tightness testing of gravity pipelines

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Page 1: Tightness testing of gravity pipelines

1Source: own photos

Tightness Testing of gravity pipelines

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Tightness Testing of gravity pipelines

The test for water tightness is to be performed on the pipe before it is completely covered, yet it has to be covered to such an extent as to prevent a change in position during the test.

Final backfilling of the trench may be started only after the entire pipeline has been checked, the tightness tests have been performed, all measurements for earthworks and pipe-laying works have been made, the pipeline has been appropriately secured and all important points of the pipeline have been staked out as fixed points. The staked-out points are to be recorded in separate as-built drawings.

Regardless of the general acceptability in testing of separate system elements, having considered most frequent leakage points (pipe saddle, house connections to revision & collection chambers), it is highly recommended that system as a whole is being tested.

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Leak tightness:

Testing should include connections, manholes and inspection chambers.

Procedures and requirements for testing gravity pipelines:

Testing with air; Testing with water.

Testing with air:

Method not appropriate for manholes and inspection chambers, just for pipelines; Suitable airtight plugs shall be used to avoid errors arising from the test equipment; Special care required for testing of large DN for safety reasons; Due to incapability for testing of the whole “system” including the collectors, house

connections, collection & inspection chambers, manholes, water testing method is recommended for application.

Tightness Testing of gravity pipelines

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Testing with water:

Test pressure is equivalent to or resulting from filling the test section up to the ground level of the upstream manhole, with a max. pressure of 50 kPa and a min. pressure of 10 kPa measured at the top of the pipe.

Conditioning time: after the pipeline and/or manholes are filled and the required test pressure applied, conditioning may be necessary (usually 1 h is sufficient, for dry climatic conditions a longer period is required as well as for concrete pipes)

Testing time: 30 ± 1 min

Source: own photos

Tightness Testing of gravity pipelines

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PLUGGING BALLOON SEALING THE CHAMBER

TESTED CHAMBER FILLED WITH WATER

Tightness Testing of gravity pipelines

Source: own photos

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Tightness Testing of gravity pipelines

Source: own photos

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Testing with water:

Test pressure is equivalent to or resulting from filling the test section up to the ground level of the upstream manhole, with a max. pressure of 50 kPa and a min. pressure of 10 kPa measured at the top of the pipe.

Settling time: after the pipeline and/or

manholes are filled and the required test pressure applied, conditioning may be necessary (generally for testing in dry climate 1 h settling time is sufficient; a longer period may be required for dry climatic conditions in case of concrete pipes);

Testing time: 30 ± 1 min

Tightness Testing of gravity pipelines

Source: own photos

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Test requirements: pressure shall be maintained within 1 kPa of the test pressure by topping up with water. Total amount of water added during the test to achieve this requirement shall be measured and recorded with the head of water at the required test pressure.

The test is satisfactory if the amount of added water is not greater than:

0.15 l/m2 during 30 min for pipelines;

0.20 l/m2 during 30 min for pipelines including manholes;

0.40 l/m2 during 30 min for manholes and inspection chambers

(m2 refers to the wetted internal surface)

Source: own photos

Tightness Testing of gravity pipelines

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Testing individual joints

Unless otherwise specified, individual joints can be tested instead of whole pipeline if the pipe diameter is > DN1000

The surface area for testing with water is taken as that represented by 1 m length of pipe, if not otherwise specified with a test pressure of 50 kPa at the top of the pipe.

Visual inspection by Contractor and Engineer has to be conducted prior to backfilling of pipelines.

Prior to scheduling of tightness testing, Contractor must officially announce testing with appropriate letter supported with required survey data of sections to be tested.

Source: own photo

Tightness Testing of gravity pipelines

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The Contractor's Surveyor is to measure all the parameters of installed system, based on submitted survey data, the Engineer will prepare test sheet for the use on testing.

Test Certificates issued by Engineer, signed and supported with survey drawings might be part of payment request and/or As-Built documentation.

Contractor is fully responsible for the quality of executed works and the strict respect of the testing procedures

Source: own

Tightness Testing of gravity pipelines

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Tightness Testing of gravity pipelines

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Tightness Testing of gravity pipelines

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13Source: own

Tightness Testing of gravity pipelines