Chair Size Design Based on User Height

Abstract

General principles derived from anatomical studies of human body sizes should be applied to chair designs. Chairs can be designed for a specific user or a particular group of users. Universal chairs for public spaces should be comfortable for the largest possible group of users and should not be adjustable, such as office chairs. However, the fundamental problem is that the anthropometric data available in the literature either come from many years ago and are out of date or do not provide a complete set of all the dimensional parameters of a sitting human body position. This article proposes a way to design chair dimensions solely based on the height range of the intended chair users. For this purpose, based on literature data, the main structural dimensions of the chair were assigned to the appropriate anthropometric body measurements. Furthermore, calculated average body proportions for the adult population overcome the incompleteness, outdated and burdensome access to anthropometric data and link the main chair design dimensions to one easily accessible anthropometric parameter: human height. This is achieved by seven equations describing the dimensional relations between the chair's essential design dimensions and human height or even a height range. The result of the study is a method of determining the optimal functional dimensions of a chair for a chosen range of sizes of its future users based only on users' height range. Limitations of the presented method: the calculated body proportions are correct only for people with a standard body proportion characteristic of adults, i.e., they exclude children and adolescents up to 20 years of age, seniors, and people with a body mass index exceeding 30.

Keywords: anthropometry; chairs; furniture design; lumbar support; seat depth; seat height; seat width.

Figure 1

Representation of the longitudinal (median) and frontal cardinal planes in chair design (inspired by EN 1729-1:2015) and humans in the sitting position.

Figure 2

The functional dimensions of a chair (𝛼—backrest angle, 𝛽—seat angle, h₈—seat height, b₃—seat width, b₄—backrest breath, b₅—armrest spacing, h₆—lumbar support height, h₇—backrest height, h₉—armrest height, r—backrest radius, t₄—seat depth normal, t₇—seat depth, t₁₀—armrest length, and t₁₁—armrest to seat length): (a) side view, dimensions in a longitudinal plane, (b) top view on a chair without armrests, (c) top view on a chair with armrests.

Figure 3

The functional dimensions of a chair and the anthropometric measurements.

Figure 4

Ratio of buttock-popliteal length (A) to total human stature (H) (calculations based on literature data [20]).

Figure 5

The ratio of buttock-popliteal length (B) to total human stature (H) (calculations based on literature data [20]).

Figure 6

Ratio of bi-trochanteric breadth (C) to total human stature (H) (calculations based on literature data [20]).

Figure 7

Elbow-to-elbow breath (D) to total human stature (H) (calculations based on literature data [20]).

Figure 8

Elbow rest height (E) to total human stature (H) (calculations based on literature data [20]).

Figure 9

Sitting height erect versus sitting height normal.

Figure 9

Sitting height erect versus sitting height normal.

Figure 10

Sitting height normal (F) to total human stature (H) (calculations based on literature data [20]).

Figure 11

Shoulder breath (G) to total human stature (H) (calculations based on literature data [20]).

Figure 12

The functional dimensions of a chair for 95% of the adult population (in centimeters).