That would depend on local codes and the fixture demands
50 choice 2
you need to figure out how much water per minute you need and get the minimum pipe diameter that will give you that. the bigger they are the more expensive they are, on a logaritmic scale.
10 centimeters/second
Diameter of water bubble?
If it is roof drains you are talking about, this calculator may help you: http://www.portalsplus.com/drain_calc.htm
Ball valve is usually preferable. full flow with no restriction and a lot easier and faster to turn off when needed.
Diameter of water fog:less dan or equal to 50um
Only circles (or spheres) have a diameter
There are two water temperatures, incoming and lake temp. On Friday, 6/15/12 water incoming water temp was 63 degrees. Air temp was 86 degrees
presure regulator is on the incoming cold water line
To increase the pressure you would have to reduce the diameter of the pipe. Half the diameter would give you twice as much pressure. Therefore to get 25 percent more pressure you would reduce the diameter by 25 percent giving you 37.5. Be careful though, this only increases the water pressure not the water flow rate.
Your incoming fill water may be hard.