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Wednesday, 25 November 2015

Method Statement of Cathodic Protection Installation Procedure for Tank External & concrete structures !!

INSTALLATION PROCEDURE FOR TANK EXTERNAL

CONTENTS

1. INTRODUCTION .....................................................................

2. CODES & STANDARDS .........................................................

3. INSTALLATION AND INSPECTION METHOD .......................

3.1 Installation of Grid System ................................................

3.2 Spot Welding Specification ................................................

3.3 Installation of Reference Electrode ...................................

3.4 Installation of Monitoring Pipe ...........................................

3.5 Common – Boxes, Tr/R) ......................................................

1. INTRODUCTION

The purpose of this procedure is to define the installation procedure and inspection method &

criterion for cathode protection system for tank bottom of Project located in Dammam City1.

2. CODES & STANDARDS

This cathodic protection material specification specified here shall be in accordance with; but not

be limited by the following codes and standards:

• RP0290-90 / NACE

Cathodic Protection of Reinforcing Steel in Atmospherically Exposed Concrete

Structures

3. INSTALLATION AND INSPECTION METHOD

3.1 Installation of Grid System

1) Installation of anode grid system shall start only after the execution of following civil works :

①. Complete construction of the concrete ring foundation.

②. Laying of a containment polyethylene flexible membrane liner.

③. Laying and compaction of sand-gravel layer

④. Installation of MMO Ti ribbon anode, conductor bar and reference electrode.

⑤. Laying and compaction of a 500~700mm of clean sand layer

2) Rolling of MMO Ti ribbon anode from coils and positioning at the spacing required on approved drawing.

3) MMO Ti ribbon anode should hold in place with sand bags to keep from rising above the compacted sand.

4) The total installed MMO Ti ribbon anode length shall not be less than the total lengthon approved drawing.

5) Cut one small sample piece of each MMO Ti ribbon anode and Titanium Conductor Bar for sample connection and to adjust the timing for proper spot welding.

6) Conductor bar from coils shall be uncoiled and positioned at the spacing required.

7) Compression splice or solderless connector shall be used for connecting power feeder and cable core. And totally cover the connection point with a splice kit as per approved drawings.

8) The following inspection and tests shall be performed in the anode grid system and related accessories on approved drawings:

①. Depth of the membrane liner with respect to the tank bottom

②. Anode spacing

③. Anode depth with respect to the tank bottom

④. Anode quantity (Not less than approved total length - Refer to approved drawing)

⑤. Conductor bar spacing

⑥. Anode/conductor bar spot welding

⑦. Before backfilling, Resistance shall be measured by a multi - meter. (Up to 1 ohm)

⑧. After backfilling, Resistance shall be measured by a multi - meter. (Up to 1 ohm)

9) Visual and dimensional (Typ. ±10%) check of grid system accessories

10) The inspection will be recorded on form no. 007, 008, 009

3.2 Spot Welding Specification

1) A spot welder must be use for all welding work. Test welds between anode ribbon an

d conductor bar should be first carried out in order to produce good quality welds (i.e.,

which cannot be pulled apart by hand)

2) Welding Specification

Description Specification Remarks

Temporary generator Min. 50KVA

Spot Welder Capacity 1.5~3.5 KVA

Base Metal Conductor bar : Bare Ti, 0.9 mm

Anode : MMO coated Ti, 0.635mm

Welding Mode Single sided spot welding

Position of welding Flat

Welding time The welding time is different due to applied current. Therefore, it shall be determined after sample test as permentioned previous column.

Tip cleaning By confirmation of contamination after each spot welding with file or sand paper if

required.

Bare Metal Surface Cleaning

Surface of area to be welded shall be cleaned

3) Single Side Spot Welding

①. Place conductor bar and ribbon anode on the mould which is contacted to the earth plate.

②. Turn on the power switch.

③. Touch “Single Side Weld Switch”.

④. Make sure that the welding tip is clean and then put proper pressure at the welding point.

⑤. Push the weld witch, and remove the tip about 1~2 second after the welding is co

mpleted.

⑥. Nugget shall be made overlapped center in MMO ribbon anode as possible.

⑦. ④~⑥ step for subsequent welding point

⑧. After welding finish, turn off the power switch.

3.3 Installation of Reference Electrode

1) Installation of permanent reference electrode at location required on approved drawings

(prior to installation, reference electrodes to be soaked in a water container for 30 min

utes minimum)

2) Connect to the test station as per the approved drawing.

