Glossary



  • CAS registration number

    A universally used unique numerical identifier allocated to a chemical substance by the Chemical Abstracts Service (CAS). A CAS Registry Number itself has no inherent chemical significance but provides an unambiguous way to identify a chemical read more

  • Cistern

    A fixed container for holding water at atmospheric pressure. Interpretation given in Schedule 2: of the Water Supply (Water Fittings) Regulations and Scottish Water Byelaws read more

  • Combined feed

    A cistern for supplying cold water to a hot water system without a separate expansion cistern Interpretation given in Schedule 2: of the Water Supply (Water Fittings) Regulations and Scottish Water Byelaws read more

  • Concealed fitting

    A water fitting which – is installed below ground; passes through or under any wall, footing or foundation: is enclosed in any chase or duct; or is in any other position which is inaccessible or render access difficult [Refer to read more

  • Contamination

    Includes any reduction in chemical or biological quality of water due to a change in temperature or the introduction of polluting substances. Interpretation given in Schedule 2: of the Water Supply (Water Fittings) Regulations and Scottish read more

  • Critical level

    The physical or piezometric level of the fluid in any part of the receptacle a minimum of two seconds after closing the water inlet, starting from maximum water level. Interpretation given in Regulators’ Backflow Specification - backflow read more