Equipment estimating procedures

The recommended, and most accurate, method of pricing equipment is with the help of vendors or recent purchase orders. However, it frequently occurs that either the purpose of the estimate does not justify the effort or the time constraint does not permit it. In those cases, the following procedures will be of great value to the Project Manager and/or the Estimator. 

In the absence of more precise information, they have proved to be very quick and reasonably accurate especially when applied to a substantial number of pieces of equipment such as the entire equipment account of a chemical process plant. They are also useful to determine whether the price quoted for a specific piece of equipment is reasonable. 

These procedures are more suitable for detailed or semi-detailed estimates where the various commodities (civil, piping, electrical, etc.) are estimated individually or related to equipment count rather than to equipment cost. These procedures should not be used in factored estimates where an error in the equipment account would be greatly amplified by the time it reaches the bottom line. 

This procedure can be applied to all types of pressure and atmosphere tanks and 

The estimated thickness is based on an allowable stress of 15,000 psi and a joint efficiency of 0.85. It includes a corrosion allowance of one-eighth of one inch (1/8 in.). 

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Another problem with risk estimates is that they are usually based on very conservati C assumptions. Thus, the aiuilyses may result in a calculation tliat presents too high a risk. Umicccsstiry equipment or procedures tnay have to be installcd/instituted at a facility to reduce tlie calculated risk. In an effort to better understand tlie significance of risk analyses, it is often helpful to place tlie estimated risks in perspective with otlicr risks. 

Increasing attention is being given to developing methods to predict failure rate data for process equipment and systems. Such methods are beginning to appear in published literature. These methods include correlations, factored estimation procedures, and analogies to predict equipment failure rates. They are desirable because they offer efficient means of providing equipment failure rate data for risk assessments, and they can be conveniently incorporated into computer software. 

Predictive hazard evaluation procedures may be required when new and different processes, designs, equipment, or procedures are being contemplated. The Dow Fire and Explosion Index provides a direct method to estimate the risks in a chemical process based upon flammability and reactivity characteristics of the chemicals, general process hazards (as exothermic reactions, indoor storage of flammable liquids, etc.) and special hazards (as operation above the flash point, operation above the auto-ignition point, quantity of flammable liquid, etc.). Proper description of this index is best found in the 57-page Dows Fire and Explosion Index, Hazard Classification Guide, 5 th ed., AIChE, New York, 1981. 

The Editorial Board lists the following criteria of content for submitted manuscripts. Style should conform with that of previous volumes of Inorganic Syntheses. The introductory section should include a concise and critical summary of the available procedures for synthesis of the product in question. It should also include an estimate of the time required for the synthesis, an indication of the importance and utility of the product, and an admonition if any potential hazards are associated with the procedure. The procedure should present detailed and unambiguous laboratory directions and be written so that it anticipates possible mistakes and misunderstandings on the part of the person who attempts to duplicate the procedure. Any unusual equipment or procedure should be clearly described. Line drawings should be included when they can be helpful. All safety measures should be stated clearly. Sources of unusual starting materials must be given, and, if... 

Once p is found, it is of course to be used in (75) (p = v/2) rather than (89) when the Doppler effect is evaluated. To solve (90) for p, one must find K. It is not usually possible to determine accurately the detection efficiency of the experimental equipment. The procedure is more useful as a means of estimating the order of magnitude of the error that might be introduced by missing levels than as a means of making quantitative corrections. 

The estimating procedures to obtain the full capital cost of the plant are described in this section. If an estimate of the capital cost for a process plant is needed and access to a previous estimate for a similar plant with a different capacity is available, then the principles already introduced for the scaling of purchased costs of equipment can be used,... 

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