Why do houses in the UK (and Ireland) usually have a cold tank in the attic, while continental countries seem to get away without this?
On the face of it, the tank-less system seems much simpler, and appears to work just as well.
Is there some historical reason for the UK system, if I can call it that?
Someone suggested to me that the UK system is unhygienic, as well as unduly complicated. But I'm sure our ancestors had good reason for what they did.
I can think of two advantages:
- you can still flush the bog many times, or make a cup of tea if the mains is cut off for any reason.
- constant head of pressure; some properties have very low mains pressure.
On Wed, 20 Feb 2008 12:51:01 +0000 someone who may be Timothy Murphy wrote this:-
We haven't discussed this for at least a month. Search engines will pull up long discussions on the subject.
If one ignores the various safety valves and other gadgets that are involved.
Someone who didn't know much about plumbing.
Provided it is installed and maintained properly a "UK" system is as hygienic as a direct system. Both can become unhygienic in various ways if this is not the case.
A storage system allows for interruptions to the supply. One can still flush the toilet and wash one's hands with hot and cold water with the "UK" storage system. With a direct system one can flush the toilet once and try and wash one's hands in water that happens to be available.
A storage system means the pipes and fittings are at low pressure, meaning less noise, stress and things like water hammer.
With a direct system fittings in bathrooms are more likely to form condensation. Water from a storage system will be a little warmer so this is less likely. Note that I said a little warmer, that is not the same as being so hot all sorts of germs breed rapidly.
A storage system allows for variations in supply. At times of peak demand the supply pressure and flow can go very low and people will not notice much.
A direct system avoids storage tanks being installed in the loft or at least high up. Plumbing is at a lower level.
A direct system avoids pumps for showers, though there are several ways of avoiding this on a system which is predominately storage.
The man advantage of this being a good head of water for filling the bath or running a shower and to compensate for low mains pressure when doing so
However in commercial installations storage for hot and cold is used and direct supply for potable use only
I would not want to drink cold water from a stored supply especially where something may have found its way into the tank and died
Tony
Better not come round here then - stored, and a plain untreated source at that (not mains). Tastes great - better than any mains water I've tried.
That one's fairly easy to prevent.
clive
whiuch will alwatys exceed that from te tank, or it wouln't ever fill up.
The ONLY two reaosn for a header - well three maybe are
- the mains delivers insufficinet RATE of FLOW (NOT pressure)
- the mains is subject to long and freqeuent outages
- you have no mains at all. And e.g. pump from a borehole etc.
And ergo bigger and more expensive pipes or pumps needed to get the flow rates to a satisfactory level.
This is bollocks. Warmer in summer, colder in winter.
And where do you think mains water comes from?
Your statement is rather like saying you'd not drink milk that came from a cow...
I know that storage tanks in schools and other commercial buildings some times contain dead pigeons as I have had the job of getting them out. I also know that there is no treatment of the water after it leaves the tanks
As regards the cow I would not drink the milk straight from the cow I would want pasteurised milk from the dairy
In case you are not aware
Pasteurization (or pasteurisation) is the process of heating liquids for the purpose of destroying viruses and harmful organisms such as bacteria, protozoa, molds, and yeasts. The process was named after its inventor, French chemist and microbiologist Louis Pasteur. The first pasteurisation test was completed by Pasteur and Claude Bernard on April 20, 1862.
Tony
In which case they do not meet the requirements of Water Byelaw 30 or of Paragraph 16 of Schedule 2 to the The Water Supply (Water Fittings) Regulations 1999, which replaced it. Any cisterns installed since the Water Byelaws were introduced should have a close-fiiting lid that excludes light and insects, with insect screens in any air vents, warning pipes and overflows. While there is no statutory requirement to bring older cisterns up to those standards, most Local Authorities and NHS Trusts are doing so as a result of risk assessments, which is good news for me, as I make and sell the insect screens.
Colin Bignell
A cold water accumulator is generally the better option than a tank in the attic.
Pressure and rate of flow are almost always related.
Ian
Not at all.
If you have a blocked pipe, flow will be nil irrepective of pressure.
If you have a river, flow will be vast at almost no pressure at all.
