Volume-II of IV - GAIL

MECON LIMITED
REGD. OFF : RANCHI (BIHAR)
PROCESS & PIPING
DESIGN SECTION
NEW DELHI
\\Akjha\work contrac\standard TS for Pipe Line WC (Vol-II) MASTER FOLDER\04A major water crossing\Major Water Crossing -Final 04.doc
STANDARD SPECIFICATION
TITLE MAJOR WATER CROSSINGS SPECIFICATION NO. PAGE 8 OF 14
3.3 Spoil
MEC/S/05/62/04 REVISION 0
Spoil which is not dumped on and including spoil acquired after cleaning the
water crossing trench, shall be transported and dumped in places, designated
thereto by agreement between CONTRACTOR and authorities and approved of
by COMPANY. Spoil shall be transported in (split) barges; only those barges
shall be used that avoid spilling during transportation due to incorrect closing of
the flaps, etc. Spoil which is dumped outside the designated places shall be
removed by CONTRACTOR at first notice by COMPANY.
3.4 Dykes, Dams and Weirs
CONTRACTOR shall install temporary provisions in the existing dykes, dams,
etc. to prevent flooding of low areas.
Therefore in general, in existing dykes, dams, etc a double substituting weir
must be installed before start of excavation in the existing dyke or dam. Such a
double substituting weir can be a closed wall of sheet piling, supported by soil.
The provisions shall be such that the underwater profile of the dredged trench,
the water movement caused by ships, etc. cause no slides/ cave-ins of the dyke
or dam.
4.0 CONTINUOUS CONCRETE COATING
CONTRACTOR shall provide concrete coating over the pipeline including the
bends in accordance with the specification issued for the purpose (refer
specification no. MEC/S/05/11/03 and approved procedure. CONTRACTOR
shall coat the weld joints in order to arrive at a continuously concrete coated
pipeline. However this concrete coating shall be applied after the hydrostatic
pretest.
5.0 HYDROSTATIC PRE-TESTING
CONTRACTOR shall hydrostatically pre-test the pipe string of each water
crossing before installation as per approved procedure.
Joint coating of the welds shall be done after this pre-test.
The section of the pipeline corresponding to the major water crossing shall,
before installation, be subjected to hydrostatic pre-testing to a combined
equivalent stress of 90% of the SMYS of the pipe material.