The purpose of generating this Method Statement is to define the procedure step by step to implement the correct practices for Installation of Domestic water pipe-work (Hot & Cold) through the guidelines contained herein so as to ensure that the job execution complies with the requirements and serves the intended function to satisfactory level.
This Method Statement refers to various work procedures contained within project Control Documents, which explains and covers the installation of Domestic water pipework (Hot & Cold)
Engineer In-charge (Plumbing) / Site Engineer (Plumbing)
4. TOOLS / EQUIPMENTS
Portable Hand tools
Portable Drill machines
Solvent for uPVC joints
Polypropylene welding machine (Thermo fusion machine)
Hot & Cold water piping material shall be as per approved material submittals.
Hot water piping : PEX : All concealed Hot water piping
PPR : All piping up to 4 inches
Copper : All piping above 4 inches
Cold water piping : PEX : All concealed cold water piping
PPR : All piping up to 4 inches
UPVC(ClassE-3505) : All piping above 4 inches.
6. HANDLING & STORAGE
On receipt of Domestic water pipes & fittings , the materials shall be handled & stored in line with the following procedure:
6.1. Pipes will be stacked on a flat surface free from sharp projections, stones or other objects likely to caused point loading or pipe deformation.
6.2. The storage area shall be kept in proper level, so that the stacked pipes may be uniformly supported throughout their length.
6.3. Pipes will not be dropped on hard surfaces and will not be dragged along the ground. Wherever possible the loading and unloading of pipes will be carried out manually by hand.
6.4. If mechanical lifting equipment is used, ensure no metallic slings, hooks or chains will be used in direct contact with the pipe. Rope or nylon belt sling will be preferred which will not damage or cut the pipe surface.
6.5. Pipe of different sizes or wall thickness will be stored separately or where this is not possible, those with larger diameters and / or thicker walls will be placed at the bottom of the stack.
6.6. The stacks will be protected from direct sunlight by covering with tarpaulin sheets.
6.7. All the pipe fittings will stored in the boxes as supplied by the fittings manufacturer.
7. INSTALLATION PROCEDURES
7.1 HOT WATER SUPPLY PIPES (PPR)
Area of installation : All piping up to 4 inches
7.1.1 All installation shall be made as per approved shop drawings.
7.1.2 Approved polypropylene pipes, fittings and valves shall be used for installation.
7.1.3 Prior to installation the pipes and fittings shall be cleaned properly.
7.1.4 All supports shall be installed ensuring correct alignment of pipes and location as per manufacturer recommendation.
7.1.5 UPVC(class-E to BS 3505). sleeve shall be provided wherever water supply pipes pass through walls, slabs,etc..Annular space between pipe and sleeve shall be filled with rock wool and both end shall be sealed with waterproof or fireproof sealant as specified.
7.1.6 In order to make proper thermo fusion joint by using thermo fusion welding machine, the pipe shall be cut perpendicular to the axis and the cut edge shall be smoothed off from any sharp edges.
7.1.7 The depth of the socket shall be marked on the pipe as per manufacturer’s recommendation. This mark shall be used as a reference to indicate how deeply the part of the pipe penetrate into the fitting.
7.1.8 Once the pipe and the fitting / piece are ready and the heating element reaches the set temperature, the fitting process shall be started.
7.1.9 The pipe should be quickly & firmly pushed into the bush up to the mark, while the fitting is slipped over the spindle.
7.1.10 During this operation the pipe and the fitting must be held firmly without any turning movement.
7.1.11 The surfaces of the pieces to be joined should be heated as per the recommendation of supplier & Manufacturer’s Thermo fusion Welding Parameters for Polypropylene Pipes.
7.1.12 After the specified time the pieces are withdrawn from the heating element & immediately joined without any turning movement.
7.1.13 The pipe shall be inserted up to the mark, i.e. right up to the bottom of the socket & the two pieces must be held together for the heating time given above.
7.1.14 The welded joint should not be stressed until the cooling time has elapsed.
7.1.15 After each welding operation , the spindle and bushing of the heating element shall be thoroughly cleaned.
7.1.16 Provision for expansion & contraction such as expansion bellows, loops will be provided as required.
7.1.17 Necessary anchor / sliding supports shall be provided as required at site to accommodate the expansion / contration of the system.
