BS5385 if I remember rightly. British standards in wall and floor tiling. Yeah.
There's a lot of surface types (plaster, plasterboard, concrete, tongue and groove, ply, then
tile boards etc etc, and even existing tiles) that we
tile to. And a lot of
tile types that have different adhesion properties. So full-bodied (or full vitrified) porcelain doesn't really absorb water, so standard adhesives don't bond to it well, you need one with polymer additives in, or whatever it is.
Ceramics with a 'biscuit' backing adhere to anything though.
Times are changing these days. People want heated floors tiled on timber of some form with huge tiles. And if they're translucent, you need light coloured adhesive and then skim the tiles individually as well as trowelling the surface.
BS states that tiles should only have a certain mm undulation over a 2m length too, and states that you need certain mm grout joints for walls and floors (2mm for walls, 3mm for floors i think I is, lads?).
So yeah, might not be as technical as electrical (you don't get killed sticking tiles in water either) but you can get sued just as easy if you screw up.