Design overdesign

There are considerable uncertainties in the literature about the computation of the heat transfer coefficient. Thus, one has to be generous with heat transfer surface unless one has company data to back up the design. Overdesign may make control and high turndown more difficult to attain. 

Initial cost of a conveyor system is usually related to life ejqjectancy as well as to the flow rate chosen. There is a great temptation to overdesign, which should be resisted. The first really longdistance belt conveyor was designed and fabricated to extremely hi standards of quality. After 35 years it was still in operation with almost all its original components. Had this operation been planned for only... 

Non-complex and/or non-critical applications in mechanical design can also make use of probabilistic design techniques and justify a more in-depth approach if the benefits are related to practitioners and customers alike. Surveys have indicated that many products in the industrial sector have in the past been overdesigned (Kalpakjian, 1995). That is, they were either too bulky, were made of materials too high in quality, or were made with unwarranted precision for the intended use. Overdesign may result from uncertainties in design calculations or the concern of the designer and manufacturer over product safety in order to avoid user injury or... 

The major assumption in weak link design is that the eost of failure of the maehine that is to be proteeted from an overload situation in serviee is mueh greater than the eost of failure of a weak link plaeed in the system whieh is designed to fail first. The situation is primarily driven by various eosts whieh must be balaneed to avoid at one extreme the eost of failure of the system, and the other overdesign of the elements in the system. The eost faetors involved are typieally ... 

Process Conceptual Design Equipment selection and sizing Inventory of process Single vs. Multiple trains Utility requirements Overdesign and flexibility Recycles and buffer capacities Instrumentation and control Location of plant Preliminary plant layout Materials of construction As above plus equipment suppliers data, raw materials data, company design procedures and requirements... 

Standard shapes for composite stiffeners are not likely to occur for most aerospace applications. There, the value and function of the structure warrant optimizing the stiffener design. In contrast, for more everyday applications such as scaffolding, stairways, and walkways in chemical plants, competitive pressures lead to a situation where compromises in stiffener efficiency are readily accepted (overdesign) in order to achieve lower cost than would be associated with optimum design. 

The key to the design of efficient laminates is to resist both the magnitude and the directional nature of the loads without overdesign in either respect. That is, the laminate is taiiored to just meet specific requirements. Structures made of isotropic materials are usually inefficient, i.e., overdesigned because excess strength and stiffness are inevitabiy available in some direction. By appropriate consideration of the loads and their directions, a laminate can be constructed of individual laminae... 

When considering the need for capital pretreatment equipment, sufficient care should be taken not to propose any particularly sophisticated external or internal water treatment regimen that of itself creates restrictive operational BW control limitations—where boiler design, steam usage, and common sense dictate no necessity for such limitations to be imposed. The overall water treatment program should not be overdesigned but should properly match the needs of the project. 

It is always best to overdesign this facility. Therefore a filter having a surface area of 6,000 ft2 will be designated for each train. 

In the last chapter the design of equipment for proposed future expansions was discussed. Obviously, if the equipment has been overdesigned to meet the anticipated future expansion, no extra space needs to be provided. If, however, additional equipment will be required, space should be allocated for it. The net result will be an increase in the initial cost of construction and some increase in material transfer costs, because the transfer lines will be longer. 

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