If you cannot find answers in the code but there is a situation you feel is "common knowledge" or even pointed out by another mfr. as long as it makes sense and is practical, you may want to still point it out. In this case, if you describe what it is you are worried about, it might help to make your case or clarify your concern. In other words, not just that you feel it is a problem but what is the hazard or consequences. Is it because the static pressure may cause the flex to collapse in on itself? Add too much turbulence and flow resistance? Not durable and easily damaged?

Following my theme of recognizing Red Flags, when you see something questionable like this, what else did they do goofy? Might want to take a closer look. I'd also try to get the mfrs. instructions. That way if anything should ever go Oops!, you can put some of it back on them.

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disgusted with some people on this forum. Out of here!