Welding processes in fabrication shops must be monitored by experienced inspectors. They conduct such activities as visual inspections, check radio graphs or UT records and monitor PWHT, painting and hydrotests. In the Fabricator shops and to give good consistent results, what do we typically expect to see as the staffing ratio for the welding inspection position? What is the critical parameter or benchmark we would use express that ratio? Inspection hours to welding hours, diameter-inches of weld? etc. Assume this for a shop that largely welds pipe spools but not pressure vessels. Please share your experience here.
From experience, this depends on the Code and % visual inspection required. Also depends on the size of the workshop and nationality/skill level of the fabricators/welders/pipe fitters.
A 90,000 Sq/meter Workshop requires more Inspectors than a 10,000 Sq/metre Workshop due to the size of the work area to be covered. I worked in China in a 90,000 Sq/meter workshop with 14 welding/fab/Nace 2 Inspectors and this was no where enough to ensure consistent quality results. Even when we increased the number to 18 Inspectors we still had major quality issues. Depends on the Contractor work ethics and compliance to the code.
No matter how many welding inspectors you have in the workshop, it all depends on the contractors attitude to being monitored, and the experience and quality of the welders. The contractors must understand the inspector is there to monitor the welders following the standards required, not to train them, that is not his objective, mind you if he is employed directly by the main contractor, he must follow his employers instructions or he is out the door. The contractors main concern is hitting there monthly target as set by the client, so its a no win situation for the inspector.
Let's start this discussion this way; A QC Inspector is the eyes on the floor. He She may be reviewing drawings with the Production foreman, checking the ovalitity of a rolled shell by a sub-contractor. Looking at a longitudinal fit-up of a 70" shell. Checking the lay out of as many as 16 nozzles, weld neck flanges, slip on flanges etc aside from actually visually inspecting each pass on the 70' long vessel. He She is documenting everything that he is doing plus may be checking to make sure that the tractability is maintained so the right part gets welded on at the right spot. There's twenty welders in the shop & He She knows them all & what processes they are qualified for, what thickness the can weld up to on what material spec. & grade they are qualified to weld on! Plus he is often the liaison with the Authorized Inspector as well and versed in not only ASME Section IX, but also in ASME Section VIII Div. 1 that the vessel has been designed to meet. I would suggest that the QC Inspector needs some help, Would you agree?
I do agree with Thomas P. It is the attitude of management towards the quality . lot of companies are picturing them as if quality is their top priority, however in real world they are poles apart from quality work. Inspectors are easy target to blame.
Just have a situation Mr Thomas p, the company I used to work till last week kick me out because the owner though I was not good for the company because I try to accomplish all the client request concerning to quality, from my experience all this issues make payment delays and rework
Heriberto, just as I said ,if your employer notices that you are carrying out your inspection duties, in full compliance with clients requirements, and you are delaying closure of the inspection request, for whatever technical reason, which will delay the EPC contractor not receiving the monthly progress payment, you can expect such drastic actions. This happens on projects all over the world, and can only be resolved in certain situations if the clients engineers bring this violation to their superiors for corrective action, i.e. reinstatement
There are quite a few fab shops that advertise 100% compliance to the Code & they have 1 QC Manager & no inspectors except the AI who might visit once or twice during vessel fabrication. What's wrong with that picture?
Timely discussion for me having just been removed from a project for doing my job as Site Quality Manager. Unfortunately the client was unable to recognize that my 'practical, common sense' approach would help them achieve their scheduling requirement with some semblance of acceptable quality. Naively they chose to listen to and believe the EPC contractors viewpoint... Good luck to both of them.
Inspectors number is not a factor in fabrication shop. If the Inspector is experienced and with commonsense two (1 Welding,1 Painting) inspectors are enough for EPC contractor side. Vendor side required more inspectors because they have to do all the paper work. Hence welding material wise each inspectors and NDT Plus documentation clerks. I have been monitored one fabrication shop alone for all the activities from EPC side with 45 welders. First to study the contractor attitude, then plan the visit timing it should not be same time in all day also start from different corner of shop. Make good relationship with workers so all the news we can get.
EPC contractor requires numerous inspectors(6-10) to cover workshop and site work, plus additional office staff to compile and submit documentation for clients review and acceptance. Client only requires two or three inspectors to monitor the EPC contractors daily work schedule plus documentation clerks. I have been QA/QC Manager on various projects worldwide, petrochemical and power plant construction, and always ensured we had fully qualified engineering staff to cover all trades.
Hire inspectors with multiple disciplines. This will keep the numbers down and when absentee acute any inspector can take over. The main factor is the Non comfortless and correction of action or engineering problems can cause money issues and more Quality Engineers to correct the issues. One inspector to a crew in a fabricating facility. Have a good Quality Plan, ITP, checklist to keep the reject rate down.Communication is the most important factor.
