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Chair

A chair is a piece of furniture consisting of a seat, legs, back, and sometimes arm rests, for use by one person. Without back and arm rests it is called a stool. A chair for more persons is a couch, sofa, settee, loveseat or bench. A chair mounted in a vehicle or in a theatre is simply called a seat.

The back often does not extend all the way to the seat to allow for ventilation. Likewise, the back and sometimes the seat are made of porous materials or have holes drilled in them for decoration and ventilation.

The back may extend above the height of the head. There may be separate headrests. Headrests for seats in vehicles are important for preventing whiplash injuries to the neck when the vehicle is involved in a rear-end collision.

Table of contents

1 Types of chairs 2 Design and ergonomics 3 Chair Seats 4 Standards and specifications 5 Accessories 6 History of the Chair 6.1 Egyptian chairs 6.2 Greek and Roman chairs 6.3 Medieval chairs 6.4 Chinese chairs 6.5 Renaissance 6.6 English chairs 6.7 18th century chairs 6.8 19th century chairs 6.9 20th Century and modern chairs 7 Phrases relating to chairs 8 References

Types of chairs

An Adirondack chair is an non-adjustable wooden outdoor lounge chair.

An Aeron chair is an ergonomic trademarked chair.

A ball chair is a chair in the shape of a large ball or egg with one section removed so you can sit inside it. Also called a pod chair or an egg chair.

A barber's chair swivels and has easily adjusted heights to make it easy for the barber. It may also recline for washing hair. It typically has footrests as the height may be adjusted and raise the patron's feet off the floor. For children's barbershops, the chairs may come in fanciful shapes such as horses and cars to distract the children while their hair is cut.

A Barcelona chair class="external">[1 is a proprietary chair characterized by leather upholstery, backward sloping seat, reclined back and no armrests.

A barrel chair [1] is a chair with a high round back like half a barrel. It is large and upholstered.

Beanbag chairs are fabric bags of beans in the shape of a chair. They are usually filled with foam chips today and made of colourful fabric for children.

A butterfly chair class="external">[1 is composed of a single piece of fabric suspended from a light metal frame.

A captain's chair was originally a low back wooden chair [1]. Today it is often applied to adjustable individual seats in a car with arm rests.

A club chair [1] is a plush easy chair with a low back. The heavy sides form armrests that are usually as high as the back.

A Cogswell chair [1] was a brand of upholstered easy chairs. It has a sloping back and curved and ornamental front legs. The armrests are open underneath.

A corner chair was made to fit into a corner. It has a rectangular base with a high back on two adjacent sides. One sits with legs straddling a corner of the base.

Dentist chairs are deeply reclining chairs to allow the dentist easy access to the patients mouth. The reclining position adjusts as well as the overall height of the chair. Associated with the chair are usually a variety of dental equipment, often including a small tap and sink for the patient to rinse his or her mouth.

A director's chair class="external">[1 is a folding chair used by movie directors. It folds side-to-side and can fold that way because the seat and back are usually fabric, typically canvas. The back is usually low and there are usually armrests.

An easy chair [1] is any large comfortable chair. It is typically upholstered.

The Eames chair [1] is a trademark for molded plywood chairs, contoured to fit the shape of a person.

An electric chair is a device for capital punishment by electrocution.

A fighting chair[1] is a chair on a boat used by anglers to catch large saltwater fish. The chair typically swivels and has a harness to keep the angler strapped in should the fish tug hard on the line.

Folding chairs collapse the back to the seat. Some further collapse the feet up to the back. This is useful for mobility and storage. Folding chairs are typically designed to stack on top of each other when folded and may come with special trolleys to move stacks of folded chairs. Stacking chairs simply stack for storage and do not collapse.

A glider offers the same motions as a rocking chair but without the dangers. A frame rests on the floor and the chair is supported by swing arms within the frame so that moving parts are less accessible.

A high chair is a children's chair to raise them to the height of adults for feeding. They typically come with a detachable tray so that the child can sit apart from the main table. Booster chairs raise the height of children on regular chairs so they can eat a the main dining table. Some high chairs are clamped directly to the table and thus is more portable.

Plastic inflatable chairs are usually children's toys. Ikea briefly marketed them as serious furniture upholstered in fabric. Some are designed for use as floating lounge chairs in swimming pools.

Kneeling chairs or knee-sit chairs [1] are chairs that are meant to support someone kneeling. This is puportedly better for the back than sitting all day. The main seat is sloped forward at the about 30 degrees so that the person would normally slide off; but there is a knee rest to keep the person in place.

A lawn chair is usually a light folding chair for outdoor use on soft surfaces. The left and right legs are joined along the ground into a single foot to make a broader contact area with the ground. Individual feet would otherwise dig into soft grass.

