Piping_Materials_Elbows and Bends_Reducers_PE & ROTO Lined Carbon Steel Piping

7/23/2019 Piping_Materials_Elbows and Bends_Reducers_PE & ROTO Lined Carbon Steel Piping

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Piping Elbows and Bends are very important pipe fitting which are used very frequently for changing direction in piping system. Piping Elbow and Piping bend are not the same, even though sometimes these two terms areinterchangeably used. A BEND is simply a generic term in piping for an “offset” – a change in direction of the

piping. t signifies that there is a “bend” i.e., a change in direction of the piping !usually for some specific reason" – but it lac#s specific, engineering definition as to direction and degree. Bends are usually made by using a bendingmachine !hot bending and cold bending" on site and suited for a specific need. $ses of bends are economic as itreduces number of e%pensive fittings.An ELBOW, on the other hand, is a specific, standard, engineered bend pre&fabricated as a spool piece !based on'()E B *+." and designed to be screwed, flanged, or welded to the piping it is associated with. 'n elbow can be- degree or / degree. 0here can also be custom&designed elbows, although most are categori1ed as either “shortradius” or long radius”.n short “'ll bends are elbows but all elbows are not bends”

2henever the term elbow is used, it must also carry the qualifiers of type !- or / degree" and radius !short orlong" – besides the nominal si1e.

Elbows can change direction to any angle as per requirement. 'n elbow angle can be defined as the angle by whichthe flow direction deviates from its original flowing direction !(ee 3ig.* below". Even though an elbow angle can beanything greater than / but less or equal to /4 but still a change in direction greater than /4 at a single point is notdesirable. 5ormally, a -4 and a /4 elbow combinedly used while ma#ing piping layouts for such situations.

3ig.* ' typical elbow with elbow angle !phi"Elbow angle can be easily calculated using simple geometrical technique of mathematics.

6efer to 3ig.7. Pipe direction is changing at point ' with the help of an elbow and again the direction is changing atthe point 8 using another elbow.

3ig.7 E%ample figure for elbow angle calculationn order to find out the elbow angle at ', it is necessary to consider a plane which contains the arms of the elbow. fthere had been no change in direction at point ', the pipe would have moved along line '9 but pipe is moving alongline '8. Plane '389 contains lines '9 and '8 and elbow angle !phi" is mar#ed which denotes the angle by whichthe flow is deviating from its original direction.

:onsidering right angle triangle '89, tan !phi" ; <!%7 = 17">y(imilarly elbow angle at 8 is given by? tan !phi*" ;< !y7 =17">%

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Elbow Radius:

Elbows or bends are available in various radii for a smooth change in direction which are e%pressed in terms of pipenominal si1e e%pressed in inches. Elbows or bends are available in three radii,a. @ong radius elbows !6adius ; *.9"? used most frequently where there is a need to #eep the frictional fluid

pressure loss down to a minimum, there is ample space and volume to allow for a wider turn and generate less pressure drop. b. @ong radius elbows !6adius A *.9"? $sed sometimes for specific applications for transporting high viscousfluids li#es slurry, low polymer etc. 3or radius more than *.9 pipe bends are usually used and these can be made toany radius. owever, C9 D 9 pipe bends are most commonly used

b. (hort radius elbows !6adius ; *./9"? to be used only in locations where space does not permit use of long radiielbow and there is a need to reduce the cost of elbows. n ac#eted piping the short radius elbow is used for the core

pipe.ere 9 is nominal pipe si1e in inches.

Elbow Radius:

3or a smooth change in direction, elbows or bends are available in various radii. 0hese radii are e%pressed in termsof pipe nominal si1e e%pressed in inches. Elbows are available in two radii,

a. @ong radius elbows !6adius ; *.9"

b. (hort radius elbows !6adius ; *./9"

where 9 is nominal pipe si1e in inches.

3or radius more than *.9, pipe bends are used and these can be made to any radius.

owever, C9 D 9 pipe bends are most commonly used. $sually in chemical, petrochemical

D refinery plants, long radius elbows are widely used. Pipe bends are preferred where pressure drop is of a maorconsideration. $se of short radius elbows should be avoided as far as possible due to abrupt change in direction

causing high pressure drop.

Elbow 6adius

4.0 End Connections:

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0he following types of end connections ae a!ailable fo connectin" elbow#bend to pipe.

F (oc#et welded

F Butt welded

F (crewed

F 3langed

A. $oc%eted Welded Elbows:

F Pipe is connected to soc#et welded elbow as shown in 3ig. – , by having a fillet weld.

(oc#eted 2elded Elbows

F (oc#et welded elbows are available up to 7” nominal si1e. owever, in $@, our practice is to use these elbows upto **>7” si1e only.

F 9imensions of soc#et welded elbows are as per '()E B*+.**

F (ince there is possibility of fluid getting entrapped between pipe G.9 and soc#et .9., this may cause corrosioncalled crevice corrosion. 0hus use of soc#et welded fittings should be avoided for services where corrosion>erosionis of great concern.

F 3illet welds are e%amined by using liquid dye penetrant or )agnetic particle inspection method. 5o radiography is possible for chec#ing soundness of these welds.

F (ince soc#et welded oints cannot be radiographed, these fittings are not recommended for critical serviceshandling ha1ardous or highly inflammable fluids. 3or such services butt welded fittings are preferred.

F (oc#et welded fittings are forged and applicable material standards are as follows?

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A$&' A(0) !3orged :arbon (teel"

0hese fittings are suitable for welding to all carbon steel pipes.

A$&' A(*+ !3orged 'lloy (teel and (tainless (teel 3ittings"

$nder '(0) '*H7 several grades are available depending upon chemical composition.

(election would depend upon pipe material connected to these fittings. 3itting material should have same chemicalcomposition as that of pipe.

(ome of the grades available under '(0) '*H7 and corresponding connected pipe material specification are listed below?

86'9E PPE )'0E6'@ (PE:

3** ? '(0) 'CC P**

377 ? '(0) 'CC P77

3C/- ? '(0) 'C*7 8r.0P C/-

3C/-@ ? '(0) 'C*7 0P C/-@

3C*+ ? '(0) 'C*7 0P C*+

3C7* ? '(0) 'C*+ 0PC7*

A$&' A,)0 !3orged carbon and low alloy steel fittings for low temperature services"

$nder '(0) 'C/, several grades are available depending upon chemical composition D tensile properties.

F 3ittings conforming to '()E B*+.** are designated as Pressure class 7///, C/// and +/// fittings for threadedand Pressure class C///, +/// and /// for soc#et welded ends.

0his designation identified the fittings with their ratings as shown below?

!6efer 0able 7, '()E B *+.**"

-essue

Class&ype

-ipe used fo Ratin" Basis

$cedule No.#Wall

desi"nation

7/// 0hreaded H/ > !I("

C/// 0hreaded *+/ >–

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+/// 0hreaded – > II(

C/// (oc#et&2elding H/ > !I("

+/// (oc#et&2elding *+/ >–

/// (oc#et&2elding – > II(

0he above does not restrict the use of pipe of thinner or thic#er wall with fittings. owever, when thinner pipe isused, its strength may govern and when thic#er pipe is used, the strength of the fitting governs the rating.

B. Butt Welded Elbows:

F Pipe is connected to butt welded elbow as shown in 3ig. + by having a butt&welding oint.

Butt 2elded Elbows

F Butt welded fittings are supplied with bevel ends suitable for welding to pipe. t is important to indicate connected pipe thic#ness schedule while ordering. 'll edge preparations for butt welding to conform to '()E B*+.7.

F 9imensions of butt welded elbows are as per '()E B*+.. 0his standard is applicable for carbon steel D alloysteel butt weld fittings of 5P( *>7” through -H”

F 9imensions of stainless steel butt welded fittings are as per )((&(P&-C. Physical dimensions for fittings areidentical under '()E B*+. and )((&(P&-C. t is implied that the scope of '()E B*+. deals primarily with thewall thic#nesses which are common to carbon and low alloy steel piping, whereas )((&(P&-C deals specificallywith schedule ( D */( in stainless steel piping.

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F 9imensions for short radius elbows are as per '()E B*+.7H in case of carbon steel D low alloy steel and )((&(P& for stainless steel.

F Butt welded fittings are usually used for si1es 7” D above. owever, for smaller si1es up to

**>7” on critical lines where use of soc#et welded oints is prohibited, pipe bends are used.

0hese bends are usually of 9 radius and made at site by cold bending of pipe.

'lternatively, butt welded elbows can be used in lieu of pipe bends but usually smaller dia lines are field routed andit is not possible to have the requirement #nown at initial stage of the proect for procurement purpose. (o pipe

bends are preferred. owever, pipe bends do occupy more space and particularly in pharmaceutical plants wheremaor portion of piping is of small dia. and layout is congested, butt welded elbows are preferred.

F Butt welded oints can be radiographed and hence preferred for all critical services.

F )aterial standards as applicable to butt welded fittings are as follows?

A$&' A+,4?

0his specification covers wrought carbon steel and alloy steel fittings of seamless and welded construction. $nlessseamless or welded construction is specified in order, either may be furnished at the option of the supplier. 'llwelded construction fittings as per this standard are supplied with *//J radiography. $nder '(0) '7C-, severalgrades are available depending upon chemical composition. (election would depend upon pipe material connectedto these fittings.

(ome of the grades available under this specification and corresponding connected pipe material specification arelisted below?

86'9E PPE )'0E6'@ (PE:2PB ? '(0) 'C 8r '>B, '*/+ 8r '>B

( *7C, ( *KH, ( CH2P: ? '(0) '*/+ 8r.:2P** ? '(0) 'CC P**2P77 ? '(0) 'CC P77

A$&' A40,?

0his specification covers two general classes, 2P D :6, of wrought austenitic stainless steel fittings of seamlessand welded construction.

:lass 2P fittings are manufactured to the requirements of '()E B*+. D '()E B*+.7H and are subdivided intothree subclasses as follows?

W- / $ )anufactured from seamless product by a seamless method of manufacture.

W- / W 0hese fittings contain welds and all welds made by the fitting manufacturer including starting pipe weld ifthe pipe was welded with the addition of filler material are radiographed. owever no radiography is done for thestarting pipe weld if the pipe was welded without the addition of filler material.

W-W1 0hese fittings contain welds and all welds whether made by the fitting manufacturer or by the startingmaterial manufacturer are radiographed.

