Guide to Piping Engineering
32
103 of 226 5.0 Piping
description
Guide to Piping Engineering
Transcript of Guide to Piping Engineering
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5.0 Piping
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5.1 INTRODUCTION TO PIPING ENGINEERING
Piping is a major contributory in the Design and Construction of
Refinery,
Petrochemical,
Oil & gas plants
5.2 BASICS OF PIPING
PIPING:
Piping is system of pipes which along with the inline components such as flanges, valves, fittings,
bolts, gaskets and supports used to convey the fluids from one location to another.
PIPE SIZE:
Pipes are usually specified by the standard pipe size designations such as Nominal Pipe size and
wall thickness.
Nominal pipe size (NPS): It is dimensional designator of pipe size. It indicates standard pipe size
when followed by the specific size designation number without an inch symbol.
Diameter nominal (DN): is also a dimensionless designator of pipe size in the metric unit
system, developed by the International Standards Organization (ISO). It indicates standard pipe
size when followed by the specific size designation number without a millimeter symbol.
Pipe wall thickness (Schedule) is expressed in numbers. A schedule number indicates the
approximate value of the expression 1000 P/S, where P is the service pressure and S is the
allowable stress, both expressed in pounds per square inch (psi).
The higher the schedule number, the thicker the pipe. The outside diameter of each pipe size is
standardized. Therefore, a particular nominal pipe size will have a different inside diameter
depending upon the schedule number specified.
ScheduleCarbon steel(ANSI B16.10)
Stainless steel(ANSI B16.19)
5,10,20,30,40,60,80,100,120,160
5S, 10S, 20S, 30S, 40S, 60S, 80S
Weight series
Std
XS
XXS
Standard
Extra strong
Extra Extra Strong
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5.2.1 PIPING CLASSIFICATION
It is usual industry practice to classify the pipe in accordance with the pressure temperature rating
system used for classifying flanges. However, it is not essential that piping be classified as Class
150, 300, 400, 600, 900, 1500, and 2500. The piping rating must be governed by the pressure
temperature rating of the weakest pressure containing item in the piping. The weakest item in a
piping system may be a fitting made of weaker material or rated lower due to design and other
considerations.
Piping Class Ratings Based on ASME B16.5 and Corresponding PN
In addition, the piping may be classified by class ratings covered by other ASME standards, such
as ASME B16.1, B16.3, B16.24, and B16.42. A piping system may be rated for a unique set of
pressures and temperatures not covered by any standard.
Nominal Pressure (PN) is the rating designator followed by a designation number, which
indicates the approximate pressure rating in bars. The bar is the unit of pressure, and 1 bar is
equal to 14.732 psi or 100 kilopascals (kPa).
5.2.2 PIPING MATERIALS:
Piping material selection is mainly based on their strength to withstand stress, corrosion
resistance, weldability, etc. Broad classifications of the piping materials are metallic, non-metallic
and lined.
Sl.
No.Material
Tolerable Temperature
rangeService
1 Carbon Steel -29 0C to 427 0CNon corrosive fluid services
where impurities are accepted
2 Alloy Steel -29 0C to 600 0CNon corrosive fluid services
where impurities are accepted
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3
Stainless
Steel/
Duplex SS
-29 0C to 800 0C
Corrosive fluid services
where impurities are not
accepted
4
Low
Temperature
carbon Steel
-48 0C to 400 0C
Non corrosive & low temp
fluid services where impurities
are accepted.
5Galvanized
steel
Drinking water, instrument air
& nitrogen (LP)
6 PVC Max 600 CFor Acidic Fluid Service
Conditions.
7 GRP Corrosive fluid / Water
Selection of the material based on temperature and pressure shall comply with some codes and
standards.
5.2.3 PIPE FITTINGS:
Fittings are used in pipe systems to connect straight pipe sections to adapt to different sizes or
shapes to regulate the flow of fluid. Different types of pipe fittings used are:
Cap Tee Reducer Coupling Olets Elbow Cross Y-Bend
Different types
reducer elbow olets tee
concentric 900
weldolet Reducer teefittings
eccentric 450
sockolet
Olets are used when there is a sudden reduction in the pipe size from large bore to small bore in
case of instrument tapping.
The above fittings are connected to the pipe by the following methods:
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Spectacle Blind/Spacer & Blind
This is used in between two flanges to completely stop or allow the flow of the fluid in the
pipeline.In a process plant, blanks are usually required to isolate individual pieces of equipment at
shutdown and to positively block off selected process lines at the
process unit limits. They are also needed during operation wherever
positive shutoff is required to prevent leakage of one fluid into another.
Blanks, especially for larger size flanges, are typically provided with a
companion spacer which has a full-size opening consistent with the inside bore diameter of the
flange.
