This document specifies the principles for the implementation of a system of cathodic protection against corrosive attacks on buried metal tanks and associated piping. This document specifies conditions and parameters to be met in order to achieve cathodic protection, as well as rules and procedures for the design, installation, commissioning and maintenance for the protection of buried metal tanks and associated piping. This document is applicable to the external surfaces of buried metallic tanks and associated buried piping. NOTE The protection of internal surfaces is covered by EN 12499. This document is applicable to buried tanks and associated piping, even if they are earthed by their own local earthing device, which are electrically separated from any general earthing systems and other buried structures. Therefore tanks which are covered by the present document include: - industrial storage tanks, irrespective of their dimensions and the nature of the stored medium (liquid or gas, flammable or not, toxic or non-toxic, polluting or not); - tanks used at petrol stations and on domestic or commercial premises, which contain flammable liquids or gases or polluting substances. This document is not applicable to: - above-ground storage tank floors in contact with the ground; - reinforced concrete containers; - buried storage tanks that are electrically connected to the whole or a part of an industrial complex; - buried storage tanks electrically connected to any general earthing systems. NOTE Cathodic protection of the last two types of tanks is covered by prEN 14505. Measurement techniques are described in detail in EN 13509.