3) The following inspection and tests shall be performed for the installation of permanent reference electrode.

①. Installed Electrodes shall be inspected to ensure the functional capability, their location and level is as per the detail drawing.

②. The measured potential of the electrodes to standard electrode (Portable Reference

Electrode) shall be as follows:

- Ag/AgCl Permanent RE (LJ Type) vs Cu/CuSO4 Portable RE: 94 ± 50mV

- Zinc Permanent RE vs Cu/CuSO4 Portable RE: 1,116 ± 50mV

- Cu/CuSO4 Permanent RE vs Cu/CuSO4 Portable RE: 0 ± 50mv

③. Check the reference cell soaked in water.

④. The inspection will be recorded on form

3.4 Installation of Monitoring Pipe

1) Installation of monitoring pipe at location on approved drawing.

2) The monitoring PVC pipe shall be penetrated through PVC sleeve in the concrete ring foundation.

3) Attention to be paid to avoid sand ingress inside the pipe.

4) Any sand which can obstruct the passage of the potable electrode to be removed.

5) The monitoring pipe shall be provided with Geo textile cloth socks to avoid entry sand in the pipe.

6) Pipe connection point of monitoring pipe to be sealed by means of PVC bond.

7) Insure that portable reference electrode passes through the monitoring pipe.

8) Installation of a cable and polypropylene rope inside monitoring pipe for connection an d pulling potable electrode, in case of future measurement.

9) Check the smooth operation of passage through the monitoring pipe with a temporary electrode instead of a potable reference electrode.

3.5 Common – Boxes, Tr/R)

3.5.1 Installation of Box

1) Install the Boxes at a location on approved drawings.

2) A minimum suitable length of slack cable shall be left in the trench at points of termination/connection to above ground apparatus.

3) The following inspection shall be performed for the installation of boxes as per approved drawing.

①. Shape & material check.

②. Cables to, boxes will be checked for correct routing and termination.

4) The inspection result will be recorded on the attached form

3.5.2 Installation of TR/Rectifier

1) Location of TR/Rectifier shall be decided as per approved drawing.

2) Prior to installation, the foundations will be checked for level and civil clearance will be obtained.

3) Fix TR/Rectifer to base utilizing anchors and the fixing holes provide. Great care to be taken in identification of polarity of all cables ensuring they match they match the polarity of the marked terminals.

4) The installation of unit will be witnessed to ensure correct orientation alignment for cabling.

5) The following inspection and tests shall be performed for the installation of TR/Rectifier.

①. Prior to removal to site the TR/Rectifier will be inspected for mechanical damage at enclosure of TR/Rectifier

②. Particular attention will be paid to control panel measuring instruments and control devices.

③. The installation of unit will be witnessed to ensure correct orientation and alignment for cabling.

④. The winding insulation resistance will be megger tested as follow.

- Using a 500-Volt megger for low Voltage transformer (up to 440 volts).

- The tests will be conducted between the primary and secondary windings to

earth and between the two winding.

- The value of insulating resistance shall not be less than 5M ohm.

⑤. The inspection will be recorded on form

INSPECTION AND TEST SHEET

Reference Electrode Function Test

GRID SYSTEM CHECK LIST

1 Anode depth with respect to the tank bottom

2 Anode spacing

3 Anode line number

4 Conductor bar spacing

5 Conductor bar line number

6 Check the spot welding

7 Conductor bar and cable connection

8 No of power feed cables

9 Reference electrode depth with respect to the tankbottom

10 Installation of permanent reference electrode

11 Number of permanent reference electrode

12 Cable routing

13 Depth of the monitoring pipe with respect to the tank bottom

14 Number of monitoring pipe

15 Test for potable reference electrode passes through the monitoring pipe before backfilling

INSPECTION AND TEST SHEET

Resistance Measurement for Grid System before Backfilling

INSPECTION AND TEST SHEET

Resistance Measurement for Grid System after Backfilling

INSPECTION AND TEST SHEET (Boxes)

1 Support as per detail drawings

2 Foundation location and details correct

3 Installation as details drawing

4 Cable connection

5 Cable installed & termination complete

6 Cable identification

INSPECTION AND TEST SHEET (TR/Rectifier)