In the piping or at the nozzle of all process and utility connections to vessels where
necessary to provide safe entry for inspection and maintenance personnel
In the suction and discharge lines of all turbines and compressors, except atmospheric
suction of air fans
At the inlets and outlets of process piping to fired heaters
All fuel and pilot gas headers to each fired heater
Spared equipment capable of being bypassed for maintenance
Safety valve bypass lines
Process battery limits
Butt welding
Socket welding
Threaded/Seal weld
Flanges
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Blanks should be made from a plate or forging specification, approved for use by ASME
B31.3, of essentially the same chemical composition as the mating flanges and piping
involved.
Pipe Fittings & Connections
Butt welded connections shall normally be used for all alloy/carbon steel piping of 2” &
larger.
Alloy/carbon steel piping of 1.5” NB and below shall be socket welded.
Threaded connections shall be avoided except in galvanized piping.
Flanged joints shall be minimized as it is a point of potential leakage. Flanges are used
when the joints need dismantling. It may be used to connect piping to equipment or
valves, to connect pipe lines of dissimilar materials, where spool pieces are required to
permit removal or servicing of equipments and where pipes and fittings are with flanged
ends.
Notes:
All pipe lines carrying toxic/inflammable fluids shall be seamless.
Utility piping can be ERW or seam welded.
Steam pipe lines shall be preferably seamless.
Hose & Hose couplings
Where temporary connections are required, there this type of fitting is provided
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5.2.4 VALVES:
Valves are used in the pipe lines to regulate the flow of fluids. Different types of valves are used
to meet the flow requirement
CLASSIFICATION OF VALVES
1. Based on functions
Isolation Regulation Non-Return Special Purpose
Gate Valve
Ball Valve
Plug Valve
Piston Valve
Diaphragm Valve
Globe Valve
Needle Valve
Butterfly Valve
Diaphragm Valve
Piston Valve
Pinch Valve
Check Valve
Multi-port Valve
Flush Bottom Valves
Float valves
Line Blind valves
Foot Valves
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Butterfly valve: these have quick opening and closing, quarter turn
mechanism to control the flow of fluid through the pipe line.
Gate valve: is a valve that opens by lifting a round or rectangular
gate/ wedge out of the path of the fluid. These are commonly used
to close or open the valve completely, sometimes may be used to
regulate the flow
Globe valve: Globe valves are spherical in shape. The two halves
of the valve body are separated by an internal baffle which has an
opening forming a seat onto which a movable disc can be screwed in
to close (or shut) the valve. In globe valves, the disc is connected to a
stem which is operated by screw action. Globe valves are used for
applications requiring throttling and frequent operation.
Based on operation
Self Operated Valves
Check Valves
Based on End Connection
Screwed Ends
Flanged Ends
Butt Weld Ends
Wafer Type
Buttress Ends
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Ball valve: These are used for tight shutoff operations. A ball valve (like the
butterfly valve, is one of a family of valves called quarter turn valves) is a
valve that opens by turning a handle attached to a ball inside the valve. The
ball has a hole, or port, through the middle so that when the port is in line
with both ends of the valve, flow will occur. When the valve is closed, the
hole is perpendicular to the ends of the valve, and flow is blocked. Cannot be used for regulating/
throttling applications.
Check valves: Check valves, also referred to as "non-return"
or "one-way directional" valves, are very simple valves that
allow fluid, air or gas to flow in only one direction. When the
fluid moves in the pre-determined direction, the valve opens.
Any backflow is prevented by the moveable portion of the
valve.
Solenoid Valves: Solenoid valves are electrically operated devices
that control the flow of liquids. Solenoid valves are electro-
mechanical devices that use a wire coil and a movable plunger,
called a solenoid, to control a particular valve. The solenoid
controls the valve during either the open or closed positions. Thus,
these kinds of valves do not regulate flow. They are used for
the remote control of valves for directional control of liquids.
5.2.5 PIPE STRESS ANALYSIS:
Piping Stress analysis addresses to the static and dynamic loading calculations which result from
the effect of gravity, temperature changes, internal and external pressures, change in the fluid
flow rate, and seismic activity.
One way to reduce stress in pipe lines is by making them more flexible to stress which otherwise
results in the failure of the pipe, leakage at the joints/flanges or detrimental distortion of
connected equipments. We accomplish this by performing Stress Analysis of critical sections
(i.e., critical lines) of the piping system. Stress Engineer identifies the Critical Lines based on the
changes in the operating conditions such as temperature, pressure and vibrations in the piping
system.
Stress of a material is defined as the internal resistance per unit area to the deformation caused by
the unit load. Different types of stresses that occur in the piping system are:
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Primary stresses Secondary
Stresses Local Stresses
1 Direct shear and bending in
nature
Bending in
natureLocalized bending and shear in
nature
2
Caused due to dead weight of
pipe, piping components, internal
pressure, Occasional loads like
wind, seismic load
Caused due to
thermal
expansion
Caused due to local load like
load of welded lug on pipe
Pipes can be made flexible to thermal expansion by providing them with expansion
loops/expansion joints or bellows. Another way is to give supports at appropriate points to avoid
failure by bending/sagging.
The purpose of the pipe stress analysis is to ensure the:
Safety of the piping and piping components.
