Garden irrigation: would you risk fitting a motorised valve in an outdoor cabinet?

[Kayos]

Are nearly all domestic water pipes not Copper? Not been a problem for the last 70 years or so?

Copper replaced a lot of lead pipes (which did slowly dissolve in some water supplies). Copper has been used for kitchen utensils for centuries without much trouble (it will dissolve in strongly acidic conditions) but is otherwise very unreactive) - and it is likely as toxic, when dissolved and ingested, as lead, even though I think we need a tiny amount of copper (but not lead) in our food intake.

It's brass that is destroyed by oxygenated water, not copper or indeed dissolved Co2.

The process is called dezincification

 

[Gareth J]

It's brass that is destroyed by oxygenated water, not copper or indeed dissolved Co2.

The process is called dezincification

Got any links/further reading? All I could fine regarding "aggressive water" was to do with cO2 dissolved. May be just a terminology thing

 

[not done it yet]

It's brass that is destroyed by oxygenated water, not copper or indeed dissolved Co2.

The process is called dezincification

No need to quote me. I do know a fair bit about chemistry.

 

[Kayos]

No need to quote me. I do know a fair bit about chemistry.

I was just updating the thread with accurate information in case someone with less knowledge comes across it

 

[Kayos]

Got any links/further reading? All I could fine regarding "aggressive water" was to do with cO2 dissolved. May be just a terminology thing

Could be, it may even be a local term

 

[not done it yet]

I was just updating the thread with accurate information in case someone with less knowledge comes across it

It would be better to quote the post that got my response, not mine. He might read it and gain some knowledge.

I replied to the specific claim that may have suggested to some that copper pipes were no good.

You had posted at least once, previously, that it was brass that was dissolved. It’s not my place to give him a chemistry lesson about brass.

 

[Gareth J]

Could be, it may even be a local term

Well, it's certainly interesting sounding but I can't make head nor tail of it. I'm not questioning the effect you know or you experience but if it is a local term, wonder what it actually refers to.

Only things I can see regarding "aggressive water" are pH and normally dissolved CO2 related.

Corrosion of brass via dissolved oxygen is noted here;

https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/abs/10.1002/sia.1278

But it's suggesting the copper, not zinc in the brass is more the problem.
More here;
https://www.researchgate.net/figure...xygen-concentrations-in-copper_fig4_282736107

Any more clues as to what process it is you're referring to?

 

[mike os]

I would think 24v solenoids would be a good bet

 

[DAPPH]

Irelevant to my post. Rain water is free from supplier or government taxes. Volume to flush the loo is not something to really worry about if sufficient rainfall can be collected - and if it’s not, the roof tank can be topped up from the mains supply - just like any gravity fed dystem would be now.

Common house brick(s) could be used to reduce the effective volume of the cistern, if deemed necessary (an alternative may be adjusting the ball valve control height, depent on the shape of the cistern.

I was thinking of the small savings in electricity possible by not pumping rainwater up to a gravity tank in the roof void .

 

[not done it yet]

I was thinking of the small savings in electricity possible by not pumping rainwater up to a gravity tank in the roof void .

Use a hand pump, if you really want to go ‘lectric-free?

Surely it would depend on whether the collected water was above or below the storage tank for the loo. Obviously a ground-floor loo could be advantagious over a top-floor one.

Savings are tiny (for pumping water, at a few metres head), so compared to mains supplied potable water that leccy can be ignored. Running the pump on solar power has up-front cost, but running costs are then zero. Horses for courses. Choose and design the system appropriately. Reducing cistern capacity is a different factor in the design of the whole system.

 

[not done it yet]

Any more clues as to what process it is you're referring to?

Likely water derived from peaty supplies 9 through peat bogs), where the pH can be quite low.

 

[DAPPH]

Use a hand pump, if you really want to go ‘lectric-free?

Surely it would depend on whether the collected water was above or below the storage tank for the loo. Obviously a ground-floor loo could be advantagious over a top-floor one.

