Engg Std Heat Exchangers

ES 3201

SHEET 1 OF 23

ENGINEERING STANDARD

HEAT EXCHANGERS

RCF LTD, TROMBAY

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HEAT EXCHANGERS SHEET 2 OF 23

CONTENTS

CLAUSE NO. DESCRIPTION SHEET NO.

1.0 GENERAL 3

2.0 RESPONSIBILITY OF SUPPLIER 3

3.0 MECHANICAL DESIGN 4

4.0 MATERIALS 8

5.0 SCOPE OF SUPPLY 11

6.0 FABRICATION 12

7.0 INSPECTION AND TESTING 16

8.0 CLEANING, PAINTING AND DESPATCH 18

9.0 GUARANTEE 20

10.0 DOCUMENTATION 21

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1.0 GENERAL 1.1 The specification defines the responsibility of the supplier and covers supplementary

1.3

1.5 The offer must be technically and commercially complete. Incomplete offers are liable to be rejected.

1.6 Any deviation from the clauses stipulated herein, specified codes and other enquiry documents shall be clearly mentioned in the offer with proper references to clause numbers. In absence of any such indication it shall be assumed that the offer complies with all requirements and such assumption shall be strictly binding on the supplier.

1.7 Some of the sizes and dimension marked under HOLD on enquiry drawings and data sheets shall be removed later on and the required size/dimensions shall have to be adopted by supplier without any commercial implication.

2.0 RESPONSIBILITY OF THE SUPPLIER 2.1 The responsibility of the supplier shall include but not be limited to the following. Any

other item/activity which is not listed here but is required for completion of the supply as per the enquiry document shall also be the responsibility of the supplier. a) Complete design of the equipment as per code/equipment specification and any

other enquiry documents; supply of civil load data for foundation design.

d) Procurement of all the materials whatsoever required to meet the scope of supply. e) Fabrication, inspection, testing, painting, packing and dispatch of the equipment. f) Submission of the periodic progress report showing the status of the job. g) Supply of the final documents as specified in para 10.0.

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requirements relating to design, materials, fabrication, inspection, testing, painting, packing and dispatch etc. The specification shall be read in conjunction with code, specification sheet and other enquiry documents. In case of conflict between code and enquiry documents, the vendor shall contact TPI for clarifications. As a general rule the most stringent requirement shall govern.

1.2 The offer shall include a sketch indicating thicknesses of major parts, empty weight, operating weight and test weight. It may be noted that decrease in offered thickness shall not be allowed.

1.4 TPI shall have the right to split the order and part orders shall be acceptable to the supplier.

b) To obtain approval of TPI on drawings and other documents as specified in para 10.0.

c) To obtain statutory approval of drawings and other documents wherever applicable.

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3.4 All equipments shall also be designed for hydrostatic test in operating position in corroded condition considering 25% of design wind load. Allowable stress during hydraulic testing shall be 90% of yield stress.

3.5 Unless other wise specified elsewhere in enquiry/order document, Wind loads shall be calculated in accordance with BIS:875 (Part 3) with following consideration: Equipment shall be considered as Important Building Class of Structure accordingly risk coefficient (K1 Factor) shall be taken from Table 1 BIS:875. Terrain category (K2 Factor) shall be taken conservatively as 2, Terrain Class shall depend upon the size of equipment. Topography (K3 Factor) shall be taken to be equal to 1.0. Force coefficient (Cf) for the equipment (non-smooth) shall be taken from table 23 accordingly wind force calculated. Wind forces shall be increased by 20% to cater for the effect of piping system, platforms and ladders etc. Vertical vessels with height/diameter ratio equal to or greater than 6 shall be analyzed for vibration due to vortex shedding when critical wind speed does not exceed 30 m/s. Unless otherwise site spectra furnished by client, Seismic loads shall be calculated in accordance with BIS : 1893. For the design values of horizontal seismic co-efficient

h Response Spectrum Method shall be computed as given in section 2 stack line structures BIS:1893, ( Part 4):2005

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3.0 MECHANICAL DESIGN 3.1 Strict compliance with the requirements of code / equipment specification and

any other referred document shall be fully ensured.

3.2 For high alloy steel parts/components designed as per ASME Sec.VIII DIV.1 lower allowable stresses shall be adopted, for tubesheet and flanges of gasketed joints unless otherwise specified. After the approval of various documents subsequent deviations shall be discouraged.