Safety of the connected equipment and supporting structure
and also to ensure that the piping deflections are within the limit
STRESS ANALYSIS I/O TABLE
Inputs Outputs
Geometric layout of pipe Stress in piping system for different loading conditions
Pipe support configuration Expansion of piping system in different operating
temperatures
Pipe diameter and thickness Deflection of piping system under occasional loading
Pressure inside the pipe Correctness of the selection f load
Cold and hot temperature of pipe Load at various supports and restrains
Weight of pipe and insulation Movement of pipe at support locations
Weight of carrying fluid Pipe terminal point loading
Pipe material property Allowable limit for the nozzle loads
Occasional loads (seismic, snow, …)
Corrosion allowance of pipe
Bend radius,
Any transient load like steam hammer
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5.2.6 PIPE SUPPORTS:
Supports are provided to the pipe mainly for the following reasons:
To Support dead weight of Piping system
To minimize Pipe Sagging
To take Expansion load in the Piping system
To absorb wind load and Seismic load
To absorb Vibration in the Piping system
To absorb Hydraulic Thrust in the Piping system
To absorb the Pressure Thrust of Bellow
To Support the system during Shut down/ Maintenance Conditions.
Various types of supports available are:
Guide Support:
This type of support is used to restrict lateral movement of pipe. This is used in
combination with rest support. This type of support also can be used to restrict
vertically upward movement of pipe.
Restraints Support:
This type of support is used to restraint movement of pipes in specific direction based on job need
.This type is used in combination with rest and guide support.
Anchor Support:
This type of support is usually used for segmenting the piping
network to restrict the movements of pipe of reasonable
amount within the defined piping network. This type of
support does not allow movement in any direction. i.e. it
ceases all axial, lateral, and torsional movements offered by
piping network. It can be achieved by welding the support
component to pipe and supporting structures or by using a combination of rest, guide and restraint
support.
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Rest Support:
This type of support is used to transfer the static load of pipe, content, insulation and piping
components to control the sagging phenomenon i.e; deflection of piping network within
allowable limits. Rest support allows movements of pipe in all directions except vertically
downward movements. Rest support means pipe resting directly on supporting structure on a
saddle plate or pipe shoe.
Rigid hangers & supports:
Rigid hangers are used at suspension points where there is no
vertical pipe movement. Where as rigid support is given from the
bottom &usually rests on the floor. E.g.: Pipe shoe,, U –clamp,
Variable effort hangers/ supports and Constant effort hangers/ supports:
These two come under flexible support using helical coil
compression spring. Variable pipe support is used to support
the weight of the pipe work while allowing a degree of
movement relative to the supporting structure. Constant pipe
support is used to support the pipe work in the case of large
vertical movement.
Spring loaded sway braces
Dynamic restraints/ rigid struts
Snubbers /shock absorber
Based on the construction Based on the functions
1 Rigid support: Welded type, Bolted type Loose/ resting support
2 Adjustable support Longitudinal guide support
3Elastic/ flexible support : Constant Snubber,
Variable Snubber Transverse guide support
4 As required Anchor support: welded type
Non-welded type
5 As required Limit stop
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INPUTS REQUIRED FOR THE SELECTION OF PIPE SUPPORTS
Piping general arrangement drawing.
Steel and structural drawing.
Equipment foundation drawing.
Location of ventilating ducts, electrical trays, pumps, tanks, etc.,
Piping specifications and line list.
Insulation specification.
Valves and special fittings list.
Determination of support location
Determination of thermal movement of the piping at each support location
Calculation of load at each support location.
Selection of the type of support i.e., anchor, guide, rest, constant or variable spring, etc.,
Checking the physical interference of the support with structures, trays, ducts &
equipment, etc.,
5.3 SOFTWARE USED IN PIPING DEPARTMENT
PDS 7.02/8
PDMS 11.5
ISOGEN 7.0
ORTHOGEN 8.000.19
Navis works 5.3/5.5 for 3D Model review package
ACAD 2007/2008 for 2D Drawing preparation
Micro station 7.01/8 for 2D / 3D drawing preparation
CEASER II Ver5.007 – Stress Analysis Package
5.4 IMPORTANT CODES AND STANDARDS
ANSI - American National Standards Institute
API - American Petroleum Institute
ASME - American Society of Mechanical Engineers
ASTM - American Society for Testing and Materials
AWWA - American water works association.
