The application of dimensioning follows a transparent procedure based on demand, performance, availability and agreed safety factors.
Static and dynamic dimensioning
A distinction is made between static and dynamic dimensioning. Static dimensioning is a simpler consideration of the average demand in a time period (e.g. one year). Dynamic dimensioning, on the other hand, takes fluctuating demand quantities into account. In practice, static dimensioning is often sufficient due to the high effort involved in the dynamic dimensioning procedure.
Dimensioning of operating resources
Operating resources are generally defined as machines, systems, devices, tools, etc. The dimensioning of operating resources starts with production equipment, as the characteristics and extent of all other resources (space and personnel) are derived from this.
Personnel requirements planning
Personnel requirements planning is an essential component in the factory planning process, as personnel costs often play a dominant role in cost structures. In direct areas, personnel requirements can therefore be calculated from the product of the annual quantity and the time required per labour unit. It is more difficult to determine personnel requirements, e.g. for warehousing, order picking and logistics activities. Up to now, it has mainly been necessary to determine all relevant workplace-related activities and their time requirements in advance. However, the key figure method can also be used here, for example, to compare the work processes of the equipment to be operated (e.g. stacker cranes and order picking devices, scheduling software, control centre) with the number of units produced. Determining the personnel requirements for activities with a high administrative component is much more extensive. In the case of existing processes, work analyses, time measurements on site or the use of MTM procedures, for example, have had to be used to determine working time requirements.
Space planning
After the planning of operating resources and personnel, the space planning takes place. The predetermination of the space required for a factory planning object is a core task within factory planning due to its significance with regard to land or building structures and the resulting investment requirements.
Four subsystems, one data basis
The basis of every dimensioning task is the production programme — the quantity structure of the planned production. From it, the capacity requirements of four subsystems are derived: equipment, personnel, space and media (supply and disposal utilities). In practice, equipment dimensioning has primacy: personnel, space and media requirements are derived from the number and type of equipment (Grundig 2018, p. 83 f.). For the space side, the article planning and sizing operational areas describes the procedure.
Target/actual capacity comparison
Methodically, period-related requirement figures (processing capacity from process plans and quantities) are compared with availability figures (existing or planned machine capacity from number, operating time and shift model). Capacity deficits from this comparison are the basis of the dimensioning decision — against the planning target for new plants, against the existing base for conversions and expansions (Grundig 2018, p. 84 f.). A distinction is made between qualitative capacity (technical capability) and quantitative capacity (number × operating time).
Size statically, verify dynamically
Static dimensioning works with average values of the reference period and is sufficient in many planning cases. Where seasonality, ramp-ups or stochastic effects dominate, a dynamic view — up to a material flow simulation — verifies the design (Grundig 2018, p. 84). Because programmes change, flexibility, changeability and deliberate reserves belong in the final design. For support functions, the entry indirect areas shows the planning approach.
Dimensioning with units and assumptions
A robust calculation states the reference period, unit, peak factor, availability and safety allowance. A simplified first estimate for equipment can be written as:
number of units = peak demand per period ÷ effective output per unit and period
Effective output combines nominal output, usable time, technical availability and a realistic performance factor. Round up to full units and then test bottleneck, shift and disruption scenarios. This logic is general guidance rather than a project-specific design.
For spatial implementation, machine, operating, buffer, traffic, safety and expansion areas are calculated separately. Connecting the result with factory planning and material flow planning prevents isolated capacity values from producing impractical layouts.
Dimensioning in practice: Our services overview brings together the relevant planning and consulting approaches.