This method of statement specifies the sequences and methodology for the installation of MEP system for Water Treatment Plant. All workers associated with the installation of MEP for Water treatment plant will be responsible in accordance with the contract requirements and project specifications.
All workers shall wear PPE as per risk assessment and project HSE plan. Proper access, sign board and barriers shall be provided as required. Sufficient illumination and ventilation shall be available at working areas all the time.
Quality Control Requirements
Check all the materials delivered to site are inspected properly as per approved MAR (Material Approval request) and proper storage.
Work shall be carried out by the site personnel under strict supervision and guidance of the supervisors/foreman / engineers.
Work inspection Request (WIR) will be submitted for witness and hold points as detailed in the attached Inspection and Test Plan for MEP.
Pressure gauges for testing will be calibrated and certificates will be provided during testing.
Referenced documents:
a. Project HSE Plan
b. Project Quality Plan
c. Approved Shop Drawing
d. Approved Material submittal
e. Manufacturer recommended installation procedures.
Roles & Responsibilities
Site Engineer
SE is responsible to carry out the work as per the Project Specification, approved shop drawings, method statements, co-ordinates with the MEP contractor and ensures all works are provided, inspected & approved by the consultant. Also responsible to ensure the specialized sub-contractor has adequate equipment, tools, materials, manpower are in place before starting the works.
QA/QC Engineer is responsible to ensure work has been done as per the specification and drawings, inspections are done as per Quality Control Procedure and offer works for (consultant / client) inspection.
Supervisor/Foreman
Carrying out the 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 achieved and coordinate for the future planning with the Site engineer.
Incorporate all the QC and Safety requirements as requested by the concerned Engineer.
If facing any type of unforeseen incidents or requirements and reporting to the site engineer immediately
Necessary Equipment & Materials
- Activated Carbon Filter
- Pumps
- Dosing System
- Cartridge filter
- UV System
- UF System
- RO System
- Pipes
- Cable Tray
- Pipe and Cable Tray Supports
- Electrical Cable
- Tanks
- Valves
- Fittings
- Control Panel
Equipment’s
- Tool Box
- Measuring Tape
- Hacksaw
- Spirit Level
- Drill Machine / Grinder
- Pressure Gauges
- Hand Pump/Electric Pressure Pump
- Ammeter/Voltmeter
- Welding Machine
METHOD AND SEQUENCE OF CONSTRUCTION
Any material delivered to the site not confirming to the approved material submittal shall be returned to the supply and replaced with approved material.
No materials will be permitted to enter the work locations without being inspected on arrival to the site.
Work shall be carried out by the site personnel under strict supervision and guidance of the concerned engineers/ supervisors/ foreman.
QA/QC inspector/ engineer shall check all the installations as per the installation/Test check sheets.
WIR will be prepared, signed by the subcontractor and shall be submitted without delay to Contractor/Consultant for their inspection and approval as per approved ITP.
RE is responsible for all the installation activities for getting the work inspected and approved by Contractor/Consultant.
Installation procedure of uPVC Pipe Work for Water Treatment Plant
All the materials received at site will be inspected, upon receipt.
Any discrepancies, damages, etc. should be notified and report to the supplier for further action.
All construction/ inspection/ testing works shall be carried out in accordance with specifications.
Work shall be carried out by the site foreman staff under the guidance of site engineer and shall further be checked and approved by consultant.
If any damage for the material has been happened on the site, the site persons will be responsible for the damage.
Handling of Materials
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 unloading of pipes to be carried safely. When mechanical fitting equipment is to be used, no metallic slings, hooks or chains should be used in direct contact with the pipe. Ropes or web slings are preferred, as they will not damage the pipe wall.
Storage (for uPVC Pipes)
uPVC 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 pipe 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. If prolonged storage is needed (more than one month) or where the temperature exceeds 23°C then the stack should not exceed 4 layers or maximum 1m 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.
Cleaning of Pipes
Prepare water hose at site.
Connect the hose to clean water connection available at the site.
Flush water through the pipe in order to remove any debris, dust, and any other unwanted material which will result in pipe blockage.
Installation of Pipe Work (for uPVC Pipes)
Mark the routing of pipe work according to approved shop drawings.
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 form the mouth to the shoulder of the socket.