A Morris chair [1] was a proprietary easy chair with adjustable back, cushions and armrests.

An office chair typically swivels and is on castor wheels. It may be very plushly upholstered and in leather and thus characterized as an executive chair or come with a low back and characterized as a steno chair. Office chairs often have a number of ergonomic adjustments: seat height, armrest height and width, back reclining tension.

A pushchair [1] is a British English term for a stroller.

A recliner [1] is a chair whose back reclines. They are typically armchairs and may come with a footrest that unfolds from the chair when the back is reclined.

A rocking chair has the legs mounted on a curved rocker so that the chair can sway back and forth. Rocking chairs can be quite dangerous for small children and pets as the rocker can crush feet as it rotates. Sometimes the rocking chair is on springs to avoid this danger.

A patio chair is any outdoor chair meant for use on a hard surface. (Contrast with lawn chairs.) They are designed so as to not collect water and dry quickly after rain.

A potty chair [1] often abbreviated simply as "potty" is a training toilet for children.

Revolving chair is an older term for swivel chair.

A sedan chair is a chair on carrying poles. The occupant is carried by two or more porters. The chair may be enclosed.

A side chair [1] is a chair with a straight back and without armrests. It is usually matched with a dining table.

A sit-stand chair [1] allows the person to lean against this device and be partially supported. It is better than standing all day.

A steno chair is a simple office chair meant for secretarial staff usage.

Swivel chairs swivel about a vertical axis. They are often on castors as well.

A visitors chair is a chair used for a visitor to someone's office. It is usually less comfortable and ornate than the main office chair.

A wheelchair is a chair on wheels for someone who cannot walk.

A wicker chair is a chair made of wicker and is thus ventilated and useful in humid conditions. Likewise a cane chair.

A Windsor chair class="external">[1 is a classic wooden chair characterized by a high-spoked back, outward-sloped legs. The seat is saddled for the contours of the human buttocks.

A wing chair[1] is an upholstered easy chair with large "wings" for armrests.

Design and ergonomics

Ergonomic designs distributes the weight of the occupant to various parts of the body. A seat that is higher results in dangling feet and increased pressure on the underside of the knees ("popliteal fold"). It may also result in no weight on the feet which means more weight elsewhere. A lower seat may shift too much weight to the "seat bones" ("ischial tuberosities").

A reclining seat and back will shift weight to the occupant's back. This may be more comfortable for some in reducing weight on the seat area, but may be problematic for others who have bad backs. In general, if the occupant is suppose to sit for a long time, weight needs to be taken off the seat area and thus "easy" chairs intended for long periods of sitting are generally at least slightly reclined. However, reclining may not be suitable for chairs intended for work or eating at table.

The back of the chair will support some of the weight of the occupant, reducing the weight on other parts of the body. In general, backrests come in three heights: Lower back backrests support only the lumbar region. Shoulder height backrests support the entire back and shoulders. Headrests support the head as well and are important in vehicles for preventing "whiplash" neck injuries in rear-end collisions where the head is jerked back suddenly. Reclining chairs typically have at least shoulder height backrests to shift weight to the shoulders instead of just the lower back.

Armrests will also support part of the body weight through the arms. They further have the function of making entry and exit from the chair easier. Armrests should support the forearm and not the sensitive elbow area. Hence in some chair designs, the armrest is not continuous to the chair back, but is missing in the elbow area.

A kneeling chair adds an additional body part, the knees, to support the weight of the body. A sit-stand chair distributes most of the weight of the occupant to the feet.

Padding will not shift the weight to different parts of the body (unless the chair is so soft that the shape is altered). However, padding does distribute the weight by increasing the area of contact between the chair and the body. A hard wood chair feels hard because the contact point between the occupant and the chair is small. The same body weight over a smaller area means greater pressure on that area. Spreading the area reduces the pressure at any given point. In lieu of padding, flexible materials, such as wicker, may be used instead with similar effects of distributing the weight. Since most of the body weight is supported in the back of the seat, padding there should be firmer than the front of the seat which only has the weight of the legs to support. Chairs that have padding that is the same density front and back will feel soft in the back area and hard to the underside of the knees.

There may be cases where padding is not desirable. For example, in hot climates, padding with fabric or plastic covers is often uncomfortable against the skin. Where padding is not desirable, contouring may be used instead. A contoured seat pan attempts to distribute weight without padding. By matching the shape of the occupant's buttocks, weight is distributed and pressure at any given point is reduced.

Actual chair dimensions are determined by measurements of the human body or anthropometric measurements. Individuals may be measured for a custom chair. Anthropometric statistics may be gathered for mass produced chairs. The two most relevant anthropometric measurement for chair design is 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. It is sometimes called the "stool height". (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 and for American women it is 15.0 inches[1]. 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 high.

