Waterbed

A waterbed, water mattress, or flotation mattress is a bed or mattress filled with water. Waterbeds intended for medical therapies appear in various reports through the 19th century. The modern version, invented in San Francisco and patented in 1971, became an extremely popular consumer item in the United States through the 1970s.

Construction

Softside Waterbed 160 × 200 cm with dual heating

Waterbeds primarily consist of two types, hard-sided beds and soft-sided beds.

A hard-sided waterbed consists of a water-containing mattress inside a rectangular frame of wood resting on a plywood deck that sits on a platform.

A soft-sided waterbed consists of a water-containing mattress inside of a rectangular frame of sturdy foam, zippered inside a fabric casing, which sits on a platform. It looks like a conventional bed and is designed to fit existing bedroom furniture. The platform usually looks like a conventional foundation or box spring, and sits atop a reinforced metal frame.

Early waterbed mattresses, and many inexpensive modern mattresses, have a single water chamber. When the water mass in these "free flow" mattresses is disturbed, significant wave action can be felt, and they need time to stabilize after a disturbance. Later types employed wave-reducing methods, including fiber batting and interconnected water chambers. More expensive "waveless" modern waterbeds have a mixture of air and water chambers, usually interconnected.

Softside Waterbed 160 × 200 cm with two waterchambers and flexible chamberisolation inside

Water beds are normally heated. Temperature is controlled via a thermostat and set to personal preference, but is most commonly average skin temperature, 30 °C or about 86 °F. A typical heating pad consumes 150–400 watts of power. Depending on insulation, bedding, temperature, use, and other factors, electricity usage may vary significantly.

Waterbeds are usually constructed from soft polyvinyl chloride (PVC) or similar material. They can be repaired with nearly any vinyl repair kit.

History in 1800s

A form of waterbed was invented in the early 19th century by the Scottish physician Neil Arnott. Dr Arnott's Hydrostatic Bed was devised to prevent bedsores in invalids, and comprised a bath of water with a covering of rubber-impregnated canvas, on which lighter bedding was placed. Arnott did not patent it, permitting anyone to construct a bed to this design.^[1][2]

The use of a waterbed for the ailing Mrs Hale is mentioned in Elizabeth Gaskell's 1855 novel North and South.^[3]

In 1871, a waterbed was in use in Elmira, New York, for "invalids". It was briefly mentioned by Mark Twain in his article "A New Beecher Church" which was published in The New York Times on 23 July 1871. Twain wrote: "In the infirmary will be kept one or two water-beds (for invalids whose pains will not allow them to be on a less yielding substance) and half a dozen reclining invalid-chairs on wheels. The water-beds and invalid-chairs at present belonging to the church are always in demand, and never out of service". No further information is available.

Heinlein descriptions

Science fiction writer Robert A. Heinlein described therapeutic waterbeds in his novels Beyond This Horizon (1942), Double Star (1956), and Stranger in a Strange Land (1961). In 1980 Heinlein recalled in Expanded Universe:

I designed the waterbed during years as a bed patient in the middle thirties; a pump to control water level, side supports to permit one to float rather than simply lying on a not very soft water filled mattress. Thermostatic control of temperature, safety interfaces to avoid all possibility of electric shock, waterproof box to make a leak no more important than a leaky hot water bottle rather than a domestic disaster, calculation of floor loads (important!), internal rubber mattress and lighting, reading, and eating arrangements—an attempt to design the perfect hospital bed by one who had spent too damn much time in hospital beds.

Heinlein made no attempt to build his invention.

The Hall Waterbed

The modern waterbed was created by Charles Prior Hall in 1968, while he was a design student at San Francisco State University in California. Fellow SFSU students Paul Heckel and Evan Fawkes also contributed to the concept. Hall originally wanted to make an innovative chair. His first prototype was a vinyl bag with 300 pounds (136 kg) of cornstarch, but the result was uncomfortable. He next filled it with Jell-O, which had an unfortunate "tendency to decompose".^[4] Ultimately, he abandoned working on a chair, and settled on perfecting a bed.^[5]

Hall was granted a patent on his waterbed, which he originally called "the pleasure pit", in 1971. He founded Innerspace Environments, a manufacturing and sales company which became the leading retailer of waterbeds in the U.S., with 30 owned-and-operated stores.^[6] Hall was unable to defend his patents against multiple competitors and couldn't take full advantage of the waterbed's subsequent popularity. Sales peaked in 1987 at 22% of the domestic mattress industry.^[7]

Advantages and disadvantages

Waterbeds have several advantages over traditional beds:

• The bed shapes exactly to the body, thus minimizing pressure, especially around the joints. Waterbeds remove pressure from the spine allowing the spinal muscles to fully relax. This can aid in the treatment of back pain for some individuals.^[8] In paralytic or movement-impaired people they can reduce the risk of bedsores.^[9]
• It is impossible for dirt and dead skin particles to penetrate the water mattress, which can then be wiped periodically with a cloth and vinyl cleaner. The cover over the mattress can be regularly washed—thus virtually eliminating house dust mites in the bed. Dust mites can trigger asthma, eczema, and allergies in people sensitive to them.
• Many modern waterbeds feature two mattresses so individual firmness and heat levels are possible.

But there are also disadvantages:

• The United States National Institute of Child Health and Human Development advises against placing babies on a waterbed or any other soft surface which might obstruct their breathing. Old-style waterbeds are a particular example, as an infant without upper body control cannot lift its face away from the plastic cover. "Your baby is safest on a firm surface. Do not place your baby on a soft mattress, sofa, cushion, waterbed, sheepskin or other soft surface." ^[10]
• Heating a waterbed is costly. A waterbed consumes between 300 and 1500 kW·h/year, depending on the climate, bed size, and other factors. The energy usage can be decreased by about 60% with the use of a soft-sided waterbed.^[11]
• Since some hard-sided waterbeds are of different sizes than other mattresses, bed sheets are harder to find and come in fewer varieties. Soft-sided mattresses are conventionally sized to avoid this problem.
• Moving a waterbed is a more difficult process than moving a normal bed; the water must be drained and the frame disassembled, then the frame must be reassembled, the mattress refilled with water, and the water heated for a potentially long period to get the new water to the correct temperature.
• Occasionally, water mattresses may leak. Plastic liners will reduce damage, but emptying, patching, refilling, and reheating it (and sleeping elsewhere until all this is completed) is certainly an inconvenience.
• Wearing clothing with zippers such as jeans while lying on a waterbed can potentially cause leaks, due to the free-swinging zipper tab potentially digging into the bedsheets and puncturing the plastic cover.
• The weight of a waterbed (a bed of 160 × 200 × 20 cm will weigh 640 kg or 1,410 lbs) will put a strain on many floorboards. If the waterbed is 35–42 sq. ft. in size, the floor load stress is 40 lbs./sq. ft. without occupants. Current IBC residential loading is 40 lbs./ ft. including occupants, so the weight of a water bed is high for new construction and can exceed the weight-bearing capacity of older homes where remodeling has already over-taxed the existing floor system.
• Many apartment leases and home insurance policies restrict the use of "water-filled furniture" due to concerns about water damage to the dwelling due to accidental leakage as well as the stress on the floor.

See also

• List of inflatable manufactured goods

References

External links

Wikimedia Commons has media related to Waterbeds.

• U.S. Patent 3,585,356—"Liquid support for human bodies"