Would a 2" PE waterline be sufficient? 3

[Will007]

For an 8 unit development spread over max Length of 3000lf.

Also, anyone know what the normal flow should be for a home w/ 40-60psi?

Thanks in advance for any help.

 

[Will007]

I guess to help clarify. This is for a reservation who do not want any fire hydrants or any of the required systems due to lack of funding and they dont want to maintain it.

They just want water to their homes. Thats all. I was thinking to put in a 4 inch line but it'll be hard to get all the materials to this remote area. So I'm trying to see if a 2" PE line will serve 8 homes. Its easier to transport the 2" PE then a 4" PVC.

Thanks for any help you can give.

I dont currently have a software that will run the numbers for me so if you have a free one I can use, please let me know.

 

[jte]

Its just a question of gallons per minute. I'm guessing there will be no irrigation systems for lawns. Figure around 10gpm per house (probably below code requirements, but not unrealistically low). If you have a 50% usage factor (everyone on the entire reservation is not showering and flushing toilets and washing dishes at once) then you need 40 gpm. Figure an equivalent length of 4000 feet to account for fittings. Very roughly speaking you'll lose about 50 psi so your source will have to be at least 90 psi. If you figure on a 25% usage factor you'll ose around 15 psi so your source will have to be at least 55 psi.

Don't forget to account for any elevation changes as well.

Would youi consider twin 2" PE lines? Not the capacity of a single 4" but perhaps more feasible. If you go with two lines be sure they can be isolated so that one can be taken out of service while the other remains in service. Probably relatively cheap to add four valves vs the inconvenience of someday losing service all together. On the other hand, what damages one line may well also damage the other.

Another thing to consider would be to add an elevated storage tank, perhaps a few hundred gallons, to account for usage surges. Depending on how you size this you may find that a 1.5" pipe will do.

jt

 

[Will007]

Thanks jt,

Their is an existing water tank on the side of the hill about 130 feet in elevation difference from the lowest home and about 50 ft elev. difference from the nearest home.

All homes are downhill from the tank. We'll be installing some small pumps in the homes to increase pressure due to the lack of pressure from the tank.

I guess we'll go with a 2" PE line and go from there.

Thanks again for your help.

 

[cvg]

see attached hydraulic table by Hazen and Williams which you can use to do your own calcs.

since you will be drawing water off at intervals along the 3,000 feet, you will have considerably less pressure drop than previously suggested.

Plan on something like 100 gallons per day per person. more for irrigation, possibly less on the reservation due to low usages. I think the 25% usage factor is probably the most likely.

for water quality and for reliability you should consider a loop. This would also greatly reduce the pressure drop.

 

[ornerynorsk]

When you're in that situation of providing just the basic necessities, a garden hose would almost do it, save for the 3000 foot run. My in-laws in remote Mindanao just got running water in their city in 2002 or 2003, and 3/4 galvanized pipe is used for "mains". No kidding. No, there are no flush toilets or washing machines or other conveniences, but that trickle of clean water does so much to improve life over the previously used hand-pumps drawing questionable-quality water that everyone had prior to that.

 

[Will007]

Thanks guys, this will help.

 

[cvg]

granted, you can deliver water through a drinking straw if that is all you can afford - however the incremental cost increase from say 3/4 inch pipe to 2 inch pipe is not that much. Going with the smallest pipe available is false economy. The trenching and labor to install the pipe and the service connections is the largest cost and is always better to provide sufficient capacity the first time around because it may never be upgraded in the future.

 

[BigInch]

And demand virtually never... decreases.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[IRstuff]

I second the notion that capacity demand will ALWAYS increase. While the current demand is low, that's simply because they can't contemplate using more. Once a new system is installed, they'll want to do more with the water, because the availability is so much higher. They're going to want to start gardens, now that plentiful water is available, but they'll quickly find that they can't take a shower while the neighbor is watering their garden, or something similar.

It's not that different than the fact that most bathrooms, even brand new ones, only carry 2 outlets per sink, yet, we have so many more bathroom appliances than even, so we wind up adding socket capacity, ala power strips, to power radios, dryers, shavers, toothbrushes, etc.

TTFN

FAQ731-376

 

[BigInch]

And ... then they'll be .... mad.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/