The insertion depth should be marked on the spigot using marker.
The jointing system for 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 glue should be applied in a lengthwise direction and not with a circular motion.
The glue should be applied simultaneously to the spigot and socket by two people.
Immediately following gluing 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 glue from around the mouth of the socket.
Leave the joint undisturbed for five minutes, and then handle with reasonable care.
Installation of Pipe Supports (for uPVC Pipes)
For the pipes above ground supports will be given of ring type pipe clamps with rubber packing and for pipes at more height will be given standard galvanized channel support with pipe clamps.
Pipe Pressure Testing Procedure
Check first the approve drawing submitted for the location and marking of the pipes.
Prepare the necessary materials for installation
Start layout of the pipe as per coordinated marking and levels.
After the layout make a support for all the pipes using thrust block, rubber clamp and steel bar.
Prepare the materials for the pressure testing such as plugs, pressure pump, pressure gauges and other equipment / tools required.
Clean the edge of the pipe and put plug on locations where valves are not required.
After putting plug, install the pressure pump with threaded nipples, connect to the valve for the purpose of bleeding to the part you can remove the air inside the pipelines then connect a G.I Tee to interlink between the calibrated pressure and the pipe to be tested.
Fill entire system with water through any water supply faucet by means of pail and put it on the pressure hand pump.
Check for any leak in the connection /layout. If so, modify/ rectify first before applying the pressure.
The working pressure of the pipe is 4 bars; however, for testing Pressure the lines until it reaches the test pressure of 6 bars which is 1.5 times of the working load.
Check the points / connections again for leakage. If there is no leak close the valve and remove the pressure hand pump.
Maintain pressure in the pipe line for at least 4 hours.
Prepare the necessary documents such as drawings, pressure test certificate indicating the start and end, together with the pressure rated and losses and get signature from Consultant.
After checking the bar rating passed, remove the pressure of the pipes up to 1 bar by experience person.
After that remove the end plugs and valves.
Remove the water and flush the lines.
Close all the end points using masking tapes.
Pump Room Equipment Installation
Mark out the location of the plinths for the pumps and filters as per approved shop drawings and cast the plinths in place up to the required thickness.
Fix the interconnected pipe work between the pumps, filters and the suction and delivery lines as per the approved drawings.
Route and level shall be as per the approved drawing and clearance to be maintained as required.
After installation of equipment’s & piping’s in pump room are completed and raise stage by stage WIR for getting approval from the consultant as per approved ITP.
Installation of cable tray and trunking shall be carried out as per specification and approved shop drawing.
Cable tray and cable trunking and related accessories shall be by an approved manufacturer and the material should be inspected prior to the MEP installation work.
Route and level shall be as per the approved drawing and clearance to be maintained as required.
Support spacing to be executed as per the approved drawing and site condition.
Spacing between others services shall be coordinated on the site.
Remove burrs and sharp edges from cable trays/trunking.
Fasten cable tray/ cable trunking to building structure.
Any cutting or drilling support channel, threaded rod, tray/trunking edges shall be cleaned up and painted with zinc paint.
Install cable tray/trunking with enough space to permit access for installing cables. Install the cable tray/trunking with proper alignment with other services.
After installation clean and cover it properly to avoid any mechanical damages from other services.
Install cables only when cable tray/trunking installation has been completed and raise stage by stage WIR for getting approval from the consultant as per approved ITP.
Install the control panel.
Terminate the cables at the control panel as well as the equipment and pumps.
Testing and commissioning of Water Treatment Plant System
Check for fresh water supply line in the pump room for filling and make up.
Check for incoming power supply for the control panel.
Verify the connection and termination of control panel.
The water has to be filled to the required level in the raw water tank.
After that close and open all the necessary valves to start the system.
First set to open the butterfly valve on the suction line and discharge line.
Run the filtration pump on HAND position to start the operation.
Check the direction of rotation of pump is proper.
The chemical system is filled with appropriate reagents and working properly.
Check for any leakage in the piping, if there is turn OFF the pump and close all the valves to rectify the fault.
If there is no leakage or fault in the system, continue the operation.
Attachments
Inspection Test Plan
Risk assessment
Manufacturers Manual
Checklist for Mechanical Installation