INTRODUCTION TO PIPING COMPONENTS

INTRODUCTION TO PIPING COMPONENTS

1. PIPES

Piping in a particular plant can be compared with arteries & veins in our body. There are mainly two types of pipes from manufacturing point of view. The first is Seamless pipes & second is Welded pipes.

Various attributes of pipe are described below.

A) End Preparation:

There are three types of end preparation of pipes.
(a) Plain End (PE)
(b) Butt weld or Beveled End (BW/BE)
(c) Threaded End

B) Design & Dimension Standard:

This will provide the following information.

Nominal Bore (NB), Thickness, Outside Diameter (OD), Tolerance & Weight.

The Dimension Standard for pipe is as follows.

ANSI/ASME B 36.10 : For Carbon Steel (CS), Low Temperature Carbon Steel (LTCS), Low Alloy Steel (LAS) Pipes

ANSI/ASME B 36.19 : For Stainless Steel (SS) Pipes

C) Material

I. CS: It is used for temperature range from (–) 29°C to 4270C.
Most commonly used CS materials are as follows:

ASTM A 106 Gr. B (Seamless pipes)

API 5L Gr. B (Seamless & Welded)

ASTM A 53 Gr. B (Seamless & Welded)

IS 1239 (Upto 6” & ERW)

IS 3589 (Above 6”)

II. LTCS : It is used for low temperature i.e. from (–) 460C to 3430C.
The most commonly used LTCS materials are as follows:

ASTM A 333 Gr. 6 (Seamless pipes)

ASME A 671 (Welded pipes)

III. LAS : It is used for high temperature i.e. (-) 290C to 538°C
The most commonly used LAS materials are as follows:

ASTM A 335 Gr. P11, P12, P9 (Seamless pipes)

ASTM A 691 Gr.C60, C65, C70 (Welded pipes)



IV. SS : It is used for cryogenic temperature range i.e. from (-) 1960C to 5380C.
Most commonly used SS materials are as follows:

ASTM A 312 TP 304 / ASTM A 312 TP 304L

ASTM A 312 TP 316 / ASTM A 312 TP 316L

ASTM A 312 TP 321

(Various shortforms:
IS Indian Standard
ERW Electric Resistance Welding
LS * Standard)


2. FLANGES

Flanges are used to make a joint that is required to be dismantled.
Various attributes of Flanges are described below:

A) Type : There are five types of Flanges.

I. Weld Neck Flange

It has Butt Weld End Connection.
Radiography Test (RT) is possible.

II. Socket Weld Flange

Here Fillet welding is done from outside only.
Die Penetration Test (DP) is possible.

III. Slip On Flange

Here Fillet welding is done from inside as well as from outside.
DP Test is possible.

IV. Threaded Flange

It is mainly used in Galvanized pipes.

V. Blind Flange

It is used for ending a line.

B) Facing : There are four types of facing.

I. Raised Face

It is specified up to 600 (psi) rating pipe class.

II. Ring Joint

It is specified from 900 rating (psi) & above pipe class.

III. Flat Face

It is only used for 150 (psi) rating pipe class.
It is specified for utility fluids like Cooling Water and Low Pressure Nitrogen.

IV. Tongue & Groove

Its use is mainly dependent upon the nature of fluid to be handled.
It is specified to handle extremely hazardous fluids like Liquid Ammonia.

C) Design and Dimension Standard : The dimensional standards generally used are
ANSI/ASME B16.5 for size upto 24’ ANSI/ASME B16.47 series A & B for size above 24’’. Series B specifies compact design & is used when space and cost are the main constraints.

D) Material : Flanges are manufactured from following forged materials.

I. Carbon Steel – ASTM A 105 (used most of the times)
ASTM A 181 (it is obsolete now)

II. Low Temperature Carbon Steel — ASTM A 350 Gr. LF 2

III. Low Alloy Steel – ASTM A 182 Gr. F 11 (generally used)
ASTM A 182 Gr. F 1/F22/F9

IV. Stainless Steel – ASTM A 182 Gr. F 304
ASTM A 182 Gr. F 304 L
ASTM A 182 Gr. F 316
ASTM A 182 Gr. F 316 L
ASTM A 182 Gr. F 321

ASTM Sec. II A defines ferrous material. It gives detail properties of Ferrous Material
- Chemical Analysis
- Physical Properties (tensile strength,
Yield strength, hardness, etc.)

