Basics of Piping

Basics of Piping

Introduction to Process Piping

Piping in a process plant is just like blood veins in human body National Institute of Design & Analysis, Lahore

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Basics of piping

Interaction Between Piping and Other Departments

National Institute of Design & Analysis, Lahore

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Receive / Study basic engineering package Receive / Study equipment plan, P&ID, Specification Prepare General Plot Plan of all facilities Prepare Layouts of each individual Units Prepare underground co—ordination plan Prepare Piping study Drawings Prepare Piping Plans /Layouts Prepare Piping Specifications Prepare Piping design / stress Analysis / support systems. Prepare M.T.O. (B.O.M.) for pipes / pipe fittings /Valves etc. Prepare Piping ISO-Metrics


Basics of piping

Broad Responsibilities of Piping Engineer

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Piping Fundamentals

It is a Tubular item made of metal, plastic, glass etc. meant for conveying Liquid, Gas or any thing that flows. It is a very important component for any industrial plant. And it’s engineering plays a major part in overall engineering of a Plant.

Basics of Piping

Let us first Discuss about WHAT IS PIPE!

In next few pages we shall try to familiarize about pipe and it’s components.


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Piping Fundamentals In any plant various fluids flow through pipes from one end to other. Now let us start with a plant where we see three tanks.

We have to transfer the content of Tank no. 1 to the other two tanks. We will need to connect pipes to transfer the fluids from Tank-1 to Tank-2 and Tank-3

LET US BRING THE PIPES.


Basics of Piping

Tank-1, Tank-2 and Tank-3

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Piping Fundamentals To solve these problems we need the pipe components, which are called

We have just brought the pipes, now we need to solve some more problems. Pipes are all straight pieces.

Basics of Piping

PIPE FITTINGS

We need some branch connections

We need some bend connections


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Piping Fundamentals These are the pipe fittings, There are various types of fittings for various purposes, some common types are -

Anyway, the pipes and fittings are in place, but the ends are yet to be joined with the Tank nozzles.

Basics of Piping

Elbows/Bends, Tees/Branches, Reducers/Expanders, Couplings, Olets, etc.

We now have to complete the end connections. These, in piping term, we call

TERMINAL CONNECTIONS.


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Piping Fundamentals So far this is a nice arrangement. But there is no control over the flow from Tank-1 to other tanks.

These are flanged joints This is a welded joint

Basics of piping

We need some arrangement to stop the flow if needed

To control the flow in a pipe line we need to fit a special component. That is called - VALVE


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Piping Fundamentals There are many types of valves, categorized based on their construction and functionality,

Basics of piping

Those are - Gate, Globe, Check, Butterfly, etc.

Other than valves another important line component of pipe line is a filter, which cleans out derbies from the flowing fluid. This is called a STRAINER


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Piping Fundamentals Here we see a more or less functional piping system, with valves and strainer installed.

If this tank nozzle expands, when the tank is hot.

Basics of piping

Let us now investigate some aspects of pipe flexibility.

In such case we need to fit a flexible pipe component at that location, which is called an

EXPANSION JOINT


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Piping Fundamentals

Basics of piping

When some fluid is flowing in a pipe we may also like know the parameters like, pressure, temperature, flow rate etc. of the fluid.

To know these information we need to install INSTRUMENTS in the pipeline.


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Piping Fundamentals There are various types instruments to measure various parameters. Also there are specific criteria for installation of various pipe line instruments.

Basics of piping

Next we shall look into how to SUPPORT the pipe/and it’s components.


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Piping Fundamentals

Basics of piping

Here are some of the pipe supporting arrangements. There can be numerous variants. All depend on piping designer’s preference and judgement.

Let us see some OTHER types of supports


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Basics of piping

Piping Fundamentals


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Basics of piping

Piping Fundamentals


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Piping Fundamentals We have just completed a pipe line design. We shall rewind and check how it is really done in practice.