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:lass :6 fittings are manufactured to the requirements of )((&(P&-C and do not require non&destructivee%amination.

$nder '(0) '-/C several grades are available depending upon chemical composition.

(election would depend upon pipe material connected to these fittings. (ome of the grades

listed below?

86'9E PPE )'0E6'@ (PE:2P C/- 2P C/-( ?

'(0) 'C*7 0PC/-2PC/-2 ?2PC/-2I ?

:6 C/-2P C/-@ 2PC/-@( ?

'(0) 'C*7 0PC/-@2PC/-@2 ?2PC/-@2( ?

:6 C/-@

A$&' A4+0?

F 0his specification covers wrought carbon steel and alloy steel fittings of seamless D welded construction intendedfor use at low temperatures. t covers four grades 2P@+, 2P@, 2P@C D 2P@H depending upon chemicalcomposition. 3ittings 2P@+ are impact tested at temp – /4 :, 2P@ at &K4 :, 2P@C at &*//4 : and 2P@H at&*4 : temperature.

F 0he allowable pressure ratings for fittings may be calculated as for straight seamless pipe in accordance with therules established in the applicable section of '()E BC*.C.

F 0he pipe wall thic#ness and material type shall be that with which the fittings have been ordered to be used, their

identity on the fittings is in lieu of pressure rating mar#ings.

C. $cewed Elbows:

F 0hese are usually used for 8alvanised piping where all oints are screwed type. 3ittings used are also galvani1edon such lines.

F 3ollowing standards are usually adopted for galvani1ed screwed fittings.

2$ (+,3 -at 22

A$&' A(0) o A$&' A(*( Class 0 forged D galvani1ed and dimensions conforming to '()E B*+.**.

F $sually we do not use fittings conforming to ( *7C part because the same are not forged and get crac#ed whiletightening. 3orged fittings having dimensional standard conforming to '()E B*+.** are preferred. 3or pressurerating of these fittings, refer Paragraph on pressure ratings of soc#et welded fittings.

F (crewed oints are made by using teflon tape for sealing.

F 0here is always a possibility of lea#age through screwed oints. 0hese type of oints are not recommended forha1ardous fluids.

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F (ometimes, seal welding is done for screwed oints in order to avoid lea#age. owever screwed connection atinstruments shall not be seal welded.

F Pipe threads are usually as per (- taper.

D. 5lan"ed Elbows:

F $sually flanged elbows are used on cast&iron piping. :ast steel flanged elbows with liner are used to some e%tentfor lined piping such as carbon steel&P03E lined !6efer chapter on lined&piping"

F 3ollowing standards are usually adopted for flanged elbows D other fittings?

'()E B*+.* !:ast ron Pipe 3langes and 3langed 3ittingsL :lasses 7,*7 and 7/"

'()E B*+. !Pipe 3langes and 3langed 3ittings".

F 's per '()E B*+.*, cast iron fittings are available in classes 7, *7, 7/. Based on pressure&temperatureconditions, proper rating can be selected as per table 7 '()E B*+.*. 'll ratings are dependent on the contained

fluid and are the ma%imum non shoc# pressures at the tabulated temperature.

F 'll class 7 D *7 flanged fittings are furnished with flat face. 'll class 7/ flanged fittings are furnished with/,/+ inch high raised face and finished in accordance with )((&(P&+.

F 0he minimum material requirements for flanged cast iron fittings shall be as follows?

Ratin" $i6e Class of 2on

7 'll '(0) '*7+ :lass '

*7 *M – *7M '(0) '*7+ :lass ' or B

*7 *-M D above '(0) '*7+ :lass B

7/ *M – *7M '(0) '*7+ :lass ' or B

7/ *-M D above '(0) '*7+ :lass B

0he equivalent ( material usually used is ( 7*/ 8r. 77/.

E. 'ite Elbows:

F 0hese are usually used for low pressure, low temperature non critical services having *-” inches and above. 0heyare economical as compared to elbows in higher si1es and hence preferred.

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F )itre bends are usually fabricated at site out of pipe by cutting and re&welding spools as shown in 3ig. K. 0he3igure is for piece - weld mitres. 0he change in direction at every weld is 77 *>7 4. 2e may also have -&piece C&weld mitre where change in direction at every weld would be C/4. $sually piece - weld mitres are preferred inorder to have smooth flow.

F $sually effective radius of mitre&bend, defined as the shortest distance from the pipe centre line to the intersectionof the planes of adacent mitre oints is *.9 where 9 is the nominal pipe si1e in inches. owever, one can selectany other radius if called for.

F t is recommended to fabricate mitre bends after #nowing length of 'rm&* D 'rm&7 up to ne%t weld !6efer 3ig. K".(o as to avoid two additional welds.

F Because of high stress intensification factor they are not recommended on high temperature lines.

F Pressure&temperature rating for mitre bend is not the same as for pipe and in order to withstand same pressure&temperature conditions as applicable to pipe, a higher thic#ness is required for mitre bend.

's per '()E BC*.C !:l. C/-.7.C", the ma%imum allowable internal pressure shall be the lesser value calculatedfrom equation given below ?

0hese equations are not applicable when N e%ceeds 77.4

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2here

Pm ; )a%imum allowable internal pressure for mitre bend.

0 ; )inimum )iter Pipe wall thic#ness.

: ; (um of mechanical D corrosion allowances.

6* ; Effective radius of mitre bend.

r7 ; )ean radius of pipe using nominal wall thic#ness.

( ; 'llowable stress of material at the given temperature.

E ; Ouality factor as applicable to pipe used for mitre bend.

N ; 'ngle of mitre cut or *>7 the angle of change in direction at mitre oint.

0hic#ness 0Q used in above equations shall e%tend a distance not less than )Q from the inside crotch of the endmitre welds where,

) ; larger of 7. !r7 R 0" /. or tan N !6 * – r 7".

$sually e%tra thic#ness is available in pipe used for low pressure services and it is possible to use the same pipe forma#ing mitre bends. owever a chec# is always required.

F 'n angular offset of C4 or less does not require design consideration as a mitre bend.

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0here are three maor parameters which dictate the radius selection for elbow. (pace availability, cost and pressuredrop.Pipe bends are preferred where pressure drop is of a maor consideration.$se of short radius elbows should be avoided as far as possible due to abrupt change in direction causing high

pressure drop.

'ini7u7 tic%ness e8uie7ent:2hether an elbow or bend is used the minimum thic#ness requirement from code must be met. :ode '()E B C*.C provides equation for calculating minimum thic#ness required !t" in finished form for a given internal design pressure !P" as shown below?

3ig.C? :ode equation for minimum thic#ness requirement calculationere,6* ; bend radius of welding elbow or pipe bend9 ; outside diameter of pipe2 ; weld oint strength reduction factor S ; coefficient from :ode 0able C/-.*.*( ; stress value for material from 0able '&* at ma%imum temperatureE ; quality factor from 0able '&*' or '&*B

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'dd any corrosion, erosion, mechanical allowances with this calculated value to get the thic#ness required.

End Connections:

3or connecting elbow>bend to pipe the following type of end connections are available• Butt welded? $sed along with large bore !A;7 inch" piping

• (oc#et welded? $sed along with pipe si1e

• (crewed?• 3langed?

Butt welded Elbows:

• Pipe is connected to butt welded elbow as shown in 3ig. - by having a butt&welding oint.

• Butt welded fittings are supplied with bevel ends suitable for welding to pipe. t is important to indicate theconnected pipe thic#ness >schedule while ordering. 'll edge preparations for butt welding should conform to'()E B*+.7.

• 9imensions of butt welded elbows are as per '()E B*+.. 0his standard is applicable for carbon steel Dalloy steel butt weld fittings of 5P( *>7” through -H”.

3ig.-? ' typical Butt&2elded Elbow• 9imensions of stainless steel butt welded fittings are as per )((&(P&-C. Physical dimensions for fittings

are identical under '()E B*+. and )((&(P&-C. t is implied that the scope of '()E B*+. deals primarilywith the wall thic#nesses which are common to carbon and low alloy steel piping, whereas )((&(P&-C dealsspecifically with schedule ( D */( in stainless steel piping.

• 9imensions for short radius elbows are as per '()E B*+.7H in case of carbon steel D low alloy steel and)((&(P& for stainless steel.

• Butt welded fittings are usually used for si1es 7” D above. owever, for smaller si1es up to *&*>7” oncritical lines where use of soc#et welded oints is prohibited, pipe bends are normally used. 0hese bends areusually of 9 radius and made at site by cold bending of pipe. 'lternatively, butt welded elbows can be used inlieu of pipe bends but usually smaller dia lines are field routed and it is not possible to have the requirement#nown at initial stage of the proect for procurement purpose. (o pipe bends are preferred. owever, pipe bendsdo occupy more space and particularly in pharmaceutical plants where maor portion of piping is of small dia. andlayout is congested, butt welded elbows are preferred.

• Butt welded oints can be radiographed and hence preferred for all critical services.

•

)aterial standards as applicable to butt welded fittings are as follows?A$&' A+,4:

0his specification covers wrought carbon steel D alloy steel fittings of seamless and welded construction. $nlessseamless or welded construction is specified in order, either may be furnished at the option of the supplier. 'llwelded construction fittings as per this standard are supplied with *//J radiography. $nder '(0) '7C-, severalgrades are available depending upon chemical composition. (election would depend upon pipe material connectedto these fittings.

Page 12 of 52



(ome of the grades available under this specification and corresponding connected pipe material specification arelisted below?

A$&' A40,:

0his specification covers two general classes, 2P D :6, of wrought austenitic stainless steel fittings of seamlessand welded construction.:lass 2P fittings are manufactured to the requirements of '()E B*+. D '()E B*+.7H and are subdivided intothree subclasses as follows?2P – ( )anufactured from seamless product by a seamless method of manufacture.2P – 2 0hese fittings contain welds and all welds made by the fitting manufacturer including starting pipe weld ifthe pipe was welded with the addition of filler material are radiographed. owever no radiography is done for thestarting pipe weld if the pipe was welded without the addition of filler material.2P&2I 0hese fittings contain welds and all welds whether made by the fitting manufacturer or by the startingmaterial manufacturer are radiographed.:lass :6 fittings are manufactured to the requirements of )((&(P&-C and do not require non&destructivee%amination.$nder '(0) '-/C several grades are available depending upon chemical composition. (election would dependupon pipe material connected to these fittings. (ome of the grades available under this specification andcorresponding connected pipe material specification are listed below?

