8113 Cathodic Protection Spec R1

ELECTRICAL DEPARTMENT

1 27.4.2007 ISUUED FOR ENQUIRY KAG MZ MZ 0 27.4.2007 ISUUED FOR ENQUIRY KAG MZ MZ

REV DATE DESCRIPTION PRPD CHKD APPRD

FACT ENGINEERING AND DESIGN ORGANISATION

1.0.0 INTRODUCTION

1.1.0 This specification covers the requirements of cathodic protection work for the proposed LPG pipeline (total length of 3.5km ( approx)) from inside BPCL- KR premises to HPCL LPG plant installation at Irimpanam. This document shall be read in conjunction with engineering specifications, data sheets, drawings, etc attached with the piping section of the tender document. The cathodic protection for the entire length of pipelines is under the scope of this tender.

1.2.0 The bidders should visit site and acquaint themselves with site conditions and existing cathodic protection works carried out in neighborhood for similar lines, before quoting. They are also expected to contact all concerned agencies like GCDA, Cochin Corporation, PWD, Railways, KWA, IOCL, BPCL, HPCL , State Electricity Board, Civil Authorities, etc who are associated with the proposed pipeline route and familiarise themselves with the necessary formalities. Comments if any from CECRI, SCIENTIFIC & INDUSTRIAL LIAISON EXTENSION UNIT (SILEU), Karaikudi on the enclosed specifications for cathodic protection shall be furnished with the bid.

1.3.0 For details like pipeline data, wrapping and coating data, route envisaged, refer piping section of the tender document. As the cathodic protection of the whole length of the pipeline is covered under the scope of this tender, it is the responsibility of the CP contractor to coordinate with both the pipe line installation contractor(s) and install the impressed current cathodic protection system for the whole pipeline to the satisfaction of the client/ consultant.

1.4.0 415V, 50 Hz, TPN, AC power supply will be made available by the Purchaser at the HPCL Irimpanam end. If power supply is required at any other point, it shall be availed from KSEB. Availing of the power supply in the name of HPCL shall be in the scope of the vendor. All liaison work for the same shall be done by the vendor. All statutory fees paid for obtaining power supply sanction will be reimbursed by HPCL on submitting proof. Necessary isolator with box, metering box with sealing facility, fuse and neutral link etc, supply of cable and cabling from metering box to isolator and isolator to T/R unit shall be provided by the vendor. Required mounting pedestal/ frame, weatherproof enclosure for metering box and isolator for the power receiving structure shall also be provided. Proper earthing with required earth pits and copper earth conductors etc. shall be done.

1.6.0 SCOPE OF WORK:

This specification together with the applicable project specifications shall govern the design engineering, supply, installation, testing and commissioning of a permanent impressed current cathodic protection system to protect the external surface of the pipeline over the entire envisaged life span (30 years) of the project, including potential logging survey over the entire length of the pipeline. The bidders scope shall include engaging CECRI, SCIENTIFIC & INDUSTRIAL LIAISON EXTENSION UNIT (SILEU), Karaikudi for site survey, soil analysis, optimum design, preparing bill of material, providing guidelines for selection, installation, testing and appraisal of the installation, etc. All instruments required for soil survey shall be arranged by the bidder/ CECRI.

In case CECRI is not engaged in site survey, design / engineering, the same shall be done by the contractor and got verified / certified by CECRI (third party approval)

2.0.0 GENERAL (CP SYSTEM):



The Pipeline shall be cathodically protected by Impressed current cathodic protection system. The cathodic protection station shall be located at the HPCL at Irimpanam. The cathodically protected section of the pipeline will be electrically isolated by use of Insulating Joints, supplied and installed by the Piping Contractor. Anode Bed shall be provided at suitable locations depending on the site conditions. However one no. anode bed shall be located at the HPCL Irimpanam.

The proposed LPG line is to be laid in close proximity (500mm away) of an 24 inch naphtha line which is also cathodically protected by impress current system. Hence effect of this 24 inch line shall also taken into consideration while designing /installing the cathodic protection system for the LPG line. Vendor shall take/incorporate suitable measures in the CP system of the LPG line to mitigate the interference and other effects from the other lines in the route.

The transformer Rectifier units shall be the source of power for the ICCP system. The output of T/R unit shall be automatically varied to achieve the set pipeline to soil potential. Suitable measures as per international practice shall be taken to mitigate any interference current and cross currents from any source.

