Hang on Guys!,
We use PVC over here in New Zealand exclusively in Commercial and Industrial Installations.
PVC is (these days, at least) Flame Retardant, Self Extinguishing.
At least the stuff we have here is.
WE don't use EMT or IMC over here.
For real rugged uses we usually use HFT grade(Black) PVC conduit or for Boiler rooms and the like we use Pyrotenax MIMS (Mineral-Insulated-Metal-Sheathed cables).
PVC has the advantages of not having to be threaded, is easy to work with and it is light in weight.
Disadvantages are that, with it being a Thermosetting material, a given length of PVC will expand and contract under temperature changes and expansion couplings have to be used in any decent run of conduit.
Here's a strange one, care of one of my older Electrician's textbooks: If PVC conduit is used, a seperate Earth Continuity Conductor must be added.
Duh!!.
Steel conduit used to be used as the Earth(grounding) Conductor here, when we used the stuff.