Sc 40 is an American spec you just want PVC pressure pipe which in the UK is designated by letters, Class E is probably the easiest to get hold of and the highest pressure rating so thickest.. Pop into your local Koi specialist or if you want white the swimming pool pipe will be upto the job.
Try here or just put "class e pipe" into Google.
Edited By JasonB on 06/09/2018 07:26:26