E) Pressure Class (Rating)

Rating is maximum allowable non-shock working gauge pressure. There are 150, 300, 600, 900, 1500, 2500 ratings. To select a pressure class the following two steps are followed.
Decide the group of material from Table 1A of ASME 16.5
Refer Table 2 of ASME 16.5 for design condition.

Spectacle Blind

It is not exactly a flange but it is kept between two flanges and is used for the temporary isolation of a line.

Design & Dimension Standard----LS 423-06
Material----Same as Flange
Facing----Same as Flange

Generally it is used up to 10” & above 10” it is used in two separate pieces. One is known as Slip Plate (Blind Part) & second is known as Slip Ring (Hollow Part).

3. PIPE FITTINGS

Pipe fittings are of different types.

3.1 Elbows : Used for change in direction of pipe routing.

(a) They are of 2 types :

45° Elbow which can be
Short Radius Elbow, R = 1D
Long Radius Elbow, R = 1.5D

90° Elbow which can be
Short Radius Elbow, R = 1D
Long Radius Elbow, R = 1.5D

(b) According to End connection elbows can be classified as

Socket Weld : for size upto 1½’’
Butt Weld : for size greater than 1½’’ ( > 2’’ in *)
Threaded : for size upto 1½’’ in G.I. Pipes

(c) Dimensional Standard

For Socket Weld & Threaded Elbows: ANSI/ASME B16.11
For Bevelled end Elbows: ANSI/ASME B 16.9

Thickness for Beveled end fittings = Thickness of pipe
Thickness for 3000# Socket weld elbows = Schedule 80 of respective pipe size.
Thickness for 6000# Socket weld elbows = Schedule 160 of respective pipe size.
Thickness for 9000# Socket weld elbows = Schedule XXS of respective pipe size.

(d) Pressure class for Socket Weld & Threaded Pipe Fitting It is as follows:

2000 psi or 2000 rating - used only for threaded pipe fittings

3000 psi - used only for Socket Weld Pipe fitting & threaded pipe fittings

6000psi - used only for Socket Weld Pipe fitting & threaded pipe fittings

9000psi - used only for Socket Weld Pipe fitting & threaded pipe fittings

(e) Material

Socket Weld and Threaded pipefitting are manufactured from following forged materials

(1) Carbon Steel – ASTM A 105

(2) Low Temperature Carbon Steel- ASTM A 350 Gr. LF2

(3) Low Alloy Steel – ASTM A 182 Gr. F11(generally used), F1, F6, F9

(4) Stainless Steel – ASTM A 182 Gr. F 304, F304L, F316, F316L, F321

Butt Weld pipe fittings are manufactured from pipes

(1) Carbon Steel – ASTM A 234 Gr. WPB

(2) Low Temperature Carbon Steel – ASTM A 420 Gr. WPL6

(3) Low Alloy Steel – ASTM A 234 Gr. WP11/WP22/WP9

(4) Stainless Steel – ASTM A 403 WP/304, 304L, 316, 316L, 321


3.2 Tee : Used for taking a branch.

(a) Tee can be

Equal/Straight tee – All 3 sizes are equal

Unequal/Reduced tee – Branch size is always smaller

Points (b), (c), (d) and (e) are same as elbows

3.3 Half Coupling : Used to take a branch upto 1½’’ size.

End connections are Socket Weld & Threaded
Used in Pipe class upto 300 rating

Points (c), (d), (e) same as elbow

3.4 Reducer/Expander : Used when change in pipe size is there.

Type – Concentric Reducer – Butt Weld

Eccentric Reducer – Butt Weld

In case of Eccentric Reducer one side is tapered while the other side is straight. Here the difference in elevation of the axis exists leading to eccentricity. Its construction is like a trapezoid.

In case of Concentric Reducer both sides are tapered and the axis is also the same. Its construction is like a cone.



