1.0 PURPOSE
This method statement is applicable for Installation & testing of all types drainage piping system in all areas for the project.
2.0 SCOPE
Supply , installation & testing of drainage piping system for all applications in line with project requirements.
3.0 REFRENCE
- Latest Approved shop drawings for the required and applicable areas for Drainage.
- Specification:
- ISO 9001:2008.
- Project Quality Plan
- Material Approval Request references:
4.0 DEFINITIONS.
- PQP: Project Quality Plan
- PSP: Project Safety Plan
- HSE: Health, Safety and Environment
- MS : Method Statement
- ITP: Inspection Test Plan
- QA/QC: Quality Assurance / Quality Control Engineer.
- WIR: Inspection Request
- MIR: Material Request
- PP-R pipe : Polypropylene random copolymer (PP-R), PN-20 to DIN 8077 and 8078 for sizes up to 4″ diameter for above grade.
- PEX Pipe : polyethylene cold and hot water pipe installed inside the Toilets DIN16892/93.
- PE 100 pipes: Polyethylene SDR 11 Domestic cold water pipes for below grade installation.
- PRV: Pressure Reducing Valve.
5.0 RESPONSIBILITIES:
Responsibilities for ensuring that the steps in this procedure shall be carried out are specified at relevant steps in the procedure:
- Project Manager
- Construction manager
- QA/QC Engineer
- Site Engineer
- HSE officer
5.1 Project Manager
The work progress shall be carried out as per planned program and all the equipment’s required to execute the works shall be available and in good condition as per project planned.
Specific attention is paid to all safety measures and quality control in coordination with Safety Engineer and QA/QC Engineer and in line with PSP and PQP.
5.2 Construction Manager
Construction Manager is responsible to supervise and control the work on site.
5.3 Site Engineer
The method of statement to the system shall be implemented according to the Consultant project specifications and approved shop drawings.
Provision of all necessary information and distribution of responsibilities to his Construction team.
The work progress shall be monitored in accordance with the planned work program and he will provide reports to his superiors.
The constant coordination with the Safety Engineer to ensure that the works are carried out in safe working atmosphere.
The constant coordination with the QA/QC Engineer for any works to be carried out and initiate for the Inspection for the finished works.
He will ensure the implementation of any request that might be raised by the Consultant.
Efficient daily progress shall be obtained for all the equipment and manpower.
He will engage in the work and check the same against the daily report received from the Foremen.
The passage of all the revised information to the Foremen and ensure that it’s being carried out properly.
5.4 QA/QC Engineer (MEP):
The monitoring of executions of works at site and should be as per the approved shop drawings and project specifications.
Ensure WIRs and MIRs are being raised for activities in timely manner and inspected by the Consultant.
He will follow and carried out all the relevant tests as per project specifications.
Obtain the required clearance prior to Consultant’s inspections.
Should acquire any necessary civil works clearances and coordination.
5.5 Site Foreman.
The carrying-out of work and the proper distribution of all the available resources in coordination with the Site Engineer on a daily basis.
Daily reports of the works are achieved and coordinated for the future planning with the Site Engineer.
Incorporate all the QA/QC and Safety requirements as requested by the concerned Engineer.
Meeting with any type of unforeseen incident or requirement and reporting the same to the Site Engineer immediately.
5.6 Safety Officer.
The implementation of all safety measures in accordance with the HSE plan and that the whole work force is aware of its proper implementation.
The implementation of safety measures is adequate to maintain a safe working environment on the work activity.
Inspection of all the site activities and training personnel in accident prevention and its proper reporting to the Construction Manager and the Project Manager.
The site is maintained in a clean and tidy manner.
Ensure only trained persons shall operate the power tools.
Ensure all concerned personals shall use PPE and all other items as required.
Ensure adequate lighting is provided in the working area at night time.
Ensure high risk elevated areas are provided are barricade, tape, safety nets and provided with ladders.
