District Cooling Plant For King Abdullah Financial District
Contract No. 504054-C-2001
Job No.Method Statement
CHILLED WATER SYSTEM PIPING INSTALLATION
1. GENERAL INFORMATION
Scope of Work
Tools & Equipments
Procedure of Work
3. QA / QC
SNC LAVALIN has awarded to KETTANEH Construction Saudi Arabia Ltd. the subcontract for the construction of KING ABDULLAH FINANCIAL DISTRICT, RIYADH, K.S.A.
The purpose of this method statement is to provide proper guidelines and references to execute the scope of work regarding the supply, installation, and hydrostatic testing of the complete chilled water piping system and all other components in accordance with applicable ASHRAE requirements and project specifications.
Scope of Work
This method statement outlined the procedure for Chilled Water Piping System Installation in the KAFD project in accordance with project specifications and approved drawings.
This method statement applies to all Chilled Water Piping System installed at the
KAFD, covering the areas as shown on the IFC drawing.
References ( Code and Standards )
Project Specification – Section 15550 (HVAC Piping & Piping Specialties)
Manufacturer/Vendor: Installation Manual
Pipes: Carbon Steel Schedule 40, Seamless Type
Pipe Fittings: Butt-weld Fittings for 2 ½” & above, Malleable Iron Threaded Fittings for 2” & below
Chilled Water Pipe Hangers and Supports
Tools and Equipments
Automatic Pipe Threading Machine
Manual Pipe Threading Machine
Various Hand Tools
Procedure of Work
Pipe and fittings shall be fabricated and installed in accordance with the applicable Project Specifications and IFC Drawings.
Pipe Preparation And Fabrication
Piping materials shall be placed off the ground on temporary stands or wooden blocks during storage with ends capped, to protect against thread damage.
Materials shall be checked and verified that it is in accordance with the project requirements and material approval.
Items shall be thoroughly cleaned before installation.
Supporting materials and brackets if required shall be shop fabricated wherever feasible.
Pipe shall be cut square & accurately to measurements
Pipe shall be reamed but not exceeding its internal diameter and shall be de-burred before any threading or welding work.
Burrs inside of female fitting shall be removed and cleaned
Threads shall be carefully cut by using threading machines and shall be clean-cut and tapered to match ASME B16.3, for malleable iron threaded fittings class 150
Threads on the pipe shall not exceed three (3) threads exposed after fixing the required fittings.
Welding shall be carefully prepared according to approved WPS & Method Statemenr
2.3.3 Pipe Assembly and Jointing
Pre-fabricated pipe spools can be assembled or joined together as may be required before delivery to site.
Prior jointing, threaded portion of the pipes shall be cleaned & all screwed joints shall be provided with Teflon Tape on male threads & Permatex Gasket Sealant
Partially assembled pipe spools shall be capped or covered on both ends to prevent dirt or foreign substance entering into the pipe.
2.3.4 Pipe Installation
Piping system shall be installed carefully as per approved IFC drawings with correct elevations and measurements and install in place without springing or forcing.
Pipe and fittings surface shall be cleaned against cuts & markings, imparted by pipe wrench & other abrasive elements during fit-up & final tightening.
Whenever pipe is passing through the walls, partition and ceiling, it shall be provided with penetration sleeve.
Sleeves shall extend completely through the construction and shall be cut flush with the finished surface.
For firewall penetrations, the space between the pipe and sleeve shall be packed with an approved fire stop material that will preserve the integrity of the fire rating.
Where piping passes though exterior walls, the opening shall be sealed with a silicone or butyl rubber caulking compound or approved caulking compound to seal against water, air and sand.
All piping shall be supported using hangers, supports and fasteners, according to submitted schedule. Hanger spacing shall be in accordance with approved schedule & shop drawings. If intermediate steel required for proper spacing of hangers, it shall be provided and shown on the Chilled Water Shop Drawings. Hangers shall be attached only to the structure that will support the load without deformation.
All chilled water piping shall not exceed the limits for support and interval as shown in approved schedule.
Suspended piping shall be supported with approved clevis or trapeze hangers and rods.
Hangers shall be adequate to maintain alignment and to prevent sagging of the pipe
Hangers shall not be installed in joints and shall not be supported from equipment, other pipe, cable tray, ductwork or other non-structural items.
Vertical piping shall be supported with riser clamps secured to the piping and resting on the building structure.
Pipe supports shall be arranged to prevent excessive deflection and to avoid excessive bending stress.
Pipe shall be supported from the building structural steel, inserts or anchors in concrete slabs.
Any additional structural steel when required to support the chilled water piping shall be provided.
2.3.6 Test and Inspection
Test and inspection of the chilled water piping system shall be in accordance with project specification. Pipes shall be hydro-statically tested in part or in whole in accordance with project specification
Internal pipe cleaning and flushing of the entire chilled water system piping shall be done prior to hydrostatic test in accordance with the manufacturer’s recommendations
After the entire chilled water piping system has been cleaned and satisfactory leak free (hydrostatically) tested, chilled water piping system shall be painted before the chilled water pipe insulation are installed.