Æ Æ

First the flow scheme is planned, 1) What, 2) From what point,

3) To which point

Pipe sizes are selected, pipe material and pipe wall thickness are selected. Types of Valves are planned

Æ Also the types of instruments required are planned We represent the whole thing in a drawing which is called Piping and Instrumentation Drawing, in short P&ID


Basics of piping

Æ

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Piping Fundamentals After the P&ID is ready we start the layout work. Here we carryout pipe routing / layout in Virtual 3D environment. We use 3D Modeling software to route piping in the Plant virtual 3D space. We call this as piping modeling or physical design.

Æ Piping from source to destination should be as short as possible with minimum change in direction. Æ Should not hinder any normal passage way. Also should not encroach any equipment maintenance space.

Basics of piping

While development of piping layout we have to consider the following

Not Preferable

Preferable


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Piping Fundamentals While carrying out pipe routing we also need to consider the following Æ Valves, strainers, instruments on the pipe should be easily accessible. Æ If needed separate ACCESS PLATFORMS to be provided to facilitate these.

Æ Specific requirements for instrument installation to be checked, like temperature gauge can not be installed in pipe which is less than 4 inch in size. Æ Specific requirements of STRAIGHT LENGTH of pipe for some components to be maintained, like for flow orifice we need to provide 15 times diameter straight pipe length at upstream of orifice and 5 times diameter straight at down stream of orifice.

Basics of piping

Æ Desired location and orientation of valves / instruments and other pipe components are to be checked and maintained, like some valves or strainers can only be installed in horizontal position.

Example of Straight length requirement for Flow Orifice


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Piping Fundamentals For Pipeline which shall carry liquid, we have to make sure that all air is allowed to vent out of the line when the line is filled with liquid. To achieve this a VENT connection with Valve is provided at the top most point of the pipeline.

To achieve this a DRAIN connection with Valve is provided at the lowest point of the pipeline Pipes are also slopped towards low points.

Basics of piping

Also arrangement is kept in the pipeline so that liquid can be drained out if required.

Let us look into typical Vent and Drain arrangeme nt in a pipeline


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Pipe Fittings ( elbows, reducers, flanges, etc) Gaskets, bolts Valves Pipe support Special items ( e.g. expansion joints…)


Basics of piping

Piping system components

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Pipe

– ASME B36.10M Welded and Seamless Wrought Steel Pipe – ASME B36.19M Stainless Steel Pipe


Basics of piping

Pipe is a tube with round cross section conforming to the dimensional requirements of

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Pipe Selection

Size Material Thickness Schedule


Basics of piping

How a pipe is selected?

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Pipe Calculation Pipe Material Selection - to select appropriate pipe material based on flowing fluid property. Find out Fluid Temp. & Pressure

Check Pipe life Expectancy

Select suitable Material per practice (Note1)

Note-1 : Material is selected per past experience with cost in mind and per material listed in design code. If material is not listed in code we may select next suitable material listed.

Check Mat. YES Pipe Listed in Material Design Code OK NO See Note-1

Pipe Sizing Calculation - to select required pipe diameter based on velocity and pressure drop. Find out Flow volume per second

Check Velocity Allowable per second

Calc. flow area required and Pipe size

Calc. Press. Drop for that Pipe size

Check Press. YES Drop meets Press. Budget

Pipe Size OK

NO Increase Pipe Size

Basics of piping

Find out type of Fluid flowing

Pipe Thickness Selection - to select appropriate pipe thickness based on flowing fluid property. Select Mat. & Diameter as above

Find out Fluid Temp. & Pressure

Decide on Corrosion allowance

Calc. Pipe Thickness per Code

Add corrosion allowance & select pipe schedule having thickness >required


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Pipe Specification

STD XS XXS o

Schedule Number: NPS+

5,5S,10,10S,20,20S,30,40,40S,60,80,80S,100,120,140, 160

o o

API Designation

o

Basics of piping

Pipe Classification – Iron pipe size ( approximate internal dia.) – Manufacturer’s weight : NPS +

