What is Function Analysis System Techniques (FAST)? Briefly explain the steps used in constructing the FAST diagram. Discuss the benefits and drawbacks of FAST diagram.

Function Analysis System Technique (FAST) is a structured method used in engineering and project management to analyze and visualize the functions performed by a system, process, or product. It helps identify and understand the relationships between various functions and components within the system, enabling stakeholders to make informed decisions and design improvements.

The steps used in constructing a FAST diagram typically include:

1. Identify Functions: The first step involves identifying and listing all the functions performed by the system or process under analysis. Functions are defined as the actions, tasks, or activities that contribute to achieving the system's objectives.

2. Determine Hierarchical Relationships: Next, hierarchical relationships between functions are established, with higher-level functions representing broader objectives and lower-level functions representing more specific tasks or actions. Functions are organized into a hierarchical structure based on their dependencies and contributions to achieving system goals.

3. Develop FAST Diagram: The FAST diagram is constructed by visually representing the hierarchical relationships between functions using a standardized notation. Arrows are used to illustrate the flow of functions and their dependencies, with higher-level functions depicted at the top of the diagram and lower-level functions below.

4. Validate and Refine: The constructed FAST diagram is reviewed and validated by stakeholders to ensure accuracy and completeness. Any inconsistencies or ambiguities are addressed, and the diagram may be refined or revised based on feedback and additional analysis.

Benefits of FAST diagram:

1. Visual Representation: FAST diagrams provide a clear and structured visual representation of the functions performed by a system, making it easier for stakeholders to understand complex relationships and dependencies.

2. System Understanding: FAST analysis helps stakeholders gain a deeper understanding of how different functions contribute to achieving system objectives, enabling them to identify areas for improvement and optimization.

3. Decision Support: By visualizing functions and their relationships, FAST diagrams facilitate informed decision-making in areas such as system design, process improvement, resource allocation, and risk management.

Drawbacks of FAST diagram:

1. Complexity: Constructing and interpreting FAST diagrams can be complex, particularly for large and intricate systems with numerous functions and dependencies. Managing the complexity of the diagram and ensuring accuracy may pose challenges.

2. Subjectivity: FAST analysis relies on subjective judgment and interpretation by stakeholders, which may lead to biases or inconsistencies in identifying and prioritizing functions and relationships.

3. Limited Scope: FAST diagrams focus primarily on functions and their relationships within a system, potentially overlooking other aspects such as environmental factors, external dependencies, or non-functional requirements.

Despite these drawbacks, FAST diagrams remain valuable tools for systematically analyzing and visualizing the functions performed by a system or process, aiding in decision-making and improvement efforts.