7.1.18 Drain valves shall be installed in the lowest point & Air Vents shall be installed in the highest point as per requirement at site during installation.
7.1.19 Water Hammer Arresters shall be installed as per approved shop drawings. (Stress analysis on water supply system and to consider all necessary measures to ensure that the system is water hammer free).
7.1.20 After getting approval for installation of pipe works, the system will be tested @ 8 bar for 6 hours. Incase any leak or drop in test pressure, the respective pipe work shall be rectified and retested.
7.2 HOT WATER SUPPLY PIPES (Copper)
Area of installation : All piping above 4 inches
7.2.1 The routing of the pipes shall be as per approved shop drawings / specifications.
7.2.2 The pipes shall be supported using approved clamps in locations shown on the shop drawings.
7.2.3 The joining of the pipes shall be using oxy-acetylene brazing & also using flanged fittings
7.2.4 The two ends to be brazed shall be cut using pipe cutter & the burrs shall be removed.
7.2.5 Upon completion of brazing, the joints shall be allowed to cool for few minutes
7.2.6 All straight length of pipes shall be insulated during installation.
7.2.7 Upon completion of installation of pipework / section of pipework, the same shall be subjected to a hydro test @ 8 bar for 6 Hrs.
7.2.8 Upon successful pressure test, the joints of the pipes shall be insulated using approved insulating materials.
7.3 HOT WATER SUPPLY PIPES (PEX)
Area of installation : All concealed piping
7.3.1 All installation shall be made as per approved shop drawings / specification.
7.3.2 Approved Cross Linked Poly Ethylene pipes, fittings and valves shall be used for concealed installations.
7.3.3 Prior to installation the pipes and fittings shall be cleaned properly.
7.3.4 The routing of the pipes shall be marked on the wall /slab & the necessary chasing shall be done by the main contractor.
7.3.5 The pipes shall be installed in these grooves in the wall / slab using supports.
7.3.6 Upon installation of the piping, the same shall be pressure tested @ 8 bar for 6 Hrs.
7.3.7 Upon successful completion of pressure test, the pipes shall be concealed by main contractor.
7.4 COLD WATER SUPPLY PIPES UPVC(Class E 3505).
Area of installation : All piping
7.4.1 All installation will be made as per approved drawings / specifications.
7.4.2 Approved UPVC pipes Class -E-3505, fittings and valves shall be used for installation of cold Water Supply.
7.4.3 All UPVC Class-E-3505, pipes shall be connected using solvent cement joints.
7.4.4 Prior to installation the pipes and fittings shall be cleaned properly using the cleaner recommended by the manufacturer M/s Hepworth.
7.4.6 The mating surfaces shall be cleaned again using the cleaning agent.
7.4.7 After the mating surfaces are thoroughly clean & dry, the bonding solvent cement(supplied by M/s Hepworth) shall be applied on both the mating surfaces.
7.4.8 After the application of the solvent the joint shall be made without any turning movement.
7.4.9 The joint shall be left undisturbed for 5 minutes prior to proceeding with further works on the piping.
7.4.10 All supports shall be installed ensuring correct alignment of pipes and location as per manufacturer recommendation.
7.4.11 UPVC(Class-E to BS 3505)sleeve shall be provided wherever water supply pipes pass through walls,slabs,etc. Annular space between pipe and sleeve shall be filled with rock wool and both end shall be sealed with waterproof or fireproof sealant as specified.
7.4.12 After getting approval for installation of pipe works, the system will be hydro tested. hydro tested @ 8 bar for 6 hours. In case any leak or drop in test pressure has been revealed, the respective pipe work shall be rectified and retested.
COLD WATER SUPPLY PIPES (PEX)
Area of installation : All concealed piping
7.5.1 Same procedure as points 7.3.1 to 7.3.7.
8. INSPECTION & TESTING
Inspection I : Installation of Hot Water Pipework
Inspection II : Pressure Testing of Hot Water Pipework
Inspection III : Installation of Cold Water Pipework
Inspection IV : Pressures Testing of Cold Water Pipework
9.01 Risk Assessment
9.02 Inspection and test plan
9.03 Quality control procedure