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Foam fascination

Volumetric weight
Volumetric weight, also known as density, is expressed in kg/m³ and gives the weight of a cubic block of foam with an edge ength of 1 metre.
The volumetric weight is considered the most important characteristic when differentiating between foams, oyher caratcteristics being to a large degree dependent on this measure.
Or production programme includes foams of volumetric weights of between 17 and 60 kg/m³, suitable for a wide variety of uses. .
Volumetric weight
   
Hardness
After volumetric weight (density), hardness is the most important characteristic of a foam.
Matresses and furniture, for example, demand complete body support from their foam elements. A material which is too soft offers insufficient support in extreme cases, while too hard a material lacks comfort. In this context thickness also plays a role. The synergy between foam quality, foam thickness and the nature of the substructure is decisive.
Hardness is labotratory tested by compressing a foam sample of given dimensions to 65%, 40% and 25% of its original thickness, while measuring the force nedded to achieve this.
In order to ensure the highest degree of comfort, different degrees of hardness are available, depending on the relevant sector and the intended application of the foam.
hardheid
   
Elasticity
Elasticity, or rebound, also plays a decisive role in the quality and comfort of foam elements. It is generally expressed as a percentage. Elasticity is gauged by dropping a steel ball onto the foam and meausuring the height of its rebound.
A value of 70% would mean that the steel ball has rebounded to 70% of its initial altitude.
EUCAFLEX - Quality types attain on average between 40 and 50%, whereas EULASTIC HR - Quality types attain 50 to 60%. .
Elasticity
   
The comfort index
The foam elements must be able to carry a person's weight and adjust to changing body positions. At the same time, body weight must be evenly supported and diffused, if pressure zones are to be avoided. The Comfort Index is calculated by recording the ratio between the force required to compresss a given block of foam to 65% of its original height and that required to compress it to 25% of the same.

The higher the Comfort Index, the better the bodu support given by the sample.
The EUCAFLEX - Standard Types have an average Comfort Index of 2, while the index of the EULASTC HR - Quality types is about 3.

The comfort index
   
Fatigue resistance and durability
It is vital that the qualities mentioned here endure for a considerable lenght of time, even under intensive use. When researching fatigue, two test methods are available: the static fatigue test, in which the foam is subjected to a fixed stress for a long period of time, and the dynamic fatigue test, in which the foam is subjected to rhythmically changing stress.
With increased vomumetric (density), fatigue performance is improved.
Fatigue resistance and durability
   
Flame resistance
Usually the behavior of the entire piece of furniture in the event of fire must be taken into account, i.e. foam plus framework and upholstery.
Fire testing of chairs and couches is limited to their inflammability in contact with small fire sources such as lighted cigarette, math or suchlike. The majority of fires that first catch in furniture are caused by careless smokers. .
Flame resistance