A25,A,B,X42,X46,X52,X60,X65,X70


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Pipe Specification

Pipe: • 1/8”,1/4”,3/8”,1/2”,3/4”,1”,1½”,2”,3”,4”,6”,8”,10”, 12”,14”,16”,18”,20”,24”,30”,32”,36”,40”,44”,48”, 52”,56”,60”

– NPS 1 ¼”,2 ½” 3 ½”,5” are not used. – Pipe is supplied in • Random length ( 17 to 25 ft) • Double random length (38 to 48 ft)

Basics of piping

– NPS:

– Pipe End: • BE (bevel end) • PE ( Plain end) • Thrd ( Threaded end)


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ASTM A53- Carbon Steel Pipe ASTM A106- Seamless carbon steel ASTM A312- Stainless Steel Pipe API 5L- Line Pipes ASTM A333- Low Temp Carbon Steel.


Basics of piping

Common Material Standards

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Fittings Produce change in geometry – – – –

Modify flow direction Bring pipes together Alter pipe diameter Terminate pipe Elbow Tee O-Let – Weld-O-Let – Socket-O-Let – Thread-O-Let Flanges Gasket Special Items


Fittings

Common Fittings include:

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Elbows

Elbow: Used to change direction of pipe. Forged Elbows : – 90 Elbow socket weld – 90 Elbows threaded – 45 Elbow threaded – 45 Elbows socket weld


Fittings

Types

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Elbow

Fitting

Welded Elbows : – 90 Elbows long – 45 Elbow long – 90 Elbows short – 45 Elbows short


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Size: Same size as that of Pipe Thickness: Same schedule as that of pipe for welded elbow For forged elbow , available ratings are as 2000,3000,6000,9000.

Fittings

Elbow Specification

Note: forged elbows are used for NPS<2”


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Branch Connection

Tee – Tee Straight – Tee Reducing O-Let – Weld-O-Let – Socket-O-Let – Thread-O-Let


Fittings

Branch connection can be obtained by using

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Fittings

Branch standard connection


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Tee

– Socket welded tee – Threaded tee

Welded tee


Fitting

Tee Straight Used when branch size is equal to header size Tee Reducing: Used when branch size is smaller than that of header. Forged tee

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Specification of tee

Fitting

Specification of tee are same as that of Elbow. Size of tee is same as that of pipes connected to it Schedule and rating are selected on basis of pipe schedule.


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O-Lets

Weld-O-Let: Used when branch connection is butt welded to header. Normally branch NPS ≥ 2”


Fittings

Used when branch size is much smaller compared to header size.

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Socket-O-Let & Thread-O-Let

Fitting

Used when branch size is much smaller compared to header size. Used when branch connection is Threaded or socket welded to header. Normally branch NPS < 2”


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Reducers Changes the diameter of Pipe. Types – Concentric Reducer

– Eccentric reducer


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Specification of Reducer

Fittings

Size (NPS of Larger end x NPS of Smaller end) Schedule Material


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Caps Used to closed the pipe.

Fittings

– Welded – Forged


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Flange A Flange is a method of connecting pipes, valves, pumps and other equipment to form a piping system. It also provides easy access for cleaning, inspection or modification. Flanges are usually welded or screwed into such systems and then joined with bolts.


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Types of Flange Weld neck flange Socket Weld flange Threaded flange Flange

Slip On Blind Lap joint Ring type joint


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flange

Flange rating


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Resilient material Inserted between flanges Compressed by bolts to create seal Commonly used types – Sheet – Spiral wound – Solid metal ring


Fittings

Gasket

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Material

Material Specification List


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Valves

– Block flow – Throttle flow – Prevent flow reversal – Controlling process & Utility service


Valves

Functions

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Valves Classification Valves are classified according to function: Block Flow (on/off) Regulating ( throttle flow) Checking ( prevent flow reversal) Switching Discharging

Classification according to operating device: – – – –

Manual Hydraulic Motor solenoid


Valves

– – – – –

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Ball Valve Gate Valve Glove valve Check Valve Plug Valve Butterfly Valve Needle Valve Relief Valve


Valves

Valves

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Ball Valve Used for On/Off purpose. Advantages: – Low pressure drop, fast operating, bubble-tight shut off.