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Pipe Standard
Pipes shall conform to
API 5L,
ANSI B36.10 for Carbon steel
ANSI B36.19 for Stainless steel
Based on chemical and material composition several codes applied
AMERICAN STANDARDS
API STANDARDS
API 5L Specification for Seamless and Welded Steel Line Pipes
API 6D Specification for Pipeline Valves, Gate, Plug, Ball and Check
API 600 Steel Gate Valves, Flange and Butt Welding Ends
API 601 Metallic gasket for refinery piping
API 609 Lug- and Wafer-Type butterfly Valves
API RP 14E Design & Installation of Offshore platform piping systems
API RP 521 Guide for Pressure Relieving systems
ASME STANDARDS
ASME B16.5 Steel Pipe Flanges and Flanged Fittings
ASME B16.9 Factory Made Wrought Steel Butt Welding Fittings
ASME B16.10 Face to Face and End to End Dimensions of Valves
ASME B16.11 Forged Fittings, Socket-Welding and Threaded
ASME B16.20 Metallic Gaskets for Pipe Flanges
ASME B36.10 Welded and Seamless Wrought Steel Pipe
ASME B36.19 Stainless steel Pipe
ASME B31.3 Process Piping
ASME B16.5 Pipe flanges and fittings ( 24”)
ASME B16.47 Large diameter flanges (>24”)
ASME B31.4 Pipeline Transportation Systems for Liquid Hydrocarbons & other
liquids
ASME B31.8 Gas Transmission & Distribution Piping Systems
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ASTM STANDARDS
ASTM A 53 Welded and seamless pipe
ASTM A 106 Seamless CS pipe for high temperature services
ASTM A 312 Seamless and welded austenitic stainless steel pipes
ASTM A 333 Seamless and welded steel pipe for low temperature service
ASTM A 335 Seamless ferritic alloy steel for high temperature service
ASTM B 423 Incoloy piping material
AWWA STANDARDS
AWWA C207 Steel Pipe Flanges for Waterworks Service examination of welded joints
AWWA C950 Fibreglass Pressure Pipe
5.5 CALCULATIONS:
5.5.1 Design of pipe wall thickness
The piping wall thickness is one of the most important calculations of the piping system design
process. In arriving at the final specification of the piping wall thickness, the designer must
consider a number of important factors:
Pressure integrity
Allowances for mechanical strength, corrosion, erosion, wear, threading, grooving, or
other joining processes
Manufacturing variations (tolerance) in the wall thickness of commercial pipe
Wall thickness reduction due to butt-welding of end preparation (counterboring)
While a number of different pipe wall thickness design formulas have been proposed over the
years, the ASME piping codes have adopted one or the other of the following formulas for
pressure-integrity design:
Thickness (tm) = (PD / 2(SE+PY)) + A
Where,
tm = Minimum thickness
P = Internal design gauge pressure
D = Outside diameter as per standard
S = Stress value for material
E = Joint Efficiency factor
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Y = Coefficient of material for that design temperature
5.5.2 Stress Analysis Case Study for Combined Cycle Power Plant
Piping stress analyses is a term applied to calculations which address the static and dynamic
loading resulting from the effects of gravity, temperature changes, internal and external pressures,
changes in fluid flow rate, seismic activity, fire, and other environmental conditions. Codes and
standards establish the minimum scope of stress analyses. Some codes prescribe loading
combinations with not-to-exceed stress limits.
The High Pressure (HP) steam system is designed per ASME-B31.1(Power Piping Code) to
convey HP superheated steam, from the HP superheater outlet to the high pressure section of the
steam turbine. HP steam line is provided with a bypass line, with a combined pressure reducing
and steam desuperheating valve and is connected to the Condenser.
Normal Operation
Start-Up/Shutdown Operation
5.5.2.1 Input Data:
Pipe Size = 8 inches for Main Steam Pipe
Pipe Thickness = 160 Sch
Insulation Thickness = 7.5 inches
Pipe size = 24 inches for Bypass connection
Pipe Thickness = STD
Insulation Thickness = 2.5 inches
Design Temperature = 955.4 ° F
Design Pressure = 1450 psi
Pipe Material = ASTM A335 P22
Insulation Material = Calcium silicate per ASTM C533 for heat retention
Pipe Construction = Seamless
Flange type = Not Allowed
Fittings Greater than 2 inch
ASTM Spec. = B16.9, B16.28
Type = Butt Weld
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Fittings Less than 2 inch
ASTM Spec. = A182 F22
ASME STD. Type = B16.11
Rating = 9000 Class
Type = Socket Weld
Attemperator weight = 1322.5 lbs per 7.87ft
5.5.2.2 Pipe Behaviour in Thermal Condition - Iteration –I
Maximum stressed Node - Iteration I
NODE NODE STRESS ALLOWABLE RATIO
TYPE (PSI) STRESS (PSI)
95 8 144000 29180. 4.935
320 1 60800. 29028. 2.095
50 1 42200. 28083. 1.503
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5 7 33000. 28619. 1.153
55 8 31400. 28639. 1.096
Ratio is more than 1, means that the stresses are exceeding the allowable stress limits and
thus the nodes get fails.
Equipment Nozzle reaction
HRSG
LOAD CASE ORCES (LBS) MOMENTS (FT-LBS)
HOT & WEIGHT FR = 4082 MR = 60244.
COLD & WEIGHT FR = 3516 MR = 72069
Turbine
HOT & WEIGHT FR = 6068 MR = 36673.
COLD & WEIGHT FR = 6679 MR = 44044.
