Inspector

This work has been supported by the Swedish Nuclear Power Inspectorate (SKI) and ABB TRC. References... 

Construction of expert systems is facilitated if it is possible (at least approximately) to describe (model) expected signal from defect and non-defect pieces. If no models for the problem are available then the knowledge about the problem has to be acquired from an expert (the NDT inspector). However, the knowledge possessed by the expert is often incomplete and not well formalised, which makes knowledge acquisition a difficult task for the knowledge engineer. 

The data can be retrieved easier, since no pile of films is laying on the table of the inspector. With each CD-ROM diskette a leaflet with relevant information for traceability of data is provided. 

If neither the accept, downgrade or reject button is pushed during inspection, the block will automatically be out loaded after the time limit has expired. The accept/reject/downgrade buttons will flash prompting the inspector for a decision. 

If improvements should be achieved by an automation of the inspection process this requires a control of the process parameters of the whole equipment by an integrated "intelligent" system and not by displays still being controlled by the human inspector. This integrated control-system ensures that the inspection conditions are at the highest reproduction level. 

Increasing production and therefore inspection rates may increase the stress to the inspector and result in a decreasing reproducability and flaw detection rate. In addition by replacing the human inspector by a fully automatic image processing tremendeous cost savings are achieved. 

Of course modem MPI and LPI equipments have all necessary control devices needed to ensure operation at nser defined conditions, but if these conditions have to be controlled by the inspector itsself besides the normal inspection work the human being is still a factor of operating the equipment. 

Quantitative determined visual recognition for usual inspections, indicate that for indications with lengths over about 1.5 mm tbe probability of recognition is about 100 %. This is also applied to the penetrant inspection. This does not include the so called "human factor" which means that it cannot be guaranted that the inspector detects all indications for instance not always observing the inspection surface with full concentration. 

Naturally, such a high probability of detection of theoretically 100% never can be realized in practice. The inspector will not recognize all good visible indications at any time because he cannot always be fiilly concentrated on his task, which is called "human factor". This human factor appears in any visual inspection and may be reduced only by a second redundant inspection or extreme signals as a light flash or an acustic signal. 

Having set up the ultrasonic instrument (according to test specifications), the inspector scans the weld volume. Any indications subject to recording are interpreted and documented in a handwritten on-site report. The test report only describes the indications detected by the inspector, but not the completeness of the lest in the sense of a documented 100% volume testing as is the case with X-ray testing. 

Assessment variations ranging from 2 to 3 dB are normal, even with well-trained ultrasonic inspectors. With longer work assignments or adverse external influences (cold, heat, dust, noises, etc.) considerably higher variations (12 dB and more) are often observed due to lack of concentration and to tiredness [1]. 

From tests with Level-2-inspectors [2, 3] we learn that 10 % of the errors in weld testing are caused hy too fast probe movements (indications are missed or overlooked), 34 % by too strong coupling variations (underestimation of indications) or coupling failures and 56 % by incomplete scanning (untested areas). 

The scan area" field which is white at the start of scanning is painted black during the test so that the inspector will immediately see which areas still remain to be tested. The zone has not been 100% scanned until the entire field is black. If the probe movement is too fast, or if there is no coupling, or if the probe is rotated at too large an angle, there is no change in the color this means that the corresponding zone has not been properly scanned. 

The principles referred to so far are common to all New Approach directives. The individual directives obviously need to be specific on topics such as the scope, the essential requirements, the classification of the products and on the use of modules for conformity assessment. The pressure equipment directive includes some additional sector specific dispositions which relate to recognised third party organisations , the European approval for materials , a committee for pressure equipment and the user inspectorates . 

Where conformity assessment involves intervention of third party, that task is normally carried out by the notified body. The pressure equipment directive enables in addition the national authorities to authorise in their territory user inspectorates for the carrying out of conformity assessment procedures which relate to product verification. These inspectorates shall act exclusively on behalf of the group of which they are part. The placing on the market and putting into service of equipment which has undergone such assessment is however limited to the territory of the authorising Member State and to those Member States which have also proceeded to such authorisation. The equipment concerned shall therefore not bear the CE-marking. 