Thumb Rule for Reduction:

Next Lower Size/2 ---> Higher Size

For E.g. if the Header Side is 6’’ then 6/2 = 3 and hence the next lower size possible is 2½’’.
Hence it can be seen that reduction from 6’’ to 2½’’ is possible. Further reduction beyond 2 ½’’ is not possible. Reducers can be manufactured in small size.

Dimension Standard: ANSI/ASME B16.9

Thickness is same as the pipe thickness.

Material: Same as BW Elbows

3.5 Full Coupling

: Used for Pipe to Pipe joint of small bore (upto1½’’)

End connections are Socket Weld & Threaded
Dimensional Standard, Material and Pressure class same as Half coupling

3.6 Weldolet:

Used to take Butt Weld branch for which Reducing tee is not possible
Used in high pressure, high temperature pipe class from 900 rating

Dimension Standard:

MSS SP 97
Header and Branch size with thickness is to be specified

Material:

Forged same as elbow / half coupling

3.7 Sockolets:

Same as Weldolet except there is a Socket weld end at Branch side.

Caps: Used at the end of the line for the termination of the line.

End Connection: The end connections are

Socket weld }

Up to 1 ½”
Threaded end }

Butt weld } Above 2”

Dimension Standard:

ANSI/ASME B 16.11 For SW & Threaded End
ANSI/ASME B 16.9 For BW/BE
Thickness for BW caps same as thickness of pipe.

Material: Same as Elbow

4. VALVES

Valves are used for main three purposes listed below.

For Isolation of flow.
For Regulation of flow.
For avoiding the reversal of the flow.

The valves used for isolation cannot be used for regulation but other way round is possible.

Various types of valves.
(1) Gate valve
(2) Ball valve
(3) Plug valve
(4) Butterfly valve
(5) Globe valve
(6) Needle valve
(7) Check valve
(8) Control valve (Handled by Instrumentation Department)
(9) Pressure relief valve or Safety valve (Handled by Instrumentation Department)

First five valves are used for isolating the flow, 5th & 6th valves are used for regulating the flow and 7th valve is used for avoiding the reversal of the flow.

4.1 GATE VALVE

It is the most commonly & very widely used valve in industrial piping for isolation of the flow. It is manually operated and it is not recommended for regulation of the flow. Installation of this valve is possible from both the ends. Hence it is bi-directional valve.

A) End Preparation:

(a) Cast Steel valves have Flanged or Butt weld end preparation.
(b) Forged Steel valves have Socket weld or Threaded end preparation.

B) Design & Dimension Standard:

The dimension Standard for gate valve is as follows.
API 600 :For Cast Steel valves (Flanged/BW valves)
API 602 :Forged Steel valves (SW/Threaded valves)
ANSI B 16.34 :For Pressure & Temperature limitation & Rating
ANSI B 16.10 :For face to face dimension of Flanged & BW end
API 598 :For Testing of valve

C) Main parts: Gate valve has following main parts.

Body
Bonnet
Internals/Trim/Wetted parts: Parts that come in direct contact with the fluid. Gate valve has following Internals/Trim/Wetted parts.
Wedge / Seat Ring / Stem / Gland Bush

D) Pressure Class:

There are 150,300,600,900,1500,2500 ratings for Flanged & BW valve.
There is 800 rating for SW or Threaded valve.

4.2 GLOBE VALVE

The fluid while passing through this valve changes its flow direction and hence this valve causes increased resistance to flow which result into considerable pressure drop. So this valve is not suitable where pressure drop is critical. This valve is mainly used for regulation of the flow.

Inlet and outlet of this valve are fixed. Hence installation of this valve is unidirectional. Flow direction is marked on the valve body.

A) End Preparation: Same as Gate valve.

B) Design & Dimension Standard:

BS 5352 :For SW/Threaded valves
BS 1873 :For Flanged/BW valves
ANSI/ASTM B 16.34 :For Pressure & Temperature limitation and Rating
ANSI/ASTM B 16.10 :For face to face dimension of Flanged/BW end valves
API 598 :For Testing of valve

C) Main parts:

Globe valve has following main parts:

Body
Bonnet
Internals/Trim/Wetted parts: Globe valve has following Wetted parts.
Disc
Seat Ring
Stem
Gland Bush


D) Pressure Class: Same as Gate valve.

E) Material: Same as Gate valve.

