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DrRocket
Post  Post subject: Engineering Inspection Issues (split from "Agenda setters")  |  Posted: Mon Jun 25, 2012 3:14 pm
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MOD NOTE: This discussion was split from the politics thread, "How many agenda setters per state?" You can locate that discussion here: topic652.html


bunbury wrote:
Every engineering firm uses third party inspectors to validate the inspections done by the fabrication shop's own personnel. This includes viewing radiographic film, witnessing dye-pentrant and mag particle inspections and UT if called for, ensuring proper segregation of carbon and stainles steels, dimensional checks and so on. Engineering firms used to employ their own inspectors but it became more cost-effective to use third party firms (such as Moody International) on an as-needed basis rather than full time employees. At the end of the job another inspector, the ASME authorized inspector, makes another review and signs off on the job. There is a saying that you don't inspect quality into a product, which is true, but you also don't guarantee a good product if you neglect the inspections.


Not only is it untrue that EVERY engineering firm uses third party inspectors to validate inspections, it is a fact that in the (aerospace) company in which I was employed for many years that engineering responsibility for non-destructive inspection fell under a group that was part of a department that I managed. Not only did we perform our own inspections and validate (and more importantly understand in depth) the methods used by sub-tier vendors, we reviewed their data in detail before accepting parts and inspections. In later assignments I also authorized projects that employed several PhD physicists is developing and refining new non-destructive test methods that included radiiographic, ultrasound, and eddy-current which augmented magnetic particle and dye penetrant inspections. Understanding the data provided by non-destructive test methods was part and parcel to good engineering and an attitude of continuous improvement and rigorous process control. The general trend from this effort was to reduce variability, increase quality and reduce cost.

Furthermore, there are three levels of ASME certified inspectors and only a level three inspector is capable of developing the specific methods that are used in a given inspection and documented in the technique sheets. Reliance on an "ASME certified" inspector without further qualifification is an abrogation of good engineering discipline. Go/no-go data is not particularly useful. It is only from variables data (the detailed technical content of a radiographic inspection report for instance) that yields useful data for sound process control. If your engineers are not reading the radiographic reports in detail then they are doing all of their job.

If indeed the Pensylvannia shops provide welds with significantly lower variability that is something that should be evident from variables data obtained from inspections. With that data engineering management should be able to make an informed decision as to whether the benefits arising would justify incrreased cost. More importantly, with good variables data and attention to process control it is generally the case that one can simultaneously reduce variability and cost. In short, you should be able to work with whatever vendor you select, whether in Pennsylvania or Oklahoma, to improve quality and reduce cost simultaneously. Try Taguchi methods -- that is one simple approach to process improvement that involves little sophistication with statistical methods and has bee shown to produce significant improvements in quality and reductions in cost.

It is becoming clear to me that your problem is not a political one involving "right to work" laws, but rather lax engineering, process control, quality control discipline and management of the overall design, development and manufacturing operations -- which includes managing your vendors, knowing their processes, and helping them to improve those processes for your mutual benefit .

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bunbury
Post  Post subject: Re: How many agenda setters per State?  |  Posted: Mon Jun 25, 2012 7:11 pm
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First of all I apologize for being too broad in saying "every" engineering firm. This was indeed an overstatement. It is a true statement for the oil, gas and chemical industries that I work in. I have no specific knowledge of other branches of engineering.

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It is becoming clear to me that your problem is not a political one involving "right to work" laws, but rather lax engineering, process control, quality control discipline and management of the overall design, development and manufacturing operations -- which includes managing your vendors, knowing their processes, and helping them to improve those processes for your mutual benefit .


Why do you insist on re-interpreting my words? I do not have a problem and have never complained about anything in this thread. You are entirely wrong about every statement in this paragraph, but I'm not interested in debating issues of quality with such a rude and over-excitable individual.

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marnixR
Post  Post subject: Re: How many agenda setters per State?  |  Posted: Mon Jun 25, 2012 8:08 pm
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bunbury wrote:
It is a true statement for the oil, gas and chemical industries that I work in.


i can confirm from my own experience that not only is third party inspection normal in welded constructions for oil and gas applications, they're a specification requirement to ensure these structures are as safe as it is humanly possible to make them - even the smallest welding defect in an offshore structure or a pressure vessel can have disastrous consequences

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DrRocket
Post  Post subject: Re: How many agenda setters per State?  |  Posted: Mon Jun 25, 2012 11:28 pm
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marnixR wrote:
bunbury wrote:
It is a true statement for the oil, gas and chemical industries that I work in.


i can confirm from my own experience that not only is third party inspection normal in welded constructions for oil and gas applications, they're a specification requirement to ensure these structures are as safe as it is humanly possible to make them - even the smallest welding defect in an offshore structure or a pressure vessel can have disastrous consequences


That strikes me as rather odd. Engineering specifications generally define product characteristics, to include weld parameters and critical flaw size, and acceptable technical methods for verification. But who or what organization is to perform those verification steps is generally a matter handled by contract language, rather than by engineering specification. Whether an inspection is performed by a third part or merely a competent organization within the manufacturer or customer organization is not important. What is important is that the inspection methods be adequate and that the interpretation of the inspection data be made by people competent to understand the implications relative to the performance requirments of the product itself. That in particular means that the design engineer responsible for the part or subsystem be awarre of the results of the inspecions -- and no third party can do that.