Special protection shall be provided at cased-crossing (Road-crossing) (Rail crossing). etc.

Surge protection shall be provided for cathodic protection system

Corrosion proof epoxy painting shall be provided for all support structures

3.0.0 CODES AND STANDARDS

3.1.0 The design and the installation shall be in accordance with the international codes and standards, and accepted engineering practices and must also conform to the local statutory regulations.

3.2.0 The following international codes and standards shall be considered as minimum requirements.

Latest version of applicable publication shall be followed;

a) BS specifications and codes of practice b) ANSI specifications c) XFPA Publications d) XACE Publications e) JEC publications f) Indian Standards g) OISD Standards h) NACE RP-01-69

In case of conflicting requirements amongst any of the above standards, the publication having stringent requirement shall be governing.

3.3.0 In case of any deviation/conflict of this specification with the codes and standards, the provisions of this specification shall be over-riding.

4.0.0 SURVEY:

4.1.0 Resistivity Measurement & Calculations:

To carry out the work of soil resistivity measurement winners 4 pin method shall be used.

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Care should be taken that measurements are not influenced by presence of overhead lines over earth shall be made at least 15m away from underground metallic structures if any such exist along ROW or anode ground bed locations. The depth of insertion of each pin while measuring resistivity shall be 1/20th of the pin spacing.

Soil resistivity shall be computed by the following relation:

P - 2piar

Where P - Average Resistivity of soil at a depth of a metre in ohm-metre a - Spacing between two consecutive pins in metres r - Resistance in ohm displayed by Megger.

4.1.1 Soil Resistivity measurement along ROW

Generally the observation shall be made enclosing the soils immediately surrounding the pipeline route between the Central electrodes where right of way has been cleared.

At places where right of way has not yet been cleared measurements shall be made right over the defined locations to account for cuttings filling also. All measurements shall be taken at right angles to ROW unless otherwise asked for by ENGINEER at site.

Each spot shall be investigated so as to obtain average soil resistivity upto the following depths:

0.5, 1.5, 3.0 & 6.0 Metres

All the river Creeks and other major water crossing/marshy lands, swamps, for resistivity/observations should be so chosen so as to obtain resistivity of the soil at river/creek beds or marsh lands. Wherever possible depth of water table shall be determined by available open wells when such facility is available near right of way.

CONTRACTOR has to provide necessary facilities for such measurements.

4.1.2 Soil Resistivity Measurement on Anode Ground Bed.

After completion of soil resistivity survey along ROW and preparation of soil resistivity plot (Resistivity contour), based on the resistivity values, the anode ground bed plots shall be selected in consultation with and as directed by the ENGINEER for the C.P. station. One no. anode ground bed shall be located at a suitable location at the HPCL in Irimpanam/ as directed by the Engineer in Charge.

The anode ground bed plot shall then be subdivided into three subplots each of which shall then be investigated for resistivity measurement at the following spacings:

1, 2, 3, 4, 5, 6 to 10 Metres.

Thus the anode ground bed subplot will have a set of seven observations at an average with a view to determine the nature of soil level and soil stratification and also possible water table depth.

4.1.2.1 Soil Resistivity Survey Instrument:

Nomenclature ; Battery Powered solid state 500 volts 5 terminal Earth Megger

Range : 0-0.1, 0-1, 0-10, 0-100 ohms.

Accuracy : Within +/- 1% of maximum value of selected range.



Sensitivity: Two position switch for low and high balance sensitivity shall be prepared

Instrument should incorporate design features for max. A.C. & D.C.ground current rejections.

Temp. Range : 0-60C fully temperature stabilized

Circuitry: Solid state suitable for rough and rugged use. Suitable for 2,3 & 4 Pin application.

Power : Replaceable/Rechargeable battery

4.1.3 Test on SOIL Samples:

To determine the presence of anaerobic bacteria, PH of soil samples is to be measured at selected location to be decided by ENGINEER. If PH values indicated need further investigation, then Redox-Probe observations may also have to be followed. Provision to carry out both these tests are to be made by CONTRACTOR. If need be chemical analysis of soils for determining concentration of various cations and anions shall also be carried out. No. of locations along ROW on which soil tests are to be made will be decided by ENGINEER from time to time as work progresses.

4.2.0 REPORT:

Each set of observations made at spot at field shall be recorded in metric units and shall be made into four copies. The original is to be assigned to ENGINEER duly certified by OBSERVER.

