METHOD STATEMENT FOR PRESSURE TEST ( MONG DUONG 1)

Mong Duong1 Thermal Power Plant ProjectPROJECT : TWO(2) x 500 MW MONG DUONG 1 THERMAL POWER PLANTMong Duong1 Thermal Power Plant ProjectPROJECT : TWO(2) x 500 MW MONG DUONG 1 THERMAL POWER PLANT

A Dec 17, 2012 Issue for Information Y.J.Heo Y.T.Lee J Son

J Son Dec 17, 2012 ADB/MD1-TPIP/EPC150911 MD1-0-T-054-05-00195 A

FOR INFORMATION

Mong Duong1 Thermal Power Plant Project

METHOD STATEMENT

FOR PRESSURE TEST

A Dec 17, 2012 ISSUE FOR INFORMATION Y.J.Heo Y.T.Lee J Son

6 Inspection & Testing

7 Safety and First AID

8 Organization For Pressure Test

9 Attachment

 This method statement shall be read in conjunction with the related specifications, Code and

standards to ensure compliance with the project requirements

3 Reference Documents

3.1 Reference Codes and Standards

 MD1-0-T-030-05-00072 :ITP for aboveground piping

 MD1-0-T-030-05-00073 :ITP for underground piping

 The test section of the line has been installed in accordance with approved drawings.

 The welded joints of the test section shall be completed the visual inspection, applicable NDT, PWHT and properly documented

 Location marking of test blind, gauge, isolation valves or temporary spools on the DWG

 Approval of test packages shall be secured before final pressure testing of the line

 Partial test of the line can be done in accordance with the approved drawing

 Vendor OEM and vendor recommendation shall be included in relevant test package

 Approved test packages shall be submitted for “walk down” inspections Furthermore, if the lines are cleared and ready for test, a written “Inspection Request” indicating the proposed date and time shall be submitted to owner one day before the execution of pressure test

 The results of test shall be recorded on “Pressure Test Report” attached to the test package

 Ensure all the above ground piping spools, valves & other components installed as specified in the given approved piping drawings

 Works shall be carried out in accordance with this method statement and project specifications

 All Equipments / Instruments shall have a valid calibration certificate and shall be recalibrated before due date, Method statement shall be followed for calibration of Equipments / Instruments

 All piping systems to be hydrostatically tested shall be vented at the high points to remove air from the system before applying pressure to the system

 All through valves shall be in fully opened position during pressure test

 All joints welded of flanged shall be uncovered for inspection during the test

 Pressure gauges used in testing shall be installed as close as possible to the lowest & highest

point in the piping system to be tested.

 All pipe supports and anchors, including any temporary supports required due to weight of test medium shall be installed prior to pressure testing All spring-loaded pipe supports shall be locked during hydrostatic testing If any temporary supports need to be installed for pressure testing, sketch or drawing of temporary supports approved by Engineering shall be attached in the test package with isometric drawings

 An adequate Pressure Relief valve shall be provided on the test manifold to protect the piping from overpressure The pop test of pressure relief valve with 110% set pressure of test pressure prior to hydro test shall be performed to ensure proper operation

 Prior to commencing pressure test, it shall be confirmed that any commitments of on-destructive examinations, line check, etc have been completed and equipment such as vessels, pumps and instruments are isolated or removed from the piping by use of blinds or other suitable means

 Any manifold employed for pressure testing of piping shall be separately calculated and

pressure tested to the specified system test pressure before use All manifold shall meet all requirements as per Design code of the Permanent Piping and approved by engineering An isolation valve & Drain valve shall be provided between the manifold and the system being tested

 Piping Walk-down Check List included in the Test Package shall be available for walk-down prior to testing Consolidated punch items will be categorized / classified as A, B and C items in accordance with the following definitions

 ‘A’ Items to be completed/corrected prior to the hydrostatic test

Examples:

Not welded on pressure part such as butt joint, branch joint, shoe or anchor support Not yet perform the NDE, if necessary

Not yet treat PWHT, if necessary

To be installed manual valves and proper supports which are born up the loading of water

Non-pressure part welding such as structure steel to support, support to support Certificate of pressure gauge, water analysis

Hydrotest PRV Calibration Certificate

 ‘B’ Items that can be completed after hydrostatic test

Examples:

Reinstatement point In-line instrument item such as Relief valve, control valve, inline mixer, transmittal, etc Interface with structural steel, cable tray, etc

