chair

Those who study chairs suggest the seat tilt back by 5 degrees, and the angle of the back in relation to the seat be 105 degrees (a greater tilt is hard on the neck).

The height of the seat is chosen so that a short person's legs won't dangle. A height that is too low makes it difficult for a tall person to get up. Because children of the same age vary so greatly in size, it's a good idea to make seating for them adjustable.

Suggested chair dimensions in inches,
for sitters of various ages
	height of seat pan at the leading edge	seat pan depth	back height	seat width
Kindergarten	11	14	10
Grades 1 – 3	13	14	11
Grades 4 – 6	13	14	13
Grades 7 – 9	15	15	15
Grade 10 - adult	17	17	20	19

T. Lauder Brunton
On the Science of Easy Chairs...On Posture and its Indications.
London: Macmillan and Co., 1892

The first essay originally appeared as an article in Nature, October 17, 1878. The chair described as ideal by Brunton is in most respects identical to that designed by NASA.