All acceptance testing shall be done in the presence of SNC QA/QC and authority having jurisdiction. Prior commencing of any testing, a Field Inspection Request (FIR) shall be requested from SNC QA/QC dept. at least a minimum of three (3) days but not less than 24 hours prior to actual test.
Upon satisfactory completion of test and inspection, all records & test report shall be prepared & submitted in triplicate by KCS’s QA/QC to SNC
Chilled Water Piping System shall be visually inspected to ensure that it has been installed in accordance with the applicable project specification, codes, standards and the system IFC drawings.
Hydrotest package is to be submitted to SNC for review and approval prior to test.
The following inspection shall be included as a minimum requirement:
Visual inspection of pipe alignment, sagging, deflection, correct support interval and elevation.
Verify rigidity of supports to maintain required location as shown on the approved IFC drawing.
Visual inspection of workmanship and quality of work, such as: joints, tightness and pipe finished surfaces.
Inspection of Hydro testing set-up, such as testing equipment, gauges, and safety valves specified pressure and duration required for the whole or section of pipes to be tested.
Verify calibration certificates of Pressure Relief Valves & Pressure Gauges.
Visual Inspection for any work procedure irregularities.
Pressure Leak Test Procedure
Testing shall commence thru following sequence:
After the installation, distribution piping to be pressure tested shall be cleaned prior to testing. The entire piping system shall be purged to remove all possible stack impurities inside the pipe.
Ensure all necessary valves for isolation, vents, and drain system are properly fitted and connected.
As a safety precaution a Pressure Relief Valve with a set-point setting of about 5% higher than required Pressure test shall be provided (Trained personnel shall do all calibration for pressure gauge & relief valve from independent calibration specialty agency).
Connect the flexible hydraulic hose to the lowest end of spool subject for testing; open all valves except drain valves. Manually pump the pressure to the piping system and close the vent valve when flow changes to a solid shaft of water.
Once purging is completed, pressure test of the distribution piping shall be performed
Plugged all discharge head point and other exit point where required.
The chilled water piping system shall be hydrostatically tested in part or in whole at a minimum pressure of (To be specified by SNC) for a period of 2 hours
Pump the water pressure to the lowest end of spool subject for testing; open the supply valves (test pressure shall be slowly raised to 100% hydrostatic test pressure) except vent valves. Care should be taken to ensure that over pressure does not occur.
Once the pressure in the pipe has stabilized, hold the pressure and conduct initial inspection & record the pressure gauge reading.
Hold the pressure inside the line for 2-hours. During this period, check all joints along the line for any physical distortion and leakage.
After 2-hour period and no visual leakage found, record again the pressure gauge reading. If any leakage found during a 2-hour period, it shall be repaired immediately and the system re-tested for the full 2-hour period.
If no leakage has been observed, then the Hydrostatic pressure test is satisfactory completed and QA/QC representative (KCS) confirms accuracy of test results as witnessed by SNC representative.
After completion of testing, system shall be depressurized by opening the vent valve and drain the water content of the system in a controlled manner by gradually opening the drain valve (located at inspector’s test point) connected with water hose through water tanker for proper disposal.
Upon completion of successful hydro testing; all external surface of chilled water piping system shall be cleaned and primed coated prior to chilled water pipe insulation installation.
The method of surface cleaning or preparation shall be in accordance with Project Specifications. The procedures, condition and precaution to be followed in preparing the surface for painting shall be in accordance with Project Specifications
The removal of all loose mill scale, rust, loosely adhering material and loose paint from a surface shall be performed by hand brushing, hand sanding, hand scraping, hand chipping or by other hand impact tools or by a combination of these methods.
Prior to hand cleaning, all grease, oil or salts shall be removed by solvent cleaning.
Care shall be exercised in the use of tools to prevent excessive roughening of the surface and the formation of ridges and burrs.
The painting system shall be done in accordance with the approved Painting System for Chilled Water Piping System
No painting shall be done on all pipelines unless hydrostatic test has been satisfactory completed, inspected and approval has been issued by SNC
3.0 QA / QC
QA / QC Inspector shall make sure that all activities related to the Chilled Water Piping System Works are carried out in accordance with the project specification and approved drawings. He shall arrange Inspection & Testing required with SNC-LAVALIN in accordance with the QA/QC Plan. He shall maintain and keep records for all QC Documents.
Site Engineer, Supervisor and Foreman shall assist the QA/QC Inspector whatever he required in relation to the quality of works, procedures or documents.
Person working with welding works shall wear the Personal Protective Equipments at all times on the job site.
Warning sign boards and barricades shall be provided where necessary to isolate the working area and prevent un-authorized personnel.
All equipments shall be tagged and checked before using.
Aside from PPE, additional safety welding requirements shall be provided where necessary such as fire extinguishers, fire blankets, welding apron, welding gloves and welding mask.
Scaffolding shall be tagged and approved by safety personnel before using.
Housekeeping shall be done before and after working to maintain cleanliness in the area.
Safety Inspector / Officer in conjunction with the site supervisor or foreman shall physically check that all safety requirements has been provided and implemented.
30 December 2012