Your material is a thermoplastic. ISO 14692 is for (reinforced) thermoset resins. The B31 codes provide no confidence in evaluating thermoplastics' flexibility (e.g., see B31.3 para. A319.1.2).
I believe a soon-to-be-released piping code (NPPS NM.1) will address these concerns.
Here's an informative link for information on NPPS NM.2 - the proposed standard for thermoset resins (FRP pipe). A New Standard for FRP Piping Perhaps someone can find and post a similar link reviewing the NM.1 content.