Pyrex

The high heat resistance allows the pipe to tolerate a longer period of use. When English-speaking philosophers talk about the material world as opposed to ideas, their phrase is tables and chairs. Specialty tobacco pipes, though commonly used for smoking marijuana, are made from Pyrex. Activities that are likely to be made insignificant or undone by some future event are said to be like rearranging the deckchairs on the Titanic. Due to its high heat resistance, it can tolerate the great temperature differences between water and the Nichrome heating element. If you nearly fell off your chair, it was because you were very surprised. Aquarium heaters are sometimes made out of pyrex. A movie or a story is said to keep you on the edge of your chair, if it is suspenseful and engaging.

Claims have been made of severe personal injury during these events. They are counter-weighted so as to not slide off the arms under the weight of the remote control. Recent reports suggest that, notwithstanding the claims made for Pyrex, the glassware can shatter violently and unexpectedly, even when used in accordance with manufacturers instructions. Remote control bags can be draped over the arm of easy chairs or sofas and used to hold remote controls. Pyrex measuring cups, which featured painted-on markings illustrating graduated measurements, are also widely used in American kitchens. They come in various shapes, some specifically sized to fit partially under a desk. Glass cookware is another common usage; a Pyrex pie plate is almost the American standard pie dish. This allows chairs on wheels to roll easily over the carpet and it protects the carpet.

Pyrex's refractory properties and physical strength make it ideal for use in laboratories, where it is used to make high-durability glass lab equipment, such as beakers and test tubes. Chair mats are plastic mats meant to cover carpet. Caltech's famous 200-inch telescope mirror at Mount Palomar was cast by Corning during 1934-36 out of Pyrex, which expands and contracts less than ordinary glass. Car seats sometimes have built-in and adjustable lumbar supports. Another useful characteristic of Pyrex is that when broken, it tends to crack into large pieces rather than shattering (it will snap rather than splinter). Obus Forme is a major brand in this category and helped develop this market niche. Pyrex is also less dense than ordinary glass. Orthopedic backrests provide support for the back.

The boron gives borosilicate glass a reduced thermal expansion coefficient (about one-third that of ordinary glass), making it more resistant to heat. In cars, they may be used to increase the height of the driver. Borrowing from the welding trade, new burners combining oxygen with natural gas were required. Some are decorative. Since Pyrex melts at a higher temperature than ordinary silicate glass, some new techniques were required to bring Pyrex into industrial production. Chair pads are cushions for chairs. Pyrex is created by adding boron to the traditional glassmaker's "frit" of silicate sand, soda, and ground lime. In the second half of 20th century, some people used custom clear plastic covers for expensive sofas and chairs to protect them.

. Covers for sofas and couches are also available for homes with small children and pets. Though borosilicates had been produced before, the name Pyrex is widely used as a synonym for the material. The chair covers may come with decorative chair ties, a ribbon to be tied as a bow behind the chair. Pyrex is a brand name of borosilicate glass introduced by Corning Glass Works in 1924. They are typically rented for formal events such as wedding receptions to increase the attractiveness of the chairs and decor. A chair cover is a temporary fabric cover for a side chair.

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. An ottoman is a short stool to be used as a footrest but can sometimes be used as a stool. In place of a built-in footrest, some chairs come with a matching ottoman. Canada's Canadian General Standards Board CAN/CGSB 44.15M [6] on "Straight Stacking Chair, Steel").

Governments will often issue standards for purchases by government agencies (e.g. Large institutions that make bulk purchases will reference these standards within their own even more detailed criteria for purchase [5]. Under these higher loads, the chair may be damaged, but it must not fail catastrophically. The specification further defines heavier "proof" loads that chairs must withstand.

It specifies things like[4]:. The Business and Institutional Furniture Manufacturer's Association (BIFMA) defines BIFMA X5.1 for testing of commercial-grade chairs. ASTM E1822-02b defines the combustibility of chairs when they are stacked. ASTM F1858-98 specifies lawn chairs.

ISO 7174 specifies stability of rocking and tilting chairs. Bean bag chairs are specified by ANSI standard ASTM F1912-98[3]. Dental chairs are specified by ISO 6875. There are multiple specific standards for different types of chairs.

ISO 9241-5:1988[2], "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. Design considerations for chairs have been codified into standards. Open center seats where a soft material is attached to the tops of chair legs or between stretchers to form the seat. Some systems include: Solid center seats where a solid material forms the chair seat.

Chair seats vary widely in construction and may or may not match construction of the chair's back. See also seats in movie theaters, and pictures of benches with and without arm rests. A loveseat in particular, has no arm rest in between. Arm rests prevent or complicate both desired and undesired proximity.

in public transport and other public places, and to prevent lying on the bench or coach. The latter may be provided for comfort, but also for privacy e.g. A couch, bench, or other arrangement of seats next to each other may have arm rest at the sides and/or arm rests in between. Hence in some chair designs, the armrest is not continuous to the chair back, but is missing in the elbow area.

Armrests should support the forearm and not the sensitive elbow area. Armrests further have the function of making entry and exit from the chair easier (but from the side it becomes more difficult). If so, armrests will support part of the body weight through the arms if the arms are resting on the armrests. A chair may or may not have armrests.

