Hi
A more recent code is EN ISO 14692 Petroleum and natural gas industries - GRP piping (there's four parts to it). This code is based on UKOOA, and aims to "unify approaches to design, manufacture, installation, etc of GRP piping systems" (it's also very similar to BS7159).
In CII we still select "UKOOA" as the design code.
Rgds,
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Phil de Vos
Piping Engineer