11.00.00 PROCESS CONNECTION AND PIPING AND
INSTRUMENTATION INSTALLATION REQUIREMENTS
11.01.00 All process connection , piping etc shall be conform to ANSI/ISA SP 77.70- 1994 (R 2005) “ Fossil Fuel Power Plant Instrument Piping Installation” , ANSI B 31.1 Power Piping ,ANSI/ASME B 1.20.01 ,ANSI/ASME B 16.5 ,PTC 19.11.1997,PTC 23.2003 & IBR .
11.02.01 Impulse Piping/ Tubing System
Instrument impulse piping, tubing fittings and
accessories for the connection of instruments and
control equipment to the process and to make the system
complete shall be furnished. All materials furnished
shall meet the requirements of ASTM and ANSI standards
for the equivalent of these standards. The impulse
piping, tubing, fittings and accessories shall have the
same design pressure and material temp.as applicable for
the particular main process piping.
11.02.02 For instruments/ devices mounted inside enclosures racks
also the impulse pipes of the same material as main
process pipe shall be employed except that tubes (as per
ASTM A 213)shall be employed for connections from tee
(inside the transmitter enclosures/racks)to value
manifolds and instruments. The impulse tube material
for high pressure application shall be 316 H stainless
steel and low pressure application 316 L stainless steel.
11.02.03 All impulse pipe shall be of seamless type and shall
conform to ANSI B 31.1 for schedule Nos .sizes and
11.02.04 The valve manifolds shall be of stainless steel 316 with pressure rating suitable for intended application.2valve manifold and 3 valve manifold shall be used for pressure measurements using pressure transmitters/pressure switches and Diff. Pressure transmitters/switches respectively. 5 valve manifold shall be used for remaining applications like DP, flow and level measurements.
11.02.05 Condensate pots, also referred to as reservoirs, shall be designed in accordance with ANSI B 31.1.
11.02.06 Fittings and fitting components shall contain no metallic mercury or mercury compounds and shall be free mercury contamination, except as alloying elements of the required base or bonding corrosion resistant plating.
Fittings and fitting components shall not contain low melting-point metals (such as lead, antimony, arsenic, bismuth, cadmium, magnesium, tin or zinc)in concentrations greater than 250 ppm, except as alloying elements of the required base materials. Asbestos shall not used .
11.02.07 All fittings shall be forged steel and shall conform to ANSI B 16.11.The material of forged tube fittings for shaped application (e.g. Tee, elbow etc.)shall be ASTMA 182 Gr.316 H for high pressure/ Temp. applications and ASTMA 182 Gr.316 L for other applications. The material for bar stock tube fitting (for straight application) shall be 316 SS. Metal thickness in the fittings shall be adequate to provide actual bursting strength equal to or greater than those of the impulse pipe or SS tube, with which they are to be used.
11.02.08 The source shut-off(Primary process root valve) and blow down valve shall be of half inch size globe valve type for all applications except for air & flue gas service wherein no source shut-off valves are to be provided. The disc and seat ring materials of carbon steel and alloy steel valves be ASTM A-105 and ASTM A-182, Gr.F22, hard faced with stellite (Min. hardness 350 BHN). The surface finish of 16 RMS or greater is required in the area of stem packing. The valve design shall be such that the seats can be reconditioned and stem and disc may be replaced without removing the valve body from the line.
11.02.09 Blow down valve shall be gradual open type.
11.03.00 Air Supply Piping
(a)The bidder shall include in his scope, all pneumatic
piping, fittings, valves air filters, regulators and
other accessories required for instrument air for the
various pneumatic devices/ instruments from the Owner’s
instrument air terminal point to the bidder’s pneumatic
devices/ instrument. The instrument air scheme shall be
subject to owner’s approval. The pneumatic piping shall
be of heavy duty GI( as per IS 1239). The quality and
itemized consumption of instrument air required
shall be indicated by the bidder.
(b) Copper tubing of 1/4″size , thickness of cu tubing shall not be less than 0.065 inch & light drawn temper tubing conforming to ASTM B-75. Copper tubing shall be PVC coated and tube fittings shall be of flare less brass.
11.04.00 Installation and Routing of Instrument Piping and Tubing
The primary impulse piping system shall include the
instrument piping and all required accessories from
process tap off up to the respective instruments. The
Contractor shall provide the necessary fittings and
accessories along with impulse pipes for completeness.
Special accessories such as condensing pots, reservoirs
and other devices etc. shall be provided and installed
wherever required by the design of the instruments in
accordance with the instructions of the instrument
manufacturer. In any case Bidder shall provide and
install condensing pots for all level measurements of
steam and water services. All flow measurements in
steam services and water services above 120 Deg.C.
Impulse piping shall include a blow down line and shut
off valve adequate for the duty requirements and for
withstanding continuous design pressure and temp.of
process medium. For process pressure equal or above 40
Kg/Sq.Cm.g or temp. above 300 Deg.C double valves shall
be used before connecting to the blow down header. The
blow down header shall have to be connected to the
nearest plant drain by the bidder and pipes of ASTM-A-
105 Gr. B to be provided by bidder on as required basis
for this purpose.
11.05.00 All impulse piping shall be supported rigidly at an
interval not exceeding 1.5 meters so as to prevent
excessive sag in piping. Process piping shall not be
used for supporting impulse piping.
Impulse piping shall be installed to permit thermal
expansion without placing excessive stress on the piping
and without affecting the gradient of slope. Long
continuous straight runs of piping shall always to
avoided. If required, expansion loops shall be provided
atleast every 2.5 meters to break the continuity.
Cold bending of impulse pipes shall be performed with
the use of a proper pipe bender with radius of bend
greater than 5 times the outside dia of the pipe. Bends
shall be true to angle and radius and shall be true
circular cross section of the pipe without buckling. Any
pipes damaged during bending operation shall not be
11.06.00 All welded and acre wed fitting shall conform to ANSI-B-
16.11. Threads of piping components shall be taper pipe
thread in accordance with ANSI-B-2.1. All threads shall
be clean machine cut with all burrs and chips removed.
Lubricant shall be of dry file type.
11.07.00 Provision for continuous purging requirement is to be made for all air & flue gas applications.
11.08.00 Testing at site
a) Hydrostatic and pneumatic tests shall be performed on
all pipes, tubes, systems and shall confirm to ANSI-B 31.1 and ANSI/ISA SP 77.70- 1994 (R 2005).
All instrument piping/ tubing shall be hydrostatically
tested upon completion of erection. The test pressure
shall be 1.5 times the maximum process pressure.
b) Air header & branch pipes shall be air tested by pressure
Decay method as per ANSI – B 31.1 after completion of
11.09.00 Material Certification
11.09.01 Material of Construction
All material used in construction of piping and components
shall be certified by the manufacturer with a certificate of compliance to the ASTM/ASME specifications. The manufacturer
shall submit quality assurance program for material control and verification.
11.09.02 Certificates of Compliance
All certificates of compliance applicable to material used in a component should be furnished by the manufacturer with the material at the time of shipment.