Friability means the ability of a solid substance to be reduced to smaller pieces with little effort.

Often, substances designated as being hazardous, such as asbestos or crystalline silica are referred to as being friable if they are present in such a state that it is possible for small particles to become dislodged, thus enabling them to become respirable (able to enter human lungs), posing a health hazard.

A friable substance is any substance that can be reduced to fibres or finer particles by the action of comparatively little pressure or friction on its mass, such as inadvertently brushing up against the substance. The term could also apply to any material that exhibits these properties. Examples include but are not limited to:

• Typically ionically bound substances <1 kg/L density,
• Clumps of dried clay,
• Chalk,
• Stone,
• Tablets,
• Crackers,
• Perlite
• Mineral fibres
• Polyurethane (foam)
• Aerogel

Tougher substances, such as concrete may also be mechanically ground down and reduced to finely divided mineral dust. However, such substances are not generally considered friable because of the degree of difficulty involved in breaking the substance's chemical bonds through mechanical means. Some substances, such as polyurethane foams, can increase in friability with exposure to ultraviolet radiation (such as is present in sunlight).

[edit] See also

• Asbestos abatement

[edit] External links

• EPA Treatise On Friable Asbestos
• UK Advisory Committee Treatise On Friable Ceramic Fibres

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