Inspectional Considerations

The standard requires that in determining the amount and nature of receiving inspection, consideration should be given to the control exercised at the subcontractor s premises and recorded evidence of conformance provided. The supplementary requirements require the supplier to use one or more of four prescribed methods unless waived bp the customer. 

Information can also be obtained by a site inspection, consideration of existing planning policies, and consideration of similar proposals. 

Inspection considerations with inspector aides-memoire References and glossary... 

Regardless of the type of hydrostatic testing method used, DOT and TC regulations both specify that the periodic retest must include an external and internal visual examination of the cylinder. It is recommended that these inspections be conducted prior to the hydrostatic retest in accordance with the applicable Compressed Gas Association standards. See references [13] through [16] and [20]. External and internal inspection considerations were discussed more thoroughly in previous sections of this chapter. 

The development of Remote Field Eddy Current probes requires experience and expensive experiments. The numerical simulation of electromagnetic fields can be used not only for a better understanding of the Remote Field effect but also for the probe lay out. Geometrical parameters of the prohe can be derived from calculation results as well as inspection parameters. An important requirement for a realistic prediction of the probe performance is the consideration of material properties of the tube for which the probe is designed. The experimental determination of magnetization curves is necessary and can be satisfactory done with a simple experimental setup. 

During the past few years radioscopy has established itself in many fields that demand instant evaluation and a high degree of automation, as is the case in serial inspection. Furthermore, user experience has clearly shown that inspection costs can be considerably reduced by this technique. 

Practical experience has shown that, depending on the field of application, a considerable reduction in inspection costs can be had when opting for radioscopy rather than radiography. By comparison with film technique, the inspection time of turbine blades for aircraft jet propulsion engines is reduced by 45% to 60%. When adding film costs, approximately DM 450.000,- can be saved per year /3/. As far as... 

The onus for the organisation of any inspection programme beyond that required by Class rests with the owner or operator of the ship. Under certain circumstances, for example, when the propagation of cracks could lead to pollution through the loss of cargo, an owner of an oil tanker operating in US coasted waters may spend a considerable amount of money on preventative inspections. 

Intelligent inspection of the relevant distribution coefficients will show whether a separation is feasible and what the most favorable eluant concentration is likely to be. In the columnar mode, an ion, even if not eluted, may move down the column a considerable distance and with the next eluant may appear in the eluate much earlier than indicated by the coefficient in the first eluant alone. A... 

AvaUabUity and cost of raw materials and processing equipment Simplicity and cost of manufacture and inspection Manufacturing hazards PropeUant viscosity and flowabUity Environmental considerations... 

The most effective specification is that which accomplishes the desired result with the fewest requirements. Properties and performance should be emphasized rather than how the objectives ate to be achieved. Excessive demonstration of emdition on the part of the writer or failure to recognize the usually considerable processing expertise held by the vendor results in a lengthy and overly detailed document that generally is counterproductive. Redundancy may lead to technical inconsistency. A requirement that cannot be assessed by a prescribed test method or quantitative inspection technique never should be included in the specifications. Wherever possible, tests should be easy to perform and highly correctable with service performance. Tests that indicate service life are especially useful. Standard test references, eg, ASTM methods, ate the most desirable, and those that ate needed should be selected carefully and the numbers of such references should be minimized. To eliminate unnecessary review activity by the would-be complier, the description of a standard test should not be paraphrased or condensed unless the original test is referenced. 

Risk-Based Inspection. Inspection programs developed using risk analysis methods are becoming increasingly popular (15,16) (see Hazard ANALYSIS AND RISK ASSESSMENT). In this approach, the frequency and type of in-service inspection (IS I) is determined by the probabiUstic risk assessment (PRA) of the inspection results. Here, the results might be a false acceptance of a part that will fail as well as the false rejection of a part that will not fail. Whether a plant or a consumer product, false acceptance of a defective part could lead to catastrophic failure and considerable cost. Also, the false rejection of parts may lead to unjustified, and sometimes exorbitant, costs of operation (2). Risk is defined as follows ... 

In the simplest terms, a fault-tree for risk analysis requires the following information probabiUty of detection of a particular anomaly for an NDE system, repair or replacement decision for an item judged defective, probabiUty of failure of the anomaly, cost of failure, cost of inspection, and cost of repair. Implementation of a risk-based inspection system should lead to an overall improvement in the inspection costs as well as in the safety in operation for a plant, component, or a system. Unless the database is well estabUshed, however, costs may fluctuate considerably. 

Visual Inspection. Visual inspection should always be regarded as the first defense against failure (1). Without scientific proof, it is estimated that 80% of defects are found by visual inspection. A pilot walking around an aircraft, or a mechanic observing a machine in operation often finds defects very quickly. The cost of this inspection is minimal. Human factor considerations are particularly important for the visual inspection process. Although the visual inspection is perhaps the most inexpensive and finds the most defects, the 20% of the defects remaining after the visual inspection must also be found thus the more costly and technically elaborate NDE methods are needed. 

General Observations. Animals are inspected at frequent intervals in order to discover any departure from normal appearance and function, the presence of abnormal patterns of behavior, and any other differences from the control animals. Simple observation of the animals may give information of considerable importance in assessing potential for toxicity and giving preliminary guidance on the nature of any injury. 

Tbe vertical iu-liue pumps, although relatively new additions, are finding considerable use iu chemical aucl petrochemical plants iu tbe United States, Au inspection of tbe two designs will make clear tbe relative advantages iiud disadvantages of each,... 

General Considerations Most pressure vessels for the chemical-process industry will continue to be designed and built to the rules of Sec. T11, Division 1. While the rules of Sec. T11, Division 2, will frequently provide thinner elements, the cost of the engineering analysis, stress analysis and higher-quality construction, material control, and inspection required by these rules frequently exceeds the savings from the use of thinner walls. 

A simple analysis shows that the engine is likely to be safe for limited demonstration use for a considerable period. After this period, continued use can only be sanctioned by regular inspection of the growing crack, or by using a more sophisticated analysis. 

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