We're building new house in Massachusetts with 6 bathrooms, we have 1 1/2" PVC Main coming into the house... from the main to the supply manifold in the boiler room is approx. 15'. I'm going to use copper, what size from the PVC to the supply manifold do I need to use?

Thanks!

Hi Bocc55:

To be 100% acurrate I actually need to know exactly what fixtures are in the home... breaking it down to 1/2 baths, full baths, kitchen sink/dishwasher, laundry, multi. Head showers, multi. Sinks in each bath, etc...

But for now, I'll give you a pipe size based on 6 full bathrooms, 1 kitchen, 1 laundry room and 2 outside faucets... ok?

In my Massachusetts code book I calculate that you have 56 factor values and a demand factor of .50 (residential demand factor) leaving you with a capacity value of 28.

This means that you will need to run an 1.5" copper main into the boiler room (type L tubing).

Given that number, unless you have a number of 1/2 bathrooms or anything else major to add or change this is the correct size tubing for your project as any capacity value between 21.1 to 41.4 will require an 1.5" copper main pipe... so you should be all set here.

By the way... you aren't planning on an underground sprinkler system are you? If so, then we may have issue with 1.5" main.. depending on number of heads planned, etc...

What area are you building in?

Let me know if want to discuss this...

MARK

Mark, great answer ! Milo