Internal assurance

The addition of carbide stabilizers to steel reduces the tendency toward internal Assuring. Elements such as chromium, molybdenum, tungsten, vanadium, titanium, and niobium reduce the number of nucleation sites by forming more stable alloy carbides which resist breakdown by hydrogen and, therefore, decrease the propensity to form methane.9 The solid-line curves in Figure 1 reflect the increased resistance to internal attack when molybdenum and chromium are present. 

Internal assurance A textile and clothing producer using forms of internal assurance can implement systems and processes with his suppliers and monitor them to ensure that they are doing what they need to do. This method involves a lot of effort and cost. Moreover, the only assurance the customers have is a producer s word and the word of their suppliers. 

The use of these techniques is an important element of industrial policy since they contribute to the creation of a business friendly regulatory environment allowing the combination of measures taken for internal organisational reasons and obligations of certification without lowering the level of safety to be achieved. Wlienever possible a choice between product control and quality assurance procedures is offered to manufacturers. 

The goals of quality assessment are to determine when a system has reached a state of statistical control to detect when the system has moved out of statistical control and, if possible, to suggest why a loss of statistical control has occurred so that corrective actions can be taken. For convenience, the methods of quality assessment are divided into two categories internal methods that are coordinated within the laboratory and external methods for which an outside agency or individual is responsible. The incorporation of these methods into a quaKty assurance program is covered in Section 15C. 

Internal methods of quality assessment should always be viewed with some level of skepticism because of the potential for bias in their execution and interpretation. For this reason, external methods of quality assessment also play an important role in quality assurance programs. One external method of quality assessment is the certification of a laboratory by a sponsoring agency. Certification is based on the successful analysis of a set of proficiency standards prepared by the sponsoring agency. For example, laboratories involved in environmental analyses may be required to analyze standard samples prepared by the Environmental Protection... 

In the previous section we described several internal methods of quality assessment that provide quantitative estimates of the systematic and random errors present in an analytical system. Now we turn our attention to how this numerical information is incorporated into the written directives of a complete quality assurance program. Two approaches to developing quality assurance programs have been described a prescriptive approach, in which an exact method of quality assessment is prescribed and a performance-based approach, in which any form of quality assessment is acceptable, provided that an acceptable level of statistical control can be demonstrated. 

Standard reference materials provide a necessary but insufficient means for achieving accuracy and measurement compatibiUty on a national or international scale. Good test methods, good laboratory practices, well-qualified personnel, and proper intralaboratory and intedaboratory quaUty assurance procedures ate equally important. A systems approach to measurement compatibiUty is ikustrated in Figure 2. The function of each level is to transfer accuracy to the level below and to help provide traceabiUty to the level above. Thus traversing the hierarchy from bottom to top increases accuracy at the expense of measurement efficiency. 

F. M. Garfield, Quality Assurance Principlesfor Analytical Eaboratories, 2nd ed., AO AC International, Arlington, Va., 1991 (Enghsh), 1993 (Spanish). 

Finally, the laboratory expends significant effort communicating results to both internal and external customers. Production, quaUty assurance, and purchasing all have various information needs ranging from the simple pass /fail decisions to statistical summaries of the data and suppHer product quahty. Customers expect to receive lot analyses in the form of a COA and often also want their own product-specific information on the document as well. This information can automatically be appHed to the COA if entered into the LIMS. Often, a quaUty-conscious customer wants information about the product in the form of process capabiUty or control charts. Using LIMS, these charts can be provided on demand. 

Economy of time and resources dictate using the smallest sized faciHty possible to assure that projected larger scale performance is within tolerable levels of risk and uncertainty. Minimum sizes of such laboratory and pilot units often are set by operabiHty factors not directly involving internal reactor features. These include feed and product transfer line diameters, inventory control in feed and product separation systems, and preheat and temperature maintenance requirements. Most of these extraneous factors favor large units. Large industrial plants can be operated with high service factors for years, whereas it is not unusual for pilot units to operate at sustained conditions for only days or even hours. 

Alternatively, reactant and product gases can be distributed to and removed from individual cells through internal pipes in a design analogous to that of filter presses, (iare must be exercised to assure an even flow distribution between the entiv and exit cells. The seals in internally manifolded stacks are generally not subject to electrical, thermal, and mechanical stresses, but are more numerous than in externally manifolded stacks. 

Tuma, L. and C. Bagner 1998. Assurance of Safe Pilot Plant Scale-Up of Chemical Processes, in (G. A. Melhem and H. G. Fisher, eds.). International Symposium on Runaway Reactions, Pressure Relief Design, and Effluent Handling, American Institute of Chemical Engineers, New York. 

This section covers only the tests that are essential on a completed motor, irrespective of the manufacturing procedure and stage quality checks. If ISO 9000 guidelines are assimilated, practised and enforced by a manufacturer so that a customer s trust is obtained, a final pre-despatch inspection by the customer may not be necessary. The customer, having gained confidence in the practices and Quality Assurance Systems of the manufacturer, may issue an authorization to the manufacturer to despatch the material under their own inspection certificate, rather than an inspection by the customer. We discuss below the test requirements procedure and the acceptance norms prescribed by various national and international standards for such machines and adopted by various manufacturers. 

All these items must be properly checked and recorded according to the manufacturer s internal quality checks and formats before they are used in the manufacture of a bus system. This will eliminate any inconsistency in a material or component at the initial stage. Similarly, stage inspections are necessary during the course of manufacturing to ensure quality at every stage and to eliminate incorrect construction and as.sembly or poor workmanship. And thus assure a product of desired specifications and quality. 

You should consider obtaining internal and external quality assurance reviews of the study (to ferret out errors in modeling, data, etc.). Independent peer reviews of the QRA results can be helpful by presenting alternate viewpoints, and you should include outside experts (either consultants or personnel from another plant) on the QRA review panel. You should also set up a mechanism wherein disputes between QRA team members (e.g., technical arguments about safety issues) can be voiced and reconciled. All of these factors play an essential role in producing a defendable, high-quality QRA. Once the QRA is complete, you must formally document your response to the project team s final report and any recommendations it contains. 

ISO 9000 (1994). Quality Management and Quality Assurance Standards—Guidelines for Selection and Use. Geneva, Switzerland International Organization for Standardization. 

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