Pipe Rack Lecture

7/24/2019 Pipe Rack Lecture

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PIPE RACK

Introduction

Piperck is the main artery of the plant connecting all equipments/ units with lines.

Normally it is erected first on before the rows of equipment becomes an

obstruction for it. Piperack carry process lines, utility lines, cables trays, air

coolers.

Attachment :- a Typical overall plot plan & Cross sectional view of a piperack.

Setting Configuration for a pipe rack

he routingis first established based on the P!I". "ue consideration should also

be taken from Plot plan, client specification, plant layout specification,

fireproofing requirement, construction material.

#$tablish the width of the rack% & no of lines 'dia of pipe, bent spacing, flange

requiements, additional / future requirements as specified by client / (##"

package).

Length / Module of Rack% & he constrains for establishing the length could be

e$pansion *oints, air cooler e$tent, pipe loops requiments, transportation, braced /

anchor bay foundation si+ing and bracing si+ing.

Structural framework

It is ideal to proided eleation -racing in both direction ranserse !

ongitudinal direction. oweer this is not always possible due to piping

requiements like access way 'sometime forklift moement), pumps located at

below at grade leel. he arious options of a structural arrangement could be

0. moment resisting framework in the transerse direction

1. Partial moment resisting frame 'below first tier). his is possible when

there are two bays in the transerse direction.ongitudinal tie beams to be at 012mm below Pipe tier 3S. his is a piping

requirement for line stop plates etc.

Atachement:- cross section of piperack showing structural framework

arrangement. Module of piperack, racing arrangement

Material of construction


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0. Superstructure% & Structural steel or Concrete. Structural steel is preferred

for quick erection, more fle$ibility in wake of more changes from

upstream department. 4arious grades of steel S152 or in kashagan

S622N). N is a special requirement due to climatic conditions in

7a+akhstan 8 normali+ation of stress 'residual during manufacturing)

1. Structural bolts% & 9rade :.: -S6; =251 9rade 2?

@. (oundation 8 3pen / Pile foundation. 9eotechnical report% & frost depth

requiements, ground water table

Pipe rack loading

"ead oad of the structure 'Self weight of structure)

ie loads on platforms air cooler leel

Cable loads

=ir cooler loads

Piping load 8 'Pipe #mpty / Pipe operating / Pipe ydrotest)

humb rule / appro$ weights'P# A P3)%

Btility acks 02? D 12? kg/mE

Bnit ack Process ack 6?? D62? kg/mE

>ain interconnecting Process rack 6??D@?? kg/mE

7asghan 4alue'min)% P# F 0 kN/mEG P3 F 1 kN/mE. 'P was

taken same as P3)

arweel 'min oading)% & P# F& 0kN/mEG P3 F ?.5kN/mEG P F

0.0 kN/mE

(ire proof loading% & "epends upon the pro$imity of the

rack to ha+ardous equipments. (ireproofing requirement of a rack

can be understood from fireproof layout drawing. Concrete

encasing 8 materials like fendolite are used. In case of beams

supporting pipes the top flange is not fire proofed.


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ori+ontal pipe forces

Piping Caesar analysis. Caesar output is input for ciil. eference

to be made to the a typical pipe layout drawing showing pipe loops

and anchor points. =nchor points, friction forces, guides forces

location in the pipe. ongitudinal anchor forces are the reaction to

the long friction forces. =nchor forces to be transferred to the

foundation.

Pipe friction forces% & Hhy there is a frictional force generated

In general coeff of friction pipe to structure is 6?J but this is for a

single pipe analysis. In case of rack tier there are many pipes all of

then will not be e$panding / Contracting together in the same

direction. So to consider 6?J of the total pipe ertical load for

friction will be unconseratie. ence a lower alue is normally

adopted 8 7ashagan 5.2J 'P# A P3)

arweel % & 02J.

hese forces are not transferred to the foundation and it shall be

resisted by the top flange of the beam for hori+ontal bending.

Pipe Anchor Longitudinal% & ocation of anchor points to bedecided by piping they may or may be at the proposed braced bay.

Normally BC sections are used at these location due to high

hori+ontal forces. hese forces are transferred to the foundation

like friction forces these forces too shall be resisted by the top

flange of the beam.

#ach module of piperack must be designed for a minimum

hori+ontal anchor forces for eg 0?kN/m udl on anchor bay beams

was considered in harweel.

Pipe anchor trans!erse% & >ainly are because of guides forces.

ocation of a guide is normally ad*acent to loops or pipe tapping /

branching. In case there is no guide force a 02J of ertical pipe


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load is considered for this condition. hese forces are transferred to

the foundation.

"emperature #orces% & climatic ariation inducts temp stress in

the steel. Strain steel F adt here by the a$ial forces in the

member needs to be calculated.

!ample temperature variation calculation done in kashagan

pro"ect.

$ind forces% Hind on structure, Pipe, cable trays, air coolers.

Hind of pipe e$plain as per harweel practice.

Seismic Load

Load Com%ination% & Structural Steel (" method (actors as

per -S2

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Pipe Rack Lecture