This content defines requirements for visual inspection that is carried out in third party inspection assignment. The visual inspection must be done based job specification and client requirement. The professional hired to be in charge of these controls Non-Destructive Testing, visual and dimensional will need to have sound knowledge & experience in the fabricating work and will be subjected to the testing of sight on a periodical basis.
Surfaces can be classified in two types: smooth surfaces (which can be pipes, flanges, etc.) & rough surfaces (which are welds, rough forged parts, rough coating etc). Also, they can be in grounded, brushed, sand-blasted and machined conditions. The visual inspection must be done directly or by specialized tools appropriate for inspection surfaces.
The area which needs to be controlled has to be on an accessible plane and must allow visual examination from 600 mm of distance and an approximate 30 degree angle. This is to facilitate the detection of visible surface defects like scratches, corrosion, and cracks.
If the area that has to be examined is a weld, then we need to do a deeper examination in the form of detecting possible craters, under cuttings and slag inclusions.
According to the national and international standards for visual examination, the factors for observation must be considered as below:
Critical indications: Those indications that, according to the third party inspector and industrial vendor Inspector evaluation, may be detrimental for the correct use/destination of the examined system, piece of equipment and/or individual component.
Indications which are major: these indications which are also detected by the vendor or the TPI inspector are of that kind which might hamper the operation of the system, individual part or the whole system
Minor indications: These are the conditions found by the third party inspector or the vendor inspector evaluation which in any way do not have any effect on the correct use or destination of the system that needs to be examined or an equipment piece and/or individual component.
In this regard the lighting in the inspection room must be of optimum quality. It can either be naturally lit or artificially provided but it should be sufficient to carry out the inspection procedure according to the standards which have been set. This makes the required amount of light close to 500 LUX. The contrast can be suitably adjusted when a black line drawn on a grey sheet positioned to the area of examination can be seen with clarity. The black line should be at least 0.8 mm in thickness.
The acceptability limits of the defect are dependent on the applicable specification and/or the requirements of the customer. Dimensional controls are carried out by the inspector right from the start, and material receiving inspection is very important item and must be done based approved inspection and test plan.
This material which is to be subject to visual examination must be positioned in the best possible way to facilitate maximum viewing ease. These are conducted by instruments which have been calibrated previously and have been accepted to be the best by quality control personnel.
All measurements inspected during the dimensional control are marked with red pencil on the drawing copy in the hands of inspector. All measurements checked shall comply with the specified tolerances. Sampling schedule for lot dimensional controls is based on international standards (if applicable).
After everything has been examined thoroughly the TPI inspection agency will issue a report and a certificate which records the date of examination, whether the examination was conducted directly or indirectly. They also have clear criteria about the references for identification regarding the component, system or part which has been examined, closely followed by the signature of the performing visual examiner.
All detected defects in visual examination process must be expressed in inspection visit report and inspection certificate. This must be done irrespective of acceptance or rejection of the indications.
Surfaces can be classified in two types: smooth surfaces (which can be pipes, flanges, etc.) & rough surfaces (which are welds, rough forged parts, rough coating etc). Also, they can be in grounded, brushed, sand-blasted and machined conditions. The visual inspection must be done directly or by specialized tools appropriate for inspection surfaces.
The area which needs to be controlled has to be on an accessible plane and must allow visual examination from 600 mm of distance and an approximate 30 degree angle. This is to facilitate the detection of visible surface defects like scratches, corrosion, and cracks.
If the area that has to be examined is a weld, then we need to do a deeper examination in the form of detecting possible craters, under cuttings and slag inclusions.
According to the national and international standards for visual examination, the factors for observation must be considered as below:
Critical indications: Those indications that, according to the third party inspector and industrial vendor Inspector evaluation, may be detrimental for the correct use/destination of the examined system, piece of equipment and/or individual component.
Indications which are major: these indications which are also detected by the vendor or the TPI inspector are of that kind which might hamper the operation of the system, individual part or the whole system
Minor indications: These are the conditions found by the third party inspector or the vendor inspector evaluation which in any way do not have any effect on the correct use or destination of the system that needs to be examined or an equipment piece and/or individual component.
In this regard the lighting in the inspection room must be of optimum quality. It can either be naturally lit or artificially provided but it should be sufficient to carry out the inspection procedure according to the standards which have been set. This makes the required amount of light close to 500 LUX. The contrast can be suitably adjusted when a black line drawn on a grey sheet positioned to the area of examination can be seen with clarity. The black line should be at least 0.8 mm in thickness.
The acceptability limits of the defect are dependent on the applicable specification and/or the requirements of the customer. Dimensional controls are carried out by the inspector right from the start, and material receiving inspection is very important item and must be done based approved inspection and test plan.
This material which is to be subject to visual examination must be positioned in the best possible way to facilitate maximum viewing ease. These are conducted by instruments which have been calibrated previously and have been accepted to be the best by quality control personnel.
All measurements inspected during the dimensional control are marked with red pencil on the drawing copy in the hands of inspector. All measurements checked shall comply with the specified tolerances. Sampling schedule for lot dimensional controls is based on international standards (if applicable).
After everything has been examined thoroughly the TPI inspection agency will issue a report and a certificate which records the date of examination, whether the examination was conducted directly or indirectly. They also have clear criteria about the references for identification regarding the component, system or part which has been examined, closely followed by the signature of the performing visual examiner.
All detected defects in visual examination process must be expressed in inspection visit report and inspection certificate. This must be done irrespective of acceptance or rejection of the indications.
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