation to be made as to what or who you call an inspector. As such the design is done by engineer, inspector certifies if it is done correctly and the ndt guy just measures.

The inspector have a job as an inspector not as a piping engineer. The inspector shall ask the piping engineer for any work related to piping design.