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3.6 Design of supports and anchor/foundation bolts shall be the responsibility of the

supplier. The type, numbers, location and any other information if furnished in the specification sheets shall be strictly adhered to. However, adequacy of the same must be checked by the supplier. In no case diameter of anchor bolts shall be less than M24 for skirt support and M16 for others. Self-supported vertical vessels with shell diameter greater than 2000 mm, length (T.L.-T.L.) 3000 mm max. shall be supported on skirt. Skirts for vessels shall be normally being cylindrical mean dia coinciding with head mean diameter. In certain cases vessel skirts may be conical in order to provide an adequate bolt area at the base rings and to minimize the vessel deflection. Maximum half apex angle of the cone shall be limited to 9 max. In no case the skirt thickness shall be more than head thickness.

3.7 All items whether internal or external which are welded directly to a shell or head shall be of the same material category as that of the shell or head. This shall apply to all nozzles, brackets, pads and upper portion of the skirt for vertical exchangers.

3.8 Base rings for skirt supported equipment shall be in accordance with standard as applicable. Base ring dimensions shall be calculated to ensure that the compressive stress on the grout under any part of the base ring does not exceed 44 Kg/cm2g.

3.10 Lifting lug shall be designed with a shock factor of 2. 3.11 Where fixed tube sheet construction is used suitable provision shall be made for

expansion to prevent overstressing of tubes and shell. Stress due to thermal expansion shall be calculated to determine the necessity of using expansion joints in clean and foul conditions.

3.12 Expansion bellows shall be designed for min. 5000 cycles, as per TEMA. 3.13 Tube and shell side components shall be designed considering mean metal

temperatures as per section UHX of ASME Sec. VIII Div.1. Unless detailed thermal calculations prove otherwise the tube sheet design

temperature shall be considered to be the design temperature of either the tube-side fluid or the shell-side fluid, whichever is higher.

3.14 Longitudinal baffle on shell side of an exchanger having two-pass system shall be designed considering total pressure drop on shell side.

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3.9 Forces & moments coming on the nozzles shall be furnished, which shall be considered in the design by the supplier, without any commercial implication. Alternatively supplier shall indicate maximum permissible forces & moments for review and confirmation by TPI.

FE Analysis shall be carried out for thin tube sheet exchanger and the same shall be submitted for TPIs reference / record. Stresses shall be evaluated as per ASME Sec. VIII Div.2.



3.15 Longitudinal baffle in removable tube bundle exchanger shall be provided with

flexible sealing (10 numbers 0.1 mm thk. S.S strips on both sides & ends on the edges adjacent to the shell) to prevent by-passing. The strip width shall be selected so that during operation they are pressed, by spring action, against the shell. The strip shall be bolted /screwed with flats along length of longitudinal baffle.

3.16 Baffles and support plates in horizontal exchangers shall be provided drain & vent with notches at the extreme point. Whenever bypass area exists, dummy tubes/sealing strips shall be provided.

3.17 Tubesheets in vertical exchangers shall be provided with drain and vent arrangement with threaded plug seal welded.

3.18 Components in contact with both shell and tube side fluids shall be designed for the most stringent pressure/temperature combination.

3.19 In no case minimum corrosion allowance for C.S and low alloy steel material shall be less than that specified in equipment specification sheet or TEMA unless otherwise specified.

3.21 Impingement Baffles Unless otherwise stated inlet nozzles on shell side shall be provided with impingement plate in compliance with TEMA requirement.

3.21.1 The flow area around solid impingement plate shall be at least equal to the inlet nozzle cross-section. In case of two phase flow impingement baffle shall be perforated.

3.21.2 Impingement baffle plate shall extent at least 25 mm beyond the projection of the nozzle bore.

3.21.3 The clear distance from the nozzle (at the inner surface) to the impingement plate shall be at least 0.25 x nozzle diameters.

3.21.4 The nominal thickness of the impingement baffle shall be at least 6 mm. 3.22 In case of girth flange design, minimum width of gasket shall be checked to withstand

required design condition. 3.23 In case of girth flange design correction factor for flange moment shall be based on

maximum bolt spacing as 2db + t where db is bolt diameter and t is the flange thickness.

3.24 For equipment to be designed as per I.B.R all requirements specified therein shall be taken care of.

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For parts/components, design of which is not covered in I.B.R, recommendations of ISO R 831 or any other international code accepted by I.B.R shall be followed and it shall be with the prior approval of TPI.

3.20 Adequacy of tube bundle against flow induced vibration shall be checked by supplier if called for and any modification, if required, shall be carried out in consultation with TPI without any commercial implication. Vibration analysis shall be submitted to TPI for review.