For adjustable chairs, the aforementioned principles are applied in adjusting the chair to the individual occupant. In some airplanes and stadiums the seat pitch is so small that there is sometimes there is no leg room for the average person. "Seat pitch" is the distance between rows of seats. The buttock-knee length is used to determine "leg room" between rows of chairs.

Elbow rest height is used to determine the height of the armrests. Hip breadth is used for chair width and armrest width. Additional anthropometric measurements may be relevant to designing a chair. Mass produced chairs are typically 38-43 cm deep.

This anthropometric measurement is used to determine the seat depth. 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. Mass produced chairs are typically 17 inches high. The popliteal height, after adjusting for heels, clothing and other issues is used to determine the height of the chair seat.

(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]. It is sometimes called the "stool height". 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 two most relevant anthropometric measurement for chair design is the popliteal height and buttock popliteal length.

Anthropometric statistics may be gathered for mass produced chairs. Individuals may be measured for a custom chair. Actual chair dimensions are determined by measurements of the human body or anthropometric measurements. By matching the shape of the occupant's buttocks, weight is distributed and pressure at any given point is reduced.

A contoured seat pan attempts to distribute weight without padding. Where padding is not desirable, contouring may be used instead. For example, in hot climates, padding with fabric or plastic covers is often uncomfortable against the skin. There may be cases where padding is not desirable.

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. 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. In lieu of padding, flexible materials, such as wicker, may be used instead with similar effects of distributing the weight. Spreading the area reduces the pressure at any given point.

The same body weight over a smaller area means greater pressure on that area. A hard wood chair feels hard because the contact point between the occupant and the chair is small. However, padding does distribute the weight by increasing the area of contact between the chair and the body. Padding will not shift the weight to different parts of the body (unless the chair is so soft that the shape is altered).

Padding can be on the seat of the chair only, on the seat and back, or also on any arm rests and/or foot rest the chair may have. Many chairs are padded or have cushions. A sit-stand chair distributes most of the weight of the occupant to the feet. A kneeling chair adds an additional body part, the knees, to support the weight of the body.

A stool or other simple chair may have a simple straight or curved bar near the bottom for the sitter to place his/her feet on. Some chairs have foot rests. Reclining chairs typically have at least shoulder height backrests to shift weight to the shoulders instead of just the lower back. 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.

Shoulder height backrests support the entire back and shoulders. In general, backrests come in three heights: Lower back backrests support only the lumbar region. The back of the chair will support some of the weight of the occupant, reducing the weight on other parts of the body. However, reclining may not be suitable for chairs intended for work or eating at table.

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. This may be more comfortable for some in reducing weight on the seat area, but may be problematic for others who have bad backs. A reclining seat and back will shift weight to the occupant's back. A lower seat may shift too much weight to the "seat bones" ("ischial tuberosities").

It may also result in no weight on the feet which means more weight elsewhere. A seat that is higher results in dangling feet and increased pressure on the underside of the knees ("popliteal fold"). Ergonomic designs distributes the weight of the occupant to various parts of the body. Easy chairs for watching television or movies are somewhere in between depending on the height of the screen.

Dental chairs are necessarily reclined. "Task chairs", or any chair intended for people to work at a desk or table, including dining chairs, can only recline very slightly; otherwise the occupant is too far away from the desk or table. Intended usage determines the desired seating position. Chair design considers intended usage, ergonomics (how comfortable it is for the occupant), as well as non-ergonomic functional requirements such as size, stackability, foldability, weight, durability, stain resistance and artistic design.

. See history of the chair for an extended look at chairs from antiquity to the modern day. Headrests for seats in vehicles are important for preventing whiplash injuries to the neck when the vehicle is involved in a rear-end collision. There may be separate headrests.

The back may extend above the height of the head. Likewise, the back and sometimes the seat are made of porous materials or have holes drilled in them for decoration and ventilation. The back often does not extend all the way to the seat to allow for ventilation. Chairs as furniture are typically not attached to the floor and so can be moved.

A chair mounted in a vehicle or in a theatre is simply called a seat. A separate footrest for a chair is known as an ottoman, hassock or poof. A chair for more than one person is a couch, sofa, settee, loveseat (two-seater without arm rest in between) or bench. Without back and arm rests it is called a stool.

Chairs also often have legs to support the seat raised above the floor. A chair is a piece of furniture for sitting, consisting of a seat, a back, and sometimes arm rests, commonly for use by one person. seat cycle strength of 100,000 repetitions of 125 pounds (57 kg) dropped from 2 inches (50 mm) above the seat. seat strength of 225 pounds (102 kg) dropped from six inches (150 mm) above the seat.

leg strength of 75 pounds (34 kg) applied one inch (25 mm) from the bottom of the leg. chair stability if weight is transferred completely to the front or back legs. chair backstrength of 150 pounds (68 kg). Metal, Metal mesh or wire woven to form seat.

Splint, ash, oak or hickory strips are woven. Caning, woven from rush, reed, rawhide, heavy paper, strong grasses, cattails to form the seat, often in elaborate patterns. Tape, wide fabric tape woven into seat, seen in lawn chairs and some old chairs. Fabric, simple covering without support.

Leather, may be tooled with a design. Wicker, woven to provide a surface with give to it. Stone, often marble. Molded plastic.

Metal seats of solid or open design. Stuffed fabric, similar to padded leather. Padded leather, generally a flat wood base covered in padding and contained in soft leather. Wood slats, often seen on outdoor chairs.

Solid wood, may or may not be shaped to human contours.