Operations level

The essential differences between sequential-modular and equation-oriented simulators are ia the stmcture of the computer programs (5) and ia the computer time that is required ia getting the solution to a problem. In sequential-modular simulators, at the top level, the executive program accepts iaput data, determines the dow-sheet topology, and derives and controls the calculation sequence for the unit operations ia the dow sheet. The executive then passes control to the unit operations level for the execution of each module. Here, specialized procedures for the unit operations Hbrary calculate mass and energy balances for a particular unit. FiaaHy, the executive and the unit operations level make frequent calls to the physical properties Hbrary level for the routine tasks, enthalpy calculations, and calculations of phase equiHbria and other stream properties. The bottom layer is usually transparent to the user, although it may take 60 to 80% of the calculation efforts. 

Practical considerations enter into the experimental plan in various other ways. In many programs, variables are introduced at different operational levels. For example, in evaluating the effect of alloy composition, oven temperature, and varnish coat on tensile strength, it may be convenient to make a number of master alloys with each composition, spHt the alloys into separate parts to be subjected to different heat treatments, and then cut the treated samples into subsamples to which different coatings are appHed. Tensile strength measurements are then obtained on all coated subsamples. 

When heavier refractories are required because of operating conditions, insulating brick is installed next to the shell and firebrick is installed to protect the insulating brick. Industrial experience in many fields of application has demonstrated that such a hning will success-billy withstand the abrasive conditions for many years without replacement. Most serious refractory wear occurs with coarse particles at high gas velocities and is usually most pronounced near the operating level of the fluidized bed. 

It is advisable to start a constant-pressure filtration test, like a comparable plant operation, at a low pressure, and smoothly increase the pressure to the desired operating level. In such cases, time and filtrate-quantity data shoulci not be taken until the constant operating pressure is reahzed. The value of r calculated from the extrapolated intercept then reflec ts the resistance of both the filter medium and that part of the cake deposited during the pressure-buildup period. When only the total mass of diy cake is measured for the tot cycle time, as is usually true in vacuum leaf tests, at least three runs of different lengths should be made to permit a rehable plot of 0/V against W. If rectification of the resulting three points is dubious, additional runs should be made. 

The basic approach is to direct the system to the safest operating level relative to people or the environment when any emergency condition is detected, including power loss. An important concept of process control safety is to have adequate redundancy to reduce unwanted shutdowns and maintain an adequate level of certainty that a safe state will result if a real emergency does occur. As far as possible, instruments should be of the fail-safe type. 

The eapaeity between the minimum and the maximum operating levels in an oil system that diseharges seal oil from the unit should be enough for a minimum... 

Provide a means of filling the tank to operating level prior to operating the blending nozzle system. Damage could result from discharging the high velocity jet into an empty tank. 

For liquid film seals, an overhead tank is normally used. The tank functions as part of the differential pressure control. The process gas is referenced to the top of the tank, and the tank s physical height becomes a manometric leg. The oil level is controlled in the tank. Figure 8-11 shows an alternate arrangement for the overhead seal tank, including the recommended operating levels and volumes. The material of the seal oil tank should be stainless, the same as that recommended for the accumulator. 

The advent of ISO 9000 certification has helped bring the quality issue to a focus. While ISO 9000 emphasis is on documentation of methodology and performance to the documented methods, the discipline that results is a direct step toward improvements in reliability. Out of this seems to come a goal of continuous improvement. This is a sharp contrast to the high growth era that took place in the early 1980s when poor quality on the part of the equipment suppliers was a significant factor in the lack of reliability at the field operation level. 

Rrst responders are divided into two levels of competency first responder awcireness and first responder of>-erational. First responders at the awareness level shall be trained to meet all of the requirements of Section -2 of this chapter and first responders at the operational level shall be trained to meet all of the requirements of Section 2 and Section -3 of this chapter. All first responders shall receive annual training to meet federal Occupational Safety and Health Administration (OSHA) and Environmental Protection Agency (EPA) requirements. 

The goal at the first responder operational level is to provide the designated first responder with the following competencies to respond safely to the incident... 

A minimum of 24 hours of training equal to the first responder operations level and additional competency in areas listed in 29 CFR (q)(6)(v)-... 

Organizational factors create preconditions for errors, At the operational level, plant and corporate management inadvertently support conditions for errors. The safety culture of the... 

Whilst the decision to pursue ISO/TS 16949 registration will be an executive decision, the attention it is given at each level in the organization will have a bearing on the degree of success attained. There are three primary organization levels the enterprise level, the business level, and the operations level. Between each level there are barriers. 

At the enterprise level, the executive management responds to the voice of ownership and is primarily concerned with profit, return on capital employed, market share, etc. At the business level, the managers are concerned with products and services and hence respond to the voice of the customer. At the operational level, the middle managers, supervisors, operators, etc. focus on processes that produce products and services and hence respond to the voice of the processes carried out within their own function. 

The typical focus for a quality system is at the operations level. ISO 9000 is seen as an initiative for work process improvement. The documentation is often developed at the work process level and focused on functions. Much of the effort is focused on the processes within the functions rather than across the functions and only involves the business level at the customer interface, as illustrated in Table 2-1. 

Just as you presented a preliminary plan at the outset of the PSM initiative, you may want to think in terms of a formal presentation to your company s management when the detailed plan is complete. Remember that senior management s buy-in will be essential to successful implementation so will the endorsement of line managers at the operating level, who will be directly affected by your plan. 

The identification of the operational level deficiencies that contribute to increased error rates can be achieved by evaluations of PIFs as described in Chapter 3. Although the factors described in that chapter are not exhaustive in their coverage, they can provide a useful starting point for an evaluation exercise. Structured PIF evaluation systems are described in Chapter 2 which ensure that all the important factors that need to be evaluated are included in the exercise. 

In the case of a latent human error the consequences of the error may only become apparent after a period of time when the condition caused by the error combines with other errors or particular operational conditions. Two types of latent error can be distinguished. One category originates at the operational level and leads to some required system function being degraded or unavailable. Maintenance and inspection operations are a frequent source of this type of latent failure. 

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