Ensure service area/inspection area openings are provided with barricade, tape, and safety nets.
Ensure safe access to site work at all times.
5.7 Store Keeper (SK)
Responsible for overall Store operations in making sure to store the material delivery to the site and keep it in suitable area that will keep the material in safe from rusty and damage.
6.0 EQUIPMENTS
Following tools shall be arranged before starting the job.
- Tool Box.
- Measuring Tape.
- Hack Saw Balde .
- Spirit Level.
- Excavator.
- Thedoiled.
- Manual pressure Pump.
- Calibrated pressure gauge .
- Isolation valves ( Pluge or gate type )
- Flexible Hose with Clamps.
- Solvent Cement.
- Electric welding machine.
7.0 PROCEDURE
Work Sequence/Procedure (Installation & Leak Test Procedure of drainage pipes).
7.1 General Requirements
All the materials received at site shall be as per the approved technical material submittals
& to be inspected upon receipt & approved by the engineer prior proceed with installation through MIR & Any discrepancies, damages etc, should be reported to the supplier for further action & to be removed from site immediately.
All construction/inspection/testing works shall be carried out in accordance with specifications & to be done by qualified Mechanical engineers and shall further to be checked and approved by MEP Subcontractor construction Manager along with QA/QC Engineer.
Contractor has to clarify the procedure for material delivery to the site through consultant Engineer at site.
7.2 Handling
7.2.1 Handling (for Drainage pipes)
During transportation pipes must be handled with care. Do not drop or drag pipes especially on hard surfaces. This is particularly important where the pipe ends have been pre-prepared in the form of spigots (e.g. chamfered ends) and integral sockets.
Where ever possible the loading and Off loading of pipes to be carried out by hand.When mechanical lifting equipment is to be used, no metallic slings, hooks or chains should used in direct contact with the pipe. Ropes or web slings are preferred, as they will not damage the pipes.
7.3 Storage
7.3.1 Storage on site (for Drainage pipes)
Drainage Pipes should be stored on a flat dry level surface free from sharp projections, stones or other objects likely to cause point loading or pipe deformation. Timber supports spaced 1.5m apart along the pipe can be used to support the pipes. The width of the stack should not exceed 3m.
Pipes of different sizes should be stacked separately or where this is not possible, hose with larger diameters and/or thicker walls should be placed at the bottom of the stack. The height of the stack should never exceed 7 layers or maximum 2m high.
All pipes and fittings should be properly covered with tarpaulins to protect them from UV rays. The tarpaulins are to be fixed to the wooden supports, which allow a free passage of air around the pipes.
Fittings will be stored in sheltered conditions in the boxes as supplied to protect them from weathering and accidental damage.
7.3.2 Transport of the drainage pipes:
The vichele should have flat bed freefrom sharp projections of any kinds. Also the pipes must be supported strongly inside the vichel and should not overhand pipe lengh more than 1 meter.
The larger size and thicker pipes should be loaded first. And for more information you can check the below photo.
7.4 Sequence of installation for Drainage piping:
The drainage piping in this project divided into 3 types:
- UPVC ( Solvent Cement/ Push Fit Joint) above ground.
- UPVC class E ( Push Fit Joint ) for External underground.( Between Manhole ).
- HDPE pipe ( Electro fusion Welding ) for chemical Waste ( Inside & Outside the building ).
7.4.1 Above Ground Piping (UPVC):
- After getting the all civil clearances (including Raft Slabs , levels, blinding, water proofing & steel fixing), prepare the pipe length & all accessories as per the approved shop drawing for the laying where applicable .
- Proceed with pipe Installation with the appropriate Slope and Route as per the approved Shop Drawing using suspended supporting system as per the project specification & leakage test to be applied to insure no leakage from joints & pipes.
- Pipes joint shall not place in the passage of pipes through the concrete wall.
