Fouling

form of hardened dental plaque

upright|thumb|150px|Schematic of size-based membrane exclusion

thumb|Limescale build-up inside a pipe reduces both liquid flow through the pipe and thermal conduction from the liquid to the outer pipe shell. Both effects will reduce the pipe's overall thermal efficiency when used as a heat exchanger.

Form of insidious localized corrosion in which a pit develops at the anode site

thumb|Current measurement instrument encrusted with zebra mussels thumb|Plant organisms, bacteria and animals (freshwater sponges) have covered (fouled) the sheath of an electric cable in a canal (Mid-[[Deûle in Lille, north of France).]]

A dispersant or a dispersing agent is a substance, typically a surfactant, that is added to a suspension of solid or liquid particles in a liquid (such as a colloid or emulsion) to improve the separation of the particles and to prevent their settling or clumping.

unproven method of supposedly reducing the effects of hard water

Specialist paint that greatly inhibits bio-fouling

severe form of highly localized corrosion attack resulting from the presence of an electrolyte in a crevice

thumb|Fouling on a heat exchanger in a steam [[power plant]] thumb|Condenser (steam turbine)|Condenser tube with residues of [[biofouling (cut open)]]

International Maritime Organization treaty