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WELCOME TO THE WONDERFULWORLD OF

PIPING

PIPE RACK

Valdel Engineers and Constructors, Ltd.

BY: SAMI UR REHMAN

PIPING DEPARTMENT

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INTRODUCTION OF PIPE RACK

A pipe rack is the main artery of process unit, it connects all equipment with lines that cannot run through adjacent areas .

The pipe rack must be erected first and its carry Process lines Utility lines Instrument and electrical cable trays Equipment.

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PIPE RACK DESIGN CRITERIA LINE ROUTING DIAGRAM SHAPES FUTURE SPACE WIDTH OF PIPE RACK CLEARANCE ANCHOR POINT

LINE ROUTING DIAGRAM A line routing diagram is a schematic representation of all process

piping systems drawn on the copy of the plot plan.

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LINE ROUTING DIAGRAM

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SHAPES These are various shapes of pipe rack like L/T/U/H/Z .

FUTURE SPACE 25 percentage extra space for future expansion or modification

WIDTH OF PIPE RACK The width of pipe rack shall be 20’,25’ or 30’ having 4 tiers maximum. The spacing between pipe rack portals shall be taken as 20’ and 25’.

CLEARANCE Clearance beneath pipe rack shall be 10 feet minimum Clearance from road shall be 25’ for main road and 15’ for secondary

road

ANCHOR POINT Assuming that Anchor point is Located at center or quarter distance from

ends of header.

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VARIOUS SHAPES OF PIPE RACK

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VARIOUS SHAPES OF PIPE RACK

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FORKLIFT

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DIRECTIONAL ANCHORS

ANCHOR POINT

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PIPE RACK PIPING

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PIPE RACK PIPING

1. Position of lines.2. Don’t run piping over stanchion .3. Place large liquid-filled lines 14”and above near stanchions.4. Provide 25 % extra space for future up to 50’ and 10% for above 50’.5. Hot insulated and mounted on the shoe.6. Warm pipes may have insulation locally removed at supports.7. Flare header requires slope and it’s mounted on shoe.8. Electrical and instrument trays are usually run on top level of the pipe rack.9. 10 ft Clearance for forklift and maintenance .10. Three ft is sufficient for up to 24 inches dia pipe.11. Preferably Meter runs should be installed directly next to the column,

Although meter runs are located in pipe rack only when absolutely necessary

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Battery limits (ISBL) &(OSBL) The process lines crossing units are normally provided with block valves, spectacle blind and drain values. These are preferable in vertical run With good accessibility

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USEFULL CALCULATION & CONSIDERATION INVOLVED DURING DESIGN

PIPE SPACING THERMAL EXPANSION SPAN LENGTH PIPE RACK LOADING

PIPE SPACING

O.D. of bigger size flange (minimum 300 rating)/2 + O.D. of smaller pipe/2 + individual insulation thickness with additional 1”clearance

Even if flange is not appearing the min. spacing shall be calculated on same basis

EXAMPLE 1 8” NB DIA CS PIPE WITH 1 ½ INCHES INSULATION-150#

6” NB DIA CS PIPE WITH 2” INCHES INSULATION-300#

ANSWER ??

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LINE SPACING

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THERMAL EXPANSION Linear thermal expansion of an object can be expressed as ∆= ℮xL Where ℮- linear coefficient of thermal expansion

L- original length ∆- change in length EXAMPLE:-2 How to calculate pipe expansion 100 feet carbon steel pipe at 6000F 100 feet stainless steel pipe at 6000 F

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SPAN LENGTH A support span is the distance between two pipe supports. But

ensure the pipe deflection and bending stresses are within safe working limits. It’s standard practice to limit the maximum span deflection in horizontal pipe lines to ½” the bending stress to 1/8” of ultimate allowable bending stress.

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PIPE RACK LOADING

Pipe rack loads shall be given by stress group to civil and structural discipline for pipe rack design.

Sustained load (Dead Load) Weight of piping, valve and insulation.

Hydrostatic load Liquid load for hydrostatic pressure test.

Thermal load Load by thermal expansion of piping and reaction force by internal pressure of expansion bellows.

Dynamic load Load by vibration of piping and by wind and earthquake.

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EXPANSION LOOP Expansion loop is provided on the high temperature lines. This

information shall be given by stress group. Generally all the loops shall be located around one column only.

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Make lines into a group and install a large size piping and high temperature piping to the edge of the rack.

EXPANSION LOOP

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When necessary to install an expansion loop on the steam line, There should be given a provision for drip leg to drain Condensate.

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Questions?

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The End!