1 Equipment undamaged

2 Orientation and alignment correct

3 Accessories installed

4 Earth as per detail drawing

5 Insulation resistance

5.1 Primary winding-Earth

5.2 Secondary winding-Earth

5.3 Primary winding- Secondary winding

INSPECTION AND TEST SHEET Cabling

1 Sufficient slack

2 Buried depth

3 Backfilling

4 Cable tag as per drawing

5 Cable Trench Preparation as per Standard

6 Sand Bedding Provided as per the Standard

7 Cable Size Check

Cathodic protection installation procedure for concrete structures

Contents

1. Introduction ......................................................................

2. Codes &Standards….........................................................

3. Installation and Inspection Method……….......................

3.1 Anode System .................................................................

3.2 Connection of Cable .......................................................

3.3 Installation of Steel Connections ..................................

3.4 Installation of Reference Electrode ...............................

3.5 Common – Boxes, Tr/R, Cabling) ..................................

1. INTRODUCTION

The purpose of this procedure is to define the installation procedure and inspection method &

The criterion for cathodic protection system for steel in concrete of the project, located

in Jeddah.

2. CODES & STANDARDS

This cathodic protection material specification specified here shall be in accordance with; but not be limited by the following codes and standards:

• RP0290-90 / NACE

Cathodic Protection of Reinforcing Steel in Atmospherically Exposed Concrete Structures

3. INSTALLATION AND INSPECTION METHOD

3.1 Anode System

1) Rebar clips shall be pushed onto the reinforcement at designated point and tied securely with cable ties.

2) The mesh anode shall run along a line of rebar clip as per approved drawing.

3) The mesh anode shall be fixed to each rebar clip with two(2) cable ties and tensioned over its full length.

4) The end of the mesh anode should be looped and weld each other, and then the mesh The anode can be stretched by cable ties and rubber clip.

5) The conductor bar shall be positioned along a line of rebar clip that cross the mesh anode as Per approved drawing. The conductor bar shall be fixed to rebar clip with cable tie like mesh anode.

6) The mesh anode shall be spot welded to the conductor bar at every crossing point. Then

each welding point shall be secured with a cable tie.

7) The installation procedures for spot welding machine is as follows:

- Make sure the mesh anode and the conductor bar are clean and free from dust.

- Place the conductor bar underneath the section of the mesh anode.

- Welding gun insert between mesh anode and conductor bar

- Press the trigger to weld.

- The welding shall be done instantly when the trigger is pressed.

8) The rebar clip must be installed tightly to the rebar cage to reduce the possibility of meshanode displacement during the concrete pouring. In particular, it is important for the anode too be stretched tightly to avoid a node movement during the concrete pouring.

9) A discontinuity check between the anode system and the rebar shall be carried out by measuring the resistance between the anode lead cable and negative cables. Discontinuity is proven by failure of this test. If there is continuity between anode and cathode then the shortcircuit should be traced and eliminated before work proceeds. The successful elimination of the short circuit shall be demonstrated be re-measuring the continuity between anode and cathode.

10) All cable tie tails to be removed.

11) The following inspection and tests shall be performed for the anode system and related

accessories on approved drawing:

- Anode spacing

- Location of anode

- Anode quantity(Not less than approved total length- refer to approved drawing)

- Conductor bar quantity (Not less than approved total length-refer to approved drawing)

- Anode/Conductor bar welding spot weld is by making a cross and rubber hammering (1kg) one arm to shear the weld if a nugget pulls out of one of the sections-the weld is acceptable (Test sample)

- Resistance measurement before concrete pouring

• Continuity test between

(1) Anode & CB,

(2) Steel & Negative Cable

(3) Steel & Steel Signal Cable (up to 1 ohm)

• Discontinuity test between

(1) Anode & Cathode

(2) Different Zone

- Resistance measurement after concrete pouring

• Continuity test between

(1) Anode & CB

(2) Steel & Negative Cable

(3) Steel & Steel Signal Cable (up to 1 ohm)

• Discontinuity test between

(1) Anode & Cathode

(2) Different Zone

- Visual and dimensional (Typ. ±10%) check of anode system accessories

1) The inspection result will be recorded on attached forms

3.2 Connection of Cable

The connection from cable to the anode system shall be made as follows:

1) Anode lead cable of the specified rating, color and size shall be prepared in sufficient length to run from the anode lead connection to the appropriate junction box by the specified route without a cable splice.

