Testing of water retaining structures

[JECCNC]

I am on a project which uses an induced draft counter flow cooling tower, the system uses sea water and has a basin about 300 meters x 35 meters and 2.5 meter deep, there is also a pump basin which is about 7 meter deep. my question is regarding the testing of this basin for leaks. some codes say 8 hrs, some 24 hrs , 3 days and 21 days. does any one know what these test times are based on? any advice on which to follow

 

[bimr]

Concrete tanks are built to the design standards set by the American Concrete Institute.

http://www.concrete.org/tkc/knowledge_center.htm

The leak test procedures used for concrete tanks is not as simple and precise as the one used for steel tanks. It is difficult to prove a concrete tank is water tight.

What are the details of the tanks that you are proposing to test?

What codes are you referring to?

 

[JECCNC]

The tank i am testing is actually a basin for cooling water, the concrete is C 50 U ,cement content 425 kg/ m3 for underwater purpose , max crack width 0.2 mm , the thickness of the concrete is 500mm.
the code i refer to are
1. bs 8007
2, contractor internal specs
3. local building code

 

[bimr]

Here is a typical specification for testing concrete structures. It is calling for a 24 hour test.

3.6 LEAKAGE TESTS FOR STRUCTURES
A. Structure Leakage Testing: Perform leakage tests of wet wells, tanks, vaults and similar purpose structures before backfilling, by filling the structure with water to the overflow water level and observing the water surface level for the following 24 hours.

1. Make an inspection for leakage of the exterior surface of the structure, especially in areas around construction joints.

2. Leakage will be accepted as within the allowable limits for structures from which there are no visible leaks.

3. If visible leaks appear, repair the structure by removing and replacing the leaking portions of the structure, waterproofing the inside, or by other methods approved.

 

[TDAA]

I have used the above (similar) as well. 24 hrs should be adequate for you to see leakage around the structure for what you are working on. It should be easy to spot moist areas on the surface, and outright leaks.

 

[zelgar]

No matter what people are telling you here, if you need to be designing the tank(s) in accordance with multiple codes, you need to use the one with the maximum time period. Otherwise, you are not complying with all of the codes (e.g., if bs 8007 requires 21 days, Contractor Interal Specs requires 3 days and the local building code requires 24 hours; you'd need to do it for 21 days to be able to state that you followed all of the codes.)

Some codes may have more strict testing requirements to accomidate some factor of the design (e.g., amount of reinforcement, thickness of tank). Some codes may have stricter requirements to minimize the chance of failure on tanks that are stampped/approved by that standard.