- Check all the joints and pipe slope before closed the false ceiling or shafts.
solvent cement weld Joint:
- Measure length of pipe required, making due allowance for any pipe fittings to be used. Cut the pipe to the measured length. Ensure that the ends are cut square and clean all burs. A chamfer to the depth of half wall thickness to be applied to each spigot.
- The spigot and socket to be jointed should be carefully examined for any damage which could impair the jointing procedure.
- The spigot insertion depth should be measured as the depth from the mouth to the shoulder of the socket.
- The insertion depth should be marked on the spigot using marker.
- The jointing system for drainage piping system is “Solvent weld”.
- The mating areas of the spigot and the socket should be thoroughly cleaned using the pipe cleaner and a clean rag.
- Using a brush apply an even layer solvent cement to the spigot and socket mating surfaces.
- The cement should be applied in a lengthwise direction and not with a circular motion.
- The cement should be applied simultaneously to the spigot and socket by two people.
- Immediately following cement application ensure that the pipe is suitably anchored, and push the spigot home in the socket without turning the pipe. The spigot should be inserted with a steady, continuous motion and held in place for 20 seconds. Remove the surplus cement from around the mouth of the socket.
- Leave the joint undisturbed for five minutes, and then handle with reasonable care.
- Plug all open ends of the pipe work.
7.4.2 Under Ground Piping (UPVC Class E):
- After getting the all civil clearances (including Raft Slabs , levels, blinding, water proofing & steel fixing), prepare the pipe length & all accessories as per the approved shop drawing for the laying through the soil Layer
- Compaction for the full width of the pipe shall be to at least 95% Modified Proctor Density, and then same shall be tested and approved by site Civil engineer.
- Mark routing and install the pipes as per approved shop drawings
- All horizontal drainage piping for sizes Ø100mm and above shall be installed with 1 % minimum slope and 2% for sizes less than Ø100mm unless otherwise indicated.
- Sanitary tees and short sweep ¼ bends may be used if change in direction of flow is from horizontal to vertical.
- Use long turn double Y-branch and 1/8 bend fittings if two fixtures are installed back to back or side by side with common drain pipe.
- Do not change the direction of flow more than 90 degrees.
- Use the proper size of standard increasers and reducers if pipes different sizes are connected.
- Reducing the size of drainage piping in direction of flow is prohibited.
- Check all the joints and pipe slope before proceed with 150 mm Thick concrete encasement.
Push –fit joint :
- The spigot and the socket to be joined must be carefully examined for any damages.
- The pipe should be chamfered to a depth of half the wall thickness and at an inclination of 15O to the pipe axis.
- Check chambered spigot should be clean and free from burrs as well the sealing ring should be correctly seated in the socket groove complete with the inserted ring.
- The spigot insertion depth should be measured and marked -as per below photos-.
- The mating areas of the spigot and socket should be thoroughly cleaned (All grease, dirt and other foreign matter should be removed from the sealing area -as per the below photo-.
- Push – fit joint shall be used for manhole (Inlet – outlet) as per approved details drawing.
- Concrete encasement shall be not used above push fit joint (special method should be used) detail for the same shall be approved by consultant.
- The spigot end and triple sealing portion of the sealing ring should be lubricated with the recommended lubricant as per below photo-. The spigot should be lubricant to the full insertion depth and around its complete circumference.
- Immediately after lubrication, the spigot should be brought into contact with the socket and the parent joint should be accurately aligned so those axes of pipes are precisely in line.
- The spigot should be hand fed into the socket until resistance from the inner sealing selection is felt.
- Correct alignment at this stage is essential to ensure that the rubber sealing ring is not pinched or torn.
7.4.4 Underground Piping for chemical waste (HDPE pipes):
Item below procedure shall be done by qualified approved personal.
