Method Statement for aux steam piping installation (rev d)

This method gives Preparation and Erection method with feasibility and optimize. In order to ensure standards, technical specifications, quality, safety and schedule for BOP Piping works ( Aux. Steam System)

D 20/07/2017 Y.S.Kwon S.Y.Kwak C.G Kim FOR APPROVAL

C 10/10/2016 Y.S.Kwon S.Y.Kwak S.J.Park FOR APPROVAL

B 16/09/2016 Y.S.Kwon S.Y.Kwak S.J.Park FOR APPROVAL

A 11/08/2016 Y.S.Kwon S.Y.Kwak S.J.Park FOR APPROVAL

Rev Date Prepared Checked Approved Details of Revision

Owner

VIETNAM ELECTRICITY

Owner’s Engineer

POWER ENGINEERING CONSULTING JS COMPANY 3

Contractor

Sub-Supplier

LILAMA CORPORATION/LILAMA18 JSC

Project

VINH TAN 4 THERMAL POWER PLANT

Project Code

VT4

UAS Code

DD09 Date

Prepared 20/07/2017 Y.S.Kwon

METHOD STATEMENT FOR AUX.STEAM VT_2 AREA PIPING INSTALLATION

KKS Code

ZEN

040353

Approved 20/07/2017 C.G Kim

Rev

D

Dept Mechanical Dept.

1.0 PURPOSE 3

2.0 SCOPE 3

3.0 REFERENCE DOCUMENT 3

4.0 MACHINERY & EQUIPMENT 3

5.0 REPONSIBILITY 4

6.0 PROCEDURE 4

7.0 INSPECTION 15

8.0 ENVIROMENT HEALTH SAFETY SECURITY (EHSS) 15

8.1 Environment 15 8.2 Health 15 8.3 Safety 18 9.0 ATTACHMENTS 18

1 Job Safety Analysis (JSA)

2 Commitment

3 WPS & PQR

This method gives Preparation and Erection method with feasibility and optimize In order to ensure standards, technical specifications, quality, safety and schedule for BOP Piping works ( Aux Steam System)

This method is Preparation & Erection application plan - Vinh Tan 4 (2x600MW) Thermal Power Plan Project

- Issued for Construction Drawings

- Construction schedule

- Inspection & Testing Plan (ITP) for BLR and BOP Piping Installation

- WPS & PQR

- Approved contract Quality Plan

- Project EHSS Plan

- All piping works shall be fabricated in accordance with ASME 31.1 and B31.1 modified, API 582 and supplemented by the requirements in this specification

- ASME SEC IX: Welding and Brazing Qualification

Machine and facilities served for construction must be completed safety check procedure before starting work at the project

Only authorized drivers and operators are allowed to operate equipments & machines

All lifting equipment as well as its accessories shall be inspected periodically

- Air compressor for cleaning

- Welding machines

- Chain Blocks, Grinding machine

- High pressure pump for pressure test

- Hydraulic Crane, trailer and Boom Truck, Etc

- It is overall responsible for Site Manager and Piping Manager to organize resource prior to perform construction as Owner’s requisition in comply with Safety, Quality and Schedule requirements

- It is responsible for Construction Manager and Site Engineer to conduct the construction activities according to the relevant project specification complied with Safety, Quality and Schedule requirements

- The QC Manager shall ensure the quality of conducted work according to project specification complied with Quality requirements and quality dossier

- All piping materials shall be delivered with smooth condition without damage from storage area to field

- Internal and external surfaces to be thermally cut or welded shall be clean and free from paint, oil, rust, scale, or other materials that will be detrimental to either the weld or the base metal when heat is applied

- Piping materials shall be stored in a suitable manner to preclude mixing of different kind of materials and easily check the quantities

- Stainless steel piping materials shall be stored in separated place from carbon steel material store and direct connection between stainless steel and carbon steel is not allowed

- Piping and fitting shall be capped in an end to prevent ingress of water and any foreign matter

- Thread end shall be plugged or capped with waterproof type material

- Identification marked on piping material shall be maintained before fully erection, fitting up, welding