Condenser
HOT & WEIGHT FR = 1102 MR = 6646.
COLD & WEIGHT FR = 1734 MR = 9026.
Pipe Behaviour In Thermal Condition - Iteration –II
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Maximum stressed Node - Iteration II
NODE NODE (TYPE ) STRESS (PSI) ALLOWABLE
STRESS (PSI)
RATIO
325 11 24500 29443 0.832
305 8 21700 29332 0.740
5 7 19800 28606 0.692
330 7 18600 29494 0.631
55 8 16000 28651 0.558
95 8 14400 29015 0.496
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Equipment Nozzle reaction
HRSG
LOAD CASE FORCES (LBS) MOMENTS (FT-LBS)
HOT & WEIGHT FR = 3924 MR = 56488.
COLD & WEIGHT FR = 3260 MR = 67373
Turbine
HOT & WEIGHT FR = 5983 MR = 33526.
COLD & WEIGHT FR = 6503 MR = 40128
Condenser
HOT & WEIGHT FR = 1109 MR = 9508.
COLD & WEIGHT FR = 1674 MR = 12032
Final Iteration
As the same Lot of trail and error iteration has been done to keep the pipe within permissible limit
in dead weight, minimum stresses at all nodes and all the three equipment nozzles within the
allowable limits as specified by the manufacturer of the same.
Finally by doing lot of iteration the best solution has arrived which gives Minimum stresses in
Piping, Meets the code limits, Meets the Equipment forces and moments.
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5.6 PIPING MATERIAL SELECTION CHART:
This chart tells the material to be used for plates, pipes, flanges, fittings, bolting for different
range of temperature.
MATERIAL SELECTION GUIDE
Design Temperature, °FMaterial Plate Pipe Forgings Fittings Bolting
-425 to -321 Stainless Steel
SA-240-304,
304L, 347,
316, 316L
SA-312-
304, 304L,
347,316,
316L
SA-182-304,
304L, 347,
316, 316L
SA-403-304,
304L,
347,316, 316L
C
ryo
gen
ic
-320 to -151 9 Nickel SA-353 SA-333-8 SA-522-I SA-420-WPL8
SA-320-B8 with
SA-194-8
-150 to -76 3½ Nickel SA-203-D
-75 to -51 2½ Nickel SA-203-A SA -333-3
SA-350-
LF63SA-420-WPL3
-50 to -21 SA-516-55, 60
to SA-20 SA-333-6
SA-320-L7
with
SA-194-4
-20 to 4 SA-516-All SA-333-1
or 6
SA-350-LF2 SA-420-WPL6
Lo
w T
emp
era
ture
5 to 32 SA-285-C
Inte
rmed
iate
33 to 60
61 to 775
Carbon Steel
SA-516-All
SA-515-All
SA-455-II
SA-53-B
SA-106-B
SA-105 SA-
181-60, 70 SA-234-WPB
776 to 875 C-½Mo SA-204-B SA-335-P1 SA-182-F1 SA-234-WP1
1Cr-½Mo SA-387-12-1 SA-335-
P12SA-182-F12 SA-234-WP12
876 to 1000
1¼Cr-1Mo SA-387-11-2 SA-335-
P11SA-182-F11 SA-234-WP11
SA-193-B7
with
SA-194-2H
1001 to 1100 2¼Cr-½Mo SA-387-22-1 SA-335-
P22SA-182-F22 SA-234-WP22
SA-193-B5
with
SA-194-3
Stainless
SteelSA-240-347H
SA-312-
347H
SA-182-
347HSA-403-347H
1101 to 1500
Incoloy SB-424 SB-423 SB-425 SB-366
E
lev
ate
d T
emp
era
ture
1500 Inconel100
SB-443 SB-444 SB-446 SB-366
SA-193-B8
with
SA-194-8
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5.7 STANDARD FORMAT USED FOR:
5.7.1 PIPING MATERIAL SPECIFICATION
PIPING CLASS DESIGNATION KEY
Flange Class :( in pounds)
150
300
600
900
1500
2500
PN160 BAR.
PN 200/325/500 BAR (IG STANDARD).
Piping Material:
C.S, ASTM A 106, GR.B / API 5L, GR.B
C.S, ASTM A333, GR.6 (LOW TEMP).
C.S, ASTM A335, GR.P11 (HIGH TEMP).
S.S, ASTM A312, GR.TP316L
S.S, ASTM A312
S.S, SMo (AVESTA 254 SMo ).
S.S, ASTM A312
C.S, ASTM A335, GR.P91 / P22
GRP
Duplex
Safurex
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PRODUCT CODE:
AC - Compressed Process Air
AL - Ammonia Liquid
AM - Ammonia Vapour
AP - Process Air (Uncompressed)
AQ - Aqueous Ammonia
AF - Flash Gas
BH - Boiler Blow Down
CD - Carbon Dioxide
CL - Steam Condensate LP 6,9 / 7/ 6 barg
CT - Purified Process Condensate
CX - Steam Condensate HP 125 barg
CY - Steam Condensate MP 55 barg
GM - Methanated Gas
GV - Convert Gas
GN - Natural Gas
SV - Vapor (Contaminated Steam)
NI - Nitrogen
DR - Drains (Compr. House)
RW - Recirculation Cooling Water
WF - Boiler Feed Water
SM - Steam MP 26 barg (Sat. & Superh.)
