Definition - What does Limescale mean?

Limescale is the hard, off-white, chalky deposit that builds up due to calcium carbonate deposits in water. It is commonly found in:

  • Kettles
  • Hot-water boilers
  • Inadequately maintained hot-water central heating systems
  • Old pipes and other surfaces where "hard water" has evaporated

Limescale damages or seriously impairs the operation of various components, causing corrosion and stress failure, and reducing efficiency of heating equipment and water supply pipelines.

Corrosionpedia explains Limescale

Limescale is formed when calcium carbonate found in hard water is heated and precipitates out. It becomes problematic with certain appliances such as kettles and hot water pipes. Buildup on the bottom of the kettle acts as an insulator, preventing the heating element from transferring heat to the water. In particular for heat exchangers, limescale deposits always cause a massive reduction of efficiency.

Although limescale causes numerous problems, such as reduced water flow in taps and pipes and buildup on bathtubs and sinks, it may also be used beneficially. Limescale consists of calcium carbonate, which can be compressed to make chalk, and also may be used (when treated correctly) as a calcium supplement.

Over time limescale can accumulate as sediment in hot water storage, reducing the capacity to store hot water and requiring more power to heat coils, causing heat loss. It can cause the insulated metal surface to overheat, resulting in stress failure. If a layer of limescale has been allowed to form, corrosion can occur beneath the scale, eroding the metal and resulting in reduced life expectancy.

An easy way to remove limescale is the use of vinegar. Vinegar’s acidic composition is a powerful tool in decomposing limescale buildup. Water softening and water conditioning can also be used to fully eliminate limescale.

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