Function analysis system technique (FAST) is a diagramming technique to graphically show the logical relationships of the functions of an item, system, or procedure. FAST was developed in 1964 by Charles V. Bytheway at the UNIVAC Division of the Sperry Rand Corporation. Prior to the development of FAST, one had to perform a function analysis of an item by random identification of functions. The basic function had to be identified by trial and error, and one was never quite sure that all functions had been uncovered. FAST provides a system to do a better job in function analysis.
10.5.1 Purpose of the FAST Diagram
The FAST diagram should be created during the information phase of the VE job plan by the whole VE team. When used in conjunction with a value study, the FAST diagram serves the following purposes:
1. It helps organize random listing of functions. When answering the questions “What is it?”, “What does it do?”, “What must it do?”, the study team develops many verb — noun function solutions at all levels of activity, which the FAST diagram can help sort out and interrelate.
2. It helps check for missing functions that might be overlooked in the above random function identification process.
3. It aids in the identification of the basic function or scope of the study.
4. It deepens and guides the involvement, visualization, and understanding of the problem to be solved and the proposed changes.
5. It demonstrates that the task team has completely analyzed the subject or problem.
6. It tests the functions through the system of determinate logic.
7. It results in team consensus in defining the problem in function terms and aids in developing more creative valid alternatives.
8. It is particularly helpful in “selling” the resulting changes to the decision makers.
