Our body dimensions, and the way we move through and perceive space, are prime determinants of architectural and interior design. The dimensions and clearances of an average adult represent minimum requirements for use in planning building layouts and furnishings. If possible, clearances should be increased to allow comfortable accommodations for persons larger than average. Since doorways and passageways must normally be dimensioned to permit the movement of furniture, they should seldom be designed merely on the needs of the average adult.
There is a difference between the structural dimensions of our bodies and those dimensional requirements that result from the way we reach for something on a shelf, sit down at a table, walk down a set of stairs, or interact with other people. The functional dimensions vary according to the nature of the activity engaged in and the social situation as shown in figure.
The interior spaces of buildings are designed as places for human movement, activity, and repose. There should be, therefore, a fit between the form and dimensions of interior space and our own body dimensions. This fit can be a static one, as when we sit in a chair, lean against a railing, or nestle within an alcove
There can also be a dynamic fit, as when we enter a building’s foyer, walk up a stairway, or move through the rooms and halls of a building.
A third type of fit is the way space accommodates our need to maintain appropriate social distances and to control our personal space.
In addition to these physical and psychological dimensions, space also has tactile, auditory, olfactory, and thermal characteristics that influence how we feel and what we do within it.