All the resistivity observations collected thus during survey along with ROW shall be plotted to give resistivity Contours. Each set of observations recorded at individual spot shall be shown in the plot. Besides marking the points of diversion of ROWs on the plot, creek, railway, road and overhead line crossing, topographical information shall be entered in the resistivity contour. Such finished resistivity contour along ROW shall be produced for ENGINEERS approval.

ln addition, the CONTRACTOR shall compile all the resistivity observations taken along ROW and on Anode Ground bed locations and submit to the ENGINEER for record.

5.0.0 PROTECTION CRITERIA

a) Minimum protective potential from pipe-to-soil shall be considered as 0.95V. b) Maximum protective potential shall be shall be considered as 1.5V. c) All these potential values mentioned in item (a) & (b) are with respect to copper-

copper Sulphate reference cell.

d) Minimum protective potential from pipe-to-electrolyte shall be considered 0.9V e) Maximum protective potential from pipes-to-electrolyte shall be considered

1.10V. f) All these potential values mentioned in item (d) & (e) are with respect to silver-

silver chloride reference cell.

g) Alternatively, a minimum potential swing of 300 mV on the protected structure shall be the guiding criteria to establish that subject pipeline is protected. Maximum protective potential swing in such cases shall be decided on merits.

h) A potential swing of 20mV shall be considered the design criteria for presence of a interaction situation requiring investigation and incorporation of mitigation measures.


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5.1.0 ELECTRICAL ISOLATION

5.1.1 Insulating joints are provided at the following point of pipeline (see pipeline specification also)

1. At BPCL-KR 2. At HPCL IRIMPANAM

6.0.0 DESIGN GUIDELINES & C.P. SYSTEM DESCRIPTION:

6.1.0 Each cathodic protection station (C.P. Station) for impressed Current (I.C.) System shall essentially consist of but not limited to the following:

A very reliable D.C.Power source, anode ground bed, arrangement for measuring pipe to soil potentials, associated anode and cathode cabling, anode junction boxes. Installation shall be designed for unattended operation and shall have in built provision for bonding to other lines laid in the same ROW.

6.1.1 The carriers in the cased crossings with end seals would be protected by Zn-sacrificial anodes if the possibility of water accumulation exists. The anodes would in that case be in the form of ribbon or arc shaped rod and would be welded to the carrier pipe by thermite welding as close to the carrier pipe as practically possible. The length of the ribbon anode would be equal to the length of the carrier pipe inside the casing and anodes will be mounted over the circumference in such a way that it is distributed equally at 120 angle between them.

6.1.2 The external of casings would be coated in the same manner like carrier pipes and also provided with zinc anodes on both sides of the pipe. The minimum weight of zinc would be decided by ENGINEER.

6.1.3 For providing such zinc anodes the pipe laying and cathodic protection agency would co-ordinate with each other.

6.1.4 As part of corrosion survey full particulars regarding secondary structure including power cables, communication lines, electrical railway tracks etc. which would adversely influence the system or would be influenced by the system must be collected. The engineering of cathodic protection system would incorporate suitable mitigation measures. In any case all the lines in common ROW or pipelines would be bonded together through test stations.

6.1.5 As part of cathodic protection monitoring, potential measuring devices would be installed at all test stations. The test station would also provide the flexibility for connecting and disconnecting sacrificial anodes. Some of the test stations having potential measuring terminals shall also have terminal facilities for measuring line currents.

6.2.0 ANODES AND ANODE GROUND BED

Anode ground bed shall be located near each C.P. station and shall be laid in low resistivity solid strata. The quantity of C.P. station shall be decided based on actual resistivity survey. However one no. anode bed complete with T/R unit etc. is proposed to be located at the HPCL. The final sizing of ground bed will be subject to ENGINEERs approval. Canistered anodes with anode lead cables shall be laid at 1 1.5m depth in horizontal configuration. General laying arrangement, spacing between two consecutive anodes etc. shall conform to the respective standards. Sizing of ground bed at each C.P. station shall be such that its total resistance to remote earth does not exceed 0.5 ohm inclusive of anode lead cables resistance. Each anode ground bed shall be located at a minimum distance of 100 metres from and at right angles to the pipelines.

6.3.0 TEST STATIONS


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6.3.1 Test station along the trunk line shall be provided along the ROW for monitoring the performance of cathodic protection system and bonding of pipelines in common pipe trench or ROW at intervals not exceeding 500 metres. However at backwater crossings the test stations may be provided at the start and end points only even if the crossing is more than 500m in length.