Joints shall be carried out using electro weld sleeve couplings – as shown in below photo- :
7.4.5 Steps of the electrofusion weld process:
1. Preparations
Good preparation consist of making sure the electrofusion control box works properly. The inserted pipe or fitting must completely cover the resistance wires at the surface of the coupler for a good heat exchange. In order to utilize the fusion and cold zones in the pipe or fitting must be inserted to the correct depth.
2. Cutting the pipe square
The pipe ends must be cut square to ensure that the resistance wire in the coupler is completely covered by the pipe or fitting.
3. Mark surface for scraping
The insertion depth +10 mm must be marked to ensure the oxidized layer will be removed from the full welding zone.
4. Scrape pipe and mark insertion depth
The full outer surface of the pipe that will be covered by the coupler, must be scraped (approx. 0,2 mm deep) to remove any surface ‘oxidation’. The insertion depth should be marked again to safeguard full insertion
5. Clean electrofusion coupler
Before assembling the pipes into the coupler ensures that all surfaces are clean and dry.
6. Insert pipe/fitting until marked line
Ensure that the pipe is pushed into the coupler as straight as possible and up to the marked insertion depth. This will ensure that all the wires are covered with HDPE during the fusion cycle.
7. Prevent misalignment and movement
Misalignment will cause extra load on the fusion zone causing additional HDPE to melt resulting in the outpouring of HDPE or wire movement. The movement of the pipe can cause melted HDPE to flow out of the joint. This can result in wire movement and possibly a short circuit and thus a bad weld or fire hazard.
8. Welding electrofusion coupler and cooling down
Commence welding after connecting the control box to the coupler by pressing the start button. Control boxes adapt the welding time to the ambient temperature. The joint assembly should not be disturbed during the fusion cycle and for the specified cooling time afterwards.
7.5 Leak Testing
- The piping system to be tested shall be closed by plugging and blanking all openings in the system in an approved manner.
- Suitable plugs are inserted at the lower end of the drain or sewer and at the head of any connections.
- A suitable bend together with a vertical length of pipe is fitted at the head of the sewer or drain to provide the necessary test head. The system then filled with water.
- Close openings in piping system and fill with water to point of overflow but less than 10-foot head of water (30 KPa) from before 15 minutes before starts to completion of inspection. Water level must not drop and inspect joints for leak & this test is applicable for gravity system.
- The sewer or drain under test should be left filled with water for min 2hours.
- For pressurized piping system the recommended pressure test to be applied is 1.5 Times the operating pressure. (Using manual pressure pump & recommended rating Plugs).
- So ensure that all piping and joints are no leak.
- During the water test, precautions should be taken to prevent any movement of the drain or sewer.
- All ends shall be plugged after completion of test to protect from debris.
- After successful testing & Inspection of pipe work, covering of pipe work can proceed as per approved drawing details.
7.6 Backfilling
- Embedded in concrete
- Place the pipe in the containment with pipe support members
- Maintain the slope properly (2%) or as shown on drawing
2. Embedded in concrete
- The type of soil shall be approved by site Consultant team.
- Backfilling shall take place immediately after the entire test has been approved by the Engineers
- Provide warning tapes or detectable warning tapes based on the type of pipe material, contractor has to specify the right one before final back filling.
- The excavated material shall be used as backfilling material and backfilling material shall be uniformly wetted with water.
- All external chemical waste manholes shall be dry type with necessary clean out, therefore, all contractor requirements for the same shall be considered.
3. Crossing with Road
- All piping (HDPE, UPVC) cross with roads shall be encased in concrete with 150 mm cover on all sides as required by local authorities. Provide thrust blocks at every change in direction. Thrust blocks shall be of 20 MPa concrete poured against undisturbed soil.
- Provide warning tapes or detectable warning tapes based on the type of pipe material, contractor has to specify the right one before final back filling.
- Provide polyethylene bond breaker between concrete and pipe. Unless indicated otherwise, all piping with less than 1 meter cover shall be encased in concrete with 150mm cover on all sides, as described above.