Savings are tiny (for pumping water, at a few metres head), so compared to mains supplied potable water that leccy can be ignored. Running the pump on solar power has up-front cost, but running costs are then zero. Horses for courses. Choose and design the system appropriately. Reducing cistern capacity is a different factor in the design of the whole system.

I used to know ( pre covid...he dead now ) a guy up in the borders who had a permanent spring coming of a hill shelf that he fitted up a hydraulic water pump arrangement to . 24/7 it clicked away squirting out about three egg cups of pumped water on each stroke up some 22 feet to a long small header tank in the roof void to supply his cottage with fresh potable water . He found the pump on You & took four attempts to get it right , installed & working .

 

[Gareth J]

Likely water derived from peaty supplies 9 through peat bogs), where the pH can be quite low.

Absolutely, that's my experience with our well supply, not excessively, but significantly acidic. There's a bit of peat in the field. Causes problems if the pH adjustment gets neglected. @Kayos was referring to something else though, something mysterious involving dissolved oxygen. Can't find any more details about it though

 

[Kayos]

Absolutely, that's my experience with our well supply, not excessively, but significantly acidic. There's a bit of peat in the field. Causes problems if the pH adjustment gets neglected. @Kayos was referring to something else though, something mysterious involving dissolved oxygen. Can't find any more details about it though

I'm sorry but I'm completely bored of this

In my old office I had a collection of 4" brass valves, fitted to a fresh water supply. All of which had worn through in under 12 months.

In my line of work (plumbing and heating) aggressive water and dezincification are common terms, all to do with dissolved oxygen and the well known effects it has on brass fittings under certain conditions

I'm sorry you can't verify it with Google, in fact I'm not sorry but if I could impart 22 years of experience I would, but I can't

Bottom line, brass valves installed on fresh water cost my company thousands, we identified the issue and it's what I posted previously

This will be my last reply on the subject, this thread has become typical of this forum where there is a refusal to believe what someone with knowledge and first hand experience of the subject posts

 

[8ob]

 

[My Old Landy]

Cheered me up no end Bob

 

[not done it yet]

Obviously no point in querying the water velocity through those valves.

Our old brass taps, with rubber washers, were OK while operated fully open but when throttled down too much, would soon wear the washer seats to the point of improper sealing (dripping while turned off).

Dripping taps soon became much larger leaks as the water (at high pressure/speed) cut away the soft brass seat. The plumbers re-seating tool, used as soon as the leak was noticed, saved many brass taps from an early trip to the scrap pile. These days we can get steel parts cut to size using jetted water.

I won’t add that abrasives are added the water jets, or it may prompt our ‘toys-out-of-the-pram’ posters to re-enter the fray. We used plain water jetting at very high pressure to cut through some rock-hard materials. I won’t go into too much detail, here.

 

[Richiew]

I won’t go into too much detail, here.

You never do. Nearly 900 posts and not one photo of anything you've ever done.

 

[Mikes]

Likely water derived from peaty supplies 9 through peat bogs), where the pH can be quite low.

There is special requirements for water services running through ground containing coal / coal waste etc. Can't remember the name of it but there is a specialised barrier pipe to protect the water from the hydrocarbons leaching into it. Normal MDPE won't do but can't remember if this also applies to copper.

 

[Mikes]

Philip, Whatever equipment you opt for, it must be WRAS (Water regulations Advisory Scheme) approved. You also need to ensure that the install meets the byelaws (suspect that you will be a Thames Water customer) and they are very strict. Your best bet would be to ask their advice which they should give. They will be particularly concerned with the length of any dead-leg formed by your new installation. From experience, they will want an absolute minimum between the tee off the water pipework and the isolating valve to the irrigation which will probably preclude you having the valves outside. The check valve will probably need to be of the double variety with verification (the little screw between the two valves). They might however tell you that they won't permit direct irrigation supplies from the mains and you need to take it through a break tank and booster. The byelaws have changed a lot in recent years so worth checking.