the schedule 40 pipe is what we use for gas piping..Dunno what it s called in the UK but I am reasonably sure that you guys use natural gas for heating your homes..so use that type of pipe..Same stuff..
Blowing down the air ines is done by opening the drain valve of your filter wide open and letting the air escape..and opening the drain on the compressor wide open..the air rushing out takes the excess moisture out...let it run until the air is dry then shut off the compressor..
Really simple deal to do..drains off any accumulated water in the lines and tank..
there ya go.
One more thing when you put in the new compressor let it run witht the lines wide open for a break in period...shoudl say something about that in the manual...