The Usability Standards contained herein provide guidance for designing and constructing more ergonomic, universally functional housing. The usability standards listed below are organized according to the traditional functions that take place within the home (e.g. sleeping, food preparation, etc.). Each category contains two components: (1) Levels of Usability (top) and (2) Usability

Criteria (left). There are four types of usability: (a) mobility, (b) operability, (c) perceptibility, and (d) security. To the right of each usability criteria is a continuum of achievement levels--Level 1: Visitable through Level 5: All-Inclusive--where the usability standard is specified. The diagram below illustrates the two basic facets of the Usability Standards.