Process Piping
Table of Content
• Process piping is used to deliver liquids, gasses, and chemicals to
areas of a manufacturing plant that handle the mixing of products.
• It convey the fluids, between the various equipment and end users.
• It consists of various components such as pipes, valves, fittings, online
measuring instruments, etc.
Selection Criteria for Pipes
• Type of fluid being transported
• Allowable Pressure Drop or Energy Loss
• Desired Velocity
• Space Limitations
• Process Requirements – Free Drain
- Straight Run
- Stress Analysis
- Temperature of Fluid
Piping & Process Relation
• Process Discipline provides all the process calculations (Pipe sizing,
hydraulic Calculations, etc.).
• Process Discipline Provides the P&ID’s.
• Piping Disciplines provides the piping material classes in order for the
process to select the appropriate material and thickness for the
piping lines.
• Process Discipline provides the piping with the design conditions of
the piping systems (Design Pressure, Design Temperature , Fluid
services).
Steps
Stages
Project Start
SOW Study and Data
collection
Site Survey
Design Basis
Memorandum
Piping Specifications
Piping Material, Class &
Specifications
3D Model Specification
Plot Plans
Supports Modelling
Model Review by Client
Piping Modelling
Equipment’s Modelling
•Piping Bulk MTO
•Piping Isometric
•Piping GAs
•Key Plans
Selection Criteria
Layout
Component design details
Fluid service
Connected equipment type
Operating scenarios
Pipe diameter, thickness
Design temperature and pressure
End-point movements
Existing structural steel locations
Special design considerations
Fluid Service
• ASME B31.3 : Process Piping
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A. Normal Service
B. Category D : IA and FW
C. Category M: Lethal Service
D. High Pressure service
E. High temperature service
F. High purity service
Pipes are designated by schedule number .
Schedule number is represented by the pressure carrying capacity of the
pipe.
• Schedule = 1000 P/S where
P = service pressure (psi) - (Internal pressure)
S = allowable stress (psi) - (Allowable tensile strength of material)
• Irrespective of pipe dia., equal schedules have equal pressure carrying
capacity. For stainless steels schedule number are designated by suffix S i.e.
5S, 10S, 40S, 80S etc.
• For pipes of all dimensions the outside diameter (O.D.) remains relatively
constant. The variation in wall thickness affects only the inside diameters
(I.D.). The higher the schedule number is, the thicker the pipe is.
Components of Piping System
• 1. Pipe
• 2. Fittings (Elbows, Tees, Reducers, Couplings, Unions, Olets)
• 3. Flanges
• 4. Gaskets
• 5. Fasteners
• 6. Valves
• 7. Special fittings
• 8. Specialty items (strainers, traps, bellows etc.)
Flanges
• Used in the places in which the pipe shall be easily dismantled for
Maintenance.
• Used to attach piping system to equipment's.
• Source of leakage in the piping system.
• Pressure rating is defined by the symbol # ,which means PSI.
• Pressure rating is defined by the Manufacturing Standard (Not by pipe
thickness).
• ASME Pressure Rating :150#,300#,400#,600#,900#,1500# and 2500#.
• API Pressure Rating : 2000#, 3000#, 5000#, 10000#, 15000#, 20000#
• Dimensional and Pressure Rating Standard is ASME B16.5 .ASME
B16.47,API 6A).
Flange Ends
• Weld neck
• Threaded
• Socket weld
• Slip-on
• lap-joint
• Blind
Flange Facing
• Raised Face (RF)
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Used for optimum gasket seating.
RF thickness is 2 mm (150#-300#)
RF thickness is 7 mm (600#-1500#)
Used in General up to 900#.
• Flat Face (FF)
• Used for low pressure .
• Used when mating between CS flanges and Cast Iron is required or when CS
flanges and Plastic flanges mating is required.
• Ring Type Joint (RTJ)
• Used in Higher Pressure application 900# and above
Gaskets
• The most common used gasket component.
• Can seal under heavy operating conditions .
• Manufactured as per ASME B16.20
• Easy installation due the robust shape of the gasket.
• Relatively higher torque value is required for gasket seating.
• Filler ring can be graphite, PTFE , Vermiculite, Phlogopite (magnesium
mica), Flexible graphite, Ceramic.
• Major component : Spiral Wound with the filler material (Sealing
Element), Inner ring and Outer(Centering) ring.
• ASME B31.3 contains requirements for piping typically found in
petroleum refineries; chemical, pharmaceutical, textile, paper,
semiconductor, and cryogenic plants; and related processing plants
and terminals. It covers materials and components, design,
fabrication, assembly, erection, examination, inspection, and testing
of piping\
• AWS A3.0 - welding, brazing, and soldering
Layout Considerations
• Operational
– Operating and control points easily reached
• Maintenance
– Ample clearance for maintenance equipment
– Room for equipment removal
– Sufficient space for access to supports
• Safety
– Consider personnel safety
– Access to fire fighting equipment
Pipe Supports & Restraints
• Supports
– Absorb system weight
– Reduce:
+ longitudinal pipe stress
+ pipe sag
+ end point reaction loads
• Restraints
– Control or direct thermal movement due to:
+ thermal expansion
+ imposed loads
Support & Restraint Selection Factor
• Weight load
• Available attachment clearance
• Availability of structural steel
• Direction of loads and/or movement
• Design temperature
• Vertical thermal movement at supports