READ THIS!!!!!!!!
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Yes, depending on height of the building but that's beside the point. It's how the marble sound is caused?Originally posted by bratpig:Actually, depending on the height of your buidling, the water tanks on the roof serve the higer floors, while the lower floors draw their supply of water directly
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There are in fact plenty of methods that can be employed to reduce the waterhammer effect other than the method you just mentioned. Unfortunately, the drawbacks usually involve a loss in water pressure itself, especially to the lower levels, which thus brings back the feasibility of implementation.Originally posted by Archirodon:This is a technical problem. All the developer has to do is to install a surge valve at the outlets of all the water tanks and this will absorb the pulling effect within the pipelines when there is a surge. Thus no knocking sound will be generated. That is why new buildings today do not have this problem except old blocks.
Some of these methods include:
-Valve closure control
-Increasing pump inertia(for downfeed, unfortunately booster pumps only provide for the topmost 2 floors)
-Surge shafts (not really a feasible thing, especially for a hdb block of flats
)
-Air or fluid admission valves (usually requires another medium to enter the supply system, risking contamination)
-Relief valves (works best only near where the pressure is to be relieved eg tap, downside is a faulty valve will cause substantial pressure loss)
-Bypass systems (an extention to the inflow relief valve device)
So, it'll be quite sometime until a feasible plan comes up, meanwhile just bear with it. -
True, another factor to add is the origin of the pump station for the area which it serves, in short its geography.Originally posted by bratpig:Actually, depending on the height of your buidling, the water tanks on the roof serve the higer floors, while the lower floors draw their supply of water directly
Some parts of singapore are located higher or further away from the pump station. For example, in sengkang and bukit merah area, the first 5 floors can be direct feed. In some parts of bukit panjang, the entire block has rely on transfer downfeed. -
Hmmm i stay at first storey also heard.
So how does the water tank theory support leh?
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Go check first if your water supply comes from direct feed, or downfeed. If its downfeed, shhhhhh.Originally posted by M©+square:Hmmm i stay at first storey also heard.
So how does the water tank theory support leh? -
*hair Stand!*Originally posted by ditzy:Go check first if your water supply comes from direct feed, or downfeed. If its downfeed, shhhhhh.
Damn it Ditzy....to go sleep i must.
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Oh no! Looks like HDB guys gonna copy what you have read here and use it as a explaination.
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has HDB replied?
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Hmm... very scientific and logical explanation, but i'm not entriely convinced.Originally posted by Archirodon:Those who thought the ghost had followed you from Lor Ah Soo to Punggol 21, those who was smoked to believe that contractor buried marbles while constructing the buildings or to please the child ghost are all bull sh*tÂ…. So, tonight you can sleep tight and not to worry about the marble dropping sound. ItÂ’s perhaps someone flushing the toilet bowl.
Water hammer produces sounds which are more like a dull thud than a crisp sound of dropping marbles. Does water hammer also produce the marble rolling sound?
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The method currently employed by HDB is the installation of pressure relief valve at height intervals of 45 metres.Originally posted by ditzy:There are in fact plenty of methods that can be employed to reduce the waterhammer effect other than the method you just mentioned. Unfortunately, the drawbacks usually involve a loss in water pressure itself, especially to the lower levels, which thus brings back the feasibility of implementation.
Some of these methods include:
-Valve closure control
-Increasing pump inertia(for downfeed, unfortunately booster pumps only provide for the topmost 2 floors)
-Surge shafts (not really a feasible thing, especially for a hdb block of flats )
-Air or fluid admission valves (usually requires another medium to enter the supply system, risking contamination)
-Relief valves (works best only near where the pressure is to be relieved eg tap, downside is a faulty valve will cause substantial pressure loss)
-Bypass systems (an extention to the inflow relief valve device)
So, it'll be quite sometime until a feasible plan comes up, meanwhile just bear with it. -
The reinforcement bars within the reinforced concrete structure are connected, so it's normal if the vibration spreads until first storey before dissipation.Originally posted by M©+square:Hmmm i stay at first storey also heard.
So how does the water tank theory support leh? -
The reinforcement bars within the reinforced concrete structure are connected, so it's normal if the vibration spreads until first storey before dissipation.Originally posted by M©+square:Hmmm i stay at first storey also heard.
So how does the water tank theory support leh? -
during day, the building structure expand due to heat.
at night, the building structure contract cuz cool down.
the expansion and contraction causes noises in the structure.
there you go, explained.
thank you very much. -
Me also have such sound in the evening
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You also have such sound in the evening, thought it was your flat, I see.Originally posted by sbst275:Me also have such sound in the evening -
woah... as a future engineer, im really impressed with the explantion about the waterpipes manz...!!
tonight can sleep well already.. -
This is a more logical explaination, and to add to it, those flats built on fabricated slabs are more prone to the sound.Originally posted by the.raven:during day, the building structure expand due to heat.
at night, the building structure contract cuz cool down.
the expansion and contraction causes noises in the structure.
there you go, explained.
thank you very much.
The water hammering theory is also true, but it does not produce a marble dropping sound, instead it sounded more like drilling or "thunder without lightning and rain". -
Got marble dropping sounds reported in the daytime? How come its usually at night or in the wee morning hours only? Suspense issit?
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I think this would make a very good research project for an undergraduate student in the local unis. Especially the civil or structure engineering lads. Would be wonderful coming up with a logical hypothesis based on some variable test conditions.
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This is an interesting and astonishing story. Of course, it is astonishing. In fact, there are many such stories in our
environment. If you want, i say one to you all. yes?
hiputong -
not yet!Originally posted by BonJovi:has HDB replied?
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You know why? Coz the above replies are cock and bu|| theory.Originally posted by Manager433:not yet! -
actually daytime might have but maybe covered up by other noises cos at night more quiet so can hear more thingsOriginally posted by ditzy:Got marble dropping sounds reported in the daytime? How come its usually at night or in the wee morning hours only? Suspense issit? -
Or its more logical to have children playing marbles upstairs in the daytime, regardless if its the roof or its unoccupied.Originally posted by hisoka:actually daytime might have but maybe covered up by other noises cos at night more quiet so can hear more things -
interesting....Originally posted by ditzy:I think this would make a very good research project for an undergraduate student in the local unis. Especially the civil or structure engineering lads. Would be wonderful coming up with a logical hypothesis based on some variable test conditions.