And yes, we talk about how to manage greywater and aspects of solar, microhydro and wind generated electricity.
But we do not talk very much about how to get running water into our self-built homes, or the parts of the electrical system after the storage batteries and the inverter.
So, I am working on the designs for our house, the one we will build for ourselves from the land we will live on, and I am thinking about questions like "How do we get water pressure? What kind of pipe to use and where? i.e., pvc pipe is commonly used for drains, but is it ok to use on the source side in a potable water system, or is there something else that should be used on the potable side? Is theree something better on the drain side?
Drains, you need a certain amount of slope for them to work properly, but how much is that?
Where do you run the pipes when you are doing cob walls (or strawbale, or earthbag, or...)?
It seems to me that there are probably some principles out there that could be helpful in figuring out placement of things like sinks and showers and bathtubs to maximize efficiency of water management, both incoming and outgoing, but I do not have a working knowledge of what they might be.
Similar questions about electrical systems - the merits of using DC versus AC, what kind of wiring to use, what conduit, if any, and how to decide whether a given run can be loose wire or should be contained in conduit? Where does the wiring go in various forms of construction?
In balloon frame houses with drywall, there is all that space inside the walls to put your pipes and wires. Not so much in many of the natural building modes.
How much water pressure does it take to provide a nice shower, or a functioning kitchen sink? Ways of providing reliable hot water for that shower or kitchen sink?
I am sure there are questions I have not thought of.
As for PVC, I am rather ungreen for some one who hangs out on this forum, but PVC or CPVC should be avoided in water supplies.
A hot water line made of CPVC will become brittle over time as the plasticizing chemicals leach into the water. This is what I have observed.
ABS is a much more stable plastic, but if the big box stores around here only Menards carry it, and I have never used it as of yet. It does seem to cost a little more,in terms of money, but it seems like a cheaper alternative environmentally. That being said, I am awash in scrounged PVC, and I intend to use it. Many parts of a city water supply pass through plastics like PVC on the way to your faucet,so if you are eating and drinking conventional food and water,you ate ingesting the leachate from such plastics.
I am eating and drinking conventional food and water, so using on hand PVC to build a greenhouse makes sense for me.
But if you are building your own water supply, copper or PEX are better choices.
I always use conduit and THHN stranded wire because the resistance of this wire is about 1/2 that of romex. I usually use ENT flex aka smurf tube. Here's a couple of pictures of our most recent endeavors.
But if you're starting from scratch, save yourself the worry and use some other pipe than PVC for pretty much all purposes. It is seriously nasty stuff, and anything you invest in higher priced pipes will last for decades and add peace of mind, if you go for something other than PVC.
First will calculate your static pressure, the second will tell you the flowrate out of tank, the third will play with flowrate, velocity, and pipe diameter.
Hydrostatic pressure in a liquid can determined using the following equation:
p = h ρ g (1)
p = pressure (N/m2, Pa, lbf/ft2, psf)
h = height of fluid column, or depth in the fluid at which the pressure is measured (m, in)
ρ = density of liquid (kg/m3, slugs/ft3)
g = the gravitational constant (9.81 m/s2, 32.17405 ft/s2)
Hydrostatic pressure in a water column (density 1000 kg/m3) - or depth - is indicated below:
hydrostatic pressure water kPa Pa bar psi meter feet
Example - Pressure acting in water at deep 1 m
The density of water at 4oC is 1000 kg/m3. The pressure acting in water at 1 m can be calculated as
p = h ρ g
= (1 m) (1000 kg/m3) (9.81 m/s2)
= 9810 Pa
Example - Pressure acting in water at deep 3 ft
The density of water at 32oF is 1.940 slugs/ft3. The pressure acting in water at 3 ft can be calculated as
p = h ρ g
= (3 ft) (1.940 slugs/ft3) (32.17405 ft/s2)
= 187.3 lbf/ft2 (psf)
= 1.3 lbf/in2 (psi)
(Examples taken from hyperphysics)
The flowrate is Q and can be found with Q= Av, where A is the cross sectional area of the pipe and v is the water velocity.
