Pipeline route markers indicate the approximate course of the pipeline. However, markers are not always placed directly above the pipeline longitudinal axis. The applicable regulations state that markers may be placed at a distance of up to ten meters from the axis. The aim here is to avoid any undue interference with farming activities. But there are still numerous pipelines in existence that benefit from an earlier regulation: for pipelines that were constructed prior to 2003, markers may be placed at a distance of up to twenty meters from the axis.
The following criteria have to be met, regardless of the distance from the axis:
- The next marker must always be visible from any location along the pipeline
- The previous and next markers must be visible from any given marker
- Between two markers, the pipeline may not deviate from the direct line connecting the markers by more than ten meters
These rules were defined more precisely with the introduction of the FPI Regulations in 2003. Since that date, all pipelines have been inspected again and additional markers have been partially put in place.