Proof testing types

Proof testing principles Proof testing types and procedures Format of proof testing procedures Proof test records Planning and scheduling Competence MOC... 

It is possible to design a hydrostatic test in such a way that it probably will be a proof test of the vessel. This usually requires, among other things, that the test be run at a temperature as low as and preferably lower than the minimum operating temperature of the vessel. Proof tests of this type are run on vessels built of ultrahigh-strength steel to operate at cryogenic temperatures. 

Another instability mode of interest is due to the flow regime itself. For example, it is well known that the slug flow regime is periodic and that its occurrence in an adiabatic riser can drive a dynamic oscillation (Wallis and Hearsley, 1961). In a BWR system, one must guard against this type of instability in components such as steam separation standpipes. The design of the BWR steam separator complex is normally given a full-scale, out-of-core proof test to demonstrate that both static and dynamic performance are stable. 

There are several ways that actual joints can be tested. For quality control purposes, a proof test is commonly used, as described above. This test imposes a stress on the specimen but limits it to a point well below where any destruction of the joint can occur. This type of test only looks for serious flaws in the bonding processes such as interface contamination, air entrapment in the joint, or undercured adhesive. The prototype joints can also be tested to destruction by using similar test methods described above for standardized testing. This, however, is generally not done at great frequency because of the cost. Generally, most actual joint tests are performed to ascertain the cause of failure (i.e., forensic analysis of the failed joint) or for nondestructive determination of the adequacy of the bond. 

The cryogenic structure takes the sample tensile load in compression on three 38.1-mm-ODx28.6-mm-ID stainless steel cylinders. As shown in Fig. 1, these cylinders extend above the cryostat and return the load directly to the bottom of the crosshead. The sample grips are of the wedge-action type, constructed from 21-6-9 stainless steel. The grips and the cryogenic structure have been proof-tested to 100 kN. 

For example, if a sensor failed a proof test, it is good practice to review the results of previous proof tests to see if this sensor had failed a similar proof test within the past few tests. If the history indicates repeating failures, consideration should be given to redesigning the SIS using a different type of sensor. 

The sensor subsystem contributes an insignificant amount to the PFD of ESD2. That probably represents an opportunity to reduce the quantity of equipment and also reduce the lifecycle cost of manual proof testing. Comparing the failure rates of the switches that indicate closure of the valve to the failure rate of the radio system, it is clear that one of the two switches could easily be eliminated. This will reduce the false trip rate as well as lower capital and lifecycle cost. One could go further, however, by looking at the safety contribution of each of the sensor types. The PFD contribution of the ZS sensor subsystem (Gate Gil) and the PT sensor subsystem (Gate G12) is shown in Table 13-4. 

Are forged from hardened and tempered high-tensile steel and are rated according to their SWL A range of types are available including those with a safety latch as shown in Fig. 19.10. Form and dimensions are set out in BS EN 1677-5 which states that all hooks shall be free from patent defect and shall be cleanly forged in one piece. After manufacture and heat treatment each hook shall be subjected to a proof load. After proof testing each hook is stamped to allow identification with the manufacturer s certificate of test and examination. 

An RCM optimization module enabling calculation of effective failure rates for common RCM activity types, i.e., age replacement, functional proof testing, inspection in time-delay models and a gradual failure progression model, see e.g. Vatn (2007) for a description of these models. The RCM module enables maintenance interval optimization taking the entire regularity model into accoimt. 

The fallacy in Dr. Finkel s statistical argument is a failure to control the probability of type-II error of her test. Type-II error is acceptance of the null hypothesis when it is in fact false. Consideration of the type-II error requires consideration of the alternative to the null hypothesis, which in this case is the theoretically likely linear response at low doses. If we use for the slope dA/da =o of the life-shortening response at low doses the value obtained above (eq. [13]) from a study of Dr. Finkel s results, namely, dA/da = 0.14% (/xc/kg) , and if we assume that Dr. Finkel s <-test acceptance region is appropriate to a one-tailed test at a = 8.9 fic/kg, the highest experimental value for which the null hypothesis was accepted, then we can calculate the probability of type-II error. It is 85 per cent. This means that if there exists in fact no threshold at 8.9 /tc/kg, Dr. Finkel s test would nevertheless have produced evidence for one in 85 experiments out of every 100 experiments performed. On the other hand, if there were in fact a threshold, the test would deny it in only 10 per cent of the experiments. Evidently the test is worthless as a proof of the existence of a threshold at this dose level (or lower, for which the probability of type-II error approaches the maximiun that is possible, 90 per cent, for a 10 per cent probability of type-I error). 

There are two types of proof tests provided for by the ASME Code. They are as follows ... 

The type of the programmable component (FPL versus LVL) will also affect the rigor of the required evaluation. A functional evaluation is needed to determine whether specific software changes affect the expected performance (integrity and reliability), specification, installation, configuration, diagnostics, or proof-test requirements. 

A typical flow chart describing the proof testing process is shown in Fig. X/2.2-1. Let the discussions begin with proof testing principles followed by types of tests and procedure. 

Judgment hy a competent person is necessary for implementation of partial proof testing. Such decisions are taken on the basis of the component types, relative costs of periodic maintenance, replacement and overhaul, and the access to the equipment. 

The manual proof test is assumed to be 100% effective and to occur annually (ca. 8000 hrs). One maintenance crew is assumed to be available for each of the three equipment types (PES, Instrumentation, Pneumatics). 

The moisture content of a plastic affects such conditions as electrical insulation resistance, dielectric losses, mechanical properties, dimensions, and appearances. The effect on the properties due to moisture content depends largely on the type of exposure (by immersion in water or by exposure to high humidity), the shape of the product, and the inherent behavior properties of the plastic material. The ultimate proof for tolerance of moisture in a product has to be a product test under extreme conditions of usage in which critical dimensions and needed properties are verified. Plastics with very low water-moisture absorption rates tend to have better dimensional stability. 

Similarly, the number and types of tests completed will influence the cost in ways that can be very complex. Recently, the author was involved in designing a proof-of-principle study intended to assess the ability of a dietary supplement to enhance weight loss among subjects instructed to follow a reduced energy diet. Sample size calculations were run for two scenarios, the first using change in body weight as the primary outcome variable, the... 

Of ultimate importance are the full reports of the clinical studies in humans and their results. These data will be treated statistically for their validity. The number of studies for a specific compound or combination of compounds will vary with the type of drug being tested, as will the number of tests needed to appraise relative or absolute safety and to clearly demonstrate efficacy. The basic requirement is the proof of safety and efficacy of the product being submitted under the NDA system. A drug that does not contribute to therapy, such as a new antihistamine that does not demonstrate greater safety or efficacy, or both, compared with drugs already on the market, will have a difficult or impossible time achieving approval. 

The proof consists in showing that if leaf test U,p,T) could be done by just adding pushdown stores of the type described in this section, then it could be done by an ordinary program scheme without augmentations, but that is impossible. 

Although only a dozen known metal complexes were tested in this manner, proof of principle was demonstrated. The test revealed Wilkinson s catalyst to be the most active hydrosilylating agent, its use in this type of reaction being known. However, the study also led to the discovery that a palladacycle, [Pd (o-tolyl)2PC6H4 (OAc)]2, which is usually considered to be potent in Heck reactions, is also an excellent hydrosilylation catalyst.37,38 Control experiments showed that the relative order of catalyst activity is the same when conventional substrates are used in place of the dyes (8). 

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