A more practical way to measure flowrate is with Q= c/t where c is the carrying amount of the tank, and t is the time is takes for it to go from full to empty.
The other formula is
V= Q / ((3600)(pi)(d/2)^2)
d : Pipe Inner Diameter (m)
Q : Water Flow Rate (m³/h)
v : Water Velocity (m/s)
I have not gotten exceptionally far in trying to apply all these to a shower system, but I will.
William Bronson wrote: Bill I was worried that you had so much water on an out side wall, till you mentioned insulation!
Your system looks great, are you tagging circuits and "water circuit" as you go?
The masonry wall only has an R-value of 4 or 5, but the dynamics of a mass wall enables much better real world performance, so the pipes didn't freeze before the restoration, but I agree; why chance it? We are adding R-15 stone wool for a mass dynamic enhanced R-20 assembly.
Oh yeah, everything is labeled. This 5 bedroom, 3 1/2 bath, 2 kitchen and 2 laundry home has 21 plumbing circuits and 32 electrical circuits, way past the capability of my memory!
Why all the curly queues in the copper line?
I take it that all the red lines are water circuits, using PEX?
Are the blue water lines also PEX?
I don't recall ever seeing a water patch panel like that, is it industrial grade water distribution panel or the new thing on the block?
And, so far as we know, there are a tiny tiny number of people who have been adversely affected by copper piping. Not from the copper, but from the solder. For a long time now, lead solder has been banned from residential plumbing. But, things can happen...
PEX will likely last longer if your water is acidic, or has a lot of dissolved minerals, which is most of the U.S.
There is no wrong answer here.
But one useful fact is this. Everything leaches something. But it's a very slow process, and the leachate gets less and less over time. So, to mitigate the risk (real, perceived, whatever), most of leaching happens when the water sits without moving for 8 hours. When you get up in the morning, let the tap run for one minute. Boom, you just flushed 99.9% of the leachate out and now you're good to go, whatever piping you choose.
Same thing when you get home from work. The water has been sitting there for 8 hours and has picked up whatever the pipe wants to give off. Another flush for one minute, and you're totally safe again, if you are concerned at all.
So, a reasonable option might be to flush before drinking/cooking with water for the first year after new piping is installed, and then never bother again.
Lead is different, and can leach for decades. If you have lead solder, you should flush the lines every time the water has sat in there for hours and hours.
A lot of this depends on the pH of the water, so your mileage may vary concerning whether or not you "need" to flush the lines.
Even places that had solid lead supply lines from the street to the house rarely caused real toxicity problems. Even under those awful circumstances, flushing still works.
John Weiland wrote:This thread started to address the use of PEX tubing in water supply lines but then trailed off. I did not come across any other PEX discussions in other threads, but admit the search was not exhaustive. All of the current water lines in our old home are copper. I assume that using PEX would significantly reduce cost and increase ease of installation on some remedial pipe work to accommodate a new hot water system. But it's always been a bit disturbing to use some sort of synthetic for home water delivery, especially hot water. Any comments or opinions on the safety of PEX for this purpose? Thanks.
John, I'd stick with copper if you can afford it. I have not seen a comprehensive field study by credible third party showing PEX is safe, on the contrary there is a lot of data showing it is not you'll find on this thread: http://www.greenbuildingadvisor.com/community/forum/green-products-and-materials/37891/what-greenest-and-best-material-use-indoor-plumbi
Read my "Terry" and Richard Beyer's opening comments if you don't want to read the entire long thread. Martin Holaday called Richard and I and asked us to stop posting on his site since we kept showing supporting data as to why much of the foam and plastics he recommends as "green" are not safe nor good for the environment: http://www.greenbuildingadvisor.com/community/forum/green-products-and-materials/37891/what-greenest-and-best-material-use-indoor-plumbi
That led me to Permie.com once called "green builing" now due to these green sites promoting sponsors and not safe materials "natural building" ....
Also, be careful what your read on the internet. Question it unless supported & posted by credible data and fact. Your life could depend on it.