Method Statement Title: Installation & Testing of Above Ground Drainage Piping
1.0 Scope :
- This method statement details the method for installation and hydrostatic testing of above ground drainage piping.
Note : For the installation & testing of Above ground drainage piping concealed in columns & shear walls, refer to method statement Ref: ETA/BDR/TW1/CD/0095.
2.0 Material :
- UPVC pipes to EN 1329 (Formerly BS 4514) and BS EN 1455 (Formerly BS 5255).
- Types of joints a) For 1 ¼” dia to 2” dia – Solvent weld jointing.
b) For 3” dia & above – Push fit jointing.
3.0 Applicable locations :
Towers, Podium & Villas.
4.0 Method :
- Storage.
4.1.1 When off-loading, pipes shall be lowered to the ground either manually or with mechanical aid like crane depending on the quantity of the pipe and should not be dropped to the ground. Refer Manufacturer’s instruction for transport, handling and storage (Annexure – 1).
- Pipes shall be given adequate support at all times and shall be stacked on a flat surface free from any sharp objects.
- Timber support of at least 3” wide shall be placed beneath the pipes with spacing not greater than 1.8 mtrs. Closer supports will be required for sizes below 160mm.
- Pipes shall not be stored under direct sunlight to avoid ultra violet degradation.
- Socketed pipes shall be stacked in layers with sockets placed at alternate ends of the stack and with the sockets protruding to avoid unstable stacks and the possibility of importing a permanent set to the pipes.
- Longer pipes of thicker class shall be kept at the bottom.
4.2 Preparation :
- Drawings for installation are approved & co-ordinated with other services.
- Location / Area ready for installation of piping.
4.3 Installation :
- Pipes are brought to the work place manually from store to the hoist area and are shifted to the respective floors through the hoist.
- Mark-up the pipe routing on the soffit of slab as per the setting-out.
- Install anchor fasteners for support as per the approved support distances for different pipe sizes.
- All supporting of pipes will be done as per specified spacing both horizontally and vertically. Supporting of both horizontal & vertical pipes shall be done in accordance with the approved details, drawings and specifications.
- Pipes will be run to proper slope requirements as per the approved shop drawing.
- Pipes & fittings will be joined by solvent weld jointing for pipe sizes 1 ¼” to 2”. Following steps, will be taken during the jointing.
- Pipes will be cut to square before assembly of fittings & all burrs to be rubbed-off.
- Cleaning fluid to be applied on both surfaces to be joined. The cleaning fluid will remove all dirt & soften the surface for the chemical solvent weld.
- Solvent cement will be applied evenly over mating surfaces of the both pipe & socket, and insert pipe into the socket with slight twisting action to full socket depth.
- Surplus cement of the joint will be removed by cloth.
- After jointing, it will be allowed for 3 minutes to get dried.
- Clean-outs are provided to enable the maintenance in case of choking of drainage system at each change of direction.
4.3.7 Expansion couplings are provided at necessary locations as per manufacturer’s recommendations & shop drawing. Refer Anneuxre-I for Manufacturer’s recommendation to allow for the expansion.
- All open-ended pipes to be plugged during installation phase.
- Pipes & fittings will be joined by push fit method for the pipe sizes 3” to 6”. Following steps taken during installation.
- Ensure that the mating areas of spigot and socket are thoroughly clean and square.
- Set the rubber ring into groove.
- Assess the full socket depth by simple measurement and mark spigot accordingly.
- Apply lubricant to the spigot side and to the side of the joint on rubber.
- Accurate axial alignment of the spigot and prior to jointing is important, hand feed spigot into rubber joint until resistance from the inner sealing section is felt.
- Complete the joint by applying leverage to the following socket and using a timber block to prevent damage.
Important Notice :
If pipes are cut on site, make sure that the new spigot are cut square with a fine toothed saw and are chamfered to half pipe thickness with a coarse file before jointing.
- All pipes and fittings delivered to site for the work should be stored in an approved manner to avoid deterioration due to accident damage and atmospheric condition.
- Before final erection, all pipes should be free of dust, scale rust or other form of corrosion.
- All pipes will be laid to a uniform slope as indicated on the drawing.
- Before laying, all pipes and fittings should be checked for defects and jointing spaces cleaned properly.
- Socketed pipes to be laid with sockets uphill. Adjust pipes to line and level.
5.0 Testing
- Air Testing
- The length of drain or sewet to be tested including any connections should be effectively plugged.
- Air is pumped into the test length by suitable means (eg., hand pump) until a pressure of 100mm of water is indicated on a manometer connected to the system.
- A suitable time should be allowed for stabilization of air temperature.
- The air pressure should not fall below 75mm of water during a period of five minutes, without further pumping.
- In case of unsatisfactory air test, hydrostatic test is to be followed so that the leakage can be assessed and located.
5.2 Hydrostatic Testing :
- Water test is conducted to ensure and prove the tightness of the joints and ensure there are no leaks in the piping system.
- The water pressure test can be applied to the system in its entirety or in sections. All openings in the piping will be tightly closed by special cast iron pipe plugs or by another suitable means and the system filled with water to the point of overflow from the highest point. The plugs can be temporally opened to make sure that all air has been vented and that water has reached all parts of the system.
- No section of the pipe shall be tested to less than 1.5 meter head of water. In testing successive sections of piping, at least the upper 3 meters of the next proceeding section will be tested. Except the upper most 3 meters, the whole system shall have been subjected to a height of less than 1.5 meter head of water.
- The water shall be kept in the system or in the portion under test for at least 30 minutes before inspection starts. While the system is under pressure, a careful inspection shall be made on all pipes and joints. If any leaks in joints or evidence of defective pipe or fittings are revealed, the defective pipe/fitting should be immediately replaced with new joints and materials.
- After the correction is made the test pressure will be maintained for minimum 30 minutes.
- Testing will be inspected by Main Contractor / Consultant to their satisfaction and document for correct test will be maintained by getting approval in test certificate by Consultant and Main Contractor.
- Acoustic Insulation
6.1 Refer MS/P-017.
7.0 Safety :
6.1 During the installation & testing, all safety precautions shall be followed as per the established Project safety plan.
7.0 Records :
- Work Inspection Request (WIR) duly signed by the Consultant.
- Test certificates duly signed by the Consultant.
8.0 Attachments :
8.1 Test Format