I am not sure about the static pressure.
My Enermax fans have 0.98 static pressure and I use them on 38 FPI EK PE rads.
No problems there, air goes through the rad and isn't even warm, so they must be working well. And that is at 850 rpm.
The new ones I bought have a bit higher CFM than this Noctua ( 68 CFM ) and static pressure 1.21
I wonder if that 15.8 DBa will be audible at all, Enermax fans I use have 9 DBa rated noise level, but I use a total 18. Will be using 12 in new build. Anyway, I am not so fused about the noise, I listen to music on headphones or on my Microlab speakers most of the time.