Engineering-hours

The life expectancy of most hot section parts is dependent on various parameters and is usually measured in terms of equivalent engine hours. The following are some of the major parameters that effect the equivalent engine hours in most machinery, especially gas turbines ... 

Combmtor inspection or overhaul. This is based on equivalent engine hours, whieh are based on the number of starts, fuel, and temperature. Figure 19-20 shows the effeet of these parameters on the life of the unit. Note the strong effeet that fuel and number of starts has on the life. 

Project Description First-year expenditure ( ) Second-year expenditure ( ) Engineering hours Net present value ( )... 

First-year expenditure Second-year expenditure Engineering hours ... 

The engineering hours spent during each phase of FEL vary widely between small and large projects. This is also true for those projects where new or emerging technology is being applied or where higher... 

General Approximate Construction Hours Approximate Engineering Hours Process Design Hours Project Duration/Peak Staffing Example Plan Contents Planning Rules of Thumb... 

Engineering hours are intimately related to equipment count and type. When a complete equipment list is available, the procedure included in Chapter 19 can be used to prepare accurate estimates. However, this is seldom the case in the early stage of any project and the project managers must do the best they can with the information they have. 

If the approximate TIC is available, the engineering hours can be developed with the aid of the Lang Factor. 

Engineering Hours = Equip. Count x Growth Factor x 650 Process Design Hours... 

The Engineering hours required for process design are not only related to equipment count and type they are also very sensitive to the type of process and stage of development of the process design. Experience shows that these factors can produce very wide variations in the hours required. 

If equipment count is not available, the approximate hours for a Phase 1 package can be developed using 12% of the engineering hours derived from the Lang Factor. 

In a typical chemical process plant, the duration of the construction phase is approximately 80% of the total project duration from the start of engineering (after completion of Phase 1) to the mechanical completion of the construction work. The remaining 20% is the lead time required for engineering and procurement activities before construction can start in a cost-effective manner. It must be noted, for initial planning purposes, that the lead time allowed should not be less than three months. Historically, the engineering hours spent during this period are normally between 30 and 40% of the project total. 

Engineering hours used during lead period... 

Preparation of the process package engineering hours, duration, and proposed execution method. 

Compliance to and documentation of regulations increase the engineering hours required to execute the project and the Project Manager must ascertain that they are acknowledged and the impact on cost, and sometimes schedule, is included in the cost estimate and project execution plan. 

The engineering hours and costs, supervision and field expenses, and other items, such as freight, duty and taxes, insurance, etc., are all detailed and priced. 

Engineering - Contractor s engineering hours must be estimated with the procedure in Section 19.8. The cost per hour including overheads... 

Note The proposed execution approach will influence the required engineering hours and must be taken into account when preparing the estimate, especially a definitive or appropriation type estimate. Refer to the discussion in Section 15.3. 

Estimating engineering costs as a percentage of the direct project costs is a very common practice in conceptual and preliminary work. It is very simple but also very risky. The engineering hours related to any piece of equipment have very little relation to its cost. 

For instance, the engineering hours related to a small or medium sized carbon steel reactor are essentially equal to those related to a larger Hastelloy C reactor. However, the difference in cost can be a full order of magnitude. Engineering hours relate best to the type of equipment and conditions specific to each project. 

The estimating system presented here proposes a relatively simple but accurate method for estimating engineering hours based on the equipment list and a general knowledge of the project particulars. It was developed from published data and a thorough analysis of nine actual projects. The analysis of the data resulted in several adjustment and correction factors - some empirical, some theoretical that recognize, and try to compensate for, the effect of conditions specific to each project, such as ... 

NOTE OF CAUTION ALL THE ORIGINAL STUDY CASES PREDATE THE WIDESPREAD USE OF COMPUTER-AIDED DESIGN PROGRAMS. ALTHOUGH THE AUTHOR EXPECTED TO SEE A DRAMATIC REDUCTION IN ENGINEERING HOURS, THAT DID NOT MATERIALIZE FOR SEVERAL YEARS. HOWEVER, IN THE LAST YEAR OR SO,... 

Table 19.25 Engineering Hours Estimating System Performance...

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