Performance-based

Nonprescriptive management programs have to be performance based because the only measure of success is success. Hence the only true measure of success of the program is not to have incidents. But from a theoretical point of view, such a goal is impossible to achieve. No matter how well-run a facility may be, accidents will occur risk can never be zero. For this reason some risk management professionals chose not to use the term compliance on the grounds that true compliance can never be reahzed. Because risk can never be zero, there are always ways of improving safety and operability. 

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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. 

In a performance-based approach to quality assurance, a laboratory is free to use its experience to determine the best way to gather and monitor quality assessment data. The quality assessment methods remain the same (duplicate samples, blanks, standards, and spike recoveries) since they provide the necessary information about precision and bias. What the laboratory can control, however, is the frequency with which quality assessment samples are analyzed, and the conditions indicating when an analytical system is no longer in a state of statistical control. Furthermore, a performance-based approach to quality assessment allows a laboratory to determine if an analytical system is in danger of drifting out of statistical control. Corrective measures are then taken before further problems develop. 

The principal tool for performance-based quality assessment is the control chart. In a control chart the results from the analysis of quality assessment samples are plotted in the order in which they are collected, providing a continuous record of the statistical state of the analytical system. Quality assessment data collected over time can be summarized by a mean value and a standard deviation. The fundamental assumption behind the use of a control chart is that quality assessment data will show only random variations around the mean value when the analytical system is in statistical control. When an analytical system moves out of statistical control, the quality assessment data is influenced by additional sources of error, increasing the standard deviation or changing the mean value. 

Using Control Charts for Quality Assurance Control charts play an important role in a performance-based program of quality assurance because they provide an easily interpreted picture of the statistical state of an analytical system. Quality assessment samples such as blanks, standards, and spike recoveries can be monitored with property control charts. A precision control chart can be used to monitor duplicate samples. 

Once a control chart is in use, new quality assessment data should be added at a rate sufficient to ensure that the system remains in statistical control. As with prescriptive approaches to quality assurance, when a quality assessment sample is found to be out of statistical control, all samples analyzed since the last successful verification of statistical control must be reanalyzed. The advantage of a performance-based approach to quality assurance is that a laboratory may use its experience, guided by control charts, to determine the frequency for collecting quality assessment samples. When the system is stable, quality assessment samples can be acquired less frequently. 

Other regulations apply in different offshore drilling areas in the United States and around the world. AH have had a profound effect on drilling fluid technology (169,170). Very few instances of water-base muds failing the mysid bioassay test exist in the 1990s. Operators and service companies have eliminated use of the mote toxic additives, reformulated old mud systems, and developed new ones to ensure acceptable environmental performance based on pertinent regulations. 

The two steps in the removal of a particle from the Hquid phase by the filter medium are the transport of the suspended particle to the surface of the medium and interaction with the surface to form a bond strong enough to withstand the hydraulic stresses imposed on it by the passage of water over the surface. The transport step is influenced by such physical factors as concentration of the suspension, medium particle size, medium particle-size distribution, temperature, flow rate, and flow time. These parameters have been considered in various empirical relationships that help predict filter performance based on physical factors only (8,9). Attention has also been placed on the interaction between the particles and the filter surface. The mechanisms postulated are based on adsorption (qv) or specific chemical interactions (10). 

Concerning the VDW parameters, the ability to directly apply previously optimized values makes convergence criteria unnecessary. If VDW parameter optimization is performed based on pure solvent or crystal simulations, then the heats of vaporization or sublimation should be within 2% of experimental values, and the calculated molecular or unit cell volumes should be also. If rare gas-model compound data are used, the references cited above should be referred to for a discussion of the convergence criteria. 

When using dimensional analysis in computing or predicting performance based on tests performed on smaller-scale units, it is not physically possible to keep all parameters constant. The variation of the final results will depend on the scale-up factor and the difference in the fluid medium. It is important in any type of dimensionless study to understand the limit of the parameters and that the geometrical scale-up of similar parameters must remain constant. 

The benefits of total performance based planned maintenance not only ensure the best and lowest cost maintenance program but also that the plant is operated at its most efficient point. An important supplementary effect is that the plant will be operating consistently within its environmental constraints. 

A new maintenance system is introduced based on the new mantra for the selection of all equipment Life Cycle Cost. This new system especially for major power plants is based on the combination of total condition monitoring, and the maintenance principles of total productive maintenance, and is called the Performance Based Total Productive Maintenance System. ... 

Performance based total productive maintenance (PTPM). 

Performance based total productive maintenance aims to maximize equipment efficiency and time between overhaul, (overall performance effectiveness)... 

Performance based total productive maintenance establishes a thorough system of PM for the equipment s entire life span. 

Performance based total productive maintenance is implemented by various departments (engineering, operations, maintenance). 

Performance based total productive maintenance involves every single employee, from top management to workers on the floor. 

Performance based total productive maintenance is based on the promotions of PM through motivation management, autonomous small group activities. 

The word total in performance based total productive maintenance has four meanings that describe the principal features of PTPM ... 

Performance Based Total Productive Maintenance Performance Productive Maintenance Performance Based Maintenance Preventive Maintenance Panic Maintenance... 

Figure 21-1. Total performance-based condition monitoring system.

Organization Structures for a Performance Based Totai Productive Maintenance Program... 

The four major categories in developing a Performance Based Total Productive Maintenance program are ... 

The seheduling of maintenanee inspeetions and overhauls is an essential part of the total maintenanee philosophy. As we move from Breakdown or Panie maintenanee towards a performance based total productive maintenance system, total eondition monitoring and diagnosties beeomes an integral part of both operation and maintenanee. Total eondition monitoring and diagnostie examines both the meehanieal and performanee... 

The old maxim if it ain t broke don t fix it is very applicable in today s machinery. A study conducted at a major nuclear power facility found that 35% of the failures occurred after a major turnaround. This is why total condition monitoring is necessary in any performance based total productive maintenance system and leads to overhauls being planned on proper data evaluation of the machinery rather than on a fixed interval. 

The objective of this approach is to improve the reliability of the system without having to design acoustical filters. For many systems, this is all that is needed. API 618 contains a chart that recommends the type of analysis that should be performed, based on horsepower and pressure. 

Professional judgment should be exercised when planning site activities and to document decisions. HAZWOPER is a performance-based standard that emphasizes hazard analyses at all stages. It encourages the development of programs that match the anticipated risk for each work activity. Eor example, professional judgment is used to decide if a comprehensive HASP or a scaled-down version is required for activities with little possibility to cause significant exposure. 

Peterson, R. J. et al., 1981, Performance-Based Evaluation of Safety Parameter Display Detection, EG G, Sd-B-81-004, November. 

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