A$&' A4+0:

• 0his specification covers wrought carbon steel and alloy steel fittings of seamless D welded constructionintended for use at low temperatures. t covers four grades 2P@+, 2P@, 2P@C D 2P@H depending uponchemical composition. 3ittings 2P@+ are impact tested at temp – /4 :, 2P@ at &K4 :, 2P@C at &*//4 : and2P@H at &*4 : temperature.

• 0he allowable pressure ratings for fittings may be calculated as for straight seamless pipe in accordancewith the rules established in the applicable section of '()E BC*.C.

• 0he pipe wall thic#ness and material type shall be that with which the fittings have been ordered to be used,their identity on the fittings is in lieu of pressure rating mar#ings.

0he term (3 indicates a multiplier of Bending and 0orsional stresses. 0his ntensifier acts local to a piping

:omponent !tees, elbows, bends, Glets, etc." and value depends on component geometry. 0he minimum value

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of (3 is *./. t is widely used by piping stress engineers in places where the actual stress calculation is quite

difficult due to its difficult geometry !Tarying thic#ness, cross section, curvature etc." as unli#e straight Pipes

the simple Beam theory is not applicable. (o in this situation it is required to assume additional stresses by

suitably incorporating a (3.

(tress ntensification 3actor for a Piping Bend>Elbow?n laymanQs language the (3 of a bend or elbow can be defined as the ratio of bending stress of an elbow to that

of straight pipe of same diameter and thic#ness when subected to same bending moment. 2henever the same

bending moment is applied to a bend because of ovali1ation the bending stress of the elbow will be much higher

than that of straight pipe. 0hat is why the (3 value will always be greater than or equal to *./ !for straight

pipe".

0he process piping code '()E B C*.C provides a simple formula to calculate the (3 of a bend or elbow. 's

per that code

(3 in&plane ; /. > hU!7>C"

(3 out&plane ; /.K > hU!7>C"

ere h;0 6* > r7U7

h ;3le%ibility characteristics, dimensionless

0 ;5ominal wall thic#ness of bend, in

6* ;Bend radius, in

r7 ;)ean radius of matching pipe, in

0he in plane and out plane concept for a bend can be obtained from the attached figure from code or in

laymanQs language the same can be e%plained as follows?

0he in&plane bending moment is the bending moment which causes elbow to close or open in the plane formed

by two limbs of elbow.

n a similar way the out plane bending moment can be defined as the bending moment which causes one limb of

elbow to move out of the plane #eeping other limb steady.

3rom the above mentioned equations the following can be interpreted?

3or the same pipe si1e and same pipe thic#ness

*. ' short radius elbow is having more (3 as compared to a long radius elbow.

7. 2ith increase in bend radius the (3 decreases and finally reaches to *./ for straight pipe.

C. 0he (3 for a - degree elbow and a / degree elbow is same as bend radius is same.

-. 2ith increase in nominal pipe thic#ness or schedule the (3 of a bend !/ degree" #eeps on decreasing till its

value is equal to *./.

Page 14 of 52



:arbon steel?

'(0) 'C& welded and seamless pipe, blac# and galvanised.

'(0) '*/+& (eamless cs pipe for high temperature services.

'(0) '+K7& Electric fusion welded steel pipe for high pressure service at moderate temperature services.

(tainless steel?

'(0) 'C*7& (eamless and welded steel pipe for low temperature services.

'-/&welded large diameter austenitic steel pipe for corrosive and high temperature services.

'(0) 'CH& Electric fusion welded austenitic chrome &nic#el steel pipe for high temperature services.

@ow alloy steel?

'(0) 'CC& (eamless ferritic alloy steel pipe for high temperature services.

'(0) '+*& :arbon and alloy steel pipe, electric fusion welded for high pressure service at high temperature.

@ow temperature carbon steel?

'(0) 'CCC& (eamless and welded steel pipe for low temperature services.

'(0) '+K*& Electric fusion welded steel pipe for atmpospheric and low temperature services!si1es A;*+in 5B"

-ipe

Based on )anufacturing Process Pipes can be classified as below

*. (eamless Pipe

7. 2elded Pipe

a. E32&Electric 3usion 2elded

*. i. @ongitudinal ('2 Pipe

7. ii. (piral ('2 Pipe

b. E62 – Electrical 6esistance welded Pipe

Page 15 of 52



(. $ea7less -ipe

'andel 'ill

&A0his process is used to ma#e smaller si1es of seamless pipe, typically * to + inches !7 to */ mm" diameter.

&A 0he ingot of steel is heated to 7,CK/ 43 !*,C// 4:" and pierced.

Page 16 of 52



&A ' mandrel is inserted into the tube and the assembly is passed through a rolling !mandrel" mill.

&A$nli#e the plug mill, the mandrel mill reduces wall thic#ness continuously with a series of pairs of curved rollersset at /4 angles to each other.

&A'fter reheating, the pipe is passed through a multi &stand stretch&reducing mill to reduce the diameter to the

finished diameter.

&A0he pipe is then cut to length before heat treatment, final straightening, inspection, and hydrostatic testing.

-lu" 'ill

&A0his process is used to ma#e larger si1es of seamless pipe, typically + to *+ inches !*/ to -// mm" diameter.

&A'n ingot of steel weighing up to two tons is heated to 7,CK/ 43 !*,C// 4:" and pierced.

&A0he hole in the hollow shell is enlarged on a rotary elongator, resulting in a short thic#&walled tube #nown as a bloom.

&A'n internal plug appro%imately the same diameter as the finished diameter of the pipe is then forced through the bloom.

&A0he bloom containing the plug is then passed between the rolls of the plug mill.

&A6otation of the rolls reduces the wall thic#ness

&A0he tube is rotated through /4 for each pass through the plug mill to ensure roundness.

&A0he tube is then passed through a reeling mill and reducing mill to even out the wall thic#ness and produce thefinished dimensions.

&A 0he tube is then cut to length before heat treatment, final straightening, inspection, and hydrostatic testing.

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+.

Welded -ipes

a. E5W -ipe

*. i. Longitudinally Welded Pipe

&A2elded pipe !pipe manufactured with a weld" is a tubular product made out of flat plates, #nown as s#elp, that areformed, bent and prepared for welding. 0he most popular process for large diameter pipe uses a longitudinal seamweld. 0he welds are made by heating with an electric arc between the bare metal electrodes.

&APressure is not used. 3iller metal for the welds is obtained from the electrodes.

&A3or diameters above C+ inches, double seam welded pipe is specified as an alternative in 'P @. 0his has twolongitudinal seams.

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@ongitudinally 2elded Pipe

E32 Pipe )anufacturing Process

7. $pial welded pipe

&A's an alternative process, spiral weld construction allows large diameter pipe to be produced from narrower platesor s#elp.

&A0he defects that occur in spiral welded pipe are mainly those associated with the ('2 weld,

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&A'n additional problem with early spiral welded pipe was poor dimensional accuracy, particularly out of roundnessat the pipe ends. 0his led to problems of poor fit&up during field girth welding. (piral line pipe gained a poorreputation in some companies as a result of these early e%periences.

&A:onsidered suitable only for low pressure applications such as water pipe.b. Electic Resistance Welded 9ERW

&A(olid phase butt weld, was produced using resistance heating D high pressure to ma#e the longitudinal weld!E62",

&A5owadays )ost pipe mills now use high frequency induction heating !3" for better control and consistency.owever, the product is still often referred to as E62 pipe, even though the weld may have been produced by the3 process.

&A0he defects that can occur in E62>3 pipe are those associated with strip production, such as laminations anddefects at the narrow weld line.

&A@ac# of fusion due to insufficient heat and pressure is the principal defect, although hoo# crac#s can also form dueto realignment of non metallic inclusions at the weld interface. Because the weld line is not visible after trimming,and the nature of the solid phase welding process, considerable lengths of weld with poor fusion can be produced ifthe welding parameters fall outside the set limits.

&An addition, early E62 pipe was subect to pressure reversals, a problem that results in failure in service at a lower stress than that seen in the pre&service pressure test. 0his problem is caused by crac# growth during the pressure testhold period, which in the case of early E62 pipe was due to a combination of low weld line toughness and lac# offusion defects.

Technical requirements for Pipes & Fittingsfor preparation of Purchase Requisition

• 18th February 2015• want2learn

• Detail Design

•

• 0 Comments20

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While preparing the purchase requisitioninquiry of any piping component there are !arious

points which nee" to be chec#e" an" con$rme" with the !en"or% &he responsible requisition

engineer shoul" inclu"e all the technical points ' clauses applicable to the pipingcomponents in the requisitioninquiry ' subsequent technical queries (&)*%

&he requisition engineer shoul" refer all the pro+ect speci$c stan"ar"s an" speci$cations

along with the applicable international co"es an" stan"ar"s while preparing the inquiry

requisition of the piping components% ,n this article few general technical requirements for

pipes ' $ttings are liste" for information% -ote that these requirements may !ary "epen"ing

upon the pro+ect requirements%

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General requirements:

• Pipe an" Fitting .aterial supplie" must be strictly in accor"ance with the latest co"es

an" stan"ar"s/ mentione" in the .aterial equisition (. or P Purchase equisition*cope of supply% &his speci$cation for pipes an" $ttings as "etaile" in subsequent pointsshall supplement the co"es an" other pro+ect speci$cations%

• 3ll items must be supplie" in accor"ance with proper wall thic#ness sche"ule as

state" in the Purchase equisition (P*% Wall thic#ness thinner or hea!ier than speci$e"tolerance shall not be accepte"%

• 4en"or must specify the material type an" gra"e together with -P an" sche"ule

wall thic#ness class within the .aterial requisition cope of upply for all pipingcomponents%

• 6utt wel" en" preparation for pipes/ $ttings an" 7anges shall be as per 3. 619%25%

• 100: ra"iography has to be performe" for all wel"e" items to gi!e a +oint factor of

1%0% ,f not speci$e"/ Pipes an" $tting shall be supplie" seamless% eamless is anacceptable alternati!e for wel"e" pipe an" $ttings but !ice;!ersa is not acceptable%

• &he chemical analysis of Carbon teel (C* ' <ow &emperature Carbon teel (<&C*

pipes an" $ttings/ forgings/ plates shall be in accor"ance with the applicable pro"uctstan"ar" with the following limitations