SL - SteamLP 6.9 / 7 / 6 barg (Sat. & Superh.)
SX - Steam HP 125 barg (Sat. & Superh.)
The first letter in the pipe class represents the flange class, second letter represents the piping
material and third letter represents the serial number
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Piping Material Specifications summary table:
PIPE
CLASS
MINIMUM
CORROSION
ALLOWANCE
FLUIDS MATERIAL PRESSURE
RATING
AB2 1.6 mm AL,AM A333, Gr.6 # 150
BB2 1.6 mm AL, AM A333, Gr.6 # 300
FB1 1.6 mm AL A333, Gr.6 #1500
AA4 1.6 mm
AC, AF, AP, AQ, AT,
BH, CD, CL, CT, CX,
CY, GM, GV, NI, SL,
SV,SY,WA,WF, SM
A106, Gr.B/
API 5L, Gr.B # 150
AA5 1.6 mm AM,GB, GN A106, Gr.B/
API 5L,Gr.B # 150
AA6 1.6 mm CW, DR, RW A106, Gr.B/
API 5L,Gr.B # 150
AA7 1.6 mm MS A106, Gr.B # 150
AA8 1.6 mm MS A106, Gr.B # 150
BA4 1.6 mm
AF,AP,AQ,CD,CL,CP
DR,GI,GM,GV,HY,NI,
RW, SM,SL,SX,SY,WF,
CM
A106,Gr.B/
API 5L,Gr.B # 300
5.7.2 VALVE SCHEDULE:
Valve schedule is a document containing the database of valves which are used in a project. This
is prepared during the detailed engineering for reference
Valve schedule contains:
Valve tag no
Operation mode of the valve
Type of the valve
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Seat material
Body material
Process connection
Line no, datasheet no, model no, P&ID reference no
Name of the supplier and manufacturer
Bore type-full/ reduced
Application
The valve schedule is developed taking data from line P&ID, line list, data sheet.
5.8 SPECIALITY ITEMS
5.8.1 STRAINERS:
It is a screen installed in the pipe lines to allow the liquid to flow and to restrict the solid particles.
These solid / larger items fall to the bottom or are collected in a basket for later clean out. The se
strainers come in different styles based on the needs.
Two common types of strainers are:
Plate Strainer is the one in which liquid flows through a perforated plate. Often this plate is
corrugated to increase the surface area.
Basket strainer is the one in which strainer is shaped like a basket and usually installed in a
vertical cylinder. The basket strainer is easier to clean and also offers more straining surface area
than a plate strainer improves the flow rate or decreases the pressure loss through the strainer.
5.8.2 STEAM TRAP:
The duty of the steam trap is to discharge the condensate and non-condensable gases while not
permitting the escape of live steam. Almost all steam traps are automated valves which open,
close or modulate automatically.
Steam traps are broadly classified based on their applications:
Mechanical traps: they have a float that rises and falls with respect to condensate level ands have
a mechanical linkage attached which opens and closes the valve. E.g. inverted bucket, float type.
Temperature traps: they have a valve that is driven on/ off either by expansion/ contraction
caused by temperature change.
Thermo-dynamic Traps: they work on the difference in dynamic response to velocity change in
the flow of compressible and incompressible fluids. As steam enters, static pressure above the
disk forces the disk against valve seat. The static pressure over a large area overcomes the high
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inlet pressure of the steam. As the steam starts to condense, the pressures against the disk lessens
and trap cycles.
5.8.3 EXPANSION BELLOWS:
Expansion bellows are used to accommodate expansion in piping due to temperature changes if
such movements cannot be taken by expansion loops, cold springing, re routing and re spacing of
pipe.