I have also worked a bit in the oil and gas industrty and am quite confident in stating that the stringency of the requirements therein is no greater than that in the aerospace industry where human lives or payloads valued in billions of dollars depend on the integrity of each subsystem and part -- and EVERY part carries a certification of compliance with the relevant specification.

Further, if "even the smallest" defect can have disasterous consequences then you have a major problem -- specifically the inability of ANY non-destructive technique to detect arbitrarily small defects. That is why it is such an important engineering function to conduct structural and fracture analyses to determine a critical flaw size and to design the product so that the critical flaw size is larger than the detectable flaw size of the available innspection methods.

In reality I think that what you are dealing with is closer to boiler code, which does impose stringent requirements for design margin and weld quality, but which is quite a bit looser than "no flaws allowed". A "no flaws allowed" requirement is not only unrealistic but is generally a sign of lax engineering since it is simply impossible to verify compliance with such a criteria. Equally lax is to place any responsibility for product quality on politicians or "right to work" laws. Quality is the responsibility of the Engineering and Manufacturing organizations, not the Quality orgaization that merely verifies the quality of work performed and certainly not politicians.

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iNow
Post  Post subject: Re: How many agenda setters per State?  |  Posted: Tue Jun 26, 2012 3:13 am
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DrRocket wrote:
A "no flaws allowed" requirement is not only unrealistic but is generally a sign of lax engineering since it is simply impossible to verify compliance with such a criteria. Equally lax is to place any responsibility for product quality on politicians or "right to work" laws.

I'm fairly sure no one here did that. My impression of the contention being made is that these laws seem to have resulted in the unintended consequence of lowering the total available supply of well trained and apprenticed welders. Maybe I'm mistaken, though.

Also, out of curiosity (and a desire to avoid google tonight) what's "boiler code?"

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DrRocket
Post  Post subject: Re: How many agenda setters per State?  |  Posted: Tue Jun 26, 2012 4:53 am
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iNow wrote:
Also, out of curiosity (and a desire to avoid google tonight) what's "boiler code?"


It is the set of ASME requirement used for boilers and similar pressure vessels. It is a conservative set of requirements designed to provide safety and reliability through high design margins of safety. It is appropriate for many applications, but not those in which minimal weight is required for performance (e.g. rockets).

http://www.engineeringtoolbox.com/asme- ... e-d_8.html

http://now.msn.com/now/0625-new-army-uniforms.aspx

iNow wrote:
My impression of the contention being made is that these laws seem to have resulted in the unintended consequence of lowering the total available supply of well trained and apprenticed welders. Maybe I'm mistaken, though.


And my point is that blaming "right to work laws" for lowering the availability of well-trained and apprenticed welders is a specious argument. Availability of anything, including well-trained and apprenticed welders is a function of the demand for that thing. Either the welders that are available and are employed to produce the product are well-traineed (as determined by their ability to perform to the standards required) or the engineering design that specifies the weld requirments for the welds is faulty. In no case is the availability of craftsmen dependent on the presence or absence of "right to work" laws. Bad engineering is not to be blamed on the politicians (there are plenty of appropriate things to blame them for) -- either the available welders are adequate and there is nothing to complain about, or the engineering and production management are to blame.

When junk is produced that is the fault of the producer, not the government. In some cases the government imposes standards in the name of public safety, but the ultimate responsibility for any product lies with the company that designs and sells it, and that company is responsible for ALL aspects of the manufacture of that product. Engineers involved in the design and manufacture of a product have a professional eithical (and sometimes legal) responsibility to produce designs and manufacture products that do what they are intended to do in a safe and reliable manner. If weld quality is adequate, then weld quality is adequate and there is no beef. If weld quality is not demonstrably adequate then production needs to be stopped and any product in the hands of the public repaired or replaced. In no case does responsibility or fault have anything to do with "right to work" laws.

It is an unfortunate fact that many companies only do the right thing when compelled to do so by statutes or fear of law suits. But that is another kettle of fish entirely.