 ‘C’ Items that can be completed/corrected during or after Initial Start-up

Examples:

Touch up paint Insulation work

 Any punch items shall be recorded on the punch list in the pressure test package and

designated to the action discipline which is responsible to clear the punch item

 The classification of Punch list items should be agreed between HDEC and EVN as necessary The classification can depend on the future work-plans for the individual items of equipment and system affected

 All weld joints which are to be taken NDE shall be confirmed by Contractor’s IPCS and attached the Preheating/PWHT/NDE Summary in the hydro test package

 Flow chart of pipe installation and pressure test

Welding

Post Weld Heat Treatment

(If required)

Painting Delivery to the site Site erection

Pressure Test

Re-welding

Preheating (If required)

Fabricated spools at shop Delivery to the laydown area

Inspection of spools as per Isometric drawings

Visual inspection for fit-up

5.2 Preparation

 Pressure Water Pump

 Pressure Gauge

 Manifold with relief valves and temporary piping or hoses

 Manifold test certificate shall be provided in test package

 Verification of safety valve on line before test by HDEC Field Engineer

 Blind flanges with bolts/nuts and temporary gaskets

 Test Packages

5.3 Hydro Testing for GRP Pipeline

Before hydro testing, pipeline should meet the following conditions:

 Construction is completed according to the design requirements

 System restraints such as thrust restraints, other supports and anchors are in place and properly cured with the no deflects

 Pipe deflection within requirement limits

 It is suggested that the length of pipeline for hydro testing not more than 1 km however

considering the system restraints and efficiency, the length can be longer

 Pressure gauge and thermometer for hydro testing should be calibrated and qualified for use

 Prior to testing, ensure no other foreign materials are found in the pipe For larger diameter pipe, workers can enter the pipe through inspection manhole to carry out the inspection and cleaning Wash the pipe with water if necessary

 Use suitable water source close to the testing site and ensure appropriate discharge locaton, take note of the safety

 Testing plan is approved

During Hydro testing:

 Fill GRP pipeline with sea water or fresh water, open valves and vents to have the air removed from the line during filling

 Pressurize the line slowly Ensure the gauge location will be able to read the highest pipeline pressure or make adjustment accordingly Lower point will have higher pressure Ensure the pressure at the lower point does not exceed the bearing capability of pipe, meter and valve

 When the pressure reaches the testing pressure (1.5 times operating pressure), stop the pump Hold for 10minutes without any pressure drop Then release the pressure to operating pressure and hold for 20-30 minutes Inspect the pipeline, if no leakages is noticed, the test is considered successful

During pressurizing process, if there are any leakages noticed, stop further pressurizing, mark the leakage locations and carry out inspection Ensure pipeline strength reliability before

continue pressurizing slowly to expose all the problems till reaching the testing pressure Inspect whether the leakages increase and any other new leakages found, mark all the leakage points, record leakage patterns in order to analyze the causes and prepare for the repair proposal

5.4 Hydrostatic Test for above ground piping

 The HDEC Field Engineer will record all the activities such as elevating pressure, holding time, decreasing time in order

 Hydrostatic testing of the line shall be using the potable or demi water (Hydrostatic testing of the stainless steel pipe line shall be using the demi water)

 The testing pressure shall be 1.5 times for hydrostatic on the design pressure of the system

 Vent lines on the highest location of the test sections, are in open position during water filling to allow elimination of air within the line

 The line is completely full if the water flows out from the vent lines Let the water flow for a few minutes to ensure that the air is completely eliminated within the line

 At the end of 1 hour holding time, verify the values of the pressure and transcribe these final values in the minutes of testing

 In any case pipe insulation shall be carried out before hydrostatic test provided that all welded joints shall be exposed for inspection during the test

5.5 Pneumatic Test

 The HDEC Field Engineer will record all activities in chart such as elevating pressure, holding time, decreasing, etc

 Instrument and service air piping etc shall be subjected to air pressure test

 The testing pressure shall be 1.2 times the design pressure of the system

 The test medium shall be dry air or Nitrogen gas

 Flange connections and all threaded joints shall be checked for leaks using a soap solution test

 Compile a minute of testing and reporting the values of pressure from the beginning of the testing

 At the end of 1 hour holding time, verify the values of the pressure and record the final values in the minutes of testing

5.6 Visual Test

 Piping which is normally open to the atmosphere such as drains, vents, sewers piping, the last shutoff valve etc shall not be subjected to field pressure testing Therefore, these lines are subjected to visual inspection for acceptance

