I just think the style and scope of plumbing moves in to commercial when you move up in size ?
My own experienc has mainly been in construction and working on large houses .
I stopped allowing plumbers to design systems as they never seemed to work I also understand that why should a plumber design a system when he will not be paid for it !
I employed M&S consultant who did design works and drawings which client paid for then plumbers quoted on and found at end of contract you have a happy client and a happy plumber !
Gasafe say 70 kw I believe ? Some of these can use that up in fires and cookers before you even get to heating ?