Inmaterials science,friability (/ˌfraɪ.əˈbɪləti/FRY-ə-BIL-ə-tee), the condition of beingfriable, describes the tendency of asolid substance tobreak into smaller pieces understress or contact, especially byrubbing. The opposite of friable isindurate.
Substances that are designated hazardous, such asasbestos or crystallinesilica, are often said to be friable if small particles are easily dislodged and becomeairborne, and hence respirable (able to enter humanlungs), thereby posing a health hazard.
Tougher substances, such asconcrete, may also be mechanically ground down and reduced to finely dividedmineral dust. However, such substances are not generally considered friable because of the degree of difficulty involved in breaking the substance'schemical bonds through mechanical means. Some substances, such aspolyurethane foams, show an increase in friability with exposure toultraviolet radiation, as insunlight.
Friable is sometimes used metaphorically to describe "brittle" personalities who can be "rubbed" by seemingly-minor stimuli to produce extreme emotional responses.[1]
A friable substance is any substance that can be reduced to fibers or finer particles by the action of a small amount ofpressure orfriction, such as rubbing or inadvertently brushing up against the substance. The term could also apply to any material that exhibits these properties, such as:
Friable andindurated are terms used commonly in soft-rockgeology, especially withsandstones,mudstones, andshales to describe how well the component rock fragments are held together.
Examples:
The termfriable is also used to describetumors in medicine. This is an important determination because tumors that are easily torn apart have a higher risk of malignancy andmetastasis.
Examples:
Friability testing is alaboratory technique used by thepharmaceutical industry to test the durability oftablets during transit. This testing involves repeatedly dropping a sample of tablets over a fixed time, using a rotating wheel with a baffle. The result is inspected for broken tablets, and the percentage of tablet mass lost through chipping. A typical specification will allow a non-zero percentage of chipping, and zero broken tablets.
