Could any of you plumbers out there tell me what "Rp 3/4" is all
about.....it's quoted in the installation book for my new Worcester
boiler (for the gas connection).
The book says i MUST use 22mm supply pipe for the gas, but the fitting
on the boiler is this "Rp 3/4", so i'd like to know what "Rp" stands
for as i've searched plumbing websites, but haven't had any luck.

hope someone can enlighten me