Safety approach to quantum gravity [@wein; @wein-kall; @wein-bern; @mr; @percadou; @oliver1; @frank1; @oliver2; @oliver3; @oliver4; @souma; @frank2; @prop; @oliverbook; @perper1; @codello; @yukawa; @litimgrav; @frankmach; @BMS; @gies-ghost; @oliverfrac; @jan1; @jan2; @creh1; @creh2; @crehroberto; @elisa1; @brightontalk; @elisa2; @je1; @max-pert; @max; @livrev]. Contrary to the calculations mentioned above it considers metric gravity not merely an effective but rather a fundamental quantum field theory, with the continuum limit taken at a non-trivial renormalization group (RG) fixed point [@wein; @wein-kall; @wein-bern]. Instead of perturbation theory, the main tool will be the gravitational average action [@mr] and a suitably truncated form of the associated functional RG equation (FRGE). Originally developed for matter field theories [@avact; @nonabavact; @ym; @mrcwqcd; @giesymfp; @avactrev] the effective average action turned out an ideal tool for investigating the RG flow of Quantum Einstein Gravity (QEG)[@mr; @percadou; @oliver1; @frank1; @oliver2; @oliver3; @oliver4; @souma; @frank2; @prop; @oliverbook; @perper1; @codello; @yukawa; @litimgrav; @frankmach; @BMS; @gies-ghost; @oliverfrac; @jan1; @jan2; @creh1; @creh2; @crehroberto; @elisa1; @brightontalk; @elisa2; @je1] and exploring its potential physics implications [@bh; @erick1; @cosmo1; @cosmo2; @entropy; @esposito; @h1; @h2; @h3; @girelli; @lhc; @mof].

The purpose of this paper is twofold: First, we develop a general framework for both exact and approximate (“truncated”) investigations of the 