1.Piping Introduction and Fundamentals

1 PIPING INTRODUCTION

2014

SUMIT

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PIPING INTRODUCTION


INDEX

CODE 3

PIPING V/S PIPELINE 4

PRINCIPLES OF PIPING ENGINEER 4

STANDARDS 5

PLANT DISCIPLINE 5

PIPING FUNDAMENTALS 6

PIPE 6

PIPING ASPECTS 7


PIPING INTRODUCTION AND FUNDAMENTALS:

Oil/gas refinery

Petrochemical plant

Chemical plant

Ammine plant

Alcohol plant

Pesticide plant

Textile plant

Cement plant

Hygienic plant: (s.s is used)

Pharmaceutical plant: more precaution is taken

Food plant:

Dairy plant

Chocolate plant

Pepsi/ coke plant

Green field project: to be constructing

Brown field project: working

ASME American society of mechanical engineering

Or

ANSI American national standard institute

CODE:

Definition: it consist of standards for design, fabrication, installation, testing and m/L

instructions

Complexity of process plant:

Fluid

Normal

Flammable

Toxic- H2

Viscous

Corrosive


Temperature > 1000f

Pressure > 6000 psi

ASME 31.3: process piping code

ASME 31.1: power piping code

ASME 31.4: liquid transportation pipe lines

ASME 31.8: gas transportation pipelines

PIPING V/S PIPELINES

Piping system inside the plant only

Pipe line b/w 2 plants/ cities/ countries

PRINCIPLES OF PIPING ENGINEER:

1) Safety:

The piping system which is design and constructed should be safe (by using

codes and standards)

2) Constructability:

The piping system which is design should also be construct able

3) Operability : the piping system which is design and constructed should also be

operable

4) Maintainability:

The piping system which is design and constructed and operated should also

be maintained which requires placing the facilities in the area by following

their maintenance requirements.

Like: a valve during the operation may have maintenance requirement so it

should be located where it can be excess by the plant technician to reduce

maintenance time.

5) Economy:

The piping system which is design, constructed, operated and maintained will

should also be economical.


STANDARDS:

These are documents prepared by professionals for the components which are to be

used in the market of piping system.

PLANT DISCIPLINES:

Process engg. ( chemical engg)

Piping engineer

Mechanical engg.

Civil engg

Electrical engg

Instrumentation engg

50%

25%

25%

PLANT

50% mechanical equipment

23 to 25 % piping

25 to 27 % civil,instrumental,electrical


PIPING FUNDAMENTALS:

1) Drawings

Flow diagram

Block flow diagram

Process flow diagram

P & id

Utility flow diagram

Layouts

Isometrics

2) Equipment supports

3) Piping supports

4) Design calculation

5) Stress analysis- Caesar II

PIPE:

It is cylindrical shape structure used to transfer the fluid, solid or semi solids from one

pt. to another under pressure.

Fluid :

Liquids( water)

Gases( air)

Solids :

pellets( tablets)

powder ( cement)

semi solids:

slurry( crude oil, grease)


PIPING ASPECTS:

1. Diameter:

IPS: ( iron pipe size)

It is dimensionless pipe designator (indicator) of pipe. It represents the

I.D of the pipe in inches.

Ex: IPS 6 I.D of the pipe is 6

NPS: ( nominal pipe size)

It is dimensional pipe designator of pipe. It represents O.D of pipe in

inches.

Ex: NPS 6OD of pipe is 6.625

NPS 14OD of pipe is 14

NB: ( nominal bore)

It is dimensional pipe designator of pipe. It represents OD of pipe in

mm.

Ex: NB 100 OD of pipe is 114 mm

NB 400OD of pipe is 400 mm

DN: ( diameter nominal)

It is dimensionless designator of pipe. It represents OD of pipe in mm.

Ex: DN 100 OD of pipe is 114 mm

DN 400 OD of pipe is 400 mm

NPS OD NB/DN

1 1.315 25

2 2.375 50

3 3.5 80

4 4.5 100

6 6.625 150

8 8.625 200

10 10.75 250

12 12.75 300

14 14 350


Note:

Up to NPS 12 , OD > NPS

From NPS 14, OD = NPS

Note:

Smallest pipe size : 3mm or 1/8

Max pipe size : 60 ( 5 feet)

Note:

Pipe of size < NPS 2 are called small bore pipes

Pipe of size > NPS 2 are called big bore pipes

Highest of small bore size = 1.5

2. Wall thickness:

It is represented by following terms.

(i). Schedule no. ( SCH)

(ii). Pipe weight designation

(i) SCH:

It is a no. which has standardize thickness as per the standards

Sch no. range :

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

Sch no. without s is for CS and AS

Sch no with s is for ss

Ex: NPS 6 SCH 10

NPS 6 SCH 10s

(ii) Pipe weight designation:

It is alternative way for representing pipe thickness

STD standard weight thickness

XS/XH extra strong /extra heavy

XXS/XXH double extra strong/ double extra heavy

Ex: NPS 6 SCH STD

STD SCH 40 for diff. pipe size

XS SCH 80


i) t = P do/ 2(SEW + PY)

ii) tm = t + A

iii) = tm 12.5 % mill tolerance

iv) Sch thickness from standards

Here:

t = thickness

P = internal pressure

Do = outer diameter

S = basic allowable stress from code

E = longitudinal weld joint quality factor from code

W = weld joint stress reduction factor from code

Y = coeff. For m/L from code

tm = min thickness

A = sum of corrosion, erosion, thread depth allowance (TDA)

= nominal thickness

3. Pipe length :

Single random length : 6 m ( 20 feet)

Double random line : 12m ( 40 feet)

Customize length : as per customer requirement ( for pipelines)


4. Pipe ends:

Plane ends: for small bores

Screwed / threaded ends: for small bores

Straight

Tapered : used in process piping and also known as NPT(

national standard tapper pipe thread )

Beveled ends: 37.5 is most commonly used bevels.