5.9 GENERAL ABBREVATIONS AND DEFINITIONS
5.9.1 GENERAL ABBREVIATIONS:
ABS Absolute
ANSI American National Standards Institute
API American Petroleum Institute
ASTM American Society of Testing and Materials
ASME American Society of Mechanical Engineers
AWWA American Waterworks Association
AWS American Welding Society
BS British Standards
BW Butt-Welding ends
CI Cast Iron
CS Carbon Steel
DN Nominal Diameter
ERW Electric Resistance Welded
FB Full Bore
FF Flat Face
F/F Face to Face
ID Inside Diameter
ND Nominal Diameter
NB Nominal Bore
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NPS Nominal Pipe Size
OD Outside Diameter
PE Plain Ends
PN Nominal Pressure
RB Reduced Bore
RF Raised Face
RTJ Ring-Type Joint
Sch Schedule (wall thickness)
SS Stainless Steel
SW Socket Weld
5.9.2 GENERAL DEFINITIONS:
Alloy Steel: A steel which owes its distinctive properties to elements other than carbon. Steel is
considered to be alloy steel when the maximum of the range given for the content of alloying
elements exceeds one or more of the following limits:
Manganese 1.65 percent
Silicon 0.60 percent
Copper 0.60 percent
or a definite range or a definite minimum quantity of any of the following elements is specified or
required within the limits of the recognized field of constructional alloy steels:
Aluminum Nickel
Boron Titanium
Chromium (up to 3.99 percent)
Tungsten
Cobalt Vanadium
Columbium Zirconium
Molybdenum
or any other alloying element added to obtain a desired alloying effect. Small quantities of certain
elements are unavoidably present in alloy steels. In many applications, these are not considered to
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be important and are not specified or required. When not specified or required, they should not
exceed the following amounts:
Copper 0.35 percent
Chromium 0.20 percent
Nickel 0.25 percent
Molybdenum 0.06 percent
Anchor: A rigid restraint providing substantially full fixation, permitting neither translatory nor
rotational displacement of the pipe.
Blind Flange: A flange used to close the end of a pipe. It produces a blind end which is also
known as a dead end.
Branch Connection: The attachment of a branch pipe to the run of a main pipe with or without
the use of fittings.
Carbon Steel: A steel which owes its distinctive properties chiefly to the carbon (as
distinguished from the other elements) which it contains. Steel is considered to be carbon steel
when no minimum content is specified or required for aluminum, boron, chromium, cobalt,
columbium, molybdenum, nickel, titanium, tungsten, vanadium, or zirconium or for any other
element added to obtain a desired alloying effect; when the specified minimum for copper does
not exceed 0.40 percent; or when the maximum content specified for any of the following
elements does not exceed the percentages noted: manganese, 1.65 percent; silicon, 0.60 percent;
copper, 0.60 percent.2
Cast Iron: A generic term for the family of high carbon-silicon-iron casting alloys including
gray, white, malleable, and ductile iron.
Cold Bending: The bending of pipe to a predetermined radius at any temperature below some
specified phase change or transformation temperature but especially at or near room temperature.
Frequently, pipe is bent to a radius of 5 times the nominal pipe diameter.
Companion Flange: A pipe flange suited to connect with another flange or with a flanged valve
or fitting. A loose flange which is attached to a pipe by threading, van stoning, welding, or similar
method as distinguished from a flange which is cast integrally with a fitting or pipe.
Continuous-Welded Pipe: Furnace weldedpipe produced in continuous lengths from coiled
skelp and subsequently cut into individual lengths, having its longitudinal butt joint forge welded
by the mechanical pressure developed in rolling the hot-formed skelp through a set of round pass
welding rolls.
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Control Piping: All piping, valves, and fittings used to interconnect air, gas, or hydraulically
operated control apparatus or instrument transmitters and receivers.
Coupling: A threaded sleeve used to connect two pipes. Commercial couplings have internal
threads to fit external threads on pipe..
Ductile Iron: A cast ferrous material in which the free graphite is in a spheroidal form rather than
a fluke form. The desirable properties of ductile iron are achieved by means of chemistry and a
ferritizing heat treatment of the castings.
Electric Flash-Welded Pipe: Pipe having a longitudinal butt joint in which coalescence is
produced simultaneously Edge preparation. Over the entire area of abutting surfaces by the heat
obtained from resistance to the flow of electric current between the two surfaces and by the
application of pressure after heating is substantially completed. Flashing and upsetting are
accompanied by expulsion of metal from the joint.
Electric Fusion-Welded Pipe: Pipe having a longitudinal or spiral butt joint in which
coalescence is produced in the preformed tube by manual or automatic Electric arc welding. The
weld may be single or double and may be made with or without the use of filler metal.
Electric Resistance-Welded Pipe: Pipe produced in individual lengths or in continuous lengths
from coiled skelp and subsequently cut into individual lengths having a longitudinal butt joint in
which coalescence is produced by the heat obtained from resistance of the pipe to the flow of
electric current in a circuit of which the pipe is a part and by the application of pressure.
Extruded Pipe: Pipe produced from hollow or solid round forgings, usually in a hydraulic
extrusion press. In this process the forging is contained in a cylindrical die. Initially a punch at the
end of the extrusion plunger pierces the forging. The extrusion plunger then forces the contained
billet between the cylindrical die and the punch to form the pipe, the latter acting as a
mandrel.One variation of this process utilizes autofrettage (hydraulic expansion) and heat
treatment, above the recrystallization temperature of the material, to produce a wrought structure.
Forged and Bored Pipe: Pipe produced by boring or trepanning of a forged billet.
Hangers and Supports: Hangers and supports include elements which transfer the load from the
pipe or structural attachment to the supporting structure or equipment. They include hanging-type
fixtures such as hanger rods, spring hangers, sway braces, counterweights, turnbuckles, struts,
chains, guides, and anchors and bearing-type fixtures such as saddles, bases, rollers, brackets, and
sliding supports.