Some of these test stations shall have, besides pipe-to-soil potential measurement and bonding facilities, four terminal facilities for line current measurement.

In addition measurement station shall also be provided at following locations:

a) At both sides of major water, road and rail cased crossings.

b) At all insulating joints. The test station shall have terminal facility for connection of grounding cell to pipeline. Besides terminals shall also be provided for pipe-to-soil potential measurement on both shoulders of joint.

c) At crossing of AC/DC electric traction system.

d) At vulnerable location with drastic change in soil resistivity.

e) At HT overhead line crossings and selected locations where HT line passes close to pipeline.

f) In vicinity of DC networks or grounding system where interference problem are suspected.

g) At valve location.

h) At crossing of other foreign pipelines (bonding facility with resistor shall be provided).

Additional test station described above, many of which shall fall intermediate between potential test-cum-bond stations shall have binding facilities. It is quite likely that some of these additional test station mentioned above may coincide with those test stations located at 500 metres interval.

Test station at location of insulating joints shall preferably be installed independently.

Details of terminal facilities and connection schemes for individual type of test station/current measuring station/test-cum-bond station shall be as per relevant standards.

6.3.2 The location of all the test station shall be marked with their connection schemes and other relevant information on alignment sheets as a part of detailed engineering. A test station schedule shall also be prepared.

6.3.3 Potential test-cum-bond station provided at 500m interval as a means to bond, monitor and control current flow in structures laid in common ROW/trench. These potential test-cum-bond station shall allow detection and mitigation of any interference on foreign structures that may result from operation of this C.P. System.

6.4.0 REFERENCE ELECTRODES

6.4.1 High purity copper/copper Sulphate silver/silver chloride reference electrodes shall be used to provide stable potential measurement references.


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6.4.2 For each automatically controlled cathodic protection system, monitoring reference electrode shall be supervised by a duplicate electrode in its close vicinity in an approved location.

6.4.3 Such duplicate electrodes shall be provided to guard against reference cell failure possibilities in an unattended automatic system. Facilities shall be provided to reject spurious signals during open or short circuiting of monitoring point.

Reference electrodes shall be provided to:

i) Obtain the most reliable indication of the protection and system behavior. ii) Ascertain the effectiveness of each C.P. station and control their output.

6.4.4 CONTRACTOR to provide 30% spare reference electrode complete with accessories. Number and type of electrodes to be supplied by CONTRACTOR shall be clearly indicated in his BID.

EQUIPMENT SPECIFICATIONS

7.1.0 TRANSFORMER RECTIFIER UNIT

7.1.1 Transformer The T/R unit shall be air cooled weather proof to IP 55, with Auto /Manual control. The transformers will be the isolation type having separate primary and secondary windings. And electrostatic shield composed of heavy copper foil, shall be placed between the two windings and ground bed to the rectifier. The transformer core and windings shall be dipped in insulating materials Thermosetting Epoxy Resin to withstand 2,000 volts (RMS value at 50 Hz) applied for one minute between the windings and between each winding and the transformer core. Magnet wire insulation and transformer interlayer insulation shall be class H type rated at no less than 180 degrees C. Actual temperature rise shall not exceed 85 degrees C at rated conditions.

Transformer regulation will not exceed 3% from full load at rated load. Transformer full load efficiency shall not be less than 95%. Derating factor of transformer shall be 20% excess current. For other details refer data sheet attached.

7.1.2. Diodes/SCRs will be of silicon type and moisture resistance giving full wave rectification. Adequate filtering circuit shall be provided on output side to smoothen the DC output. The input and output side shall be provided with RC circuit of suitable capacity across each diode/SCR to protect against voltage surges. The RC circuit shall be designed to such a manner that voltage across the device is less than peak inverse voltage (PIV) of diodes/SCRs at peak surge voltage. The normal output current rating of diodes/ SCRs shall be twice the current output rating of T/R unit and PIV shall be 1.2kV (min.). Sinks of sufficient size to be used to prevent the core temperature from exceeding 100C at rated ambient temperature.

7.1.3 A.C.Input Rating

The T/R Unit shall operate at 230V10%/ 415V+/-10% 50 Hz input power.