4.3 CHECK VALVE

-It is sometimes referred to as Non Return Valve.
-It is self-operated valve and allows the flow to pass in one direction and will not allow reverse flow.
-Installation of this valve is unidirectional.
-Flow direction is marked on the body.

A) Type and End Connection:

1) Lift Check Valve (up to 1 ½’’) : Socket Weld / Threaded / Butt Weld
2) Swing Check Valve ( >= 2’’) : Flanged / Butt Weld
3) Wafer type Check Valve: Wafer type / Wafer lug type. It is to be kept between two flanges.

B) Design & Dimension Standard:

BS 5352 : For Lift Check Valve
BS 1868 : For Swing Check Valve
API 594 :For Wafer Check Valve
ANSI/ASTM B 16.34 :For Pressure & Temperature limitation and Rating
ANSI/ASME B 16.10 : For Face to Face dimension
API 598 :For Testing of valve


D) Pressure Class: Same as Gate Valve

E) Material:

Lift Check Valve (up to 1.5” & SW / Threaded / BW): Same as forged Gate Valve
Swing Check Valve (>= 2’’& Flanged / BW): Same as cast steel Gate Valve
Wafer type Check Valve (Wafer type / Wafer lug type): Same as cast steel Gate Valve.

4.4 BALL VALVE

This valve is used for isolation & for quick on / off. It is mainly used in utility line i.e. cooling water, instrument air etc. and in hazardous and combustible fluid. Rotating the lever by 900 opens or closes this valves fully. Hence this valve is called quarter turn valve. Fire safe design as per API 607 is available for this valve. Installation of this valve is possible from both the ends. Hence it is bi-directional valve.

3-way and 4-way construction is possible in ball valve by providing “T” or “L” port in the ball.

A) End Connection:

Socket Weld & Threaded End – up to 1.5’’, 3-piece design
Flanged / Butt Weld- 2 piece design

B) Design & Dimension Standard:

BS 5351 For Ball Valves
ANSI/ASME B 16.10 For Face to Face dimension ANSI/ASTM B 16.34 For Pressure & Temperature limitation and Rating
API 598 For Testing of Valves

C) Main Parts:

Ball valve has following main parts.
Body
Ball valve has following internals.
Ball
Seat
Stem

D) Pressure Class: Same as Gate Valve

E) Material: Same as Gate Valve
Here Seat material is PTFE (Poly Tetra Fluoro Ethylene)

Fire safe valves are available as per API 607 & has following seats
Primary Soft Seat of PTFE
Secondary Metal to Metal Seat

4.5 BUTTERFLY VALVE

It is mostly used for isolation and in specific case used for regulation.
Regulation is not as precise as Globe Valve

A) End Connection: Same as Wafer check valve

Wafer type / Wafer lug type / Flange end/Butt end


B) Design & Dimension Standard:

API 609 For Butterfly valve
ANSI/ASME B 16.10 For Face to Face dimension
ANSI/ASTM B 16.34 For Pressure & Temperature limitation and Rating
API 598 For Testing of valve

C) Main parts:

Butterfly valve has following main parts:
Body
Butterfly valve has following internals:
Disc / Shaft / Seat

D) Pressure Class: Same as Gate Valve of cast steel type

E) Material: Same as cast steel Gate Valve
Seat Material: EPDM, Nitrile - These are one kind of Rubber, soft material
EPDM- Ethylene Propylene Di Monomer

4.6 PLUG VALVE

This valve is used for regulation, isolation and quick on / off in combustible or Hazardous fluid. 3-way and 4-way construction is possible in plug valve by providing “T” or “L” port in the plug.

A) End Connection:

Socket Weld/Threaded
Flanged/Butt Weld

B) Design & Dimension Standard:

BS 5353 For Plug valve
ANSI/ASME B 16.10 For Face to Face dimension
ANSI/ASTM B 16.34 For Pressure & Temperature limitation and Rating
API 598 For Testing of valves

C) Main Parts:

Plug valve has following main parts:
Body
Cover
Plug valve has following internals.
Stem
Plug
Sealant

D) Pressure Class: Same as Gate Valve

E) Material: Same as Gate Valve

4.7 CONTROL VALVE

These valves are self operated type. They have actuators. Actuators operate on the signal received from an instrument. They are used for very fine throttling and to have desired process parameters (pressure, temperature, flow) of fluid.