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Header: A pipe or fitting to which a number of branch pipes are connected.
Hot Bending: Bending of piping to a predetermined radius after heating to a suitably high
temperature for hot working. On many pipe sizes, the pipe is firmly packed with sand to avoid
wrinkling and excessive out-of-roundness.
Instrument Piping: All piping, valves, and fittings used to connect instruments to main piping,
to other instruments and apparatus, or to measuring equipment.2
Kinematic Viscosity: The ratio of the absolute viscosity to the mass density. In the metric
system, kinematic viscosity is measured in strokes or square centimeters per second.
Lapped Joint: A type of pipe joint made by using loose flanges on lengths of pipe whose ends
are lapped over to give a bearing surface for a gasket or metal-to-metal joint.
Nipple: A piece of pipe less than 12 in (0.3 m) long that may be threaded on both ends or on one
end and provided with ends suitable for welding or a mechanical joint. Pipe over 12 in (0.3 m)
long is regarded as cut pipe. Common types of nipples are close nipple, about twice the length of
a standard pipe thread and without any shoulder; shoulder nipple, of any length and having a
shoulder between the pipe threads; short nipple, a shoulder nipple slightly longer than a close
nipple and of a definite length for each pipe size which conforms to manufacturer’ standard; long
nipple, a shoulder nipple longer than a short nipple which is cut to a specific length.
Pipe Alignment Guide: A restraint in the form of a sleeve or frame that permits the pipeline to
move freely only along the axis of the pipe.
Pipe Supporting Fixtures: Elements that transfer the load from the pipe or structural attachment
to the support structure or equipment.
Pipeline or Transmission Line: A pipe installed for the purpose of transmitting gases, liquids,
slurries, etc., from a source or sources of supply to one or more distribution centers or to one or
more large-volume customers; a pipe installed to interconnect source or sources of supply to one
or more distribution centers or to one or more large-volume customers; or a pipe installed to
interconnect sources of supply.
Piping System: Interconnected piping subject to the same set or sets of design conditions.
Purging: The displacement during welding, by an inert or neutral gas, of the air inside the piping
underneath the weld area in order to avoid oxidation or contamination of the underside of the
weld. Gases most commonly used are argon, helium, and nitrogen (the last is principally limited
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to austenitic stainless steel). Purging can be done within a complete pipe section or by means of
purging fixtures of a small area underneath the pipe weld.
Saddle Flange: Also known as tank flange or boiler flange. A curved flange shaped to fit a
boiler, tank, or other vessel and to receive a threaded pipe. A saddle flange is usually riveted or
welded to the vessel.
Schedule Numbers: Approximate values of the expression 1000P/S, where P is the service
pressure and S is the allowable stress, both expressed in pounds per square inch.
Seamless Pipe: A wrought tubular product made without a welded seam. It is manufactured by
hot-working steel or, if necessary, by subsequently cold-finishing the hot-worked tubular product
to produce the desired shape, dimensions, and properties.
Socket Weld: Fillet-type seal weld used to join pipe to valves and fittings or to other sections of
pipe. Generally used for piping whose nominal diameter is NPS 2 (DN 50) or smaller.
Source Nipple: A short length of heavy-walled pipe between high-pressure mains and the first
valve of bypass, drain, or instrument connections.
Spiral-Welded Pipe: Pipe made by the electric-fusion-welded process with a butt joint, a lap
joint, or a lock-seam joint.
Stainless Steel: An alloy steel having unusual corrosion-resisting properties, usually imparted by
nickel and chromium.
Swivel Joint: A joint which permits single-plane rotational movement in a piping system.
Tack Weld: A small weld made to hold parts of a weldment in proper alignment until the final
welds are made.
Tee Joint: A welded joint between two members located approximately at right angles to each
other in the form of a T.
Tube: A hollow product of round or any other cross section having a continuous periphery.
Round tube size may be specified with respect to any two, but not all three, of the following:
outside diameter, inside diameter, and wall thickness. Dimensions and permissible variations
(tolerances) are specified in the appropriate ASTM or ASME specifications.
Welding Fittings: Wrought- or forged-steel elbows, tees, reducers, and similar pieces for
connection by welding to one another or to pipe. In small sizes, these fittings are available with
counter bored ends for connection to pipe by fillet welding and are known as socket-weld fittings.
In large sizes, the fittings are supplied with ends chamfered for connection to pipe by means of
butt welding and are known as butt-welding fittings.
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Wrought Pipe: The term wrought pipe refers to both wrought steel and wrought iron. Wrought in
this sense means ‘‘worked,’’ as in the process of forming furnace welded pipe from skelp or
seamless pipe from plates or billets. The expression wrought pipe is thus used as a distinction
from cast pipe. Wrought pipe in this sense should not be confused with wrought-iron pipe, which
is only one variety of wrought pipe. When wrought-iron pipe is referred to, it should be
designated by its complete name.
