METHOD STATEMENT FOR CHILLED WATER PIPING PART 2

 METHOD OF STATEMENT

FOR CHILLED WATER PIPING PART 2

METHOD STATEMENT  FOR CHILLED WATER PIPING PART 1 FOR PROJECT STANDARDS AND FOR PROJECT INSTALLATION DETAILS THA HOW TO DO INSTALLATION AND WORK 

 

I. INSTALLATION GENERAL REQUIREMENTS: 

I.1 Check and ensure all drawings used for installation are latest and approved for construction.

 

I.02 Mark the pipe routing and support locations on the ceiling as per approved drawings.

 

I.3 Check the co-ordination of piping layout with other services and reflected ceiling and decide pipe route with minimum bends / offsets.

I.4 Check and ensure sufficient clearance around pipe is available for insulation.

I.5 Check the access and clear space around valves, vent points, drain point’s locations for maintenance and servicing.

I.6 Fabricate the structural supports from G.I. angles/channel as per support schedule as required.

I.7 After consultant or site engineer representative inspection. Prior to installation clean all pipes and apply primer / red oxide.

        j. CHILLED WATER PIPES INSTALLATION PROCEDURES

METHOD STATEMENT  FOR CHILLED WATER PIPING PART 2

J.01 Drill the holes in the slab / shaft for fixing supports.

J.02 Fix the anchors and threaded rods with hangers / structural supports as applicable. Threaded rod length shall be sufficient to allow for leveling of piping.J.03 Cut the pipes accurately to measurements determined at site.

J.04 Prepare the pipe ends according to the type of joints i.e. Threaded joints, welded joints / grooved coupling joints.

J.05 The end preparation shall be done at site work shop.

J.06 Threading & grooving as applicable shall be done as per fittings / couplings manufacturer's recommendations.

J.07 End preparations for welded joints shall be done as per approved welding procedure.

J.08 After the end preparation clean the pipe ends and ensure no material and dust are left inside.

J.09 Qualified and approved welders by consultant shall be engaged in welding works.

J.10 Install the pipe spools at heights as per approved drawings in a neat and tidy manner.

J.11 Insert the approved hard insulating material of suitable thickness between the pipe and support.
J.12 Align and level the piping as per approved drawings.

METHOD STATEMENT  FOR CHILLED WATER PIPING PART 2

J.13 Install supports for horizontal and vertical as per schedule of supports.

J.14 Sleeves / openings of suitable sizes shall be provided at wall crossings.

J.15 Expansion couplers shall be installed at locations where piping crosses building expansion joints.

J.16 Install the piping connections with valves and accessories wherever equipment are installed.

J.17 For AHU’s and FCU’s, not installed, complete the by-pass connections as per approved drawing.

J.18 Fix the blind plugs / temporary valves on all drain, air vent, pressure gauge, thermometer, and test points tapings as applicable.

J.19 Check and ensure proper supporting is provided as per approved drawings.

J.20 Make temporary tapping provisions at multiple points for easy and quick filling and draining of pressure testing water.

J.21 Ensure all joints are properly tightened.

J.22 During  initial water filling, employ sufficient man power to monitor the entire length of the piping system for possible leakages.

METHOD STATEMENT  FOR CHILLED WATER PIPING PART 2

J.23 If leakages are observed, arrest the leakages immediately. If leakages are major, isolate the leaking portion with nearest isolating valve and / or stop the water filling.

J.24 Ensure no leakages throughout the entire piping system.

J.25 Observe leakage and pressurize the system using hydraulic test pump.

J.26 During pressurization observe the joints and entire piping system for leakages.

J.27 Pressure the system till pressure on the pressure gauge at lowest part of the system indicates the 1.5 times the maximum working pressure of the system under testing. (100 psig/690kpa)

J.28 During hot ambient conditions system pressure may raise due to increase in the ambient temperature. Ensure under no circumstances the system is pressurized above 1.5 times the maximum working pressure. (100 psig/690kpa)

J.29 observes the pressure gauge readings for 6 hours and ensure that there are no leakages.

J.30 the hydraulic pressure testing shall be witnessed by consultants.

J.31 Proceed with insulation only after satisfactory completion of hydro-static pressure testing.

METHOD STATEMENT  FOR CHILLED WATER PIPING PART 2

         K. INSULATION OF CHILLED WATER PIPES

K.01 For all pipe sizes, insulation pipe section of suitable thickness, as per approved drawings / submittals may be used.

K.02 Pipe surface should be cleaned and made free from dust and Grease. Insulation to be applied only when at normal temperature.

K.03 Adhesive of even coat is applied on the inner surface of the insulation section.