- Welding joints shall be identified by welding joint numbers, welder numbers and welding complete date located 50-70mm away from the weld seam All welding joints shall be written

by welding foremen or each welder

6.1.1 Material storage plan

All material (including Pipe spool, valve, etc for piping installation work) shall unload in VT2 near working area Storage area as below If needed, some of material shall lift to the TBN BLDG top floor

<Material unloading area besides VT2 TBN BLDG(Left) and the top floor(Right)>

6.2 SCAFFOLDING

- Scaffolding materials shall have to be checked prior to use on certified quality control CA, CQ

- Workers have to be trained with a practicing certification by qualified experts before working at the scaffold installation location

- Scaffolding shall have to be installed to the main structure ensuring safety, clean during work

- To ensure the safety(e.q to avoid falling objects or workers), improper connection of scaffolding through structures has to be restricted while plant operating

- Proper scaffolding work as below

<Scaffolding connected to the main structure>

<Scaffold has to be installed to prevent falling material damage plant equipment)

6.3 CRANE WORK PLAN

- The crane will be carried out by skilled operator who have been trained

- Position of the crane will be preset for working

- Kind of mobilization is mentioned in “Permit to Work”

<In standing position of the crane can reach to 50m(Left), and preset position of the crane(Right)>

6.4 CLEANING PRIOR TO WELDING

- Prior to the start of welding, edges and a minimum of 25mm of adjacent material shall be thoroughly cleaned of contaminants which could adversely affect weld quality (e.g oxide, oils, grease, NDE materials)

50m

- For copper/nickel and nickel based alloys, the joint area shall be scratch-brushed, using a stainless steel wire brush reserved for such materials, followed by thorough solvent cleaning Both operations shall be performed immediately prior to the start of welding

- The cutting process is carried out by skilled workers who would cut by hand mower with full labor protection, with cans of slag and protected against fire blankets and fire watch men could check

- Welding process is also done by welder, conducted before and after heating The surface has

to be cleaned before welding and welding rods have to be checked properly with basic materials by engineers The welder has to be equipped labor protection before working, in the welding process with technical monitoring safety monitoring fire watch person, around welds always fireproof blanket fire extinguisher etc

- After finishing preparation, alignment, fit-up and tack welding shall be carried out for the purpose of spool erection using the latest revision of isometric drawings

- Pipe Clamps, welded clips, tack welds or other appropriate means shall be used to properly align the joint for welding

- Tack welds shall have the same quality requirements as the final welds Tack welds which is incorporated into the final weld, shall be made with electrodes that meet the requirements of the final welds and cleaned thoroughly When tack welds are to become part of the finished weld, they shall be visually inspected and defective tack welds should be removed Tack weld shall be made by qualified welding procedures

qualified welder Tack welds made by an unqualified welder shall be

removed Tack welds that remain shall be made with an electrode and WPS that is the same as or equivalent to the electrode and WPS to be used for

the first pass The stopping and starting ends shall be prepared by grinding

or other means so that they can be satisfactorily incorporated into the final weld Tack welds that have cracked shall be removed

- In the process of working the temporary materials as fixtures, shelving, etc welding rod to correct the basic material of the pipe work installation this is common regulations and strict

QC inspection, if there are mistakes in the materials used temporary or improper welding rod designed for basic material of the tube, the tube will be removed

6.6 : WELDING

6.6.1 PREHEAT FOR WELDING

- Unless specifically agreed otherwise minimum preheat shall be in accordance with Project requirement

- Welding shall be performed in accordance with piping requirement and approved WPS

- Welding procedure specification ( WPS ) A WPS is a written qualified welding procedure prepared to provide direction for making production welds to Code requirements The WPS or other documents may be used to provide direction to the welder or welding operator to assure compliance with the Code requirements The completed WPS shall describe all of the essential, nonessential supplementary essential variables for each welding process used in the WPS These variables are defined in Article IV, Welding Data The WPS shall reference the supporting Procedure Qualification Record(s) (PQR) The organization may include any other information in the WPSthat may be helpful in making a Code weldment

