Method Of Statement For Installation Of Domestic Hot & Cold Water Supply Copper Piping

SCOPE OF WORK

This Method Statement describes the procedure for the installation of copper pipes for domestic water services (hot & cold) inside buildings for the XYZ project.

PIPE STORAGE & HANDLING:

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  • All pipes shall be stored in proper storage conditions, which are free from dust, sunlight and extreme temperatures.
  • For long-term storage, the pipes shall be stacked in racks with adequate spacing and supports & with larger diameter pipes placed at the bottom.
  • While handling the pipes, care shall be taken to avoid their coming into contact with sharp corners such as loose nail heads, sharp metal surfaces etc., as pipes may be damaged or coatings (if any) be removed by being rubbed against these during transit.
  • All open ends of the pipes shall be plugged with end caps or wrapped with polyethylene sheets to prevent entry of dust & other foreign particles.

INSTALLATION PRE REQUIREMENTS

  • Piping materials, fittings, supports & hangers etc used for Installations shall be in conformance to Specifications and/or Material Approvals. Water supply pipes (hot & cold) above the ground within the buildings shall be copper tube conforming to EN1057, (formerly BS 2871) part 1, Table X.
  • Copper pipes embedded in walls shall be copper tube with green colour Insulation conforming to EN1057, (formerly BS 2871) part 1, Table Y.
  • Copper pipe fittings shall conform to EN1254 (formerly BS 864 part 2)
  • Both Hot water supply & return pipes are insulated with Preformed sections of glass fibres bonded with a heat resistant resin together with Glass reinforced Aluminium foil. Density is 64kg/m3 for insulation (25mm) of pipes inside buildings.
  • Ensure the pipes are free from dust and damages prior to installing.
  • Location of pipe sleeves and possible routing obstructions are checked prior to the installation of pipes.
  • Ensure marking of pipe routing and supports on the ceiling are clearly visible.

METHOD STATEMENT FOR INSTALLATION

  • All pipe routing shall be as shown on approved Shop drawings.All Pipe supports and clamps shall be installed as per manufacturer recommendations.
  • Installation of all supports shall be in accordance with approved supporting detail drawings.
  • Where steel plates forms part of the ceiling, the suspension rods are connected to stud welded rods (which are already stud welded to the steel plates) using threaded connectors.
  • Supports shall be arranged as near as possible to joints & changes in direction. Vertical rising pipes particularly in shafts shall be adequately supported at the base to withstand the total weight of the riser.
  • Seismic supports for the pipes are provided, wherever required.
  • All pipe work shall be erected to present a neat and orderly appearance, arranged to or at right angles to the structural members of the building, giving maximum head room and shall not obstruct windows or door ways.
  • All tube surfaces & Inside of fitting socket is neatly cleaned before installation.
  • Ensure the ends of the copper tube are cut square and remove any burrs from the inside or outside.
  • Jointing of copper pipes & fittings of sizes 15mm to 42mm is made by Soldering, while pipes of diameter larger than 54mm is joined by Brazing.

Copper Pipe Soldering

  • The inside of the fitting socket and the outside of the tube is cleaned with a cleaning pad, fine sand paper or steel wool.
  • Using a brush, an adequate but not excessive amount of flux is applied to the outside of the tube and the inside of the fitting socket. The tube is inserted to the fitting until it reaches the tube stop. Excess flux is wiped off.
  • The assembly joint is heated evenly on all sides using fuel torch. Care must be taken to ensure that the tube and fittings are properly supported with a reasonable, uniform capillary space around the entire circumference of the joint.
  • When the correct temperature is reached, solder (lead free) is applied to the mouth of the fitting and the melted solder will flow freely and be drawn into the joint by capillary action. Briefly reapply the fuel torch and wipe off excess solder.
  • The joint is then allowed to cool without disturbance and cleaned generally.

Copper Pipe Brazing

  •  All Copper Pipes & fittings above 52mm diameter shall be jointed using the Brazing technique.
  • The pipe and fitting is assembled as normal.  Method of application of flux is similar to that of soldering. Filler rod with silver content is used for brazing.
  • The joint shall be heated quickly and evenly on all sides to approximately 700/750o C red heat in poor daylight. An oxy-propane, oxy-acetylene or other suitable torch is used with a large soft, neutral or slightly reducing flame. This is kept moving through out the making of the joint to avoid excessive local heating.
  • The filler rod is then applied to the space between the tube and the fitting, allowing the brazing alloy to melt and flow into the annular gap.  The gap between the socket and tube is filled with the filler alloy leaving a small, uniform bead of brazing alloy around the mouth of the socket.
  • The joint is then allowed to cool without disturbance and cleaned generally.
  • For copper pipes (Table Y) embedded in walls the joints & elbows shall be covered with wrapping tape.
  • All open ends of pipes which are left as the work progresses, shall be temporarily closed with polythene sheet, plastic caps or metal flanges, as required.
  • Adequate clearance shall be provided between insulated pipe work running together and between walls and floors.

Domestic Water Piping Accessories Installation

  • All Domestic water-piping accessories viz., Valves, Air vents, water hammer arrestors and Pressure gauges shall be installed as per manufacturer recommendations.
  • Location of all above-mentioned accessories shall be as indicated on approved Shop drawings and shall be in accessible positions.
  • Flexible joints with bronze couplers shall be provided for the copper pipes at the expansion joints, as shown on the approved shop drawings.

 Copper Pipe Insulation Procedure

 All Hot water supply & return pipes are insulated with Aluminium foil faced preformed sectional fiberglass insulation. The Insulation thickness shall be 25mm (density 64kg/m3)

DOMESTIC WATER PIPING INSPECTION & TESTING

All piping system shall be tested to a pressure equivalent 1.5 times the maximum working pressure. The indicated pressure shall be maintained for the required holding period without further application of pressure and without visible leakage or a drop in the indicated pressure.

All pipe Installations shall be inspected in accordance to the Inspection test plan & checklists.

Tests shall be performed on isolated portions of piping in order to facilitate general progress of construction.

Any modification made in the Piping system after a successful test shall call for re-testing of the affected portion of the piping system.

Results of Inspection & testing shall be recorded on the Inspection checklist forms.

HEALTH & SAFETY REQUIREMENTS

Adequate safe access to the Installation area is provided. Risk assessment will be prepared and submitted for approval. Workmen shall wear all appropriate safety personnel protective equipment such as helmet, coverall clothing, safety shoes, goggles & gloves, wherever required. If work is in high level, only approved scaffolding and safety belts should be used.

REFERENCED DOCUMENTS

  • Shop Drawings
  • Material Approvals
  • Risk Assessment
  • Inspection checklist
  • ITP
  • Checklists for inspection & testing
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