5. Pipe joining methods:

(i). Screwed joining method

(ii). Socket weld method(sw)- for plane ends pipes

(iii). Butt weld method(bw)


(i) Screwed joining method:

It requires an external ad for joining two pipes.

Advantages:

It can be easily made on the site

It can be used where welding is not permitted due to fire hazard

Disadvantages:

It is not used for big bores and high pressure and temp. Lines.

There is joint leaks

A seal weld can be used for threaded joint but the code doesnt

allow to consider the welding strength as the joint strength

(ii) Socket weld joining method:

Gap of 1/16 or 1.5 mm is to be maintain to accommodate pipe

thermal expansion

Two circumferential weld is done


Advantages:

End preparation is not required

Alignment if end is not required

The welding is less time consuming

Disadvantages:

Not used for big bores and high press. and temp. lines

1.5 mm gap pocket fluid is not permitted by code for corrosive

and abrasive fluids.

(iii) Butt weld method:

It is generally used for joining big bore pipes

Root gap for proper weld preparation , mostly 75

Advantages:

It is the best way for joining big bore, high temp and pressure

lines

The joint is reliable and leak proof

The joint can be radiograph


o NDT techniques

Radiography

VT

MPT

DPT

RT: to find weld defects

UT: to find the flow dimension

Radiography:

it is the method in which welding flaws (defects) are

found by passing radiation through the welding by

placing a source ( radiation emitter) (ex:cobalt)

whose radiation forms a lighter and bitter shape of

image on film wrapped on welding from pipe

outside which helps in finding the defects in

welding.

Disadvantages

End preparation is necessary

Alignment of ends is necessary

Welding is more time consuming than the socket weld

A backing ring is required to avoid weld penetration to pipe ID

o Backing ring shapes:

Circular

Square

Rectangular

o M/L of backing ring:

Ferrous or non ferrous

Consumable or non consumable

6. Pipe manufacturing methods:

(i). Seamless ( E=1)

(ii). ERW(electric resistance weld)

(iii). EFW(electric fusion weld)

(iv). FBW(fusion butt weld)

(v). SAW(submerge arc weld)

(vi). DSAW(double submerge arc weld)

Ex: NPS 8 SCH 40 ERW


Note: other than seamless, all other methods (E< 1)

7. Piping grades:

(i). Carbon steel :

Max temp : 800f( 427c)

Max carbon content : 0.35 %

Grades:

A, B, C

C is better than A & B


Ex:

ASTM A53 GR A for ambient condition

ASTM A53 GR B for high temp

ASTM A106 GR B for high temp

ASTM A106 GR C for high temp

A53 is most commonly used carbon steel m/L

ASTM : American society for testing & m/L

Note:

Killing steel:

Killing is the process in which oxygen is removed by adding aluminum (Al2O3) and

manganese (Mno) which can be used for temp beyond 8000 f

(ii) Alloy steel:

Main alloy elements Cr,Mo

Max temp 1200f

Grades:

P1,P2,P5,P11,P12,P22

Ex:

ASTM A335 Gr P1

ASTM A335 Gr P11

ASTM A335 Gr P12

(iii) Stainless steel:

Main alloy elements: Cr,Ni

Called as austenite ss due to the presence of Ni

Carbon content : 0.08 %

Max temp: 1600 f

Note:

It is used for ambient temp also for corrosive fluid

Grades:

304, 304L, 316, 316L, etc

Ex:

ASTM A312 TP 304

ASTM A312 TP 304L


ASTM A312 TP 316

ASTM A312 TP 316L

TP- tabular product

L- Low carbon content: 0.03 % max

Note:

At high temp. carbon present in the ss reacts with cr to form

crc(chromium carbide) due to which the white surface layer of

chromium(cr) is depleted, making steel prom to corrosion, to

avoid this either low carbon ss or ss with stabilizer like

chromium , titanium is used which have more attraction and

reaction to carbon than chromium.

Most commonly used ss is 304 with 18 %Cr and 8 %

Ni

8. Pipe symbols:

Rise symbol:

It is for pipe going up/coming towards us.


Drop symbol:

It is for pipe going away from us/dropping/ going down

Incomplete circle with pipe going inside it.

Single line drawing symbol:

In this the pipe is drawn with solid central line, this type is used up to

size 6 inch or 12 inch

Double line drawing symbol:

In this type the pipe is drawn in double line or the actual size of pipe is

drawn to scale with the chain dotted central line. (CL)


Joint symbols:

Threaded joints

Socket weld joint(SW)

Butt weld joint(BW)

Note:

1.Piping Introduction and Fundamentals

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