Roof top water tanks can been seen on many of the F&SM structures.
Could someone please explain in detail, how the water is pumped into the tanks and where the original source comes from. Then what areas is the water used for and how is it distributed. I would like to add EXTRA detail to these structures, but I need to know more of the design. I don't want to put alotta pipe work everywhere, just 'cause it looks good.
also...... how are the tanks waterproofed..............
Do I need a plumber on occassions to stop the leaks................
I am sure there would be several answers to this question, depending on design, location, etc............
I would like to someday, have a fully detailed Roof Top Water Tank.........
About those roof top water tanks.
I believe they are all about creating ample water pressure for the buildings they reside upon.
The pressure is maintained by good old fashioned gravity.
I may be wrong, but I believe their levels are maintained in a manner similar to a toilet tank.
Getting the water up to the tank by a small pipe requires little pressure. The feed water pressure may be supplied by the municipality, or a designated pump in the building. I'm uncertain myself.
Even today you will see elevated water storage tanks mounted on towers spread all across Canada and the US.
Instead of many individual roof mounted tanks, the towns use just one large elevated tank to maintain water pressure fed through pipes to all the structures in the area.
I believe this is how it works. If I'm of base, somebody more knowledgeable will jump in and set the record straight.
Doug - As a retired Fire Chief in a metropolitan area, I can say that your description of elevated tank operation is essentially correct.
In many cities buildings over 6-8 stories required such rooftop tanks to maintain adequate water pressure on the upper floors and for use in conjunction with fire protection (standpipes, sprinklers, water curtains).
As to Mario's question, do these tanks sometimes leak? You bet. It would not be very unusual to see a small puddle under, or evidence of leakage from, the tank itself. Many tanks weathered dramatically. The maintenance of these tanks was once a big-time job, so it would not be at all unusual to model guys painting or working on a tank, or taking down an old, worn-out wooden tank and replacing it with a new steel one. The sides of water tanks were also often adorned with interesting signage, particularly atop industries, adding to a modeler's fun.
Doug: You are correct. The technology antedates powerful pumps and is used where the lay of the land does not permit a reservoir, a natural or man made lake, with sufficient hydraulic head within piping distance of the town.
It was common in Europe as well, and many, many small towns had a central water tower just like towns on the North American prairies. Is there not also such a central water tower in Alice Springs?
You are also correct in stating that a small pipe suffices to fill the tank which acts as a buffer as well as creates pressure. For a small installation, such as a small hotel in some godforsaken cattle or sheep station, a hydraulic ram taking its power from the local creek was often used to feed a continuous small supply of water into the tank from which water was then drawn occasionally at a far faster rate.
Doug, I believe your explanation of roof water systems is correct with one nitty point of correction. I believe that water pressure in a closed system depends on height of the water, so a pump on the ground floor would need to produce as much pressure to fill the tank as the water has that is flowing out on the ground floor level.
Tanks are usually filled via a small pipe going to the top of the tank. Pressure to move the water up can come from the city water supply or an in-house pump. Distribution usually comes from a discharge pipe out the bottom. This pipe can be larger than the input pipe depending upon the use for the water. This pipe usually went directly into the building were it split off to various uses.
Uses for the water vary. Sprinkler systems, boilers, waste disposal, etc.
Logic for roof top tanks was to supply a constant flow at a good pressure via gravity.
We include this detail in our kits... look at the second photo from the top of the Hyde Pulp Mill.....
Wood roof top tanks are just like RR water tanks. Angled staves are pressed together, and held in place via tight bands. The water gets into the wood causing swelling which basically seals the joints. Anything with water will eventually leak, so build a plumbing supply nearby.
I agree with others who have responded to your post. As an aside... I have had some experience with late 19th century homes, having had one for the better part of 35 years. Found an unused galvanized tank in the attic. Many middle and upper-class homes had water tanks located on or above the upper storey... purpose was to maintain a consistent and reliable water source, per several replies. I imagine city apartment buildings had the same. With today's reliable city water, we tend to forget the purpose of small details/problems like this that were commonplace through the mid-20th century.
Best, Bill F.
Doug, you are dead right on the money....as a young buck control engineer about 100 years ago I had the experience of not being able to shut off a pump by emote control....thephones soon rang.... remote water tower overflowed, and the neighbors had their lawns sprinlked for a month...all at one time...(grin) The law of gravity has not yet been ammended or repealed...hehehe
ole geezer in Nowhere, Texas
Any pump will do. Electric or small gasoline engine. usually a small shed will accommodate either. Water is pumped under low pressure and flow until tank is full. then the pump/engine shuts off. Water is then available at any time at a predictable pressure(i.e. .434 lbs. per foot of elevation measured from the top of the water level to the spigot elevation.) This scheme allows the pump to run infrequently, instead of every time water is used. A rooftop tank on a six story building would supply approximately 30 psi.to the ground floor......rapid calculation is 5 lbs per floor...first floor doesn't count...but add one floor for the roof......aint ya glad you asked??? Anyhow, A pipe... anywhere from two to 3 inches depending on predicted need is used to supply tank. At the 25 psi a two inch pipe can supply 600 gpm (gallons per minute). That's quite a bit of water! Anyway, this is more than you wanted to know... I m just showing off! By the way, water is usually supplied to the pump by City Water...so a pipe into the shed/pump and then an exit pipe up to the tank.