Chapter 22
Industrial Process Piping
Learning Objectives
• After completing this chapter, you will
– Describe different types of pipe and their respective
uses
– Define methods of connecting pipes
– Identify pipe fittings and valves
– Identify symbology associated with industrial process
piping
Part I
Definitions
Definitions
• Piping
– Any kind of conduit used in a wide range of
applications
• Plumbing
– Small diameter pipes that carry liquids, solids,
or gases
• Water
• Natural gas
• Waste
Definitions
• Process piping
– Transport of fluids between storage tanks and
process equipment
• Transportation piping
– Carry products hundreds of miles
• Petroleum products
• Gases
• Coal slurries
Definitions
• Pipe drafting
– Visualization of pipes and fittings in various
orthographic and pictorial views
• Double line
• Single line
– Most visualization problems for beginners
• Isometric
• Flow diagram
– Schematic, non-scale diagram of system layout
Double- and Single-Line Drawings
Definitions
• Piping drawing
– Most complex
• Scale drawing
• Provides several views
– Plan
– Elevation
– Section
• All equipment, dimensions, and notes shown
• Drawn from flow diagrams, manufacturer
specifications, and mechanical drawings
Definitions
• Piping isometric
– Pictorial drawing
– Illustrates pipe run in three dimensions
– Information from piping drawings
• Spool drawing
– Drawn orthographically
– Shows all pipe and fittings used to assemble a
segment
– Usually non-scale
Part II
Types of Pipe
Cast Iron and Steel
• Most common
– Commercial
– Industrial
• Carbon steel
– Strong
– Relatively durable
– Can be welded and machined
– Not as expensive as copper
Copper
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Manufactured by hot piercing and rolling
Corrosion resistant
Good heat transfer properties
Expensive
Applications
– Instrument lines
– Food processing
– Residential water lines
Plastic
• PVC
– Applications
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Acids
Salt solutions
Alcohols
Crude oil
Plastic
• Polyethylene
– Temperature resistant to 150°F
– Applications
• Water
• Vent piping of corrosive and acidic gases
• Conduit
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Electrical and phone lines
Water lines
Farm sprinkler systems
Chemical waste lines
Clay
• Corrosion proof
• Applications
– Sanitary and industrial sewers
– Chemical waste, except hydrofluoric acid
Glass
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Chemical resistant
Transparent
Clean
Applications
– Chemical plants
– Food and beverage industries
– Pharmaceuticals
Wood
• Continuous stave wood pipe
– Used in Pacific Northwest
• Redwood and Douglas fir
• Transport of water
Steel Tubing
• Small diameter
• Flexible
• Applications
– Boilers
– Superheaters
– Hydraulic lines
• Automotive
• Aircraft
Pipe Sizes
• Availability
– 1/8” to 44” diameter
• Process piping
– 1/2” to 24” diameter
• Instrument lines
– 1/8” to 1/2” diameter
Pipe Sizes
• Nominal pipe size (NPS)
– 1/8” to 12” diameter
• Inside diameter (ID)
– 14” diameter and greater
• Outside diameter (OD)
• Inside diameter
– (Outside diameter) – 2*(Wall thickness)
Part III
Pipe Connection Methods
Pipe Connections
• Welded
– Butt-welded
– Socket-welded
– Solvent-welded
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Screwed
Flanged
Soldered
Bell and spigot
Pipe Connections
• Mechanical unit
• Flaring
Pipe Fittings
• Enable pipe to change direction and size
• Provide for branches and connections
• Types
– Welded
– Screwed
Welded Fittings
Screwed Fittings
• Union
– Connection in a straight run of pipe
• Coupling
– Attaches two lengths of pipe
• Half coupling
– Used for instrument connections
Screwed Fittings
• Street elbow
– 90-degree elbow
– Can be attached directly to a fitting
• Bushing
– Reducing fitting
• Plug
– Seals the screw-end of a fitting
Screwed Fittings
Flanges
• Creates a bolted connection point
• Circular piece of steel
– Contains center bore equal to pipe ID
– Several bolt holes spaced evenly around center
bore
Flanges
• Types
– Slip on
– Weld neck
– Blind
– Stub end
– Reducing and expander
– Orifice
Flanges
Valves
• Purpose
– Provide on/off service
– Control and regulate fluids
– Maintain constant pressure
– Prevent pressure buildup
– Prevent backflow
On/Off Valves
• Gate
– Exclusively provide on/off service
– Fluid flows with minimal friction and pressure
loss
• Plug
– Cock valve
– Requires ¼ turn to open and close
– Low throttling ability
– Used on small diameter lines
Regulating Valves
• Globe
– Regulates pressure
– Fluid flows in “S” pattern
• Angle
– Special type of globe valve
– Creates 90-degree direction change
• Butterfly
– Regulates pressure in low-pressure situations
Backflow Valves
• Check
– Prevent backflow
• Swing check
– Similar to gate valve in design
– Operates by gravity
– Best for low-velocity liquids
Safety Valves
• Keep pressures at or below a given point
– Pop safety
• Used for steam, air, and gas lines
– Relief
• Used for liquids
Control
• Instantaneous control and adjustment
– Flow
– Pressure
– Temperature
• Contains a controller, or actuator
• Operation
– Electric motor
– Air or hydraulic cylinder
Part IV
Pipe Drawings
Piping Drawings Requirements
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Pipe length dimensions
Dimension locations
Location of fittings and valves
Elevation location of all pipe direction
changes in section views
Piping Drawings Requirements
• Size and type of valves and fittings
• Pipe diameter, contents, and identification
number
• Pipe flow arrows
• Equipment names and numbers
Piping Details
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Special pipe connections or fittings
Special valve arrangements
Small diameter pipe and fitting assemblies
Special pipe support arrangements
Piping Details
• Tank attachment details
• Minor structural alterations
• Operating and installation procedures
Piping Details
Piping Isometric
Piping Isometric
Summary
• Piping drawings are used in both
commercial and residential applications
• Piping drawings may be orthographic or
axonometric
• Selection of pipe and fittings are application
specific