- Procedure qualification record (PQR): The completed PQR shall each welding process used during the welding of the test coupon Nonessential

or other variables used during the welding of the test coupon may be recorded at the organization's option All variables, if recorded, shall be the actual variables (including ranges) used during the welding of the test coupon If variables are not monitored during welding, they shall not be

recorded It is not intended that the full range or the extreme of a given range of variables to be used in production be used during qualification unless required due to a specific essential or, when required, supplementary essential variable.The PQR shall be certified accurate by the organization The organization may not subcontract the certification function This certification is intended to be the organization's verification that the information in the PQR is a true record of the variables that were used during the welding of the test coupon and that the resulting tensile, bend, or macro (as required) test results are in compliance with Section IX One or more combinations of welding processes, filler metal, and other variables may be used when welding a test coupon The approximate thickness of weld metal deposited shall be recorded for each set of essential and,when required, supplementary essential variables Weld metal deposited using each set of variables shall be included in the tension, bend, notch toughnes

- Welding shall be inspected by subcontractor, piping field engineer prior request inspection by

QC engineer, DHI and Client/PMC

- Welding shall be used throughout for joining pipe, fittings and other components unless otherwise specified on the approved design drawing Screwed joints, socket connections and flanged joints shall only be used where shown on approved design drawings

- Weld seams on pipes and valves shall be carried out with adequate care so that no spatter deposits are formed in the pipe and no loose beads occur which might endanger valves or machinery After completion of the weld joints on the pipes, the welder must put in indelible crayon his identification number using indelible crayon on which the welding was completed

- When temporary attachment such as strong back use for welding work, welding shall be used same as applied WPS

- Welding Consumable Control

- Receiving inspection of welding material shall be handled in the same manner as described in Quality Procedure

- Welding material shall be stored indoor under supervision of the material controller He shall record and issue status of welding materials

- Electrodes, filler wires and fluxes shall be kept clean, dry and properly stored according to manufactures recommendations

- Welding electrodes, filler wires, or fluxes that are damaged, damp, greasy or oxidized shall not be used

6.1.2 WELDING PROCESS

- welding process is performed by qualified welders,

- Welding machine, oven welding rods, welding rods are checked closely before posing

on welding

(fireproof blankets, trays welding slag, welding rod oven)

- welding at position 1 will have fire wardens fire extinguishers, fireproof blankets, trays welding slag, welding rod oven

(fire extinguishers in location welding)

(welds made in time is 2 hours)

3000

pipe

fireproof blankets joint welding

Size fire blankets

- All NDE works shall be performed in accordance with applicable code/ standard, project specification and approved NDE procedure

- When Pre/Post weld treatment is required by relevant code/standard and project specification

It shall be performed in accordance with approved Heat treatment procedure

- Preheating and post heating, and inter pass temperatures are given in the applicable WPS

be done as required by WPS and

project specifications

6.9 HYDROTEST & RE-STATEMENT SPOOL

• The QC 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.

• The Hydrostatic test shall be conducted at a pressure not less than one and half (1.5) times design pressure but not less than 3.5kg/cm2, for a period of 30 min and these tests will be carried out in the presence of Owner

• 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

Pressure g

Hold period

Pressurize Inspect Depres Inspection for leakage Depressurize Time (hr)

6.10 PIPE ERECTION AT VINH TAN 2 TPP

- All pipe erection shall be followed above mention and project pipe requirement

- For Aux Steam pipe from VT2 Erection, the end joint for connection to exist operating system shall be welded with approved by Client All Permit to work (PTW) shall be approved before starting pipe works

- ISOLATE working area shall be performed strictly according to approved document and VT2 requirement

- Latest Pipe spool shall be prepared before erection and welding to TP (Terminal Point)

- Sequence of work as below:

- Installation of Aux Steam piping work(From VT2 Aux Header to the wall side of TBN Bldg.) shall have be done in 1.5 month since work start with proper permission from VT2

- Connection working between VT2 Aux header and VT4 Aux piping would be conducted during the shut down period of VT2 TPP

would be noticed at least one day before.

Prepare spool and site condition

at VT2

Install scafolding at aux steam

header

Prepare surfce of reduce, install

support, temporary support

Cut and bevel header cap Fit up

with reduce ecc Install gate

valve, check valve and spool

Install shoe and pipe support on the pipe sleeper and piperack, tack welding to enough strong, install pipe, fit-up and welding After thay install shoe clamp

Visual check and NDE

Hydro test