Detectable failure

An inherent problem is the location of the sensors. It is not possible to locate the sensors inside the packages which are to be sterilized. Electromechanical instmmentation is, therefore, capable of providing information only on the conditions to which the packages are exposed but cannot detect failures as the result of inadequate sterilization conditions inside the packages. Such instmmentation is considered a necessary, and for dry and moist heat sterilization, a sufficient, means of monitoring the sterilization process. 

It is important to emphasize that direet studies sueh as those earned out on the eyelopropylmethyl radieal ean be done with low steady-state eoneentrations of the radical. In the case of the study of the eyelopropylmethyl radical, removal of the source of irradiation leads to rapid disappearance of the EPR spectrum, because the radicals react rapidly and are not replaced by continuing radical formation. Under many conditions, the steady-state concentration of a radical intermediate may be too low to permit direct detection. Failure to observe an EPR signal, therefore, cannot be taken as conclusive evidence against a radical intermediate. 

It is often deemed that quality assurance serves prevention and quality control detection, but a control installed to detect failure before it occurs serves prevention, such as reducing the tolerance band to well within the specification limits. So quality control can prevent failure. Assurance is the result of an examination whereas control produces the result. Quality assurance does not change the product, quality control does. 

Appraisal costs - cost incurred in detecting failures, such as reviews, assessments, inspections, audits, tests including test and diagnostic equipment... 

The main purpose of identifying failure detection methods is to determine whether the failure mode is "hidden," i.e., not detectable for some period of time. If there is no means to detect failure, "none" should be entered into the worksheet. 

Module 6, Column Diagnosis (COLDIAG). This module uses chromatographic parameters such as efficiency, asymmetry, retention time, selectivity and operating pressure, to detect failures of the column or other chromatographic hardware. Table II lists the types of column failure which the module can currently handle. Note that the module will also correctly diagnose some problems which are NOT column malfunctions but which might be interpreted as such by a user. 

Environmental and accelerated ageing tests were performed on the indoor dye modules described in Sect. 7.6 in order to detect failure mechanisms. Contrary to expectations, many modules survived humidity/freeze cycling tests (10 cycles, 85%, 20 h at 55°C per cycle) without major degradation, demonstrating the capability of the sealing concept (see Fig. 7.8). This was also true for temperature cycling (between —5 and 55°C). However, it has... 

Each company should have a policy that strictly prohibits the deliberate falsification, mutilation, obliteration, or destruction of raw data and associated GMP documentation. Companies must insist on strict adherence to such policies and should take aggressive disciplinary action when lapses are detected. Failure to do so may subject the company and its corporate officers to severe regulatory sanctions, including criminal prosecution under the Federal Food, Drug, and Cosmetic Act, or the general criminal laws of the United States (Title 18, U.S. Code). Even inadvertent (non-deliberate) acts that result in loss of data or records should be prevented, and, if they occur, they should be promptly and thoroughly investigated. 

At first glance it seems that one of the simplest ways to detect failure of a fluid film would be to watch for a sudden increase in the coefficient of friction. Classical hydrodynamic lubrication is characterized by coefficients of friction substantially lower than 0.01. Under confirmed conditions of elastohydrodynamic lubrication at contact pres-sures of ca. 690 MPa (100,000 Ib/in ), Sanborn and Winer [24] observed... 

Maintenance To detect failure arising during the service life of a product. This failure detection function can be seen in inspection of road and rail bridges for structural determination or of civil airlines for stress cracks or corrosion (see below). 

The standard methods for EIS determine an average impedance for the whole exposed area of a sample. Many samples, in particular coated samples or those undergoing localized corrosion, have spatial variations in behavior. A local EIS method has been developed to measure these variations [24-26]. The local AC solution current density is mapped across a surface using a two-electrode microprobe. The ratio of the applied AC voltage (using distant reference and counterelectrodes) to the local current density gives the local impedance. It is possible to obtain a full EIS spectrum at each location, or to map the impedance at a fixed frequency. This method provides information on the location of the attack, and can detect failure prior to visual observation. 

On-line diagnostics to identify and locate all detected failures. This function allows a short time to repair the system. 

A SW verification corresponds to conformity criterion if verification was completely finished before the system was put into operation, i.e. all detected failures was analyzed and eliminated by that time. 

The scratch tests are very similar to the nanoindentation tests and can be considered side by side. In both teclmiques, a prime tip is used for the adhesion measurements by dragging across the measuring surface under an increasing load, which results in an indentation. Scratch and indentation tests are suitable for the analyses of the coatings and thin films [100]. Sharp diamond indenters are usually used for the adhesion and scratch resistance determination between the substrate and coating. These techniques can fail for the analyses of hard coatings on soft substrates due to no detectable failures as a result of small critical loads. Therefore,... 

Identify current controls preventing the cause of the failure mode from occurring or detecting the failure before it results in the consequences. Each of these controls should be assessed to determine how well it is expected to identify or detect failure modes... 

A set of equipment used in a safety instrumented function is non-redundant (lool). The total dangerous detected failure rate is 0.002 failures per year. The total dangerous undetected failure rate is 0.0005 failures per year. Restore time average is 168 hours. The equipment is inspected and tested every two years with 100% test coverage. What is the PFD What is the PFDavg ... 

SOLUTION The diagnostics operate rapidly and complete execution sixty times per expected demand period. The diagnostic test time plus the response time is within the process safety time. Therefore dangerous detected failures will be converted into safe failures. The remaining dangerous failure rate is 0.5 x 10 failures per hour. That meets the requirements for SIL2 per Figure 7-4. 

A more sophisticated approach moves the valve in an analog manner monitoring valve stem position and actuator pressure. Another sophisticated technique pulses the solenoid and measures the pressure response waveform. Certain patterns in the pressure response indicate failures. These methods are capable of doing a better job detecting failures than the simple digital feedback techniques. 

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