2) The pre-stripped copper core of the anode lead cable shall be compressed crimped to a titanium rod.

3) The assembly shall be encapsulated with a suitable, mechanically strong adhesive lined heat shrink type, which extends 50mm either side of the crimp. Care shall be taken during the application of heat shrink to ensure no damage results to the cable insulation.

4) The Titanium wire shall be positioned in the correct orientation and secured to the conductor bar.

5) The cable leading from the anode lead connection shall be securely fastened to the conductor bar and then to the reinforcement by the use of non-metallic cable ties.

6) A connection between the titanium wire and conductor bar shall be made by metallurgical welding, taking care to ensure that the process in no way damages conductor bar or the cable connection system.

7) The installation procedure for spot welding the anode lead connection to the conductor bar is as follows:

- Make sure the anode lead connection and the conductor bar are clean and free of dust

- Firmly fix the positive connection to the top of the conductor bar using 2 cable ties.

- Anode lead connection shall be placed onto the conductor bar to make a direct connection.

- Press the trigger to weld

8) The following inspection should be performed as per approved drawings :

① Check the connection of cables to boxes

② Cable identification.

9) The inspection result will be recorded on the attached form.

3.3 Installation of Steel Connections

The connection from negative cable and steel signal cable with the repair shall be made as follows:

1) Manufacturing

① A 30mm deep hole shall be drilled in one end of a 12mm diameter rebar that is 100 mm long.

② Negative cable of the specified rating, colour and size shall be prepared in sufficient length to run from the negative connection to the appropriate splice location by the Specified route.

③ The pre-stripped copper core of the negative cable shall be placed inside the hole and braze welded to the rebar. Care shall be taken to ensure no damage results to the cable insulation.

④ The assembled connection shall then be encapsulated with a suitable, mechanically strong, adhesive lined heat shrink tube once the connection has cooled to ambient temperature. This encapsulation shall cover 50mm of cable insulation and shall extend to the midpoint of the steel rod.

⑤ The bare portion of the rebar shall be suitably welded to the designated steel reinforcement of the structure to be protected taking care to ensure no damage occurs to the cable or connection encapsulation.

2) Installation

① At the locations shown in general on the drawings, the reinforcement shall be thoroughly cleaned to expose the bright steel. The system negative cable shall then be connected to the reinforcing steel in the manner shown on the design drawings and as described below.

② The connection shall be positioned in the correct orientation and secured to the reinforcement as tack welding.

③ The cable leading from the negative connection shall be securely fastened to the reinforcement by the use of non-metallic cable ties.

10) The following inspection should be performed as per approved drawings :

① Check the connection of cables to boxes

② Cable identification.

11) The inspection result will be recorded on the attached form.

Installation of Reference Electrode

1) Installation of reference electrode at the location required on approved drawings. At a give n location, the reference electrode shall be placed at the level of and parallel to the reinforcing steel. All cables shall be secured to the reinforcement with cable ties, and routed to the location of the appropriate junction box as shown on the design drawing.

2) The following inspection and tests shall be performed before the installation of permanent reference electrode.

3) The measured potential of the electrodes to a standard electrode (Calomel Reference Ele Strode) shall be as follows:

* Ref.electrodes shall be inspected to ensure its functional capability before & after concrete encapsulation.

A. Test procedure before encapsulation

- Prepare supplied Ag/AgCl ref. Electrode and calomel ref. Electrode.

- Fill a bucket with sea water

- The permanent Ag/AgCl ref. Electrode shall be at the left side of the bucket

- The calomel ref. Electrode shall be on the right side of the bucket.

- Measure potential difference between the two electrodes as shown on below diagram.

VOLTMETER (LC-4)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Seawater

- A setting procedure for LC-4 meter carried out as follows:

a) Turn range switch to 200mV~2V range.

b) Turn function switch to DC. (Center of LC-4 meter)

c) Turn power switch to 10M position (Input Res range of the LC-4 meter). The display should turn on and within a few seconds indicates “ 000”. If “Lo bat ” appears in the display, then the 9V battery must be replaced as soon as possible.

d) Connect lead cable of Ag/AgCl ref. electrode to the center terminals (+) and lead cable

of Calomel ref. Electrode to com (-).

e) Turn range switch to a lower range if necessary to obtain a more detailed reading

(DC volt range of LC-4meter). When the display shows “1” followed by blanked digits, the input is higher than full scale. Use higher scale if available.

f) ΔV=±5mV maximum from the calibrated value (Portable Calomel ref. Electrode).

