Although most sofa beds use a queen short mattress measuring , other common sizes include , , and . The average sofa bed mattress thickness is . Sofa mattresses can be produced out of many different materials; the majority are made of springs or foam.
Spring sofa mattress Spring sofa mattresses usually contain: •
Free length represents the overall length of a spring when no load is applied. •
Solid height is the compression length when the spring has been deflected enough to allow each adjacent coil to touch each other. •
Working length represents the difference between free and solid heights. •
Active coils is the number of coils that are free to deflect under load, i.e., the total number of coils minus the number of closed coils forming the ends, which measures the spring quality. •
Hydrogen embrittlement represents the hydrogen absorbed in
electroplating of carbon steels.
Foam sofa mattress • Density measures the kilograms (or pounds) of polyurethane foam per cubic meter (or cubic foot). High-density foams can be made very soft, whereas low-density foams can be made very firm. • Indentation force deflection (IFD) measures the foam's support, representing the Newtons (or pounds of force) required to indent a foam sample by a specified percentage of its original thickness. • Foam durability, flex fatigue, and compression set are other terms related to foam performance.
Pocket-coil mattress Pocket-coil mattresses are mattresses with coils resting inside the base of the mattress. Each coil is encased in a pocket, allowing the mattress to keep its shape over time.
Slide-away bed A slide-away bed is a sofa bed that slides to the wall to form a sofa. The
mattress is hinged to create a seating surface and back support. The bed frame support is a telescoping frame that allows the bed platform to recess below the seating cushion. == Sleeping chair ==