7.1.4 D.C.Output Adjustment

7.1.4.1 Manual Mode

Suitable tappings shall be provided in the primary side of T/R unit so that DC output voltage is obtained in voltage steps from 0 to 50V. Alternately a separate auto transformer can be provided so that primary input voltage can be varied to achieve 0 to 50V voltage control on D.C. output side.

7.1.4.2 Automode



Automatic potential control (APC) shall be accomplished by a separate controller. The controller shall be capable of maintaining a desired (set) structure to reference cell potential of +0.5 to 2.5V. The APC controller shall adjust the output voltage and current to maintain protective potential on the pipeline. The manual and automatic modes shall be capable of operating completely independent of each other.

7.1.5 Electronic Controllers

The SCRs of the transformer rectifier shall be controlled by commands from electronic circuit cards. These cards shall be the plug in type printed circuit cards mounted on the front panel of the rectifier for easy field replacement.

The printed circuit card contact pads will be gold plated to provide easy conduction and to eliminate contact corrosion. Completed printed circuit and controllers will be sealed with a circuit card sealant to prevent atmospheric corrosion and fungus contamination.

7.1.6 Reference Cell Selector Circuit and Control

A circuit shall be used which will accept three (3) reference cell input. This circuit will automatically accept the reference with the lowest potential above a pre-selected value higher than the native potential of steel. This limit will minimize the possibility of a rectifier utilizing an erroneous reference electrode signal which could cause over protection to the pipeline. Switches shall be provided to measure the potential of each reference cell used and to allow manual selection of the reference cell to be used.

7.1.7 Separate Drainage Control

Provision shall exist to individually drain each protected structure and have both auto and manual mode available on each drain.

7.1.8 Output Ripple The output ripple shall be less than 5% at rated output voltage and current.

7.1.9 Input Overload Protection

Protection from overloads on the input will be provided by moulded case, magnetic circuit breakers on the input side. These circuit breakers will hold a 100% of rated load. They may trip between 101% to 125% of the rated load and must trip at 125% and above. The trip point will be unaffected by ambient temperature. Circuit breakers will be manually reset type. The trip handles of individual pole circuit breakers will be mechanically linked so all lines are opened when an overload occurs. HRC fuse of suitable rating to be provided as back-up to input breaker.

7.1.10 Output Over load Protection

Protection from overloads on the output will be provided by an electronic current limiting feature. The transformer rectifier will be capable of indefinitely sustaining a short circuit across the output and will respond quickly enough to prevent damage to any part of the circuit. This shall include any overload to T/R unit and overprotection to pipe/structures due to reference cell failures also.

7.1.11 Sun/Rain Shade

Sun/Rain shade to be used of 1m length using 10 SWG M.S. sheet protruded all around of 2m protrusion 0.5m shall be at 45 angle.

7.1.12 Mounting


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The T/R unit at HPCL end shall be located in substation building. Incoming cabling to TR unit (for power supply)shall be arranged by the purchaser.

7.1.13 Housing

T/R units shall be suitable for outdoor installation.

7.1.14 Annunciation

Arrangement shall be provided for giving visual indication of but not limited to the followings:

i. Loss of power supply ii. Actuation of any protective device iii. Failure of auto mode iv. Fault on cable on Primary and Secondary circuit v. Under voltage and over voltage on supply side.

7.1.15 Testing and Inspection

Each unit shall be inspected and tested in the manufacturers shop. The results will be recorded and submitted. Inspection shall include but not limited to the following:

i. Mechanical: Wiring connections, panel components, doors, latches, hinges, finish, appearance.

ii. Electrical: Read and record A.C.volts input, DC ampere output, dielectric strength, ripple voltage at rated output and current limiting test. In addition, a temperature rise test on the transformer windings and diodes/SCR and full load efficiency test shall be conducted after the unit has been operated at full load for 24 hours.

7.1.16 Facility shall be provided for continuous remote monitoring of healthiness of cathodic protection system like DC voltage (4-20mAoutput), DC current (4-20mA output), reference (PSP) voltage (4-20mA output, and required potential free contacts for alarm for under protection, over protection & all reference electrode failure. The purchaser shall do required cabling from TR unit to DCS.

7.1.17 Facility shall also be provided for current interruption test to be conducted on the pipeline for measuring of potential. The current interrupter test kit shall be the part of TR unit with adjustable timers for setting ON and OFF time.

7.2.0 ANODES & ANODE BEDS

7.2.1 The contractor shall furnish the detailed specification viz. type, material, composition, weight etc of the anodes proposed depending on the soil survey and site conditions.

