Final Design

Values-Based Safety Process Improving Your Safety Culture With Behavior-Based Safety, 55 

Second Edition Terry E. McSween Copyright 2003 John Wiley Sons, Inc. ISBN 0-471-22049-3 

Over the long term, the safety process should be responsive to data and experience. The group should ensure an observation process that gets modified on the basis of incidents and near misses. The important thing is to create an adaptive system that responds to experience in ways that will help employees prevent future incidents and injuries. 

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In general, the final network design should be achieved in the minimum number of units to keep down the capital cost (although this is not the only consideration to keep down the capital cost). To minimize the number of imits in Eq. (7.1), L should be zero and C should be a maximum. Assuming L to be zero in the final design is a reasonable assumption. However, what should be assumed about C Consider the network in Fig. 7.16, which has two components. For there to be two components, the heat duties for streams A and B must exactly balance the duties for streams E and F. Also, the heat duties for streams C and D must exactly balance the duties for streams G and H. Such balemces are likely to be unusual and not easy to predict. The safest assumption for C thus appears to be that there will be one component only, i.e., C = 1. This leads to an important special case when the network has a single component and is loop-free. In this case, ... 

These small positive and negative errors partially cancel each other. The result is that capital cost targets predicted by the methods described in this chapter are usually within 5 percent of the final design, providing heat transfer coefficients vary by less than one order of magnitude. If heat transfer coefficients vary by more than one order of magnitude, then a more sophisticated approach can sometimes be justified. ... 

The final design shown in Fig. 16.7 amalgamates the hot-end design from Fig. 16.5c and the cold-end design from Fig. 16.6c. The duty on hot utility of 7.5 MW agrees with Qnmm and the duty on the cold utility of 10 MW agrees with Qcmm predicted by the composite curves and the problem table algorithm. 

Following this approach, the design is straightforward, and the final design is shown in Fig. 16.176. It achieves the energy targets... 

After development of a new process scheme at laboratory scale, constmction and operation of pilot-plant faciUties to confirm scale-up information often require two or three years. An additional two to three years is commonly required for final design, fabrication of special equipment, and constmction of the plant. Thus, projections of raw material costs and availabiUty five to ten years into the future become important in adopting any new process significantly different from the current technology. 

Listed conditions are typical final design conditions are established by customer requirements. 

D. R. Mouta and co-workeis, Mayards Analysis of the Final Design of the Improved Black Powder Process, Vols. 1—2, Rpt. J6329, Illinois Institute of Technology, Chicago, 1963. 

The upper use temperature for annealed ware is below the temperature at which the glass begins to soften and flow (about Pa-s or 10 P). The maximum use temperature of tempered ware is even lower, because of the phenomenon of stress release through viscous flow. Glass used to its extreme limit is vulnerable to thermal shock, and tests should be made before adapting final designs to any use. Table 4 Hsts the normal and extreme temperature limits for annealed and tempered glass. These data ate approximate and assume that the product is not subject to stresses from thermal shock. 

The design and testing of these developmental plants are well underway. The evolutionary designs have received final design approval from the U.S. NRC. As of 1995 evolutionary ALWR designs very similar to these, by the same U.S. manufacturers, are already being built in Asia the GE-Advanced BWR in Japan and the ABB-CE System 80+ PWR in South Korea. The N-4 PWR is under constmction in Prance, and the SizeweU PWR has completed constmction and has initiated operation in the U.K. 

Flux response to concentration, cross flow or shear rate, pressure, and temperature should be determined for the allowable plant excursions. Fouling must be quantified and cleaning procedures proven. The final design flux should reflect long-range variables such as feed-composition changes, reduction of membrane performance, long-term compaction, new foulants, and viscosity shifts. 

The final design should meet process requirements (within reasonable expectations of error) at lowest cost. The lowest cost should include operation and maintenance costs and credit for ability to meet long-term process changes, as well as installed (capital) cost. Ex(mangers should not be selected entirely on a lowest-first-cost basis, which frequently results in future penalties. 

For preliminai y-screeniug worh the simpler methods may be adequate, but for final designs one shoiild seriously consider using a more rigorous approach. 

In most cases, available methods are incomplete or unreliable, and some supporting experimental work is necessary The methods given here shomd allow theoretical feasibility studies, help minimize experimentation, and permit a measure of optimization in final design. 

The scale-up of the Scheibel column is still considered proprietary, and therefore the vendor (Glitsch Process Systems Inc.) should be consulted for the final design. From pilot tests in 0.075-m diameter column, industrial columns up to 3 m in diameter and containing 90 actual stages have been provided. 

As with the other extractors, the final design of a Karr column depends on the scale-up from a pilot test. The following procedure is recommended. 

Overall Scale-Up Factor The final design filtration rate is determined by multiplying the bench-scale filtration rate by each of... 

After the final designs are complete it is recommended that the actual touch (actual) and step voltage (actual) are rechecked for both power plant and switchyard areas separately, to ensure that they are within the tolerable limits as determined above. After the ground stations have been finally installed the actual step and touch voltages must be measured to verify the designs. 

Here Acto is the cyclic stress range for failure in Nf cycles under zero mean stress, and Acr m is the same thing for a mean stress of a .) Goodman s Rule is empirical, and does not always work - then tests simulating service conditions must be carried out, and the results used for the final design. But preliminary designs are usually based on this rule. 

This, then, is our final design equation. It shows how the survival probability depends on both the stress (rand the volume V of the component. In using it, the first step is to fix on an acceptable failure probability, Pp 0.3 for chalk, 10 for the cutting tool, 10 for the vacuum-chamber window. The survival probability is then given by P = 1 -. ... 

The Souders-Brown correlation considers entrainment as the controlling factor. For high liquid loading situations and final design, complete tray hydraulic calculations are required. 

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