K.04 Pipe section is slipped over the pipe longitudinal joints of pipe section is sealed with an overlap of aluminum foil. Avoid longitudinal joints facing upwards.

K.05 adjoining sections of insulation is butted firmly together by application of adhesive on the sides.
K.06 Cut slices of insulation and slip it firmly between joints to ensure tight packing of joints.

K.07 Seal all joints with aluminum tape.

INSULATION OF VALVES AND FITTINGS

K.08 Insulate valves, strainers, flanges and other fittings with identical material thickness and finish like the piping insulation

K.09 Fill all edges with filler sliced from the same insulation material and ensure no air gaps.

K.10 For site shaping of sections cut, scrape, or miter to fit contour of pipe fitting or valve.

K.11 For insulation of elbows cut one or more wedge shaped slices and fix firmly. Pack joints with slices of insulation.

K.12 When insulating flanges and flanged fittings the insulation cover to extend at least 50 mm onto the adjacent pipes to permit easy stripping of insulation to attend to valve for maintenance.

K.13 Insulate strainers to permit removal of mesh without disturbing the insulation of strainer

          L. PRE-INSULATED PIPING INSTALLATION PROCEDURE 

A.     All materials shall meet or exceed all applicable referenced standards, federal, state and local requirements, and conform to codes and ordinances of authorities having jurisdiction.

B.     Pre-insulated Piping:

1.      All straight sections of steel pipe shall be factory insulated. Field weld joints shall be provided with field insulation kits to be compatible with the pre-insulated pipe.

2.      The carrier pipe shall be concentrically located within the jacket.

3.      Carrier pipe shall be standard weight, carbon steel, seamless, ASTM A-53, Grade A, sch 40.Pipe; all piping shall be shipped from the factory to the job with ends capped.

4.      Provide polyurethane insulated underground carbon steel core piping system with HDPE outer shell.  The pre-insulated pipe shall be in unitized factory prefabricated sections.  Pipe shall be listed suitable for use with 38°F chilled water.

5.      Sock-o-lets for vents, drains, instrument taps and thermowells shall be located in each valve pit per plan and shall be welded on in the shop.  Insulation shall be held back from such fittings to allow field installation of nipples and instruments.

6.      Insulation.  The insulation shall be formed-in-place closed-cell polyurethane foam providing intimate contact with both the core pipe and casing pipe.  It shall be 90-95 percent closed cell structure per ASTM D2856, compressive strength 3.5 kg/sq cm.  40 psi; thermal conductivity of 0.14 BTU-in/hr. ft2 F (.0202 w/m-0K) at an initial temperature 75 0F (240 C) per ASTM C518 and 3.5 kg/sq cm. (40 psi) compressive strength per ASTM D1621.

 

7.      After hydrostatic testing of the carrier pipe, field joints shall be insulated, with kits provided by the pre-insulated pipe manufacturer.  Field joint insulation shall be applied in straight sections by pour foaming in-situ, using molds furnished by the system manufacturer. Field joint insulation surface shall be sealed with a heat shrinkable sleeve. Insulation and jacket on all fittings shall be factory applied after pipe spool fabrication, extending continuously onto adjoining straight section(s) of pipe.

8.      Underground piping shall be bedded in compacted sand. Cover with densely compacted backfill.  Piping trench for a distance of 8'-0" out from building shall not have pea gravel or sand but shall be select backfill densely compacted as specified for building floor slab backfill.

9.      Prepare shop drawings to scale indicating the entire site plan with all underground piping thereon.  Elevations of all piping shall be indicated.  Details of piping and bedding shall be drawn indicating size materials and arrangement. All shop drawings shall be submitted to the pipe manufacturer for their review and shall bear their stamp of approval prior to A/E review.  Excavation for and laying of pipe shall not be started until these shop drawings are approved.

10.  Prior to fabrication, the Contractor shall review drawings of all disciplines, visit the site and make on-site measurements to ascertain that no interferences will be encountered upon installation.  If there are any significant deviations from the Contract Drawings, produce "Interference Drawings."  Before fabricating the piping and installing related equipment, the Contractor shall send a letter to the Owner stating that no interferences exist in the proposed installation.  By submitting this letter, the Contractor certifies that he has performed the above requirements and no interferences will result during installation. There will be no additional compensation for minor deviations.

11.  Piping has a design pressure of 150 psig and shall be tested at a pressure of 225 psi.  Test only one line at a time.  Isolate piping from building and existing system during tests. Do not insulate field weld joints until after hydro test.

A.     Factory technical assistance shall be provided by an authorized representative of the manufacturer.  The representative shall be thoroughly qualified in knowledge and experience in the proper installation methods of this type of piping system