An 80% capacity factor (car loading) is widely used in lift traffic design; however, it is applied differently in calculations and simulations. In round-trip time calculations, an 80% car factor is typically assumed to determine handling capacity. For consistency, in simulations, cars may be allowed to fill to 100%, with average capacity factor assessed across the peak period to confirm it does not exceed 80%.

This paper examines the origin and purpose of the 80% capacity factor, demonstrates its implementation in both calculation and simulation, and explains the importance of using area, not mass, as the basis for these assessments. The paper addresses common misconceptions that incorrectly conflate allowances for passengers occupying more space (e.g. as they are carrying baggage) with the 80% capacity factor. Instead of adjusting the 80% capacity factor, a better approach is to vary the area per person in the analysis to reflect different passenger types.

By consistently applying the 80% capacity factor, designers can better communicate their work and ensure realistic and robust lift system designs.