The design of any layout is governed by a number of factors and the best layout is the one that optimizes all the factors. As discussed by Muther (1955) the factors influencing any layout are categorized into the following eight groups:
- The material factor: Includes design, variety, quantity, the necessary operations, and their sequence.
- The man factor: Includes direct workers, supervision and service help, safety and manpower utilization.
- The machinery factor: Includes the process, producing equipment and tools and their utilization.
- The movement factor: Includes inter and intradepartmental transport and handling at the various operations, storages and inspections, the materials handling equipments.
- The waiting factor: Includes permanent and temporary storages and delays and their locations.
- The service factors: Include service relating to employee facilities such as parking lot, locker rooms, toilets, waiting rooms etc. service relating to materials in terms of quality, production control, scheduling, dispatching, waste control; and service relating to machinery such as maintenance.
- The building factor: Includes outside and inside building features and utility distribution and equipment.
- The change factor: Includes versatility, flexibility and expansion.
Each of the above mentioned factors comprise a number of features and the layout engineer must review these in the light of his problem. Usually the layout design process is a compromise of these various considerations to meet the overall objectives in the best possible manner.