8/12/2019 Piping Layout Unit V
1/14
1.Flow diagram or System flow diagram or Process flow
diagram(PFD)
2.Pipe Sizing
3.Piping and Instrumentation Diagram(P&ID)
4.Piping Layout
5.3D Modelling
6.Piping Stress Analysis
7.Detailing or Detail Drawing Preparation
HIERARCHY OF PIPING
DESIGN
8/12/2019 Piping Layout Unit V
2/14
Flow DiagramWhat is that?It is a diagram schematically showing the operational relationships among themajor system components and by stating the design and expected process
variables for selected modes of operation
Flow Diagrams should show the following:
All major equipment
Equipment names
Equipment identification numbers
Major bypass and recirculation lines
Control valves
Interconnections to other systems
Equipment ratings or capacities
Pipe sizes if required by office practice
8/12/2019 Piping Layout Unit V
3/14
Flow Diagram
Flow Diagrams should not show the following:
Pipe class
Pipe line numbers, unless required by office practice
Minor bypass lines
Isolation and shutoff valves
Maintenance vents and drains
Relief and safety valves
Instruments
Code class information
Seismic class information
8/12/2019 Piping Layout Unit V
4/14
Pipe SizingInput Parameters:
1.Mass flow rate
2.Pressure
3.Temperature
Steps:
1.Find out the diameter(ID) required for given flow rate by usingequation
Qv=AV (V is assumed initially based on guidelines)
2.Based on ID select OD
3.Now calculate minimum thickness As per code
4. Check provided Thk > Min.Thk
5. Actual Velocity < Assumed Velocity
8/12/2019 Piping Layout Unit V
5/14
Pipe SizingExample:
1.Steam mass flow rate(Qm): 130 tons/hr.2.Steam pressure: 92 kgf/cm2
3.Steam temperature: 520 C
Qm=AV
Qm=130 tons/hr=36.11 kg/s
Qv=Qm / density =36.11 / 0.037857
Qv=1.367 m3/s
1.367=A (55)A=0.02485 m2 Min.internal dia Di=177.9mm
From available market diameter Do=219.1mm
8/12/2019 Piping Layout Unit V
6/14
Specification of Materials
Carbon Steels:ASME SA 106 Gr.A/B/C
Alloy Steels:ASME SA 335 P11,SA 335 P22 Nickel and Nickel Alloys - ASTM B-366, ASME SB-366.
Stainless Steel:ASTM A-403 and ASME SA-403, 304 etc.,
Chrome-molybdenum:ASTM A-234 & ASME SA-234
Aluminum:ASTM B-361, 5083, 66061, 5086
Titanium:ASTM B-363 & ASME SB-363,
Other Materials: Nylon Bronze Polyamide
CPVC Polyethylene (PE)
EPDM PVC (Polyvinyl Chloride)
Fiberglass / Composite
Iron (Gray / Cast/ Ductile)
brass
8/12/2019 Piping Layout Unit V
7/14
8/12/2019 Piping Layout Unit V
8/14
8/12/2019 Piping Layout Unit V
9/14
Piping And InstrumentationDiagram(P&ID)
What is that?
It provides a schematic representation of the piping, process control,and instrumentation which shows the functional relationships amongthe system components.
The P&ID should show the following:
Mechanical equipment
All valves associated with the process piping
Vents and drains
Special fittings
Sampling lines
8/12/2019 Piping Layout Unit V
10/14
Instrument designations
Equipment names and numbers
Pipeline identification no.
Valve identification
Reducers and increasers, swages, etc.
Direction of flowInterfaces for class changes
Seismic category
Interconnection references
Vendor and contractor interfacesIdentification of components and subsystems by others
Cont..
8/12/2019 Piping Layout Unit V
11/14
The P&ID should not show the following unless there is a
compelling need to do so for clarity. Items identified by an
asterisk may be shown, if necessary.
Instrument root valves*
Equipment rating or capacity
Control relays*
Manual switches*
Indicating lights*
Primary instrument tubing and valves
Pressure, temperature, and flow data
Vendor package piping which has no interface withengineering or construction*
Elbows, tees, and similar standard fittings
Extensive explanatory notes
Cont..
8/12/2019 Piping Layout Unit V
12/14
Piping LayoutP&ID is the piping designers roadmap for laying out pipingsystems.Equipment Layout,Structural Drawings of the plant are neccessaryinput to the piping layout.
Some important Piping layout considerations:
One of the most important aspects of piping layout is the avoidanceof interferences
Piping Flexibility -based on the temperature, sufficient looping orexpansion joints should be provided to accommodate expansion.
Vents and DrainsPipe Supports Location of supports, guides, and anchors is a vital
point
Heat Tracing
8/12/2019 Piping Layout Unit V
13/14
Cont...Desired location and orientation of valves should be provided.
Desired location and orientation of instruments and other pipecomponents are to be checked and maintained, like some strainers
can only be installed in horizontal position.
Minimum Hydraulic resistance i.e. minimum pressure drop.
Specific requirements of STRAIGHT LENGTH of pipe for some
components to be maintained, like for flow orifice we need to provide15 times diameter straight pipe length at upstream of orifice and 5times diameter straight at down stream of orifice.
8/12/2019 Piping Layout Unit V
14/14