3.25 Baffle and support plates shall be tied together with tie rods and spacer pipes unless otherwise specified. Tie rods and spacers should be preferably on the peripheral open area so as to block the bypass area between outer most tubes and shell inside.

3.26 Unless otherwise stated all girth flange joints shall be confined type. 3.27 For equipment to be lined with refractory material by the supplier, calculation for

refractory thickness along with the properties of the refractory selected shall be submitted for comments & approval in addition to other design calculations.

3.28 Bolts of size M52 and above shall be designed and spaced so as to permit tightening with a hydraulic stud tensioner. The bolts shall have an extra threaded length at one end of appx. 1 bolt diameter and shall be provided with threaded protection caps. Hex nuts shall have suitable holes for manual tightening.

3.29 Kettle- type shells must be provided with rails on which the tube bundles can be supported and guided. The baffle should be designed accordingly. Also proper tube bundle holding arrangement shall be provided at last support baffle to avoid any damage during handling/ transportation.

3.30 U-tube exchanger, requiring shell removal requirements shall be provided an additional saddle at tubesheet. The saddles on shell shall have suitable spool-saddles for shell movement/removal.

3.31 Where the operating load on the sliding saddle > 2500 kg. It shall preferably rest on low friction pad or rollers. The drawing shall show this pad included in the saddle height. No slotted holes are required in the saddle base. But the saddle shall be guided and prevented from lifting. When low friction pads e.g. Teflon are used, counterpart shall be polished SS plate and be designed so that low friction pads are entirely covered by the SS plate under all operating conditions. When the rollers are used, the rollers shall be prevented from running out. The roller can, for example, be 40 mm nominal diameter CS bars linked together in parallel at 60 mm spacing. They shall extend to the outer vertical webs of the saddle, but shall not be attached either to the saddle or to the supporting steel. The vessel drawings also shall show that the saddle resting on the rollers is 40 mm shorter than the fix saddle.

3.32 When deciding which saddle should be chosen as fixed, the permissible deflection of any large bore pipe attached to the equipment shall be taken into consideration.

3.33 When design pressure is more than 400# class and/or shell thickness is 50 mm and above, selfreinforced forged nozzle shall be provided. Nozzle size 3 NPS Shell to SR nozzle welding shall be set-in type welding. For small sizes shell to SR nozzle welding may be set-on type welding.

3.34 Minimum nozzle diameter shall be 1 nominal.

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4.0 MATERIALS 4.1 All materials, whatsoever, required to complete the supplies shall be procured by the

supplier and all such materials shall be covered with due identifiable material test certificates.

4.3 Material procured to other approved specification than stipulated in design code shall be acceptable provided it meets all the requirements of applicable design code.

4.4 Unless otherwise specified all C.S and low alloy steel materials including forging used for pressure parts shall be fully killed and in normalized condition.

4.5 Unless otherwise specified copper or copper alloys shall not be used. Copper content up to 0.40% are acceptable in carbon steel and 0.6% in stainless steel.

4.6 Material used in low temperature service shall be impact tested (Charpy-V) if required as per design code and specification. Impact test temperature and energy value shall be in accordance with code requirement, unless specified otherwise.

4.7 For coarse grained and high tensile materials in carbon steel (UTS 52 Kg/mm2) and low alloy steel, guaranteed impact strength shall be ensured at a temperature 15OC below envisaged hydraulic test temperature as a precaution against brittle fracture during hydraulic test. Similar precaution shall be taken for thicker plates > 50 mm for equipment designed for pressure 15 Kg/cm2g.

4.8 C.S. and low alloy steel exceeding thickness of 50 mm shall be vacuum degassed except for plate ring flanges.

4.9 All plate materials over 50 mm thickness shall be ultrasonically tested both on surfaces and edges as per ASTM A 435.

4.10 Unless more restrictive prescription given by material specification the maximum carbon content of carbon steel used for fabrication as shown by laddle analysis shall be 0.23% for plates, pipes & tubes.

0.25% for forging. 4.11 Temper embrittlement

The risk of temper embrittlement (TE) must be taken into consideration for Cr-Mo low alloy steel plates and forgings (P. Nos. 4, 5A and 5C as per ASME PV Code ) used in pressure vessels and piping operating in the temperature range of 375C to 575C.

In order to reduce the risk of TE the following requirements shall be applied: 1 Cr- Mo (P4) Base Metal

Phosphorus (P) max 0.007 weight %. Tin (Sn) max 0.01 weight %. X = (10P + 5Sb + 4Sn + As) x 100 < 15 (Elements weight %)

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4.2 Materials indicated in specification sheets are recommended for the required service conditions. Supplier however, may use better or equivalent material with prior approval of TPI. Details of such materials must be indicated in the offer with proper reference.



