CP (cathodic protected):
The ARG pipeline system is protected by a daily monitored cathodic protection (CP) system. CP stands for cathodic protection and means that the pipeline in the ground is coated with a low-current flow to prevent rust formation.
More information can be found in the DVGW Code of Practice GW 10:2008-05 “Kathodischer Korrosionsschutz (KKS) erdverlegter Lagerbehälter und Rohrleitungen aus Stahl – Inbetriebnahme und Überwachung [Cathodic Protection of Buried Steel Tanks and Pipelines – Commissioning and Monitoring] and DIN EN 12954:2001-04.”
“Proof of the efficacy of the CP system must be provided at least once a year by checking the cathodic protected object. This means that the criterion of protection potential according to DIN EN 12954 must be demonstrated on all coating defects of the protected object.”
Intensive cathodic protection surveys may be used to reveal corrosion spots that need closer examination (e.g. excavation or pigging).
For life cycle assessments, particularly of crack-like defects, the dynamic operating loads are a key factor that affects the remaining service life.
ARG pipelines are licensed to operate for an unlimited period; a lifetime of more than 100 years is generally expected. With appropriate maintenance, the pipelines can be operated for several decades. A so-called intelligent pigging is carried out at regular intervals, where a device equipped with highly sensitive instruments – the pig – is sent through the pipeline. The device uses ultrasound to check every millimetre of the inside for corrosion. It is also able to detect any pipe deformation. Thanks to underground laying, the pipeline is largely protected from the weather. Externally, corrosion is prevented by a plastic jacket with and so-called cathodic protection.
The life cycle of the ARG pipeline system is measured by a process for assessing the strength of defective pipelines developed by TÜV Rheinland, which has been applied and further developed for about 30 years, and which is mentioned in the standard DIN 2413, paragraph 4.2.3, for lifetime assessments of pipes with surface damage.