Volume-II of IV - GAIL

MECON LIMITED
Delhi
PROCESS & PIPING
DESIGN SECTION
TECHNICAL SPECIFICATION FOR
PERMANENT CATHODIC
PROTECTION SYSTEM
TECHNICAL SPECIFICATION NO. : MEC/TS/05/62/016B REV-1 Page 7 of 24
The detailed specification of each system and equipment shall be furnished by the
CONTRACTOR. However, certain minimum requirements for the major equipment are
highlighted in this document.
All equipment shall be new and procured from approved reputed manufacturers.
Equipment offered shall be filed proven. Equipment requiring specialised maintenance
or operation shall be avoided as far as possible. Protytype equipment shall not be
accepted. Make and construction of all materials shall be subject to owner’s approval.
As far as possible, equipment including test stations, anode lead junction boxes etc.
shall be located in safe non-hazardous areas. However, all equipment to be installed in
hazardous areas shall be of flameproof type confirming to IS:2148 and suitable for gas
groups IIA & IIB and temperature class – T3.
7.1 Cathodic Protection Stations
The number and exact locations of CP stations shall be worked out based on the
corrosion survey data collected. In addition, the following guidelines shall be followed
for selecting the locations.
i) Number of CP stations and their selected location shall ensure that these
remain valid and are adequate for the full design life of the system after
considering all foreseeable factors.
ii) As far as possible, the availability of nearly low resistivity areas for location of
associated ground beds must be ensured while selecting the locations of CP
stations.
iii) As far as possible, locations of intermediate CP stations shall co-incide with the
locations of SV stations.
The proposed locations of CP stations are detailed in project specifications. The same
shall be verified for adequacy by the contractor and any additional requirements shall
be clearly brought out at the bidding stage itself.
7.2 Transformer Rectifier Unit/ CPSSM
7.2.1 Cathodic protection transformer rectifier unit (T/R Unit) working on controlled
rectification principle shall supply power for cathodic protection system. The T/R unit
shall be provided at CP stations where reliable power supply is available and specified
in project Specification.
The T/R unit shall be filed proven. The design, internal component quality, ratings and
layout of components shall ensure high MTBF and low MTTR.
The T/R unit shall conform to MECON’s specification no MEC/TS/05/62/072 and T/R
unit data sheet.
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