For someone seated, the buttock popliteal length is the horizontal distance from the back most part of the buttocks to the back of the lower leg. This anthropometric measurement is used to determine the seat depth. Mass produced chairs are typically 38-43 cm deep.

Additional anthropometric measurements may be relevant to designing a chair. Hip breadth is used for chair width and armrest width. Elbow rest height is used to determine the height of the armrests. The buttock-knee length is used to determine "leg room" between rows of chairs. "Seat pitch" is the distance between rows of seats. In some airplanes and stadiums the seat pitch is so small that there is sometimes there is no leg room for the average person.

For adjustable chairs, the aforementioned principles are applied in adjusting the chair to the individual occupant.

Chair Seats

• Solid wood, may or may not be shaped to human contours.
• Wood slats, often seen on outdoor chairs
• Padded leather, generally a flat wood base covered in padding and contained in soft leather
• Stuffed fabric, similar to padded leather
• Metal seats of solid or open design
• Molded plastic
• Stone, often marble

• Wicker, woven to provide a surface with give to it
• Leather, may be tooled with a design
• Fabric, simple covering without support
• Tape, wide fabric tape woven into seat, seen in lawn chairs and some old chairs
• Caning, woven from rush, reed, rawhide, heavy paper, strong grasses, cattails to form the seat, often in elaborate patterns
• Splint, ash, oak or hickory strips are woven
• Metal, Metal mesh or wire woven to form seat

Design considerations for chairs have been codified into standards. ISO 9241-5:1988[1], "Ergonomic requirements for office work with visual display terminals (VDTs) -- Part 5: Workstation layout and postural requirements " is the most common one for modern chair design.

There are multiple specific standards for different types of chairs. Dental chairs are specified by ISO 6875. Bean bag chairs are specified by ANSI standard ASTM F1912-98[1]. ISO 7174 specifies stability of rocking and tilting chairs. ASTM F1858-98 specifies lawn chairs. ASTM E1822-02b defines the combustibility of chairs when they are stacked.

The Business and Institutional Furniture Manufacturer's Association (BIFMA) defines BIFMA X5.1 for testing of commercial-grade chairs. It specifies things like[1]:

• chair backstrength of 150 pounds (68 kg)
• chair stability if weight is transferred completely to the front or back legs
• leg strength of 75 pounds (34 kg) applied one inch (25 mm) from the bottom of the leg
• seat strength of 225 pounds (102 kg) dropped from six inches (150 mm) above the seat
• seat cycle strength of 100,000 repititions of 125 pounds (57 kg) dropped from 2 inches (50 mm) above the seat

Large institutions that make bulk purchases will reference these standards within their own even more detailed criteria for purchase [1]. Governments will often issue standards for purchases by government agencies (e.g. Canada's Canadian General Standards Board CAN/CGSB 44.15M [1] on "Straight Stacking Chair, Steel").

Accessories

In place of a built-in footrest, some chairs come with a matching ottoman. An ottoman is a short stool to be used as a footrest but can sometimes be used as a stool. If matched to a glider, the ottoman may be mounted on swing arms so that the ottoman rocks back and forth with the main glider.

A chair cover is a temporary fabric cover for a side chair. They are typically rented for formal events such as wedding receptions to increase the attractiveness of the chairs and decor. The chair covers may come with decorative chair ties, a ribbon to be tied as a bow behind the chair. Covers for sofas and couches are also available for homes with small children and pets. In the second half of 20th century, some people used custom clear plastic covers for expensive sofas and chairs to protect them.

Chair pads are cushions for chairs. Some are decorative. In cars, they may be used to increase the height of the driver. Orthopedic backrests provide support for the back. Obus Forme is a major brand in this category and helped develop this market niche. Car seats sometimes have built-in and adjustable lumbar supports.

Chair mats are plastic mats meant to cover carpet. This allows chairs on wheels to roll easily over the carpet and it protects the carpet. They come in various shapes, some specifically sized to fit partially under a desk.

Remote control bags can be draped over the arm of easy chairs or sofas and used to hold remote controls. They are counter-weighted so as to not slide off the arms under the weight of the remote control.

History of the Chair

Egyptian chairs

Greek and Roman chairs

Medieval chairs

To the same generic type belongs the famous abbots’ chair of Glastonbury; such chairs might readily be taken to pieces when their owners travelled. The faldisterium in time acquired arms and a back, while retaining its folding shape. The most famous, as well as the most, ancient, English chair is that made at the end of the l3th century for Edward I., in which most subsequent monarchs have been crowned. It is of an architectural
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