The user inspectorate must fulfil the same technical criteria as the notified body. In addition, it must be organisationally identifiable and demonstrate its impartiality. It must not engage in any activities that might conflict with its independence of judgement and integrity. Given that the authorisation of user inspectorates to carry out conformity assessment is an innovation for technical harmonisation at Union level, the Commission shall monitor the application of this measure and evaluate its effects three years after the coming into force of the directive. 

Edcfy-cufrent NDT inspections using spatial data (sampled scans) ha >e many benefits. They separate the two conflicting aspects of an inspection scanning and signal interpretation. An instrument/display (client/server) based NDT inspection based on sampled scan data aides in the training and certification of inspectors. It can be used over the Internet or in-house Intranet networks to train or examine inspectors at multiple or remote sites. This saves travel time and resources as defects, instrumentation and teaching can all be consolidated Samples can be maintained and distributed from a central certification body providing more control andflexibility. 

Sampled scan data would be a benefit when it comes to certification of new inspectors or re-certification of existing staff. A large database of scans could be compiled and used randomly at test centres, which would help to avoid the samples becoming too familiar. Examinations could also be more easily tailored to the probes, types of materials and types of defects the inspector is likely to see. 

A large percentage of eddy-current inspections are conducted in the field, away from the home base and often in remote or inaccessible locations. Using local telephone lines or mobile phone lines would allow the inspector to beam his data back to the office. In this way highly qualified personnel can be consulted when problems or difficult to interpret results occur. Inspectors no longer need to feel isolated on site. 

Sampled scan data can be used to improve certification, re-certification by providing a richer and more tailored environment and provides for inspection and inspector auditing... 

Inspection data can be quickly communicated back to the office for further analysis, which helps to support inspectors in the field... 

Umfiorm Building Code, International Conference of Building Inspectors, Whittier, Calif., 1994. 

Mock OSHA Inspection. Maintenance can learn a lot about how the Occupational Safety and Health Administration (OSHA) trains thein inspectors and what is emphasized in an OSHA inspection. Some of the training of OSHA inspectors follows a program involving the recognition of potential hazards, avoidance of these hazards, and prevention of accidents (RAP). 

It is also a guideline to ensure product quahty through the suitabihty of the manufacturing equipment, air and water quahty, sanitation, insect and rodent control, and housekeeping. The FDA periodically sends inspectors to audit chemical companies who manufacture bulk pharmaceutical chemicals or inactive ingredients called excipients to ensure conformance. Whereas GMP conformance ensures that the product meets pharmaceutical quahty standards, it does not ensure conformance to customer-service-related requirements. 

Miscellaneous Uses. Inks used by inspectors to stamp the grade or quaUty on meat must, bylaw, be made from food-grade colors. Dyes used in packaging materials that come in direct contact with a food must also be food-grade or, if not, it must be estabUshed that no part of the colorant used migrates into the food product. Pet foods, too, if colored, must contain only those colorants recognized by the FDA as suitable for the purpose. 

Examination and Inspection The code differentiates between examination and inspection. Examination applies to quality-control functions performed by personnel of the piping manufacturer, fabricator, or erector. Inspection applies to fiinctions performed for the owner by the authorized inspector. 

The authorized inspec tor shall be designated by the owner and shall be the owner, an employee of the owner, an employee of an engineering or scientific organization, or an employee of a recognized insurance or inspection company ac ting as the owner s agent. The inspector... 

The authorized inspector shall have a minimum of 10 years experience in the design, fabrication, or inspection of industrial pressure piping. Each 20 percent of satisfactory work toward an engineering... 

It is the owner s responsibility, exercised through the authorized inspector, to verify that all required examinations and testing have been completed and to inspect tne piping to the extent necessary to be... 

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