Evolution of Chairs Quiz

The chair has been used since antiquity, although for many centuries it was a symbolic article of state and dignity rather than an article for ordinary use.
Until the 16th century, people sat on chests, benches, and stools, which were the ordinary seats of everyday life.
The chair was in existence since at least the Early Dynastic Period of Egypt (c. 3100 BC).
It was not until the 16th century that chairs became common.
In Europe, it was owing in great measure to the Renaissance that the chair ceased to be a privilege of state and became a standard item of furniture for anyone who could afford to buy it.
Once the idea of privilege faded the chair speedily came into general use.
The chair began to change every few years to reflect the fashions of the day.
Chairs can be made from a variety of materials, including wood, metal, and other strong materials.
Chairs can have hard surfaces of wood, metal, plastic, or other materials, or some or all of these hard surfaces may be covered with upholstery or padding.
The design may be made of porous materials, or be drilled with holes for decoration; a low back or gaps can provide ventilation.
Chairs can also be made from more creative materials, such as recycled materials like cutlery and wooden play bricks, pencils, plumbing tubes, rope, corrugated cardboard, and PVC pipe.
In rare cases, chairs are made out of unusual materials, especially as a form of art or experimentation.
Seat height can be adjusted to help distribute the weight of the occupant to various parts of the body.
Foot rests are common, and around 15% of women and 2% of men need them.
Chairs can be purchased in a variety of sizes and styles, and can be used for a variety of purposes.
Chair design is based on measurements of the human body or anthropometric measurements.
The two most relevant anthropometric measurement for chair design are the popliteal height and buttock popliteal length.
For someone seated, the popliteal height is the distance from the underside of the foot to the underside of the thigh at the knees.
The term "sitting height" is reserved for the height to the top of the head when seated.
For American men, the median popliteal height is 16.3 inches (41 cm) and for American women it is 15.0 inches (38 cm).
The popliteal height, after adjusting for heels, clothing and other issues, is used to determine the height of the chair seat.
Mass-produced chairs are typically 17 inches (43 cm) high.
Researchers such as Mary Blade and Galen Cranz found that sitting on the edge of a high stool with feet on the floor is less harmful for the lower back than sitting up straight on a conventional chair.
Reclining angle
Different types of chairs can have a variety of seating positions, depending on the intended task.
Chairs intended for people completing work or dining can only recline very slightly (otherwise the occupant is too far away from the desk or table).
Dental chairs are necessarily reclined.
In order to recline, the back-rest may be independently adjustable.
A reclining seat and back will reduce the load on the occupant's back muscles.
Back and head support
Padding
Armrests
Seat size and legroom
Armrests further have the function of making entry and exit from the chair easier (but from the side it becomes more difficult).
ISO 9241 specifies the requirements for chairs used in offices.
Dental chairs are specified by ISO 6875.
Bean bag chairs are specified by ANSI standard ASTM F1912-98.
ISO 7174 specifies stability of rocking and tilting chairs.
ASTM F1858-98 specifies plastic lawn chairs.
ASTM E1822-02b defines the combustibility of chairs when they are stacked.
BIFMA defines ANSI/BIFMA X5.1 for testing commercial-grade chairs.
Large institutions will reference these standards within their own detailed criteria for purchase.
Governments will often make bulk purchases of chairs that meet these standards.