Carbon 0%2= .a>imum wt: (pipes*

Carbon 0%2= .a>imum wt: (forgings*

Carbon qui!alent (C* shall not e>cee" 0%?=:

Where C @ C A .n9 A (CrA.oA4*5 A (CuA-i*15

&he abo!e formula for C is applicable when the carbon content is greater than 0%12:

• C ' <&C materials shall be fully #ille" an" $ne graine" an" shall be pro"uce" by a

low sulphur an" low phosphorous re$ning process% &he components must be supplie" innormaliBe" or normaliBe" an" tempere" con"ition%

• 3ll 3ustenitic stainless steel/ "uple> stainless steel items must be supplie" in solution

anneale" an" quenche" con"ition as per correspon"ing 3&. stan"ar"%

• epair wel"ing for parent plate wel" en" 7ange is not accepte"%

• &he carbon content of =19 must be limite" to 0%0=:% 3ll .aterials speci$e" as

F =19 WP =19 &ype =19 may be "ual certi$e" for both =19 ' =19</ if speci$callymentione" in the pro+ect speci$cation%

•

3ustenitic stainless steel has to be capable of passing an inter;granular corrosion testin accor"ance with 3&. 3292/ Practice %

• 3ll "uple> stainless steel shall ha!e ferrite content between =5: 95: (!olume

fraction* on base metal an" on heat aecte" Bone to =5: 0 : as per 3&. 592 fourpoint count metho"%

Requirements for Pipes:

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• Dimensions of C an" 3lloy steel (3* pipe shall comply with 3. 6=9%10. or

3. 6=9%1E. as applicable%

• C pipes shall be supplie" in "ouble ran"om lengths (11 to 1=m* for pipe siBes 2 to=9/ an" in single ran"om lengths (5 to m* for pipe siBes 1%5 an" smaller%

• / Duple> tainless teel (D* an" Carbon teel gal!aniBe" pipes shall be supplie"

in single ran"om lengths (5 to m* for all pipe siBes%• ,t is not permitte" to +oin lengths of pipe by circumferential wel"s to ma#e single or

"ouble ran"om lengths%

• Plain en" pipes must ha!e square en"s cut with burrs remo!e"%

• 3ll stainless steel pipes shall be supplie" in solution anneale" con"ition%

• 3ll threa"e" ' couple" pipes shall be supplie" with en"s threa"e" in accor"ance with

3. 61%20%1 (-P&*%

• ach length of the threa"e" pipe shall be supplie" with full coupling screwe" han"

tight at one en"%

• Gal!aniBing of pipes shall be in accor"ance with 3&. 315=% &hrea"e" portion of

pipes shall be free of gal!aniBing%

• Pipes shall be heat treate" in accor"ance with pro"uct speci$cation requirements

after completion of all forming an" wel"ing operations%

• Carbon teel ' <ow &emperature Carbon teel (<&C* Pipes shall be fully #ille" $ne

graine" an" shall be supplie" in normaliBe" or normaliBe" an" tempere" con"ition%

• Wel"e" pipe shall be supplie" with single straight seam for siBes up to =9 an"

"ouble straight seam for siBes greater than =9 sub+ecte" to appro!al from thecontractor%

• piral seam wel"s are not acceptable%

• 3ll D wel"e" pipes with a wall thic#ness greater than =0 mm must be 100:

ultrasonically e>amine"%

Requirements for Fittings:

• Dimensions of butt wel"e" $ttings must be in accor"ance with 3. 619%E%

• Forge"/ threa"e" an" soc#et wel"e" $ttings shall be in accor"ance with 3.

619%11%

• Hther $ttings "imensions shall comply with . P;5/ . P;E5/ . P;E or 6

=EE as applicable%

• 4en"or shall pro!i"e calculations as per 3. 6=1%= for the $ttings not co!ere"

un"er the abo!e mentione" stan"ar"s%

• Inion "imensions shall be in accor"ance with 6 =EE%

• 3ll screwe" $ttings shall be threa"e" -P& in accor"ance with 3. 61%20%1%• 6ranch reinforcing $ttings (i%e% lbowlets/ oc#olets/ wel"olets/ etc%* shall be "esigne"

in accor"ance with the requirements of 3. 6=1%=% &he !en"or shall submit "rawings"uring bi" stage an" calculations for re!iew an" appro!al after awar" of contract%

• 6utt wel" elbows shall be long ra"ius type (ra"ius @1%5 nominal pipe siBe*% hort

ra"ius elbows are not permitte"%

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• For re"ucing $ttings speci$e" with two sche"ules in the ,nquiry Purchase

"escription/ the $rst sche"ule refers to the larger en" or run pipe/ the secon" sche"ulerefers to the smaller en" or branch pipe%

• Fittings shall be forge" to the $nal shape an" siBe% Fittings shall not be machine"

from bar stoc# or soli" forge" billets without speci$c appro!al%

• Gal!aniBing of $ttings shall be in accor"ance with 3&. 315=% &hrea"e" portion of

$ttings shall be supplie" with threa"s free of gal!aniBing%

• wage nipple shall be pipe swage" by forging only% .achining of bar stoc#/ forgings

or hea!y wall pipe not permitte"% Dimensions shall be in accor"ance with .;P;E5%

• 3ll re"uction siBes for tees an" re"ucers to be in accor"ance with 3. 619%E%

• C ' <&C $ttings shall be fully #ille" an" $ne graine" an" shall be supplie" in

normaliBe" or normaliBe" an" tempere" con"ition%

• 100: of C ' <&C wel"e" $ttings/ with wall thic#ness greater than ch 80 shall be

e>amine" by .agnetic Particle >amination for wel" be!el en"s% 3cceptance stan"ar"sshall be in accor"ance with 3. 4,,, Di!ision 1/ 3ppen"i> 9% &his shall be "one after $nalheat treatment%

•

100: of ' D wrought $ttings ha!ing wall thic#ness more than 20mm shall ha!ethe be!el an" wel" en" o!er a wi"th of 25mm/ e>amine" by Dye penetrant .etho"%3cceptance stan"ar"s shall be in accor"ance with 3. 4,,, Di!ision 1/ 3ppen"i> 8%

• 100: of D wel"e" $ttings with a wall thic#ness greater than =0mm shall be 100:

ultrasonically e>amine" in accor"ance with 3. 4,,, Di!ision 1%

• 100: of D forge" $ttings wel" be!els shall be e>amine" by Dye Penetrant

inspection%

• 100: of C/ <&C ' forge" $ttings/ with wall thic#ness greater than ch 80 shall

be e>amine" by .agnetic Particle Dye penetrant e>amination% 3cceptance stan"ar"sshall be in accor"ance with 3. 4,,, Di!ision 1/ 3ppen"i> 9 8% &his shall be "one after$nal heat treatment%

Positie material i!enti"#ation:

• Positi!e .aterial ,"enti$cation (P.,* shall be con"ucte" for all C3 alloy piping

items as per the pro+ect speci$cation inclu"e" in the ,nquiry Purchase requisition%

$pe#ial Requirements:

$our seri#e requirements:

• 3ll materials speci$e" for sour ser!ice shall/ as a minimum/ meet the requirements of

-3C .015 ,H 15159 latest e"ition%

•3ll wel"e" pipes $ttings in sour ser!ice shall be J,C teste"/ if require" by the pro+ect

speci$cation% ,t shall be con"ucte" for one pipe $tting per heat in accor"ance with -3C &.;028? olution 3 with acceptance criteria as speci$e" in -3C .;015%

%mpa#t test requirements:

• 3ll C/ <&C/ wel"e" austenitic an" "uple> stainless steel piping components shall be

impact teste" (for using in low temperature ser!ices* in accor"ance with 3. 6=1%=%

Page 23 of 52



• For carbon steel pipes an" $ttings/ the impact test temperature shall be the

Kminimum metal temperatureL as "e$ne" in the pro+ect% &he impact test requirement an"acceptance criteria shall be as per Cl% =2=%2%2 an" Cl% =2=%=%5 of 3. 6=1%= respecti!ely%

• For wel"e" an" D items/ the impact test temperature shall be the Kminimum

metal temperatureL as "e$ne" in the pro+ect but not more than (;101 Deg% C* an" (;50Deg% C* respecti!ely% For items/ the acceptance criteria shall be as per Cl% =2=%=%5 of

3. 6 =1%=% For D items/ test results shall be at least ?0 +oules in trans!erse "irection(for stan"ar" specimen 10 > 10 mm* as an a!erage of three tests/ one result may belower but not less than =0 +oules%

• For <&C items/ the impact test temperature shall be (;?9 Deg% C*% &est results shall

be at least 2 +oules as an a!erage of three tests (for stan"ar" specimen 10 > 10 mm*/one result may be lower/ but not lower than 21 +oules%

-lastic -ipin" $yste7: A &ool A"ainst Ce7ical Coosion / -at (

1% ,ntro"uction to Plastic Piping ystem

Because corrosion is a problem in operating and maintaining any :hemical Process Plant, one would prefer avoidingsteel completely as a piping material but since its not feasible because of the usefulness of steel in sustaining the

Pressure and 0emperature conditions normally foreseen in any Process Plant. 0hat brings the concept of composite piping constructed from the highly :hemical 6esistant Polymer :ompounds as base material, reinforced withsuitable fibrous materials such as 8lass which provides it the requisite strength.

2% P<3&,C .3&,3<

Basically C types of (ynthetic Polymer :omponents have found acceptance in industrial use.

Page 24 of 52



• 0hermoplasts

• 0hermosets

• :omposite Plastics

2%1 &hermoplasts

0he 0hermoplastics are Polymer :ompounds, which are normally available in crystal form.

Gn application of heat and pressure these crystals attain the requisite level of flowability to be able to attain thedesired shape by molding process. Gn re&heating the plastic material can once again undergo the transformationfrom solid to a flowable state which allows their reprocessing into the desired shape.

(ome of the commonly used 0hermoplasts are as follows

• Polyethylene

• Polypropylene

• Polystyrene

• Polyvinyl :hloride

• 3luor&Plastics

By and large the thermoplastics are structurally wea# materials and have limited temperature endurance.

