You are asked to install a hot and cold water system in a property.
It's a new build with 4 showers , two bathrooms , utility room and kitchen. There is ample head height.
With no hope of upgrading the mains supply.
The flowrate is 14/lmin.
What system do you propose?
Or do you walk away?
Would it help if I repeated the answer 3 times in one post? 5? 11?
A mains system with the same size pipes will provide more litres per minute
Rubbish.
More pressure = higher speed.
Higher speed = more litres per minute through same passage.
How long have you been a plumber? Never looked at the results of what you installed?
Have you ever installed a h&c water system in a large property?
What part of: "I don't install open vent rubbish don't you understand?"
Therefore I don't do "h&c systems".
Presumably you mean "high use" property, and yes, I have designed and installed high use water supply.
And can you point to the legislation in the building regulations that state 14l/min supply to a large property is illegal?
There is obviously no reg that literally says 14l/min is illegal.
It is in the results/consequences that will occur where you breech the regs.
You can debate the definition of terms like "adequate", but even without accounting for tanks and cisterns, garden supply or diversity factor, 4 baths plus 2 showers plus 1 kitchen brings the flow to 2 litres per minute max.
That is NOT adequate by anyone's standards, at least not in England.
It would also create so much flow at lower levels, that the top level would experience reverse flow, (not adequate) and failure of taps. (not adequate either.)
If you can't see that, I am really wasting my time trying to explain the basics. What kind of jobs does your boss send you out on? Changing ball valves?
You are either not actually a plumber, or if you are, you must be working for the council.