Regarding the out-of-roundness of pipes

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I would like to ask everyone about the issue of pipe ovality. I am currently working with heating pipes such as PB and PERT, all of which are DN40 or smaller; it seems that the standards do not specify any requirements regarding ovality – there is only a standard for the average outer diameter, with no standards set for the maximum or minimum outer diameter. Generally, for inspection we accept the pipes as long as they aren’t too flat. However, in the case of heat-fused pipes, an oval shape can affect the quality of the heat fusion process; and if leakage occurs, it’s difficult to determine the cause. Last time, there was a batch of pipes that were coiled, and they appeared oval in shape. The supplier explained that the tolerance for ovality in coiled pipes is higher than that for straight pipes, so even though those pipes were still considered acceptable, the roundness of the DN16 pipes was already close to 1 mm – they felt very oval to the touch. I just don’t know if there’s a standard for defining it? Generally, how do we determine whether the out-of-roundness of a batch of pipes is acceptable? Is there also a difference in the out-of-roundness between coiled pipes and straight pipes?