Civil Engineering - Water Test for Gravity Pipelines

       1.    The test pressure for gravity pipelines up to and including 750 mm nominal bore shall not be less than 1.2m head of water above the pipe soffit or ground water level, whichever is the higher at the highest point, and not greater than 6 m head at the lowest point of the section. Steeply graded pipelines shall be tested in stages in cases where the maximum head, as stated above, would be exceeded if the whole section were tested in one length.

       2. The pipeline shall be filled with water and a minimum period of 2 hours shall be allowed for absorption, after which water shall be added from a measuring vessel at intervals of 5 minutes and the quantity required to maintain the original water level noted. Unless otherwise specified, the length of pipeline shall be accepted if the quantity of water added over a 30-minute period is less than 0.5 litres per linear meter per meter of nominal bore.

    3.     For man entry Sewers special equipment is available to test joints or short section pipes insitu.

Gravity pipelines exceeding 750 mm. nominal diameter shall either have short lengths or each joint individually tested by means of an approved joint testing apparatus with a hydraulic testing which shall consist of a ring to seal internally the joint surround and enclose the joint area which shall then be tested by pumping water into the sealed space until the pressure reaches 0.1N/mm² .  A period of two hours shall be allowed for absorption. Thereafter the test pressure shall be maintained for 30 minutes, and make up water shall be pumped in at 5-minute intervals if necessary to maintain the test pressure.  The average quantity of make up water shall not exceed 0.002 liters per hour per millimetre of nominal bore of the sewer at any joint tested.

Sewer pipelines exceeding 750mm. diameter shall be visually inspected internally, before and after backfilling and any defects shall be remedied.

Where required the sewer shall be tested for obstruction by the insertion and pulling through of twin-coupled rubber plungers of the same diameter as the sewer.

All sewers, which in the opinion of the Engineer are submerged under the water  table, shall be tested for infiltration after backfilling.  All inlets to the system shall be effectively closed and the residual flow shall be deemed to be infiltration.

Civil Engineering - Testing of Gravity Pipelines

    1.  Gravity pipelines laid in open cut shall be tested after they are jointed and before any concreting or backfilling is commenced, other than such as may be necessary for structural stability whilst under test.

     2.   The pipelines shall be tested by means of air and by a visual examination, in lengths determined by the course of construction. Generally pipelines will be tested as complete lines or between manholes.

Visual examinations shall be done by mirror and light, in which case, deviation of plus or minus 20mm, i.e. for 160mm and 200mm pipelines a 75% and 80% clear gauging is required.

3.    A further air test shall be carried out after the backfilling is complete. Failure of this test may require a water test.

4.    Engineer shall arrange for CCTV survey of lengths of sewers.

This survey may be done following completion of certain sewer lines and/or will be done prior to the end of the defects correction period. Should however the inspection of the selected pipelines fail, the Contractor shall first rectify the faults and subsequently arrange for hire of equipment and personnel to repeat the tests and for the survey of any other lengths.

The process shall be repeated at the Contractors expense until satisfied that the whole of the works is constructed in accordance with the drawings and the Specifications.

5.    A pipeline shall have failed the CCTV inspection if any of the following are identified:

·        Any evidence of cradling of the pipes;

·      Any evidence that the pipeline is out of tolerance (e.g. depressions with ponded water, bends in the sidewall);

·        Any dislocated or damaged joints;

·        Any evidence of infiltration;

·        Any projecting connections.

Civil Engineering - Appropriate British Standards for Cement, Steel Reinforcement, Rainwater Pipes, Soil, Waste and Ventilating Pipes and Gutters

Cement
 

Cement type	BS
Ordinary Portland Rapid hardening Portland Portland - blastfurnace Low-heat Portland Sulphate-resisting Portland Low-heat Portland - blastfurnace Supersuiphated Masonry Pozzolanic cement with pfa as pozzolana Portland pfa	12 12 146: Part 2 1370 4027 4246: Part 2 4248 5224 6610 6588

 
 Steel Reinforcement 

Type	BS
Carbon Steel Bars Cold Reduced Steel Wire Steel Fabric	4449 4482 4483

Rainwater Pipes and Gutters

Material	BS
Cast Iron Aluminium uPVC	460, Type A 2997 4576:Part I

Soil, Waste and Ventilating Pipes

Material	BS
Cast Iron uPVC (Soil and Ventilating) Polypropylene (Waste) Plastics (Waste)	416, Type A 4514 5254 5255