Only problem with your comment is that multiple discipline inspectors are far and few available. It is normal to employ qualified and certified inspectors in their discipline i.e. Welding-Mechanical-Coating-Electrical. Hoping you've covered all bases for the construction in progress
The project has to be included. Lets talk about a continuing problem in the Welded Spool fabricating facilities, from the spool fabrication shops to the projects. MTR's, PMI, and Vendor FW's correctly added to drawings and information getting to the projects. Delivery of the welded piping spools with required data for project installation. Process is important. The lack of required information from the spool fabrication facilities. This is very costly due to the lack of required information, checklist, process to the inspectors. The projects suffer.
In pressure pipping with natural gas where a consequences of failure could be very serious you are looking to get a 100% finish product. In case of welding the only way to assure that is to proceed with tests ( visual, mpi, penetrate, ultrasound and Xray/gamma ). You are correct saying that there has to be a sufficient welding supervision ( before , during and after a process of welding ) by a qualified welding inspector ( CSWIP 3.1 ).
In regards to a ratio - in my opinion 0.1 - 0.2 % of failures ( 1-2 joints per 1000 ) is quite normal ( human factor ) and I would call a welder having this ratio a very high quality one. Saying that one please don't forget that you are still expecting those failed joints to be fixed anyway.
In respect to any higher ratio of failed joints I would strongly recommend to investigate following: welding technique, quality of preparation, quality of welding equipment, quality of consumable and storage finally quality of actual based material ( you might find a multiple discrepancies between certificates and actual material ). Finally you might look at your procedures. They might be prone for welding imperfections also.
I wouldn't be keen to blame welding inspections for high failure ratio as the bottom line is if your welds are perfect they will pass doesn 't matter what acceptance criteria will you take.
More often than not the problem is $$$$! The shop won't hire more inspectors unless someone pays them to do so! Next is availability, an experienced welding inspector does not walk by the shop door looking for a job, This experience must be with multiple welding processes multiple disciplines working with several different Codes & Standards, These people must be interviewed by someone that can ask the right questions. A resume is required. Statements from previous employers help.
"Q.C. Inspectors do not contribute anything to moving the vessel out the door" "They are an expense we cannot charge for" I see them as overhead!
The more eyes you have looking at a fabrication drawing the better!
Yes, there does need to be a balance point. NCR's cost time & money, so does rework! Make welders responsible to follow the WPS from the root gap to the amount of reinforcement allowed. Make sure the layout of nozzles is correct before burning holes in the shell!
Before a spool leaves the fabrication shop it must be inspected by a qualified welding inspector, it only takes one pair of eyes to do that, to many comments from additional inspectors on the same joint will only cause confusion and delay from sending to site, where another pair of eyes once it gets on site,will look at it before it is erected, so how many inspectors does it take to change a light bulb???
All of you i think have good idea about this issue, but for me as inspectors i prepare not only to do inspection as per specification and codes. i tried to educate all the welders by performing toolbox meeting regarding any problem in fabrication specially in welding.this include how to identify and correct the imperfection. because some of the welder know how to operate the machine how to weld because they are qualified before they can start welding but they don,t have any knowledge about WPS and how parameters affect the welding.so as for me i will educate them how to use this WPS. sometimes they just post the procedure and not reading it.
AndyQualified Welding Inspector & AWS CWIYes of course you can cut the straps with oxy acetylene or any way that is easy, and then smooth them with a grinder or sanding pad or such. I believe there is a diagram in the code book. Should round the edges or corners slightly too. ASME or API
MatthewQuality ProfessionalI am being technical, but I disagree. But the only danger is oxygen cutting the side bends is when dealing with non-carbon steel. In my interpretation, AWS D1.1 and API 1104 prohibit oxygen cutting side bends to 1/2" width. Per those codes, you must oxygen cut specimens to 3/4" width and then machine them to 1/2". ASME Sec. IX allows it only if the metal is found in P No. 1.
JonWelding inspector AWS-CWI Currently looking for next projectWhy ask the question if you know the answer? Yes you may oxy cut to 3/4 then machine to 1/2. And if it's stainless just machine cut it gives both options. Per API 1104.
Figure 4.33 allows for grinding (as opposed to machining) on the reinforcing welds and backing strip. Root and face bends allow for thermal cutting and grinding.
I haven't found anything which definitively prohibits grinding on side bends, but that gets into the fallacy of proving a negative. Everything I have found in the D1.1 for welder qualification points back to sec. 4.9.3.1 and figure 4.13 which explicitly states machining. I would interpret this in the realm of AWS "shall:" statements and err on the side of caution.
Perhaps a bandsaw would provide a better means of extracting the side bend specimen. There are some good port-a-band(saw) products out there, that might get you there in the field depending on diameter and thickness.
Side bends are different. If you thermal cut these specimens you are introducing a HAZ into the area of interest. The Code says to leave 1/8” on either side to remove by grinding or machining thereby removing this HAZ.
Thats how I interpret it. Any thoughts?
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William Komlos likes thisSec. 2.6.5.1 Preparation
Side bends...shall be machine cut, or they may be oxygen cut to approximately a 3 / 4 -in. (19-mm) width and then machined or ground to the 1/2 -in (13-mm) width. The sides shall be smooth and...
That means it is not acceptable to cut the side bend specimens to 1/2", Kieth Proctor hits the nail on the head.
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