Just about every engineering company in the world is using models as a design tool. Buyers of engineering design services are requesting models. They do not like to review drawings for approval. They can see the model and suggest changes that could not be seen until the plant was constructed.Buyers are not just interested in a good design but are interested in a complete job ( plant on stream). They can control sub-contractors. Even if the buyers do not specify a model, changes are they will use it.Individuals in your drafting and design groups cannot contribute to a total proejct with drawings, but with model they will contribute and benefit. Think about these not so often talked about reasons for using a model.

MANAGEMENT AID
Models aid internal work assignment.

REPLACES DRAWINGS
A model can replace some drawings. You don't need drawings where the models can be used. If you use drawings the checking time can be reduced, if checked against the model.

STATUS IS OBVIOUS
Project managers are not "kidded" on the status of the project. Sections leaders can state the status of the job and no one can dispute it.

MISTAKES ON DRAWINGS
You can see things on the model that are obviously wrong that could never be caught on drawings. Consideration must be given to how serious the mistakes are when using drawings.

ACCELERATES SCHEDULE
There is no evidence that a model impairs schedule. In most cases, a model will expedite a job because it improves visibility and communication. There are fewer changes with a model because the design is better the first time round.

SHOWS HOLDUPS
Internal constraint or holds as a result of the contractor reviews are identified and visible.

ELIMINATES PROBLEMS
Models normally will add cost to a design activity but you cannot place a value on what problems you eliminate. The cost of a model is analogous to an insurance policy.

BETTER UNDERSTANDING OF PLANT
With a model your designer can play all three roles : designer, contractor operator and maintenance persons. He will understand the plant better from all aspects of operation.

OPTIMUM INSTRUMENTS LOCATIONS
Your drawing may allow the plant to be built, but how many instrument piping and location mistakes exist. Are the instruments readable and servicable ? Are the instruments available and can they be maintained ?

CONFIDENCE TO DESIGN
You know your design is right the first time and you have confidence the plant will work.

DEFINITION AND NEED
The Design model is communication tools and is the most used and important model in the engineering model series because it has to do with piping systems. In addition, it integrates other disciplines ( structural, equipment, instrumentation, electrical, HVAC). By looking at the "whole job", improvements are made in each discipline. Interference are eliminated, valves are located for accessibility, instruments are located for accessibility, maintenance and safety studies are complete and accessways are checked for location and safety. Designing has become so involved and complicated that new methods of communication are needed. Design models are bridging this communication gap, and cutting engineering and construction cost and improving operations and management techniques. How many people can understand a plant by looking at a set of drawings ?

COST CONSIDERATIONS
Models aren't costly, mistakes are. Mistakes are costly and as the saying goes " It is less costly to correct plastic than steel." Costs are continually changing. The major consideration is what method of design will give the best, but least expensive way to match the flow diagram. A good designer will always strive for the best configuration at minimal cost. Model costs depend on details. Models don't cost. They save. Forget the cost of the model. If it is done right it does not cost anything.