Safety of pipelines
We want third parties to be safe in the vicinity of our installations and pipelines. That’s why we set high requirements on the quality of our pipelines and installations and strive for the highest possible levels of safety. Our infrastructure is continually being adapted to changing circumstances, which can be either technical or social in nature. In that way, we can keep security of supply and safety at the required level. The pipeline network is fully compliant with the relevant legislation and regulations and with the strict requirements that we ourselves expect it to meet.
A number of preventive measures are taken to keep underground pipelines in good condition. Aboveground pipelines are coated and have to undergo regular sight inspections. Underground pipelines are coated and cathodically protected against corrosion. The integrity of the transport system is monitored with the help of a continual inspection programme. Internal inspections are performed with intelligent pigs that are driven through the pipeline by the gas flow. The data is collected and analysed and, where necessary, adjustments are made to the network. Hundreds of kilometres of pipeline are inspected internally every year. In addition to this, pipelines that cannot be inspected by using robots are monitored by aboveground inspection methods falling within the External Corrosion Direct Assessment (ECDA) integrity approach.
Recording pipelines on zoning plans
For gas pipelines, the Decree on external safety for pipelines (BEVB) and the corresponding regulations apply. This decree specifies that pipelines for the transport of dangerous substances, including gas pipelines from a pressure of 16 bar, should be included in zoning plans, including the corresponding obstacle strip and a building licencing system in that strip to protect the pipe and the energy supply. The risks of high-pressure gas pipelines should be calculated using the computer programme CAROLA, which is derived from PIPE SAFE.
Preventing damage to pipelines as a result of third-party excavation work
The external safety policy aims to prevent as far as possible the potential for and the consequences of the unwanted escape of natural gas as a result of damage to the gas infrastructure. In order to be able to guarantee safe and reliable gas transport, it is of vital importance that the infrastructure remains undisturbed. That means that we make particular efforts to prevent any possible damage to the infrastructure.
Excavation work is still the main cause of damage to the underground pipeline network. Since 1 July 2008, the Act on Information Exchange for Underground Networks (Wet Informatie uitwisseling Ondergrondse Netten (WION)) has come into force in the Netherlands. Excavators are obliged to report planned excavation work. This Act also comprises precautionary measures for the relevant networks, such as marking the pipeline at the place where proposed work is planned and supervision during the work.
Gasunie participates in the Pipeline Owners’ Association in the Netherlands (Vereniging voor Landeigenaren in Nederland VELIN). This involves endeavouring to communicate precautionary measures in a uniform manner. Consequently a standard format for KLIC communication statements has been designed and general excavation conditions have been drawn up for work carried out close to transport pipelines. Reference is made to these conditions wherever possible. To lay down the agreements with the groundwork contractor, the Gasunie supervisors make use of an electronic form, in the form of a special app based on the VELIN model form Confirm Agreements Groundwork Activities.
Our pipeline incidents in a European context
European gas transport companies register their pipeline incidents in a similar way. A comparison of pipeline incidents involving gas outflows from our company with those from other European gas transport companies (source: database of the European Gas Pipeline Incident Data Group (EGIG) shows that our average score is better than the European average.
Safety of installations
Our transport installations and other installations fulfil specific requirements laid down by legislation and regulations with regard to external safety. We report on these in comprehensive safety reports. Large locations are also subject to reporting obligations within the scope of the Decree on the Risks of Serious Accidents (Besluit Risico’s Zware Ongevallen (BRZO)) and/or Supplementary Risk Inventory and Evaluation (Aanvullende Risico Inventarisatie en Evaluatie (ARIE)).