7.2.2 Sheet steel anode canisters of suitable size shall be furnished for each anode. Anode canisters shall be filled with tamped coke breeze having carbon content of at least 98% and maximum resistivity 50 ohm-cm.

7.2.3 Each anode bed shall contain anodes with canisters positioned in the soil with suitable backfill at appropriate depth with due regard to type of configuration. Anode bed shall be located preferably 100m (min.) or more from the pipeline/structure under protection. Anode-bed plot limited upto ROW shall be surveyed for topographic details. Its location and orientation shall be reviewed by ENGINEER.

7.2.4 Layout of anodes, installation in anode-bed shall be detailed out in a separate drawing showing anode installation details, anode grouping, anode wiring etc. Type of layout whether vertical installation/ horizontal installation in shallow depth to be considered shall



be decided in consultation with ENGINEER on the basis of Corrosion survey report prepared by CONTRACTOR.

7.2.5 Necessary connection of anode lead cable to anodes, packing of anodes in canisters filled with backfill, soldering of canisters shall be done at site. Each anode shall have lead cables of sufficient length to reach anode junction box without in between joints. Exact length and termination details shall be shown in construction drawings.

7.2.6 Anode bed separation from pipeline shall be tested for interaction.

7.2.7 At landfall points, anode land beds may be laid, if situation demands, between low and high water line or very near low water line. The configuration shall be horizontal in such cases.

7.2.8 Overall resistance of the each anode bed upto its main junction box shall not exceed 0.5 ohm unless agreed otherwise. Potential gradient around the anode bed shall be within safety requirements and its effective boundary shall be defined and secured.

7.2.9 The boundary of the anode bed should be clearly marked with the help of permanent boundary and fencing.

7.3.0 ANODE JUNCTION BOXES (AJB)

Anode junction box drawing shall be furnished by the contractor. The height of the pedestal above ground level may require to be greater depending on the highest flood level of the site of its installation. Junction boxes to be mounted above ground shall have steel enclosure which shall be dust and weather proof as per IP-55 with hinged lockable shutter. It shall have terminal block with adequate number of terminals. Provision shall be made for measurement of individual anode current . The AJB shall be of 10 SWG sheet steel, shunts used for current measurement of each anode shall be 10 amps/75 mV rating. The AJB assembly shall be grouted on concrete pedestal made of M 200 grade reinforced concrete.

7.4.0 CABLE AND CABLE LAYING

7.4.1 Anode & Cathode Header Cable

XLPE insulated and PVC sheathed armoured copper conductor (single core) of minimum size 50mm2 to be laid by CONTRACTOR in all types of soils (including rock) at an average depth of 1 m below ground level.

7.4.2 Anode Lead Cable

Individual pre-packed cannistered anodes complete with minimum 6 mm2 XLPE insulated PVC sheathed unarmoured single core copper conductor of sufficient length to reach AJB shall be supplied and laid by CONTRACTOR in all types of soils (including rock). Length of each lead cable should be sufficient to reach AJB without any joint in between. Anode lead cables shall be laid in trenches at average 1m below ground level having a 6 top cover of sand one layer of brick soling followed by natural backfilled soil. All anode lead cables shall be laid in PVC/PE conduits of 2.5mm minimum wall thickness. If any road or rail crossings are encountered, they shall be routed through 2 GI conduits instead of PVC/PE conduits at such road/rail crossings.

7.4.3 All the Instrumentation wires shall be with PVC insulation of 600/1100V grade and not less than 2.5 mm2 cross-section copper conductor.

7.4.4 Cable Termination:



The cables shall be taken through double compression glands inside the panels or any other electrical equipment such as T/R unit. The individual cores shall then be dressed and taken along to the cable ways (if provided and shall be fixed to the panels with Nylon straps) D.C.output cable terminals shall be provided with terminal lugs of matching current rating. Termination of other cables shall be made of crimped lugs made with proper tools. Only control cables of single strand may be directly terminated on the terminals. An aluminium tag with cable number engraved on it shall be attached to each cable at both ends. Power cables shall be identified with red, yellow, blue PVC adhensive tapes. Where copper to aluminum connection is made necessary, bimetallic washers shall be used. Drilling of holes for cable glands shall be included wherever necessary. Cables shall be neatly arranged dressed in trenches in such a manner so that criss-crossing is avoided and final take off to equipment is facilitated. Cable trenches in CP room should be suitably covered by MS slabs. Detailed layout to be prepared and furnished by CONTRACTOR for ENGINEERs approval

7.5.0 TEST STATIONS:

7.5.1 All test stations shall have weather proof enclosure with hinged lockable front cover. Enclosure shall be made of sheet steel of at least 3mm thickness. Enclosure shall be weather proof having degree of protection IP-55 as defined in IEC-529 and shall be suitable for MS post mounting.