Page 25 of 52



3ig *.0hermoplast Piping :omponents

2%2 &hermosets

0he 0hermosetting Plastics are Polymer :ompound !resins", which are normally available in liquid form at ambient

temperature. Gn addition of :atalyst and 'ccelerator these 6esins undergo a chemical transformation into a rigid product that sets into the required shape by curing process.

(ome of the commonly used 0hermosetting Plastics are as follows.

• Epo%ies

• 3urans

• Phenolics

• Polyesters – Bisphenol, sophthalic, alogenated

• Polyurethane

• Tinyl esters

Even though the 0hermosetting Plastics are relatively superior to 0hermoplastics in terms of structural strength andtemperature endurance, still in its virgin form they find limited use in ndustrial applications.

Page 26 of 52



3ig 7.0hermoset Piping :omponents

2%= Composite Plastics

's it is evident from the foregoing discussion that both 0hermoplastics and 0hermosetting Plastics in their virginform lac# ability to sustain the level of mechanical loading normally encountered in the ndustrial applications. 'nattempt to stri#e an appropriate balance between the two desired properties of the material !i.e. )echanical (trengthand :orrosion 6esistance" therefore has always remained a desirable obective. 0his brought forward the concept of:omposite Plastics where in a reasonable degree of mechanical strength is imparted to the base Polymer which initself is adequately resistant to the :hemical :orrosion, by way of reinforcing it with a suitable reinforcing material.

)ost of the commercially available composite materials in the 6einforced Plastic category use

a combination of 0hermosetting Plastic 6esins !e.g. Polyester, Epo%y, Tinyl Ester etc." and 3iberglass or (ynthetic3ibers as reinforcing material. n order to provide an ultra superior chemical resistance, it is also possible tomanufacture a composite material using 0hermoplastic )aterial !e.g. PT:, PT93, PP etc" as a base liner over which

the layers of 0hermosetting 6esins and 3iberglass are applied to attain the required mechanical strength.

Manufacturing Process:

0he composite plastics pipes are commonly produced by * of the following methods

• Custom Contact Molding:

t is a manual> semi automated process in which the composite sections are manufactured by application of variouslayers of resin and 8lass 3ibers !in various forms such as surface mat, roving mat, chop&strand mat etc." either byand @ay&up or by (pray @ay&up method.

• Filament Winding:

t is a fully automatic process in which an automatic control over winding angle !/ to / degree" and winding pressure can be e%ercised to obtain the varying degree of oop – '%ial ratio and 8lass – 6esin percentagecomposition. 5ormally a winding angle of - C> - 9egree provides a 7?* oop – '%ial ratio which is condition ofoptimum internal pressure requirement. By increasing the winding pressure the 8lass – 6esin proportion could bevaried from H/ J – 7/ J to +/J – -/ J. ' composite section of high 8lass content will result into high strengthand low chemical resistance and visa versa.

Page 27 of 52



• Pultrusion:

's the name implies this is a sort of e%trusion process by pulling the filaments through a resin bath tub andsubsequently passing it through an e%truding die and then through a an atmosphere of controlled elevatedtemperature. 0he above process is commonly used for manufacturing rolled sections such as 'ngles, :hannels, Beams etc.

• Resin Transfer Molding:

0he above process is used for speciali1ed applications for manufacture of sandwich structures with certain corematerial.

3ig C.:omposite Piping :omponents

=% &MP,C3< .CJ3-,C3< PHP&, HF &J.H&&,-G P<3&,C

0he 6einforced 0hermosetting Plastic )aterial typically represents a mechanically wea# structure with highcoefficient of thermal e%pansion, low thermal conductivity and high strength – weight ratio. 0he appro%imate values

of various mechanical properties of the 6einforced Plastic are in the following range.

9ensity /./ – /./+ @bs > inchC

:oefficient of – *C in> in G 3 % */&+

0hermal E%pansion

Page 28 of 52



)odulus of Elasticity *./ – C./ P( V */+

$ltimate 0ensile (trength *7 – *// P( V */C

Sield (trength *7 – *// P( V */C

0hermal :onductivity *. – 7 B0$> r. 3t G3

(.0 -LA$&2C -2-2N; $<$&E':

0he Plastic Piping (ystem consists of Piping Profile fabricated from plain end pipe, plain and flanged end 3ittings!i.e. Elbows and 6educers" and stub&in branch connections. 0he 3langed Woints are (tub Ends with loose Bac#ing3langes. n case of 3langed 0apping @ong (tub 3langes are recommended to be used in place of pipe stub&in and(hort (tub 3langes.

0he pipe to pipe and pipe to fittings oints are laminated oints. 'ccessories to Piping (ystem include (oft 6ubber>:'3 8as#ets and 3ull 0hreaded 3asteners with 2ashers.

(.( Desi"n Consideations fo -lastic -ipin":

• Gwing to wea# mechanical properties a minimum of 5( 7” line si1e is recommended for Plastic Piping.owever tapping of small si1e !i.e. smaller than 5( 7”" are permitted for drain> vent etc. provided the

branch connection is adequately supported.

• (ince the piping oints employed as per most (tandard are laminated oints !6efer 95 *+++ Part H fordetails" requiring a large overlap length, care shall be ta#en to ensure adequate spacing between the ointsto avoid the overlapping of the laminate structure.

• Gwing to its large :o&efficient of 0hermal E%pansion the Plastic Pipelines e%hibit a high tendency to growunder moderate temperatures. 0his may result into si1able deflection of the branches and the corners of the

Piping Profile. t shall therefore be ensured that the branch connections are not over stressed, either by providing adequate fle%ibility on the branch piping or by fi%ing the branch points by e%ternal means todisallow its deflection.

f free movement of the corners of the piping profile can be allowed !i.e. e.g. not being hindered by any othere%ternal item" then it is preferable to leave the profile to grow freely.

owever if the growth of the profile has any adverse effect on the system stability !i.e. e.g. supports falling off fromthe e%ternal structure" it may be appropriate to restrict the growth of the sides of the profile by providing fi%edsupports at various locations as per Plastic Piping (upport recommendations.

• $nli#e (teel, bellows are not used on Plastic Piping. 0he thermal stress behavior is addressed either by

providing in&built fle%ibility in the system or by arresting the a%ial growth of the pipe runs within the pipelength itself. n case the later method is employed, the pipe may have to be guided at close intervals toavoid failure due to buc#ling.

• Gwing to its wea# nature, the plastic piping shall not be supported by a line contact between the pipesurface and the e%ternal structure ta#ing the load. ence as a general rule :lamp and (hoe type supportsshall be employed on Plastic Piping (ystem

Page 29 of 52



• 'll concentrated loads !e.g. Gn&line Talves, nstruments etc" shall be directly supported to ensure that theload is transferred to the grade> e%ternal structure without stressing the piping.

• 'll the valves employed on Plastic Piping shall be provided a 3i%ed 0ype (upport to ensure that the Pipingis not over stressed in case of amming of the Talve hand wheel while operating.

• 9ue to e%cess thic#ness of Plastic Pipe !as compared to (teel" it is li#ely to obstruct the opening of the flapof (andwich type Butterfly> 2afer :hec# Talve into the pipe. n order to address the above issue the (pacer 6ings !made of same or equivalent material as pipe" will be employed across the valve. 0he above (pacer6ing is procured as a (pecial Part.

(.+ Bill of 'ateial Consideations fo -lastic -ipin":

0he Bill of )aterial for Plastic Piping is wor#ed out similar to the steel piping with the following e%ceptions.

• (ince most (tandard requires the 3langed !one end or both end flanged" 3ittings i.e. Elbows and 6educersto be shop fabricated it requires a careful consideration to assess the precise requirement of the 3langed3itting of each type and differentiate the same from the plain end fittings.

• (ince all Branch connections are stub&in type the material required for fabricating branch connections shall be accounted for, while computing the pipe quantities.

• n case of 3langed 0apping the branch connection is made by employing @ong (tubs 3lange instead of pipestub&in with a (hort (tub 3lange. :are shall therefore be e%ercised to differentiate the above 3langes0apping from the rest of branches to be able to estimate the requirement of @ong and (hort (tub 3langesaccurately.

• (pacers shall be accounted for !as (pecial Parts" across all (andwich 0ype Butterfly Talves and 2afer:hec# Talves.

(., &ecnical $pecification Consideations fo -lastic -ipin":

• 0he Tendors scope includes supply, fabrication, erection, supporting and testing of Plastic Piping as per theEnquiry 9ocument.

• tems such as 8as#ets, 3asteners, Gn&line Talves, nstruments, (pecial Parts are e%cluded from theTendorQs scope.

• 'll Piping items in Tendors scope shall be fabricated by and @ay&up method to ensure superior :hemical6esistance properties.

• 0he whole @aminate (tructure shall be $T absorbent.

• 0he Piping items shall be fabricated and supplied as per the $5 C/C/ –*+ !Part&*" and all other relevant95 (tandards referenced there in.

• 0he (tub Ends for 3langes shall be fabricated as monolithic structure

• 0he 3langed Elbows shall be in accordance with 95 *+++ Part&7 without the straight portion.

Page 30 of 52

http://www.piping-engineering.com/butterfly-valve-regulation-valves.html





• 0he Piping )aterial shall comply with the 8eneral Ouality and 0esting 6equirements as per 95 *+++Part *

• 0he nspection and 0esting (hall include, but not limited to, the following test

(hort 0erm ydro test

@aminate (tructure and 8lass :ontent'dhesive (hear (trengthardness 0est !(tyrene :ontent"(urface 3inish and 9imensional :hec#

• 36P Piping with 0hermoplastic !e.g. PT:, PP etc" liner shall be subect to additional lea# test using air at/. Bar&g !ma%" prior to lamination of liner weld seams.

• t is recommended to follow the @aminate (tructure of the 36P Piping as per most 0echnical (pecification.0he Tendor shall confirm the same for the specified wall thic#ness indicated in the Enquiry 9ocument.'lternatively the Tendor can propose its own @aminate (tructure for companyQs review and approval.

(.4 2nstallation Consideation fo -lastic -ipin":

• 0he Plastic Piping (ystem shall be installed with permanent supports in place. Erection of Plastic Pipingwith temporary supports is not acceptable.

• 0he pipes shall not be stretched in order to match the terminal ends

• 0he 3lange Woints shall be tightened to the specified 0orque Talue only by employing 0orque 2rench.

• 's far as possible the Piping profile shall be prefabricated in the Tendors shop at site, leaving only a fewfield oints for final fit&up.

