Pushfit PAH!:ban:
Seriously, you'll find that these will add up in terms of cost if you use them all the time. I have used pushfit, and still do. There is a place for it but it looks awful in exposed areas so I use it as little as possible.
Also, you shouldn't use these where access is an issue. I have used them inside walls etc but I pressure tested them first and there is a plan B should they fail.
You will know that brass/copper fittings conduct electricity, and plastic doesn't. It's all about electrical bonding in the bathroom. A lot of hot and cold taps in the bathroom are bonded together near the taps. If you then go and pipeslice the pipes lower down and insert plastic iso valves, you have interfered with the bonding.
Also, they don't have a great pressure/temperature curve, not as good as Hep20.
I assume your plumbing course is teaching you to solder using ring solder and end feed, you'll need it. I hardly use endfeed. I was given a load of enfeed fittings and have worked my way through most of them now, I prefer the ring solder but back the solder up with my own. All the TS plumbers I've spoken to do the same with ring solder joints, as the solder in these fittings cannot be totally relied upon without.
I usually carry a quantity of 15mm connectors, straight, elbow and tees in solder ring, and similar in 22mm, and a length of pipe each, plus a load of iso valves and other misc plumbing. I do keep Speedfit, but I've been using it less now and tend to just stock up on what I'm short of. I also tend to plan ahead what I am likely to need and either get it in or make sure I've got it.
I'd be interested to know what you cover on the course in time Lee.