The facilities regulations § 57

§ 57 Pipeline systems

The pipeline systems shall be designed such that interior maintenance can be performed.
Chambers for sending and receiving cleaning and inspection tools shall be designed such that they cannot be opened under pressure.
For flexible pipeline systems and pipeline systems of other materials than steel, utilisation factors and any load and material factors shall be stipulated so that the safety level for such systems is not lower than for steel pipelines and steel risers.
Section last changed: 01 January 2011

It should be possible to take a reading of the pressure in the launchers and receivers as mentioned in the second subsection, both before start-up and during operation.
In order to fulfil the requirement for safety level as mentioned in the third subsection, the failure likelihoods in the standards DNV-ST-F101 and DNV-ST-F201 Paragraph 2, Table 2-5, should be used.
For general requirements related to design, see Sections 5, 10, 12 and 15.