What is the purpose of keeping tremie pipe’s tip immersed in freshly-placed concrete for about 1m in underwater concreting?

  What is the purpose of keeping tremie pipe’s tip immersed in freshly-placed concrete for about 1m in underwater concreting? The size of tremie pipe is about 300mm with sections having flange couplings fitted with gasket to prevent water leakage. The tremie pipe should be closed initially to prevent water from entering the pipe. It should be designed with sufficient thickness and weight so that it would not be buoyant when empty inside water. The placement of tremie concrete is commenced by putting the closed pipe underwater to the location for concreting, followed by partial filling of tremie pipe with concrete. In order to have tremie concrete flowed out of the pipe, it is necessary to fill the pipe with concrete of sufficient height to overcome the water pressure and frictional head. After that the tremie pipe is raised about 150mm to allow concrete to flow out. To enhance sufficient bonding, each succeeding layer of concrete should be placed before the preceding layer has rea...
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WHAT IS FIRE FIGHTING SYSTEM ??WHAT IS THE CFO REQUIREMENT FOR BUILDING

Fire Fighting system

To begin with, FIRE is one of the five elements of Nature. As such, FIRE is omnipresent and is also known to be omnipotent. FIRE in the form of flame & heat is not only essential for the sustenance of life but has also enormously contributed to the progress, prosperity and comforts of human race. Nevertheless, FIRE also has its destructive side. FIRE kills people & destroys property – the two most precious things for a human being. It is common knowledge that FIRE has destroyed the art, architecture and history over the centuries, bringing in its wake destruction and distress to human race. Obviously, it is the duty of one and all of us to prevent fires and minimize the life and property losses.

• Fire fighting system required in the commercial or high rise buildings are as per the requirement of the CFO ( Chief Fire Officer)

 a) Hydrant system
 b) Sprinkler system
 c) Alarm system

a) Hydrant system:

1) Main Fire Pump [ Design pressure 3.2 Kg/cm2 at topmost hydrant]
2) Booster Pump [Design pressure 3.2 Kg/cm2 at topmost hydrant]
3) Wet riser cum down corner ( 4" dia to 6" dia)
4) Courtyard hydrant at ground floor level (45 Mtrs C/C)
5) Hydrant on every floor ( Single or double as per NOC )
6) Hose reel with rubber hose and shut off nozzle on every floor
7) Hose box with canvas hose at ground floor ( double or single door boxes)
8) Branch pipe ( nozzle) in every hose box
9) Siamhose connection ( This is provided if power failure takes place than fire tanker from outside of the pump room or from the approch road can be connect to this connection)

b) Sprinkler System;-

1) Main sprinkler pump [if separate system suggested]
2) Jockey pump [if separate system suggested]
3) For basement car parking /offices
4) If building height more than 60 meters.
a) Every floor lift lobby ( 12th floor onwards )
b) Every floor lift lobby ( 50mtrs. Onwards )( Brihanmumbai municipal corporation BMC )
5) Sprinkler gong ( Alarm) valve

c) Alarm System:-

As per CFO, Combined alarm panel ie – manual alarm panel + public address system to be provided in buildings.

1) Main alarm panel at Entrance level [ gr. Floor ]
2) Manual call point and hooter box at every floor level
3) Smoke detector in lift machine room / electric meter room / pump room.[connected to Alarm panel through Manual call points ]
4) Flow switch (For sprinkler of every floor lift lobby) [ connected to Alarm panel through Manual call points ]







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