B. Test procedure after encapsulation

- Encapsulate max. 7~10 days before installation

- Surface of this encapsulation shall be rough ended to get a good bond with the concrete.

- After encapsulation, allow min. 2~3 days for concrete curing

- Keep in wet or moist condition until installation.

- Remove from water at least 1 hour before testing.

- Above concrete to be cured, put on a wet sponge, and then contact Calomel ref.

Electrode as show below diagram.

- A setting procedure for LC-4 meter carried out as follows:

a) Turn range switch to 200mV~ 2Vrange.

b) Turn function switch to DC. (Center of LC-4 meter)

c) Turn power switch to 10M position (Input Res range of the LC-4 meter). Display should turn on and within a few seconds indicate “ 000”. If “Lo bat ” appears in thedisplay, then the 9V battery must be replaced as soon as possible.

d) Connect lead cable of Ag/AgCl ref. electrode to center terminals (+) and lead cable of Calomel ref. Electrode to com (-).

e) Turn range switch to a lower range if necessary to obtain a more detailed reading.

(DC voltage range of LC-4 meter). When the display shows “1” followed by blanked digits, the input is higher than full scale. Use higher scale if available.

- After input res range turn to100M, measurable potential.

- After input res range turn to10M, measurable potential.

- Criteria of potential difference between 100M range and10M range is ΔV=2mV (Max.)

4) The inspection result will be recorded on attached form no. 001, 004, 005

5) After installation of the encapsulate RE, it shall be kept wet or moist until concrete pour.

3.5 Common – Boxes, Tr/R, Cabling)

3.5.1 Installation of Box

1) Install the Boxes at a location on approved drawings.

2) A minimum suitable length of slack cable shall be left in the trench at points of termination/connection to above ground apparatus.

3) The following inspection shall be performed for the installation of boxes as per approved drawing.

①. Shape & material check.

②. Cables to boxes will be checked for correct routing and termination.

4) The inspection result will be recorded on attached form no. 017.

3.5.2 Installation of TR/Rectifier

1) Location of TR/Rectifier shall be decided as per approved drawing.

2) Prior to installation, the foundations will be checked for level and civil clearance will be obtained.

3) Fix TR/Rectifer to base utilizing anchors and the fixing holes provide. Great care to be taken in identification of polarity of all cables ensuring they match, they match the polarity of the marked terminals.

4) The installation of the unit will be witnessed to ensure correct orientation alignment for cabling.

5) The following inspection and tests shall be performed for the installation of TR/Rectifier.

①. Prior to removal to site the TR/Rectifier will be inspected for mechanical damage at enclosure of TR/Rectifier

②. Particular attention will be paid to control panel measuring instruments and control devices.

③. The installation of unit will be witnessed to ensure correct orientation and alignment for cabling.

④. The winding insulation resistance will be meager tested as follows.

- Using a 500-Volt Megger for Low Voltage transformer (up to 440 volts).

- The tests will be conducted between the primary and secondary windings to earth and between the two winding.

- The value of insulating resistance shall not be less than 5M ohm.

⑤. The inspection will be recorded on form no. 018.

3.5.3 Cabling

All cables shall be laid in single run.

1) Buried cables should lie at a depth that will protect them from disturbance by plough or other excavations. Cable tiles or cable warning tape should be used to warn of the presence of the

cable during any subsequent excavation.

2) The cable shall then immediately be tagged with its unique ID as per approved drawing.

3) The cable lengths shall be checked against the cable schedule lengths or approved drawing in order that wastage is minimized.

4) Check the visual on form

REBAR IN CONCRETE CP SYSTEM CHECK LIST

Date:

No Description. Results Remark

Acc, Rej, N/A

1 Anode spacing

2 Location of anode

3 Anode quantity (m)

4 Conductor bar quantity

5 Number of conductor bar

6 Anode/ Conductor bar spot welding

7 Conductor bar and anode feeder cable connection

8 Number of anode feeder cables

9 Cable routing & installation

10 Resistance measurements

11 Installation of reference electrodes

12 Number and location of reference electrodes

13 Number & location of steel connections

INSPECTION AND TEST SHEET