Lowering into the Trench

The VCP pipes should be lowered in the trench in a proper controlled manner either with ropes or protected straps which provides suitable lifting tackle. Special care should be taken in lowering the pipe into the trench to prevent damaging the joint material or disturbing trench condition. Never allow the pipe to be dragged along the ground or even at the trench bottom.

Cleaning and Lubrication

The surface of joints shall be cleaned well and free of dust. Then apply the CPC recommend lubrication on both joints surfaces socket and spigot.

Preparation of Trench

The trench bedding shall be prepared in proper way make sure it’s homogeneous, leveled and dry (no water table).

Line up the Pipes

The pipes shall be lined up and shave the pipes together with a steady pressure, (for small diameters this can be done by hand while for larger sizes, a bar may be used). Special care should be taken not to damage the lip of the socket by using a wooden block.

Special device may be used for big diameters.

Laying Pipes in Trench

The pipes should be laid in the trench in the upstream direction with the bell end laid upstream.

Alignment (Colored Marking)

The pipes should be laid in the trench in the upstream direction with the bell end laid upstream. The colored (White/Yellow) marks printed at the external side of the pipes should be kept always at the crown. (Aligned with other yellow marks of the pipes).

Tips for Installation of Pipe Line:

Pipes with “K (C)” Joint System

1.Clean the spigot and inside of socket sealings from dust.

2. Apply the lubricant inside socket and on spigot end sealings.

3. Keep a wood pieces on socket side and push with steel rod to insert spigot into the socket.

Pipes with “L(F)” Joint System

1. Clean the spigot and inside of socket sealings from dust.

2. Apply the lubricant inside socket and on spigot end sealings.

3. Keep a wood pieces on socket side and push with steel rod to insert spigot into the socket.

Note: Shall use crowbar for small diameters to push spigot inside the socket whereas crowbar or bucket of excavator for the larger diameters.

Pipe Line Testing at Site

The pipeline testing shall be carried out before any backfilling takes place and this shall be repeated after back filling as well to ensure that there are no damages to pipeline during back filling. These tests shall be conducted in accordance with the standard specifications of water and air testing of drains and sewers.

1.Water Testing of Pipe Line:

Preparation:
The special attention should be paid to the following points:
a. Shall inspect pipeline for possible visual damages during laying.
b. Shall thoroughly check the end stoppers for any visual defects.
c. Shall close all opening in the line with watertight sealsand ensuring that it’s adequately strutted against movement.
d. Shall fix the ventilating valve at the high point of the section.
e. Shall ensure that testing time should not exceed the test period as mentioned in the standard (15 minutes).

Procedure:

a.Shall fill the line with water, commencing at the low point till you reach a head of 5.0 meter (resting Pressure) measured at the low point of the line.
b.Shall ensure to expel all air from the line.
c.Shall inspect the line for any obvious visual leaks.
d.Shall maintain test pressure (5.0 m) for one hour by topping up with water.
e.Shall maintain test pressure for another 15 minutes (fest measuring time).
f.Shall measure the amount of water required to maintain this pressure for 15 minutes, by adding water to maintain the original level and record the quantity added. This quantity should not exceed 0.07/L/m² of wetted inner surface.
g.The pipeline is considered acceptable if no leakage is visible in the pipes, and if water loss in the water head does not exceed the allowable value (0.07/L/m² during test time (15 min.).

Air Pressure Test of Pipe Line:

The air test is an alternative to the water test. Whereas Pipes can be considered faulty only in the event of failure under the water test.

Procedure:

The test shall be applied as detailed below:
a.Shall inspect the pipeline for possible visual damage during laying.
b.Shall thoroughly check all plugs and equipment.
c.Ensure that the ends of the line are adequately strutted against movement with all plugs held firmly in position.Pump or blow in air until a pressure of slightly in excess of 4in. (100 mm) water gauge is indicated on the manometer connected to the system.
d.Pumping or blowing warms the air, so a minute or two should be allowed for this to cool down to match to the pipe temperature.
e.If necessary, then reduce the pressure to 4 inch (100 mm) of water gauge.
f.During a further period of 5 minutes the air pressure should not fall below 3 inch (75mm) of water gauge.

Initial Backfilling:

The Initial back filling starts to take place after the pipeline has been installed and tested. Initial back filling means back filling around the pipe carefully placed up to 12″ (30 cm) above the pipe so as not to disturb the final alignment and to protect the pipe from damage during the final back filling.

Final Backfilling:

The final backfilling extends from the initial backfilling to the top of the trench. This should be done in layers and big stones should be avoided, mechanical compactors not to be used unless a considerable depth of layers has been done.