Piping Fundamentals:

M.N.Raghu

Piping Fundamentals Agenda:

•Definition of Pipe and Piping

•Concept Layout Development

• Piping Components• Orientation of various tapings, components, etc.• Piping Drains & Vents• Material & Sizing

PIPE:

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.

PIPING:

The term Piping means not only pipe but also includes components like fittings, flanges, valves, bolts, gaskets, bellows etc.

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: Tank-1, Tank-2 and Tank-3

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 PLACE THE PIPES.

We have just brought the pipes, now we need to solve some more problems.

Pipes are all straight pieces.

We need some branch connections

We need some bend connections

Even some pipes are

of diffe

rent sizes!

To solve these problems we need the pipe components, which are called PIPE FITTINGS

These are the pipe fittings,

There are various types of fittings for various purposes, some common types are -

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

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

We now have to complete the end connections.

These, in piping term, we call

TERMINAL CONNECTIONS.

These are flanged joints

This is a welded joint

So far this is a nice arrangement.

But there is no control over the flow from Tank-1 to other tanks.

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

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

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

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

Let us now investigate some aspects of pipe flexibility.

This tank nozzle expands, when the tank is hot.

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

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.

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

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

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

Preferable

Not Preferable

While development of piping layout we have to consider the following:

� Material to withstand the high pressure and high temperature.

� Piping from source to destination should be as short as possible with minimum change in direction.

� Should not hinder any normal passage way. Also should not encroach any equipment maintenance space.

� Valves, strainers, instruments on the pipe should be easily accessible.

� If needed separate ACCESS PLATFORMS to be provided to facilitate piping operation.

� 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.

� Specific requirements of STRAIGHT LENGTH of pipe for some components to be maintained, like for flow orifice we need to provide 15 D straight pipe length at upstream of orifice and 5 D straight at down stream of orifice.

Example of Straight length requirement for Flow Orifice

� To ensure that there is no air-trap in the pipeline, a VENT connection with Valve is provided at the top most point of the pipeline.

� A DRAIN connection with Valve is provided at the lowest point of the pipeline for liquid drain from pipeline.

� Pipes are also slopped towards low points.

Let us look into typical Vent and Drain arrangement in a pipeline

� Provision to be made to absorb thermal expansion in pipes during high temperature applications.

� Avoid Piping load transfer to applications- with suitable supports and anchors.

� Underground / Embedded piping issues.

� Insulation / Freeze protection issues

� There are many recognized international codes which lay down guide lines and mandatory requirements for design of piping.

� Most followed standards are:

� ASME ANSI B31.1- Power Piping Code &

� IBR - Indian Boiler Regulation (in INDIA)

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. Drop meets

Press. Budget

Pipe Size OK

YES

Increase Pipe Size

NO

Pipe Material Selection - to select appropriate pipe material based on flowing fluid property.

Find out type of Fluid flowing

Check Pipe life

Expectancy

Select suitable Material per

practice (Note-1)

Check Mat. Listed in

Design Code

Pipe Material

OK

YES

See Note-1

NONote-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.

Find out Fluid Temp. & Pressure

Pipe Thickness Selection - to select appropriate pipe thickness based on flowing fluid property

Select Mat. & Diameter as above

Decide on Corrosion allowance

Calc. Pipe Thickness per

Code

Find out Fluid Temp. & Pressure

We have just completed a pipe line design. How Piping design is done in practice?

� Determine the Flow scheme: 1) What, 2) From what point, 3) To which point

� Selection of Pipe material, Pipe sizes and Pipe wall thickness are selected.

� Selection of suitable Valves and fittings wrt functions required

� Instrumentation required

All of the above are represented in a drawing which is called Piping and Instrumentation Drawing, in short P&ID. This drawing contains all the information about a pipe like, Pipe size, Flowing Fluid, etc.

Sample P and I diagram

3D drawing of a Typical piping system

After the P&ID is ready, the layout work, pipe routing / layout is generally done in a Virtual 3D environment using a customised software. This is called as Piping modeling or Physical design.

Piping Example

Observe: Bending of pipes is better than bend fittings to avoid leakage and pressure drop issues.

Piping Example

Piping Example

Thanks,M.N.Raghu

www.bflhydro.com

Any Questions?