what is the difference between the PE pipe and HDPE pipe.
Plain End
PE would be Polyethylene, check ISO for TC.
Plain End
That is the correct spelling of pipe, which has a number of uses.
Polyethylene: Plastic, very stable, easily jointed, less prone to cracking/rotting out than cast or steel pipe.
Yes
Some uses for a half pipe would be in reference to sporting competitions. Snowboarding, skateboarding and BMX bike competitions all utilize the half pipe to perform tricks.
Pipe organ.
surfing
Snowboarding.
A pipe or tube.