• n case of 36P Piping with 0hermoplastic @iner, the 3ield 2eld will always be located at the convenientheight> location to allow down hand welding> ointing.

Page 31 of 52



3ig *.:omposite Piping (ystem

,ntro"uction to ubber <ine" Piping

:orrosion is a menace in operating and maintaining a :hemical Process Plant. ence given a choice one would betempted to dispense away with (teel all together as a material of construction for piping used in a :hemical Plant.$nfortunately it is not practical to undermine the usefulness of (teel in sustaining the Pressure and 0emperatureconditions normally foreseen in any Process Plant. 0hat brings the concept of composite piping wherein an attemptis made to ma#e use of the mechanical strength of (teel, at the same time to impart a high degree of corrosionresistance to the wetted surface of the component made of (teel.

:arbon (teel Piping internally lined with 6ubber is a classic e%ample of such composite piping. 9ue to the intimate bonding between 6ubber and (teel during vulcani1ing process, it provides one of the most practical solutions indealing with chemically corrosive fluids within the limitations posed by the endurance of 6ubber for the operatingtemperatures.

<,-,-G .3&,3<

3ollowing are the commonly used 6ubber varieties in the :hemical Plant in general

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• 5atural 6ubber

• Butyl 6ubber

• 5itrile 6ubber

• EP9)

<,-,-G PHC

0he 6ubber @ining is a process of application of liner material !normally in the form of rubber sheets or e%trudedtubes" over the internal surface of the steel piping followed by vulcani1ing at the required temperature to attain thedesired degree of hardness.

0he @ining Process generally consists of following steps

• nspection of Piping tems for verifying its fitness for the purpose. 0he aspects which need to be considered

with respect to above, are the accessibility of the internal surface for application of lining and suitability ofthe internal contours for achieving a defect free lining.

5ote? n order to provide reasonable access to the internal surface of the Piping for application of liner, necessitatesthat Piping profile is bro#en down into flanged spools> fittings of predetermined dimensions.

• (urface preparation in terms of removal of scale> rust either by wire brushing or sand> shot blasting.

• 'pplication of 6ubber (olution> lining material

• :uring of @iner material !i.e. vulcani1ing" at the required temperature either by employing hot water orsteam. 0he vulcani1ing of 6ubber could also be done at ambient temperature by adding certain accelerators

along with the filler materials used in the 6ubber (toc#.

• nspection of the lined surface for possible defects such as pin holes> blisters etc.

• ydro testing of the lined components

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3ig * 6ubber @ined Piping

3ig 7? 6ubber @ined 3ittings

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I66 <,-D P,P,-G M&.

0he limited temperature endurance of the 6ubber @ining )aterial prohibits any welding on steel subsequent tolining. 0hat means that the 6ubber @ined Piping (ystem needs to be necessarily prefabricated. 't the same time thetotal profile is also required to be bro#en down into flanged spools of such configuration that the internal surfacerequiring lining is accessible from at least one of the open ends for application of lining. t is from the above concern

that the line si1e of 6ubber @ined Piping is recommended to be 7” 5P( and above.

' 6ubber lined Piping (ystem therefore is an assembly of various flanged (pools> 3ittings prefabricated to a predetermined dimensions. 0he supporting system employed for 6ubber @ined Piping is normally a clamp and shoearrangement. 2elding of any support component to steel surface of the lined piping is completely prohibited. 0heaccessories to 6ubber lined Piping include soft 6ubber gas#et and full threaded 3asteners.

1. DESIGN CNSIDE!"#INS:

• ' minimum of 7” 5P( line si1e is recommended for 6ubber @ined Piping

•

0he ma%imum length of straight 3langed (pools shall be as per 3ig C&'. 0hese dimensions are decided toallow a reasonable accessibility for lining application and to avoid any pipe to pipe welding oint within thespool length based on (ingle 6andom @ength of (teel pipe. t is logical to use straight Pipe (pools of(tandard 9imensions !i.e. the ma%imum recommended spool length as per 3ig C&' (tandard" as far as

possible, to minimi1e the number of flange oints and at the same time to facilitate interchangeability of thespools. owever the last spools at the corners or branch locations of the profile !or at any location specificsituation" shall be adusted to suit the dimension of the profile.

0he straight 3langed (pools employ fi%ed flange at * end and loose flange !i.e. lap flange with stub end" at the otherend to accommodate the bolt hole rotational mismatch of the flanged fittings bolted to the straight spools.

• n order to facilitate interchangeability, all flanged fittings !including 0ee" shall be of a (tandard 9imensionas per 3ig C. $se of flanged fittings of non&standard dimensions is however permitted !under e%ceptionalsituations" provided they are procured as non&standard (pecial Parts.

• 3or tapping of small si1e !i.e. nstrument > 9rain&Tent :onnections etc" a sandwich type :arrier 3langewith no11le of the required si1e will be employed and procured as a standard (pecial Part.

• t is li#ely that due to erection deviations, the prefabricated>lined chain of flanged spools may either leavesome gap or may have e%cess length while connecting the end terminals at site. ' design solution !i.e. byemploying spacers" for such deviations is impractical and hence the spools requiring adustment as per sitecondition shall be fabricated as per actual site condition and sent for lining on a rush basis. 9uring orderfinali1ation a commitment on crash delivery of such spools !including material supply" will be obtainedfrom the Tendor. 0he complete activity shall be coordinated from site in consultation with Proect 8roup.

• 's a contingency measure some (olid (pacers !made of ard 6ubber> Ebonite" of predetermineddimension are procured as standard (pecial Parts. 0hese spacers can be cut into small rings at site to suitthe 8ap !encountered during assembly of 6ubber @ined Piping" and sandwiched between the flange oint tofill the gap. t may however be noted that the above solid spacer can be used to fill small gaps !of the orderof 7 mm" only due to the limited strength of the 6ubber. 'ny gap in e%cess of 7 mm shall be handled asdescribed in the earlier paragraphs.

• 9uring the design stage it may be necessary to incorporate some spacers to bridge the corner to cornerdimensions of the profile. @ined (pacers fabricated from :arbon (teel and subsequently 6ubber lined are

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employed for the above purpose. 's far as possible the @ined (pacer of discrete thic#ness of /mm, Kmmand *// mm shall be used.

• 0he 6ubber @ining may obstruct the opening of flap of (andwich type Butterfly> 2afer :hec# Talve intothe pipe. n order to address the above issue the @ined (pacer !0ype&*" shall be used across the Talve. 0hethic#ness of the above spacer shall be decided as per the requirement of the valve under question.

• 'll the straight flanged spools !including non&standard special parts" shall be assigned part no., in thesometric 9rawings.

• 0he supporting of 6ubber @ined lines is done similar to :arbon (teel Piping with the following e%ceptions.

*. 0he lines are recommended to be supported, by employing (hoe and :lamp type supports.

7. 5o welding !e.g. 9ummy> 0runnion" is permitted on the 6ubber @ined Piping components subsequent to lining.

$. %ILL & M"#E!I"L CNSIDE!"#INS:

En8uiy Bill of 'ateial:

• 0he Enquiry BG) shall be prepared on completion of about /J of the sometrics for 6ubber @inedPiping.

• 0he Pipe quantity shall be indicated in terms of the total requirement for each si1e based on the sometrics

• 0he quantity of 3langed 3ittings shall be counted from the sometrics and indicated in numbers.

• 0he 3lange quantity shall represent the requirement of 3langes on straight Pipe (pools.

0he quantity of each of fi%ed and loose type 3langes of a particular si1e will be equal to the number of straight

spools of that si1e.

• 0he quantity of (olid (pacers of each si1e is estimated based on the following equation

O ; !C/ V 5o of @ines per si1e" > // !rounded to ne%t number"

0he above equation is based on an estimated requirement of * spacer !7 mm long" per line per si1e.

• 0he total quantity O of @ined (pacers for each si1e is estimated to be equal to the number of lines in thatsi1e. 0he above total quantity is split into C parts as below

(pacer of / mm width /J of O

(pacers of Kmm width 7J of O

(pacers of *//mm width 7J of O

• 0he requirement of non&standard (pecial Parts will be pic#ed up from the sometrics.

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• $nli#e other Piping (ystems, no spares are included in the Bill of )aterial of 6ubber @ined Piping unlessrequired as per the :ontract 'greement.

Ode Bill of 'ateial:

• 't the ordering stage an updated Bill of )aterial is issued along with the :onstruction sometrics fore%ecution purpose.

• 0he above Bill of )aterial will account for only as much material as required for the sometrics beingreleased for fabrication

• t is e%pected that nearly H/J of the sometrics would be included in the above lot.

5inal Bill of 'ateial:

0he 3inal Bill of )aterial will account for the remaining *J !i.e. *//J requirement of the Proect" of thesometrics which will be issued along with the above BG).

'. #EC(NIC"L SPECI&IC"#IN CNSIDE!"#INS:

• 0he Tendors scope includes supply, fabrication, rubber lining, testing and delivery of rubber lined flangedspools !including non standard special parts" as per sometrics.

• tems such as 8as#ets, 3asteners, Gn&line Talves, nstruments, (pecial Parts !with the e%ception of non&standard (pecial Parts" are e%cluded from the TendorQs scope.

• 0he 6ubber @ining shall be carried out as per B( +CK-.

• Prior to 6ubber&@ining the internal surface to be lined shall be appropriately prepared by way of grinding

e%cess weld deposits>sharp corners. Besides the surface shall be made free of rust> scale by sand blasting.

• 0he Tendor shall confirm the suitability of 6ubber )aterial against the 3luids indicated in the Enquirydocument

• n absence of specific requirement 5atural 6ubber shall be used

• 0he 3inished lining shall have H/ (hore 9 ardness and shall be suitable for the temperature range of -4: to 4:.

• ' minimum of C mm 0hic# 6ubber @ining shall be achieved on all surfaces.

• 0he 6ubber @ining shall be done by Tulcani1ing Process under controlled temperature.

• 0he 6ubber @ined Piping items shall be tested in 'ccordance with B( +CK- and shall include, but notlimited to, following tests.

Tisual nspection

Peal 0est

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(par# 0est

ardness 0est

3latness 0est of @ined (ealing (urfaces

• Gutside surface of all 6ubber @ined items shall be painted with 7 coats of Primer !e.g. Epo%y> XincPhosphate"

• 0he straight 3langed (pools !including non&standard (pecial Parts" shall be suitably mar#ed !2hetherProof )ar#ing on the Body and Punching on the 3lange rim" the Part 5umber and the sometric 5umber.

