Service failure

Cooling water service failure 3. Same 3. Check and monitor reliability of water DAC 2/93... 

For brasses, the ammonium ion is the principal cause of SCC. Few service failures have been reported when ammonia is not present. 

Defect. A defect is an imperfection in a component, resulting from the way it was manufactured, shipped, handled, or installed, that may contribute materially to failure or limited serviceability. Failures resulting directly or indirectly from defects account for less than 1% of all failures. 

Operation at high or low rates Emergency shutdown, service failures etc. 

In-service issues. As mentioned previously, many early service failures of bonded structure were due to adherend surface treatments that were unstable in long-term exposure to water. A majority of these problems were resolved by the adoption of surface treatments such as chromic and phosphoric acid anodize for aluminum details. The remaining few were alleviated by the adoption of phosphoric acid anodized honeycomb core and foaming adhesives resistant to water passage. Other service durability issues such as the cracking of brittle potting compound used to seal honeycomb sandwich assemblies, and subsequent delamination, have been minor in scope. 

Measurement must address end-of-pipe performance (through measures such as injury rates and gallons spilled), process efficiency and indicators of performance (through measures such as in service failure of equipment). Using indicators should make it possible to identify problems before they result in poor performance. Process efficiency measurement helps track implementation of the project and continuous improvement in the use of resources. 

When selecting in-process measures, try to use measures for which data are already available. For example, avoid using in-service failure data unless the maintenance systems can make this information readily available. These measures will be used to identify potential problems and correct them as early as possible. During the development of the integrated systems, data that will be available for in-process measurement should be identified and measures developed. These measures are most likely to be calculated annually as the volume of data required to provide useful data will be collected only over relatively long periods of time. 

In-service failures at the Aberdeen Valley, Blllericay Town, and Westing Height continue at a high rate. The new maintenance program will be installed by year end. 

Continued exposure of the nickel-chromium alloy to more severely sulphurising and reducing atmospheres results in local depletion of chromium to such an extent that nickel sulphide and the eutectic are formed internally. The latter constituents are not often observed in service failures, but the relative instability of nickel sulphide in the presence of chromium sulphide can result in its reduction to nickel during slow cooling on shut down. That nickel sulphide is formed is suggested by the frequent occurrence of blisters, associated with the formation of molten eutectic on the surface of sulphur-attacked specimens . 

Stress-corrosion cracking occurs in titanium alloys in a number of environments, although the number of failures that have occurred under service conditions is very small. Because of the widespread use of titanium alloys in aeroplanes and space vehicles and their increasing use in marine applications it is important that the possibilities of service failures should be removed. As a result a considerable and increasing amount of work has been done on this subject over the last decade as indicated in a recent extensive survey. ... 

Some liquid metals have been observed to cause embrittlement in many titanium alloys. In mercury, for example, Ti-8Al-lMo-lV exhibits both intergranular and transgranular fracture with velocities as high as lOcm/s. Heat treatment affects this behaviour in a manner similar to that observed in aqueous and methanolic solutions. Some alloys are embrittled by liquid cadmium and zinc. More surprising, perhaps, is the observed solid metal embrittlement which has been found on titanium alloy components coated with cadmium, silver or zinc Service failures of cadmium-plated Ti-6A1-4V fasteners have been reported , and cracking of this alloy and... 

Failure and incident databases are available that provide generic or industry-wide in-service failure rates and on-demand failure probabilities for various components. These can be used for assessing risks of new facilities with no operating experience, as well as for estimating the likelihood of rare events such as vessel mechanical failures at operating conditions and for fully quantitative risk studies. 

Other degradation laws can be combined with a Weibull plot, particularly when a lower threshold of, for example, voltage is anticipated. An example of its application to electrical cable insulation lifetime is given in [9]. As well as service failures Weibull plots have proved useful in assessing the failure of fibres and fibre bundles. 

These pressure tests should be seen in the context of the mechanical stresses and subsequent failures in the field. In spite of all precautions on installation it must be assumed that pipes will be damaged, backfill and trenches will differ from those specified, welds may be imperfect and there will be bending stresses. Poor installation practice has been the principal cause of service failures, particularly of PVC pipe, and when installed correctly pipes taken from service (now 40 years) show no evidence of deterioration. In addition, polymers have improved greatly since pipes were first manufactured. Marshall and co-workers [2] describe the situation in more detail and recommend an approach to testing based on fracture mechanics. 

These examples illustrate the application of Weibull plots to service failure data in order to predict the probability of failure before the end of the service life, coupled with a power law to relate time to failure to the applied electric stress (voltage). 

Describe strategies for dealing with service failures and medication errors. 

In writing on human error, Senders and Moray (1991, p. 128) conclude Human error rates can be reduced to as low a level as desired, at some unknown cost. The occurrence of a particular error at a particular instant, however, cannot absolutely be prevented. Even if the patient suffers no permanent harm, a service failure or mistake in a pharmacy is a significant event. The consequences of a service failure or mistake in a pharmacy include a deterioration of trust in the pharmacist and the system, the spread of negative word-of-mouth advertising, the possibility of legal action, possible board of pharmacy involvement, the erosion of customer patronage, and a diminished level of profit (see Chapters 7, 28, and 30 on minimizing the occurrence of prescription errors). 

While it would appear intuitive that companies, as a matter of course, would try to correct their mistakes, research indicates that over 17 percent of companies do nothing following a service failure or mistake and that as many as one-third of the service recovery initiatives are unacceptable to the consumer (Kelly, Hoffman, and Davis, 1993). The paradox of service... 

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