5.7 Testing Medium

 In general, test medium shall be potable water, which is free from all silt and non corrosive Stainless steel shall be tested using de-mineralized water, Test reports collected from HDEC shall be attached with Hydro test record Both test mediums and certificates which are

applicable to testing shall be provided by Company in accordance with Project specification The test medium temperature shall be 5℃ to avoid the possibility of brittle fracture

5.8 Test Pressure

 The hydrostatic test pressure which is calculated and approved by engineering shall be

indicated in the line list/test package

 The pressure difference between high and low positions of the test section shall be 1 bar per 10m

 Conversion of Hydrostatic head to Pressure

P=r X g X (h1-h2)

Where: P: Water head difference (N/m2 = Pascal)/ 105 = Bar

ρ: Water density (kg/m3) g: Gravitational acceleration (9.8m/s2) h: Static head (m)

* The Pressure of test section on the highest location will be decreased by 1 bar for every 10 m from the lowest location of the test section

5.9 Test Pressure Gauges

 All gauges used for field testing shall have scale range of 1.5 to 4 times of the test pressure with 100mm dial

 All pressure gauge dials shall be in kgf/cm2

 All pressure gauges shall be duly calibrated every six month as per Manufacturer's

recommendation using a standard dead weight gauge tester

5.10 Preparation of Test package

 Test package shall include the following documents: Test report (Certificate), Line list with test pressure, Certificates of Test gauge calibration and Water analysis, Mark-up P&ID and isometric drawings as built, Welding inspection / Pre-heating / PWHT-NDT summary report, Piping Walk-down check list, Punch list, etc

 The IPCS will be used to determine the completion status of welds per isometrics in a test pack

 Test package has to be approved by HDEC prior to submitting to EVN to review

5.11 Filling

 Ensure suitable pumps are available for filling of the system and its pressurization The

specification of pumps to be used shall be provided before testing

 Liquid testing medium shall be filled from the lowest point in the system to minimize the risk of trapped air pockets

 After water filling and before pressurizing the line, supports shall be inspected for abnormal movement, if any is found it shall be corrected before pressurizing

 Pressure shall be applied only after the system / line is ready and approved by company

 Pressure shall be applied by means of a pressurizing pump, which shall be disconnected from the system and isolated by blind as soon as the test pressure is reached and the system is stabilized

 Piping systems shall not be pressurized at a rate exceeding 7 bars per minute

 After all punches are cleared and walk down is completed totally, the line shall be filled with water, and shall be pressurized After the pressure is built up to the required test pressure and

preliminary inspection by HDEC is completed, Company Inspectors shall be notified for final inspection of the test section

 Pressure relief valves shall be set up adequately to avoid increase in pressure

 PRV discharge shall be to safe location

 Care shall be taken to avoid increase in pressure due to temperature variation during the test by monitoring the test pressure and releasing the same so as to maintain required pressure

 Test pressure and duration shall be maintained for at least 10 minutes after the pressure is raised

to the required test pressure and become stable to permit / allow for inspection of all joints for leakage or signs of failure

 Any leakage found at the time of testing shall be marked, empty the line as the sequence of draining fully or partially if necessary and make the repair Then, the hydrostatic test shall be repeated

5.13 Draining

 After successful completion of the test, the system shall be depressurized gradually and then drain completely

 After the hydro-test has been completed, pressure shall be released in a manner and at a rate

so as not to endanger personnel or damage equipments

 De-pressurize the system through vent or flange “called vent.” Open manifold valves before commencement of water draining to avoid negative pressure near the pump till gauge zero, then open the vent valve

 When draining the systems after testing, vent valves at high point shall be opened before opening drain valves to obviate vacuum arising in the system and possible resultant damage to vessel, etc

 All vent and drains shall be opened before the system is to be drained and shall remain open till all draining is complete so as to prevent formation of vacuum in the system

 Testing/draining of the system is completed, all temporary blanks and test blinds shall be removed All inline instruments, expansion joints, strainers, filter elements, and other

components removed or restrained for the test shall be reinstated when pre-commissioning activities are completed

 Flanged connections, which are adjacent to temporary spool pieces, shall be reinstated with new gaskets And all temporary gaskets which are used in flange connection for hydrotest shall

be replaced with new ones New bolts and nuts shall be provided as per bolting and torquing procedure by qualified fitters if test bolting is not of correct grade for the service