• (ince the Tendor is required to Ouote on a @ump (um basis it may be pertinent to get the units rates at thetime of enquiry to process the order amendment at a later date based on the final status of engineering.

5ormally unit rates of following items shall be obtained for each si1e

@ined Pipe without 3langes

@ined @oose 3lange including welding

@ined 3i%ed 3lange including welding

@ined Branch :onnection including welding

Gnly @ining

). INS#"LL"#IN CNSIDE!"#INS:

• 0he 3inal 8routing of the Equipment connected with 6ubber @ined Piping is done only after the erection of the connected 6ubber&lined Piping.

• 0he 6ubber @ined Pieces are handled carefully to avoid damage to the lined surface.

• 0he 3lange Woints shall be tightened to the specified 0orque Talue by employing 0orque

2rench.

• 0he (olid 6ubber (pacer !for site adustment" shall be machine cut as per the required thic#ness !ama%imum of 7mm gap". 0he above (olid (pacers shall not be provided near the equipment connection.

•

n case the gap is more than 7 mm the corrective action shall be ta#en by re&fabricating the pipe spool as per the required dimension and sending it for lining.

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3ig C? 9imensions for @ined Piping

6ubber linings are mainly used for protection against corrosion and>or erosion damage.

' wide range of rubbers and elastomers are available for lining vessels, tan#s and piping.

6ubbers can also be made with anti&static properties to give a low surface electrical resistance.

ard rubbers, i.e. hardness greater than (hore 9 +/, can only be applied by autoclave vulcani1ation, and therefore

hard rubber lining is restricted to small equipment or components. Gnly soft rubbers can be applied on site.

ard rubber linings can only be applied to rigid structures and they are also sensitive to large temperaturefluctuations. (oft rubber linings remain elastic over a large temperature range, and consequently they canaccommodate maor deformation, vibrations and significant temperature changes.

2ith respect to safety aspects, pressure rating, etc. the regulations which apply to piping, equipment and structuresare also valid for rubber&lined systems.

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.aterial election

)aterial selection is determined by?

& service conditions !pressure, temperature, medium, etc."

& design

& manufacturing method

0he following rubber types are used for lining purposes !classification according to '(0) 9 *-*H"?

& soprene or natural rubber !56"

& (ynthetic isoprene rubber !6"

& (tyrene&butadiene rubber !(B6"

& :hloroprene rubber !:6"

& Butyl rubber !6"

& Broom&butyl rubber !B6"

& :hloro&butyl rubber !:6"

& 5itrile&butadiene rubber !5B6"

& Ethylene propylene rubber !EP, EP9)"

& $rethane rubber !$6"

& :hlorosulphonated polyethylene !:()"VV

& 3luoro elastomer !3Y)"V

V :ommercially available under trade name “Titon” !9uPont product"

VV :ommercially available under trade name “ypalon” !9uPont product"

9epending on the degree of vulcani1ation, rubbers can be classified as softQ rubber or as hardQ rubber. 0he hardnessof soft rubbers is e%pressed in (hore ', and the hardness of hard rubbers is e%pressed in (hore 9 !'(0) 9 77-/".

ard rubbers !or Ebonites", i.e. with a hardness higher than (hore 9 +/, can be produced from 56 or blends, e.g. 56>6, 56>(B6 and 56>6>(B6.

Properties of ubber

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Each rubber material has a specific limit in terms of allowable service temperature and chemical resistance. 0hechemical resistance and temperature limits for continuous service of several rubber types are given below.

1. Natural ru**er +N!,

(oft and hard natural rubber linings are suitable for handling most inorganic chemicals, with the e%ception of strongo%idising agents such as chromic and nitric acids. 5atural rubber linings are also suitable for handling hydrochloricacid. 5atural rubber is also resistant to most organic fluids, including alcohols and most esters. 0hey should not beused in the presence of aliphatic or aromatic hydrocarbons, halogenated hydrocarbons, mineral oils and certainvegetable oils. 0he allowable service temperature range is &-/ 4: to =H/ 4:.

0he bond strength of 56 linings on steel is e%cellent. 0he hardness is typically (hore ' for soft rubber and (hore9 K for hard natural rubber.

$. Synt-etic isoprene ru**er +I!,

soprene rubber is a synthetic alternative form of 56, and has similar properties.

'. Styrene*utadiene ru**er +S%!,

(tyrene&butadiene rubber can be used for the containment of automotive bra#e fluids, alcohols and mi%tures ofalcohol and water. 0he allowable service temperature range is &C/ 4: to =H/ 4:. 0he hardness is in the same rangeas that of soft natural rubber !56".

). C-loroprene ru**er +C!,

:hloroprene rubber is resistant to o1one and sunlight, and reasonably resistant to oils and chlorine. (pecialcompounds are suitable for use with refrigerants !e.g. 3reon *7 and 77".

0he allowable service temperature range is &C/ 4: to =*/ 4:. ardness is appro%imately (hore ' +/.

/. %utyl ru**ers +II!0 %II!0 CII!,

Butyl rubbers have e%cellent tolerance to hydrochloric acid. Butyl rubber is resistant to o1one and sunlight, non&flammable hydraulic fluids, animal and vegetable oils, water, alcohols, #etones and acids. Butyl rubber should not be used in the presence of free halogens, petroleum oils or halogenated or aromatic hydrocarbons. 0he allowableservice temperature range is &C/ 4: to =**/ 4:. ardness is in the range of (hore ' to ' +/.

. Nitrile *utadiene ru**er +N%!,

5itrile butadiene rubber !also #nown as Bu5a&5" is a copolymer of butadiene and acrylonitrile. 0he acrylonitrilecontent must be at least CJ by mole to obtain good chemical resistance. 5itrile rubbers are resistant to petroleum&

based hydraulic and lubricating oils, animal and vegetable oils, acetylene, alcohols, water, al#alis and fuel oils. 5itrile rubber should not be used for phenols, #etones, acetic acids, most aromatic hydrocarbons and nitrogenderivatives. 0he allowable service temperature is &C 4: to =H/ 4:. ardness is appro%imately (hore ' +/.

2. Et-ylene propylene ru**ers +EPDM 3 EPM,

Ethylene propylene rubbers are resistant to o1one and sunlight, o%idi1ing chemicals, non&flammable hydraulicfluids, pure aniline, fire e%tinguisher liquids, acids, hot water and steam. owever, these rubbers are not resistant tomineral oils, petrol solvents and aromatic hydrocarbons. 0he allowable service temperature range is &-/ 4: to =*/4:. ardness is typically in the range (hore ' -/ to ' H/.

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4. 5ret-ane ru**er +5!,

$rethane rubber has e%cellent wear>erosion resistance and is chemically resistant to mineral oils, fuels and o1one.$rethane rubber should not be used for concentrated acids, #etones or chlorinated hydrocarbons, and shall not beused for water above / 4:.

Gtherwise, the allowable service temperature range is &-/ 4: to =K/ 4:. ardness is typically in the range (hore '/ to ' H/.

6. C-lorosulp-onated polyet-ylene +CSM,

:hlorosulphonated polyethylene is a highly wear&resistant synthetic rubber with e%cellent resistance to heat, o1onesunlight, o%idising media, sodium hypochlorite and sulphuric acid.

:() rubber has also good resistance to most oils, lubricants and aliphatic hydrocarbons, but is unsuitable for usewith esters and #etones. 0he allowable service temperature range is &C 4: to =H/ 4:. ardness is appro%imately(hore ' +/.

17. &luoroelasto8ers +&9M,

3luoro&elastomers are copolymers of he%a&fluoro&propylene and vinyldiene fluoride. 0hey are suitable for both high&temperature and vacuum applications. 0hese materials have e%cellent resistance to oils, fuels, lubricants, carbontetrachloride, most concentrated acids and many aliphatic and aromatic hydrocarbons such as toluenes, ben1ene and%ylene.

0hey should not, however, be used with low molecular weight esters and ethers, #etones, certain amines and hotanhydrous hydrofluoric or chlorosulphonic acids. 0hese materials are also resistant to o1one and sunlight and can beused in contact with many corrosive gases, e.g. bromine and chlorine. owever, they are not resistant to ammonia or highpressure steam. 0he allowable service temperature range is &7/ 4: to =7C/ 4:. ardness is typically in the range(hore ' +/ to ' /.

6educers used in Piping ndustry? ' short literaturePipelines are not of uniform si1e and there is requirement of reducing or e%panding the lines depending on process

requirement or availability of material. ere comes the importance of a special pipe fitting called 6educers.

6educers are most e%tensively used in piping industry to reduce or e%pand the straight part of run pipe. Basically,

reducers are available in two styles?

• :oncentric reducers and

• Eccentric reducers.

Concentic Reduces:

's shown in 3ig. *. n this type of reducers area reduction is concentric and center line of the pipe on bigger end and

smaller end remains same. 0hese styles are normally used for vertical lines.

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3ig.*? :oncentric 6educers

Eccentic Reduces:

's shown in 3ig. 7 , in this style of reducer there is an offset in between the center lines of bigger end and center line

of smaller end. 0his offset or eccentricity will maintain a flat side either on top or on bottom side.

3ig.7? Eccentric 6educer

0his offset or eccentricity can easily be found out by the following equation?

Eccentricity;!Bigger end 9&(maller end 9">7

2hile using this type of reducer the user has the option of orienting the flat side. $sually for hori1ontal lines,

eccentric reducers are oriented with either the flat side up or down and the same with deviation is mentioned in

isometric.

5ormally eccentric reducers with flat side down are preferred for following cases on hori1ontal lines?

F Gn (leepers and Piperac#s

F Gn lines requiring gravity flow

F Gn pump suction line which handle slurry.

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Eccentric reducers with flat side up are used for all pump suction lines !e%cluding pumps handling slurry" on

hori1ontal lines. 0his way one can avoid air getting trapped inside the pipeline during initial venting through pump

casing and will help in avoiding :avitation.

9epending on end connections of this fitting with straight pipe, reducers are grouped as follows?

Butt Weldin" educes: 0he applicable pressure rating, dimensional and material standards for butt weldingreducers are same as those applicable to butt welding elbows.