7.5.2 Name plate should be provided inside each test station giving the following information

a)Connection scheme diagram b)Chainage location of test station and direction of flow.

7.6.0 INSULATING JOINT (I.J) GROUNDING CELL Grounding cell across each insulating joint shall be provided while its connection to pipe on both shoulders of joint shall be through test station. Besides the above, measurement cable from pipe from both shoulders of I.J. shall be taken out and terminated at test box.

Cables for connecting of grounding cell to pipe shall be 1C x 16mm2 (minimum), XLPE insulated PVC sheathed unarmoured copper conductor and shall be CONTRACTORs supply.

Grounding cell for each I.J. shall consist of a pair of zinc rods of required size and weight. The pair shall be separated by insulation spacers and the entire assembly wrapped with PVC tapes shall be packed in chemical backfill of Bentonite, Gypsum and Sodium Sulphate. Each zinc rod shall be complete with 1C x 15 mm2 (minimum) XLPE insulated PVC sheathed copper cable of minimum 3m length to reach test station.

The entire grounding cell consisting of zinc rod surrounded by backfill with an overall dimension of 615 x 515 x 1500mm shall be laid underground at a minimum depth equal to pipe burial depth and adjacent to pipe.

7.7.0 EARTHING

Earthing of T/R unit shall be done as per standards. Total resistance of each earthing grid to earth shall not exceed 1.0 ohm.

8.0.0 TRANSPORTATION, HANDLING AND STORAGE

8.1.0 All equipment/material shall be protected for inland transport, carriage at site, outdoor storage during transit and at site and shall be protected against corrosion, incidental damage due to vermin, sun light, rain, high temperature, humid atmosphere etc., for the entire period of despatch, storage and erection. The contractor shall be responsible for any damage to the equipment during transit due to improper and inadequate packing



9.0.0 SHOP TESTING AND INSPECTION

9.1.0 All plant and equipment covered by this contract shall be subjected to inspection and testing as defined in reference codes and standards. The contractor shall provide all service to establish and maintain quality of workmanship in his works and that of sub contractors.

9.2.0 For all manufactured items inspection by HPCL at the works is mandatory before despatch.

10.0.0 TESTING AND COMMISSIONING

10.1.0 The Contractor shall carry out all the pre commissioning tests and commissioning procedures after installation of the system as required and directed by the Site in Charge. Skilled labour, personnel, tools, equipment, instruments and all consumables required for testing and commissioning shall be provided by the Contractor.

10.2.0 The contractor shall have necessary instruments for carrying out the tests especially high input impedance digital multimeter, standard Cu/ CuSO4 half cell etc. Half cell chemical is to be changed periodically.

10.3.0 The contractor shall take readings of pipe line potential at all the monitoring points of the cathodic protection system by means of Cu/ CuSO4 electrode using high input impedance voltmeter.

10.4.0 The anode currents at each of the junction boxes shall be taken by measuring the voltage drop across the one ohm resistor provided in the junction box with the switch kept disconnected while taking the current measurement. After taking the measurement the switch shall be closed.

10.5.0 The current and the potential readings shall be submitted to the Engineer in Charge. Based on the above readings and on review of the same by the owner and the consultant, contractor shall carry out any modification/ rectification, installation/ replacement of anodes if required, at the rates quoted.

Final commissioning report and all final documents/ drawings shall be furnished as per Vendor Data Requirements. All drawings shall be submitted in soft copy also. After installation of cathodic protection system the vendor shall impart training to purchasers personnel on its operation and maintenance to the full satisfaction of the purchaser. During guarantee period ,contractor shall take periodic PSP readings.

11.0.0 AMC COMPREHENSIVE

AMC Comprehensive (including supply of spares and consumables)shall be provided for 2 years after the guarantee period. AMC shall cover taking periodic PSP reading for the smooth operation of the system for the 2 years AMC period. Terms and conditions of AMC to be followed is given elsewhere in the document.

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8113 Cathodic Protection Spec R1

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Transcript of 8113 Cathodic Protection Spec R1