No. Flow (assuming there is some, granted) is always (approximately) proportional to pressure, the exact relationship depending on the resistance of the transport medium (and the viscosity of the fluid).
The *hydrostatic* pressure (when there is no flow) will be unaffected by the pipes etc.
The mains may deliver insufficient pressure (to fill a header tank at all in extreme circumstances, but often insufficient to run a combi boiler shower) OR insufficient flow (either due to the external pipes or internal pipes). You could, of course, claim that insufficient flow is because the pressure is too low but there are "normal" ragnges for mains pressure. Most reasonable people would say a mains pressure way below the normal would count as insufficient pressure (even if the symptom is poor flow) and one where the hydrostatic pressure was high (you can't seal the cold tap with your thumb for example) but which failed deliver adequate quantities of water, had a flow rate problem. The two are never not intimitely connected though!
Its also exactly as proportional to viscosity, pipe cross sectional area and length, so why not say.
"YES flow is always proportional to pipe length and cross sectional area"
I said as much.
If it has enouh pressure to fill a header tank, ipso facto it has enough
*pressure* to run a shower. Ife run swers off header tanks. Not great, but they work. It may not be able to sustain a decent *rate* though. However unless its severely limited upstream in te mains that is most likely to be inadequate post stopcock plumbing, which is addressable.I challenge you to find even one area where there is insufficient mans PRESSURE or for that matter flow, to run a decent shower, if fed directly from the mains via reasonable bore sizes.
Thats sort of low state would be almost automatic cause for a water company refund, as its simply not fit for purpose.
Precisely. However anything above about 0.5 bar static is probably enough for a decent shower, and is what you need to get water into a header tank in a three storey building.
I very much dowubt that mains pressures less than that are acceptable anyway. Likewise fklow artes to a single property that cant fill a header tank in a couple of minutes. Whih are ALSO enough for a shower.
The only argument I can see that has any validity is that of supply reliability: You may JUST be happier with a tank of cold water that you can rely on for two bog flushes and a couple of quick washes.
>
Coo yes, who'd a thunk it. Blocking the pipe reduces the flow and increases the pressure. Unblocking the pipe increases the flow and decreases the pressure. It's almost as if, in some spooky way, the flow and the pressure were related.
And if you dam the river the flow reduces and - whadja know - the pressure increases. Amazing!
Ian
Because it is driven by, and depends on, the pressure. To correct your statement:
"At a given pressure, flow is always proportional to pipe length and cross sectional area"
I didn't say you didn't, I was merely restating the more limited case.
My comment referred to combi boilers showers where there are many instances of where they cannot be installed as the mains pressure is too low - clearly, with a tank system, the crap shower you may get from the mains can't be worse than the crap shower you get from the tank, if the tank is still filling. The reason, in these cases, that the rate is low is because there is inadequate presssure. The generally accepted minimum pressure water companies are required to provide is about 1bar. Historically they have been providing 1.5 to 2 bar to overcome such problems. Now that the government is taking action to force water companies to reduce leakage, they have realised that targets can be met by reducing all supplies to the minimum where possible and this lowering of the pressure is causing problems (for some people at the end of pipes, three storey buildings etc).
If you look on combi boiler sites they will say don't have one if your mains pressure is low.
Indeed, such arguments are already in place.
Well 0.5 bar would be trickling 16feet up so a bit light I would say! 1.0bar maybe
This is particularly important in business premises, where you have to send everyone home when the toilets stop working. Depending on your business and numbers of staff, you could rack up millions in losses due to a simple water supply failure otherwise. There have been a few cases where this has been overlooked in premises where millions of £'s have been spent on emergency electricity supplies to enable critical business activities to continue during a power cut, only to find the building has to be closed because the toilets stopped flushing when a water main burst.
snipped-for-privacy@davenoise.co.uk...
Why? Unpasteurized never did me any harm, nor a childhood of drinking from the bathroom tap that was supplied from a lead tank through lead pipes.
On Wed, 20 Feb 2008 20:09:49 -0000 someone who may be "TMC" wrote this:-
And I know that there are/were no dead pigeons in the storage of any houses I have looked after.
That is another low risk thing which those who wish to regulate every aspect of life have been having a go at.
I suspect that most readers of this group are aware of what pasteurisation is and who it was named after.
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