$oc%et weldin" educes: 's shown in 3ig.C. such reducers are available in concentric type only D in the form of a

coupling with one end soc#et to fit larger diameter pipe and other end soc#et to fit smaller diameter pipe. (tandards

are same as those applicable to soc#et welding elbows.

3ig.C? (oc#et 2elded 6educers

$cewed educes: 'vailable only in concentric type and are in the form of coupling having one end to fit bigger pipe and other end to fit smaller pipe. '()E B*+.** is applicable dimensional standard. )aterial standards

including pressure ratings are same as of screwed elbows.

5lan"ed educes: 0heir pressure rating, use, material and dimensional standards are same as those applicable

to flanged elbows. 6egardless of reduction their face to face dimensions are governed by the larger pipe si1e.

Page 44 of 52



Design Guidelines for PE & ROTO LinedCarbon teel Piping

Carbon steel piping with internal P H&H lining is use" for liqui" ser!ice with high chlori"e

as well as higher o>ygen content% &he ma>imum operating temperature of the P ' H&Hline" piping is 90 NC% 3lso/ these types of coatings are suitable for gas;liqui" ratio !alues

upto =00%

3 P liner consists of a number of Polyethylene pipe lengths/ which are fuse" together an"

inserte" into sections of carbon steel pipelines an" 7owlines% &he Carbon teel pipe pro!i"es

the pressure containmentO while the P liner pro!i"es corrosion protection% 3t the en"s of the

sections/ the liners are terminate" by P stub en"s% Connections between P line" carbon

steel pipes shall be 7ange"%

&he P ' H&H lining is carrie" out only after the pipe spools are fabricate" ' hy"roteste"%

-o wel"ing is allowe" on the pipe spool once the P or H&H lining is "one% &he pipetrunnion member ' line stop members/ if applicable/ shall be wel"e" prior to the lining%

Jy"rotesting of the spool or pipelines is "one before the lining ' after the lining also%

&herefore/ gas#ets are require" to be consi"ere" for each 7ange" +oint for hy"rotest

purpose%

&he requirements to be consi"ere" while "esigning of P line" piping are mentione" below

P&'R()( lining !imensional limitations:

&he longest continuous length of liner/ which can be installe" in straight pipe/ "epen"s on

"iameter an" wall thic#ness/ but is generally re"uce" in practice by local cur!ature of the

line%

For o plot piping scope the P lining can be "one for a pipe spool of upto 250m length% For

shop line" piping the ma>imum length of P line" pipe spool is #ept as 18m because of the

transportation limitations% .inimum pipe spool length requirement is 5m (can be as less as

2m if agree" with P lining !en"or*% P lining can be "one only for straight pipe spools% ,t can

not be "one for pipe spools with re"ucers or branches% ,n such cases (for pipe spools with

re"ucers or branches* rotolining is carrie" out %

6en"s for P lining shall not be less than 20D ra"ius (recommen"e" ra"ius is ?0D where!er

possible*% P or H&H lining cannot be carrie" out for pipe spools with ori$ce 7anges

because of the small siBe ori$ce 7ange tapings% ,n this case/ one option is to use a suitablematerial for the upstream ' "ownstream pipe spools ' the ori$ce 7anges% 3n" the other

option is to use carrier rings with ori$ce tapings ' ori$ce plate of the suitable material which

will get san"wiche" between two P line" 7anges which a!oi"s the use of e>pensi!e

material for the upstream ' "ownstream pipe spools%

*nnulus +ents:

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!ery P line" pipe spool shall ha!e !ent points% &he minimum number of !ent points shall

be one on each 7ange" en" of a section of line" pipe% &he !ent points to be pro!i"e" with

!al!es for oil ' gas application ' without !al!es for water ser!ice application% &he !al!es

shall be opene" only for !enting purpose% Continuous !enting is not permitte"% &he purpose

of !enting is as follows%

• &o !ent the (ambient* gas from the pipeannulus "uring installation%

• &o !ent the permeate" 7ui"s accumulate" in the annulus to pre!ent collapse%

• &o allow monitoring of the integrity of the P liner "uring the ser!ice life%

4ent holes shall be "esigne" such that no e>trusion of the P liner will occur% For larger

"iameter lines/ !ent "iscs with multiple holes or wire screens may be use"% 4ent holes shall

not be larger than = mm in "iameter% 3ll !ents shall be !al!e" (e>cept for water ser!ice

where !ents can be plugge"* an" shall ha!e a snor#el to pre!ent ingress of "irt/ moisture

an"or air%

&he "esign of the !ent point assembly shall be agree" with the Company%

,esign Gui!elines for R()( -ine! Piping:

otolining is a metho" of lining the insi"e of pipes or other parts with a seamless/ one piece

inner layer of plastic% ,n this lining technique the line" spool is pro"uce" by heating an"

rotating a carbon steel spool with a polymer/ which is in a granular form/ place" insi"e the

pipe spool% &he polymer melts an" forms a liner on the internal surface of the carbon steel

pipe% 3lso/ the polymer forms a bon" with the metal%

&he choice of which polymer to use is base" on the chemical resistance properties that are

require" of the $nal part% Polyethylene/ Polypropylene/ P4DF or number of other polymers is

use" for rotolining

application% &he lining thic#ness !aries from 2 mm to 8 mm% &he hea!y lining thic#ness

allows post machining of critical surfaces that woul" not be possible with a thinner lining

applie" by other metho"s% 4irtually any type of metal wel"ment or casting can be rotoline"%

&ypical items that can be rotoline" are tan#s/ carbon steel pipes/ $ttings/ an" comple>

wel"e" structures%

Rotolining Pro#e!ure:

• &he rotolining process comprises placing a polymer ha!ing an a!erage particle siBe of

0;1000 Qm containing a melt processible fluoropolymer/ in a cylin"rical article to beline" (the pow"er being present in sufficient amount to ma#e a lining at least 500 Qmthic#*%

• &he cylin"rical article is rotate" to bring the ra"ial acceleration at the substrate

surface to be coate" to 100 msec2 or greater/ pressing the pow"er against the article tobe line" by means of the centrifugal force generate" by that rotation/ at the same timeheating the melt processible 7uoropolymer to a temperature equal to or higher than themelting point of the melt processible 7uoropolymer/ but not higher than ?00N C%/ therebya"hering the melt processible 7uoropolymer to the surface of the article to be line"%

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• During the heating cycle/ the polymer particles begin to stic# to the hot metal

substrate% 3 s#in is forme"% &his s#in gra"ually forms a homogenous layer of uniformthic#ness% Iltimate wall thic#ness is "etermine" by the amount of material that is initiallyplace" into the ca!ity%

• 3""ing a small amount of a heat stabiliBer such as PP (polyphenylene sulphi"e* to

pre!ent the "ecomposition of the 7uoropolymer on heating can gi!e an e>cellent coating

with minimal bubble formation%

• 3fter a pre"etermine" time at a speci$c temperature/ the entire polymer is

"istribute" o!er the surface of the spool% &he spool is then coole" by a combination offorce" air an" water mist%

• &he part is then remo!e" from the machine an" surfaces such as 7ange face an" H

ring sealing areas are machine" into the plastic% <inings are spar# an" ultrasonicallyteste" to insure liner integrity%

• &he process itself intro"uces no force or shear to the material% &he result is a

relati!ely stress free lining% otoline" parts are completely seamless an" wel" free%

*!antages of R()(-%.%.G:

• eamless construction with a !ery smooth interior surface%

• Polymer rotolining ha!e an e>cellent chemical resistant/ relati!ely high temperature

performance an" an e>cellent metal to plastic bon"%

• &hic#er lining ' uniform wall thic#ness can be achie!e" than electrostatic or spray

coating%

• Drastically re"uces permeation through the coating an" possible corrosion of the

metal substrate%

• &hic#er coating can be repaire" by wel"ing if mechanically "amage"% &hin coatings

must be strippe" an" recoate"/ if repairs are not possible%

R()( lining !imensional limitations:

Gui"elines for H&H lining "imensional limitations are as per below table

Page 47 of 52



otolining <imitations

otolining Dimensional table

3ll "imensional gi!en in abo!e table shall be consi"ere" as "iagonal lengths% &he abo!e

"imensions shall be !eri$e" with the H&H lining contractor prior to issuing the isometrics

for fabrication%

Page 48 of 52



For H&H lining minimum branch;o siBe shall be 1 -6%

&he thic#ness of P ' H&H lining on the 7ange raise" face (collar thic#ness* is as per below

&able

Flange Collar thic#ness

&he abo!e thic#nesses shall be !eri$e" with the P ' H&H lining contractors prior to

issuing piping isometric "rawings for construction%

Flange /oint !etails for P& ' R()( lining piping:

&ypical P H&H line" 7ange +oint "etail is as follows

Page 49 of 52



&ypical Flange" +oint

&he 12 -6 annulus !ents shown in the abo!e s#etch are for P line" pipe spool only%

Gal!anise" carbon steel retainer rings are use" between P H&H line" 7ange +oints to

hol" the stub en"s in place (to a!oi" the plastic material from "eformation*% &he wi"th ofretainer ring is calculate" as follows

3 @ (2 > 6 A 2 > &* =mm

Where/

3 Wi"th of retainer ring

6 &hic#ness of 7ange raise" face

& Collar thic#ness

etainer rings are generally pro!i"e" by P lining !en"or/ still it has to be con$rme" with the

!en"or at the start of the pro+ect%

Following s#etches pro!i"es the information regar"ing the use of retainer ring ' insulating

gas#et for P ' H&H lining 7ange +oints%

Page 50 of 52



Flange" +oints

&he use of insulating gas#et for P ' H&H lining piping is restricte" for the insulating spools

only where!er shown in PF% For 7ange +oint between P H&H line" C piping ' or

D mating 7ange insulating gas#et is not require" to be pro!i"e"%

For insulating +oint insulating gas#et/ e>tra long slee!es/ washers ' e>tra long bolts are

require"% &he spectacle blin"/ spa"e ' spacers shall be consi"ere" of suitable material for P

' H&H line" piping an" the blin" 7ange shall be epo>y coate" or H&H line"% &his shall be

$naliBe" with the client ' construction contractor prior to start of a pro+ect%

3 typical isometric of Potoline" pipe is shown below

Page 51 of 52



&ypical isometric "rawing

Documents

Piping_Materials_Elbows and Bends_Reducers_PE & ROTO Lined Carbon Steel Piping