Disadvantages:

Valve

– Expensive, heavy, poor throttling


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valves

Globe Valve


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Globe Valve

Valves

Most economic for throttling flow Can be hand-controlled Provides “tight” shutoff Too costly for on/off block operations Disadvantage: Large pressure drop.


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Valves

Gate Valve


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Gate Valve

About 75% of all valves in process plant An optimum engineering and economic choice for on/off service. ( isolation valve) Advantage Disadvantage – Poor throttling characteristics


Valves

– Small pressure drop across valve

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Check Valve

– – – –

Size limitations Cost Availability service


Valves

Prevent flow reversal Doest not completely shut off reverse flow Available in all sizes, rating, materials Valve type selection determined by

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Types of check valve

valves

Swing check valve


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Types of Check Valves

Valves

Ball check valve


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Types of Check Valves

Valves

Lift check valve


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Plug Valve

Valves

Used for on/off purpose Required 90Deg turn to operate.


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Valves

Butterfly Valve


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Butterfly Valve Used as cutout/isolation valves Advantage: – Quick acting – Low pressure drop – Can be used only for low press/ low temp systems due to force involved in valve operation.


Valve

Disadvantage

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Valve

Needle Valve


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Valves

Relief Valve


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Relief Valve

valves

Special type of valve designed to operate automatically ( Self-actuating) in a system overpressure condition. Also called safety valve


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Pipe Supports and restraints

– – – – –

Transfer load of piping to structure and then ground To ensure that material is not stressed beyond a safe limit Prevent pipe sagging To permit thermal expansion To minimize load on equipment nozzles


Pipe Supports

Function of supports and restraints

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Support Selection

– – – – – –

Weight Available attachment clearance Availability of structure steel Direction of loads and/or movement Design temperature Vertical thermal movement at support


Pipe Supports

Support and restraints selection factors are:

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Common support types

Pipe Supports

Anchor Guide Stopper Vertical support


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Piping Supports

Common support types


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Pipe Supports

Pipe Rack


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Piping SPEC

Piping SPEC

It is final guide line for piping engineer All piping component material & type enlisted in it Process data range is given Welding type mentioned.


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Piping SPEC

Piping SPEC


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Piping SPEC

Piping SPEC


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Piping Drawing

Piping Drawing


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Piping Drawing

The main purpose of drawing is to communicate information in a simple way for construction apart from specification Three type of drawing are developed from schematic (block flow diagram) – Process flow diagram (PFD) – Piping & instrumentation diagram (P&ID) – Piping Drawing


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Piping Drawings

Block Flow Diagram

BFD

– A BFD is a schematic illustration of major process. Block used, represent a unit operation.


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Process flow diagram

Process flow diagram

PFD


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PFD

Process Flow Diagram


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Piping & Instrumentation diagram

P&ID


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Piping Drawings


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Piping Drawings


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Piping Drawing


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Piping Drawings


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Piping Drawings


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Piping Drawings


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Design

Design


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Fluid Service

ASME B31.3


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ASME B31.3

ASME B31.3


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Material

ASME B31.3


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Strength & Temp

ASME B31.3


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Fatigue

ASME B31.3


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Fluid Service

ASME B31.3


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Fluid Service

ASME B31.3


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Fluid Service

ASME B31.3


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Fluid Service

ASME B31.3


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Operating condition

ASME B31.3


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Load types

ASME B31.3


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Load types

ASME B31.3


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Load types

ASME B31.3


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Stress categorization

ASME B31.3


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Stress categorization

ASME B31.3


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Allowable stress

ASME B31.3


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Wall thickness correction factor

ASME B31.3


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Design Pressure

ASME B31.3


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Design Pressure

ASME B31.3


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Basics of Piping

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