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marnixR
Post  Post subject: Re: How many agenda setters per State?  |  Posted: Tue Jun 26, 2012 5:41 am
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DrRocket wrote:
But who or what organization is to perform those verification steps is generally a matter handled by contract language, rather than by engineering specification.


unless specifications have changed since i last worked in this area, the specification requires the inspection by a third party, which can't be just any tom dick and harry, but needs to come from organisations that are themselves approved and qualified to perform such inspections (e.g. Lloyds)
whereas the 100% inspection of each weld can be done by the producer or the customer, examination of the method used and in-depth study of selected samples is the duty of the 3rd party inspection

DrRocket wrote:
In reality I think that what you are dealing with is closer to boiler code, which does impose stringent requirements for design margin and weld quality, but which is quite a bit looser than "no flaws allowed". A "no flaws allowed" requirement is not only unrealistic but is generally a sign of lax engineering since it is simply impossible to verify compliance with such a criteria.


i don't remember saying that no flaws are allowed - it's just that particular types of defects are not allowed
e.g. in the case of welds for offshore structures or nuclear installations these include metallographic examination of selected sample welds where for instance the wrong type of bainite can fail you that part of the inspection

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DrRocket
Post  Post subject: Re: How many agenda setters per State?  |  Posted: Tue Jun 26, 2012 6:16 am
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marnixR wrote:

i don't remember saying that no flaws are allowed - ...


marnixR wrote:
i can confirm from my own experience that not only is third party inspection normal in welded constructions for oil and gas applications, they're a specification requirement to ensure these structures are as safe as it is humanly possible to make them - even the smallest welding defect in an offshore structure or a pressure vessel can have disastrous consequences


Bold added.

If "even the smallest welding defect can have disasterous consequeces" then the critical flaw size is 0, and no flaws can be allowed.


Apparently such is not the case in reality.

marnixR wrote:
unless specifications have changed since i last worked in this area, the specification requires the inspection by a third party, which can't be just any tom dick and harry, but needs to come from organisations that are themselves approved and qualified to perform such inspections (e.g. Lloyds)
whereas the 100% inspection of each weld can be done by the producer or the customer, examination of the method used and in-depth study of selected samples is the duty of the 3rd party inspection


That may be the case, but frankly it astonishes me. I would expect the company responsible for the final product to have internal experts more than capable of making such a determination and that a working group including those experts as well as people from any involved vendors would be formed to review and approve all technique sheets. Any involvement from 3rd party consultants would, I should expect, be in advisory capacity to that committee if they were needed. I would be aghast at any company ceding ultimate authority for approval of critical non-destructive testing techniques related to flaws that could cause a catastrophic failure to a third party -- ultimate responsibility quality cannot be delegated. Moreover, I would expect that the final customer, the end user, would insist that his own non-destructive test people and engineers would review the inspection data before accepting final delivery -- though I have certainly seen people and organizations take the word of others for such items, and live to rue the day that they did (this is called sloppy engineering and program management).

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marnixR
Post  Post subject: Re: How many agenda setters per State?  |  Posted: Tue Jun 26, 2012 8:41 pm
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DrRocket wrote:
If "even the smallest welding defect can have disasterous consequeces" then the critical flaw size is 0, and no flaws can be allowed.


the sentence was "even the smallest welding defect CAN have disasterous consequences" - my bold added
not all of them do

DrRocket wrote:
Any involvement from 3rd party consultants would, I should expect, be in advisory capacity to that committee if they were needed.


have a look at the Lloyd's site - they obviously make a good earning from providing an "independent and impartial third-party certification services to all industries within the upstream, downstream, power, marine and manufacturing sectors"

i think the emphasis lies not so much on the customer leaving everything to Lloyd's but more on getting an official and impartial stamp of approval for the quality of their work

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DrRocket
Post  Post subject: Re: How many agenda setters per State?  |  Posted: Tue Jun 26, 2012 11:01 pm
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marnixR wrote:
DrRocket wrote:
If "even the smallest welding defect can have disasterous consequeces" then the critical flaw size is 0, and no flaws can be allowed.


the sentence was "even the smallest welding defect CAN have disasterous consequences" - my bold added
not all of them do


Of course not all of them do. Actual material properties vary from sample to sample. But when "even the smallest defect CAN have disasterous consequences" you have, by definition, a situation in which the allowable critical flaw size is ZERO. That is intolerable from an engineering design perspective. Period.

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marnixR
Post  Post subject: Re: Engineering Inspection Issues (split from "Agenda setter  |  Posted: Wed Jun 27, 2012 6:03 am
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the conclusion of an absolutist mind - the world doesn't work in absolutes
some fairly large defects are acceptable whereas other ones which appear minor are actually more damaging - it's all a matter of how likely said defect is to cause crack growth and propagation
a good engineer knows how and when to make the distinction

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bunbury
Post  Post subject: Re: Engineering Inspection Issues (split from "Agenda setter  |  Posted: Thu Jun 28, 2012 12:14 am
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Certainly. Acceptance criteria are established that allow certain defects based on empirical knowledge of safe levels for the intended service.


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marnixR
Post  Post subject: Re: Engineering Inspection Issues (split from "Agenda setter  |  Posted: Fri Jun 29, 2012 6:53 am
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also remember that whilst rolled and forged structures have a lower load below which a structure has an indefinite fatigue life, the same does not necessarily go for welded structures

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bunbury
Post  Post subject: Re: Engineering Inspection Issues (split from "Agenda setter  |  Posted: Fri Jun 29, 2012 1:40 pm
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The acceptance criteria I am referring to are incorporated into the design codes we use. The empirical evidence is gathered over years, decades and in the case of the boiler and pressure vessel code, centuries. Of course there is no excuse for sloppy engineering.


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