Control Valves can be of the following types based on parameters to be controlled:

· Pressure control valve-Receives signal from Pressure Indicator / Pressure Transmitter.
· Temperature control valve-Receives signal from Temperature Indicator/Temperature Transmitter
· Flow control valve-Receives signal from Flow Indicator/Flow Transmitter

There are two types of signal:

· Pneumatic – Valve has pneumatic actuator.(tubing is used)
· Electric – Valve has electrical (solenoid) actuator. (cables are used)

Based on construction, control valve has following types:

· Butterfly Valve
· Globe Valve
· Ball Valve

A) End Connection: Flanged End or BW. Flange end is always preferred because of regular servicing & maintenance.

B) Material: Same as other cast steel valves.

C) Design & Dimension Standard: Same as other valves.

D) Pressure Class: Same as other valves.

4.8 SAFETY VALVE

This valve is also known as Pressure relief valve. It is used for safe operation of plant. This valve releases excess pressure when it exceeds set pressure. Pressure is set by spring.

Inlet of this valve is one size lower or equal to the inlet pipe size. Outlet is at least one or more size higher to outlet pipe size.

A) Material & Pressure Class: Same as Gate Valve
Outlet Pressure class <= Inlet Pressure class
B) Main Parts:

Pressure safety valve has following main parts.
Body / Bonnet
Safety valve internals: Spring / Disc / Stem

C) Design & Dimension Standard: API 526: For Pressure & Temperature limitation and Rating and for Center to Face Dimension.


5 FASTENERS

It consists of Bolts, Full threaded Stud Bolts and Nuts.
Bolts have Hexagonal or Round head while Studs are without heads.
One stud with two nuts forms a set of fastener.
Fasteners are used for flange joints in piping to retain flanges and gaskets.
Threading is done on the studs and bolts by two methods.

1. Cut threads using cutting tool on Lathe.
2. Thread Rolling using rollers on thread rolling machine.

A) Design & Dimension Standard:

ANSI/ASME B 16.5 For Studs (Length & Diameter)

ANSI/ASME B 18.2.1 For thread types with details of Studs & Bolts

ANSI/ASME B 18.2.2 For Nuts

B) Material:

(1) CS : ASTM A 193 Gr B7 : For Stud,

ASTM A 194 Gr 24 : For Nut

(2) LTCS : ASTM A 320 Gr L7 : For Stud,

ASTM A 194 Gr 4 : For Nut

(3) LAS : ASTM A 193 Gr B16 : For Stud,

ASTM A 194 Gr 4 : For Nut ,

(4) SS : ASTM A 193 Gr B8 : For Stud,

ASTM A 194 Gr 8 : For Nut.

6 GASKETS

Gaskets are used to avoid Static leakage and metal to metal contact.
There are two types of gaskets from material point of view.

1. Metallic Gasket:

Metal is used in the construction of Gasket either as main
material or as reinforcing material..

e.g. Spiral wound gasket.

Used with RF flanges up to 600 rating.

Thickness of spiral wound gasket is 4.5 mm.

Ring joint Gasket used with RJ flanges from 900 rating.

2. Non-metallic Gasket:

Metal is not used in the construction of gaskets.
e.g. Flat Gasket
Thickness of this gasket is normally 2 to 3 mm.
It is used in FF and T&G type of flange.




A) Design & Dimension Standard:

ANSI/ASME B 16.20 For Metallic Gaskets
ANSI/ASME B 16.21 For Non-metallic Gaskets

B) Material:

For Metallic Gasket

(1) S.S. ring for ring joint gasket.
(2) Spiral wound Gasket

(a) S.S. (as reinforcement) & for inner and outer (centering) ring.

(b) Filler material as follows.

Graphite used for high temperature.
PTFE used for low temperature.
CAF – It is banned to use from health hazard point of view.

For Non-metallic Gasket

(1) Flat Gasket

(a) CAF (Compressed Asbestos Fiber)- It is banned to use from health hazard
point of view.
(b) PTFE
(c) Graphite