2 Cr - 1 Mo / 3Cr 1 Mo (P5A and P5C) Base Metal

J = (Si + Mn)(P + Sn) x 104 < 120 for P.No. 5A 100 for P.No.5C (Elements in weight %)

Step cooling tests shall be performed if nominal thickness exceeds 50 mm. procedures for heat treatment, testing and evaluation as per API 934.

Weld Metal (as deposited)

X = (10P + 5Sb + 4Sn + As) x 100 < 15 (Elements weight %) The above guidelines shall be adhered to unless, on specific jobs, codes/standards or end user specification impose more stringent requirements.

4.12 All forgings shall be ultrasonically tested as per Sec. ASTM A 388 for thickness greater than 100 mm with the criteria shown in ASME Sec.VIII Div.2 para AM-203-2. In case any defect is found, no repair by welding shall be allowed. ASME flange for equipment designed as per ASME Sec.VIII Div.1 need not be UT tested.

4.13 All forgings including nozzles flanges shall be examined for surface defects MP/DP after machining.

4.14 For SS 316 and 316L material, ferrite content for plates, pipes, tubes & forgings shall be maximum 2%. However, for SS316L Urea grade ferrite content shall be maximum 0.6%.

4.15 Intergranular corrosion test shall be carried out on all SS 316L Mod (Urea grade) materials, weld and HAZ as per ASTM A 262 practice C if specified. The corrosion rate shall not exceed 0.025 mm / month.

4.16 Inter granular corrosion test shall be carried out on all SS 316L materials, weld & HAZ as per ASTM A 262 practice E (Strauss test) unless otherwise specified in specification.

4.17 For equipment designed as per IBR, materials shall strictly comply with the requirement of the IBR code. All materials must be procured from well known steel maker recognized by IBR (refer Appendix G of IBR).

4.18 For equipment designed as per IBR, certificate for materials in respect of yield point at design temperature, the average stress to produce elongation of 1% in 100,000 hrs and the minimum stress to rupture in 100,000 hrs shall be obtained from the steel makers wherever design conditions call for use of these data.

4.19 For IS 2062 materials without mill test certificates, check test, if called for by the inspector, shall be performed without any commercial implication. Material shall be fully killed.

4.20 All nozzles 10 NPS shall be seamless. 4.21 Spiral- wound gasket shall be provided with S.S guide rings. Outside diameter of

gaskets shall extend up to bolting. 4.22 All pipe fittings including elbows for sizes 10 NPS shall be forged / wrought. 4.23.1 All heat exchanger tubes shall be cold drawn and seamless.

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4.23.2 Where seam welded tubes are permitted as an alternative, the weld shall be

inspected through out the whole length by eddy current or ultrasonic method. 4.23.3 As a general rule the preferred tube size is O.D. The minimum tube wall thickness

for O.D. carbon steel tubes is 2.11 mm (B.W.G.14) and for stainless steel 1.65 mm (B.W.G.16). (Heat exchanger for steam systems, under the preview of IBR requires, according to paragraph 338, a minimum tube wall thickness of 2.03 mm for both carbon and stainless steel. The nearest TEMA wall thickness is B.W.G. 14 = 2.11 mm).

4.23.4 Circumferentially finned tubes are not permitted. 4.24 The mean bending radius of U - tubes shall be not less than 1.5 times the tube

outside diameter. Thickness of two-inner most rows of U-tube bundle shall be higher by 2 gauge.

4.25 All SS tubes shall be subjected to non-destructive examination like eddy current or ultrasonic test at mill. C.S. and low alloy steel tubes shall also be subjected to such examination when design pressure exceeds 100 Kg/cm2g.

4.26 Unless otherwise specified tube sheets and girth flanges shall be of forged quality and ultrasonically tested.

4.27 Tubesheet and girth flanges must be in one piece. Segmental butt-weld construction shall not be accepted.

4.28 All tubes including U-tubes must be in one piece. Circumferential welds are not allowed.

4.29 Where heat treatment of U-bends is required, the heat treated portion shall extend at least 150 mm beyond the point of tangency.

4.30 Shear test according to ASTM A 264 is required for clad plates. At least 14 Kg/cm2 shear strength shall result from such test. All clad plates shall undergo ultrasonic examination at the steel work in accordance with ASTM A 578 level S8.

4.31 Gasket for all medium except cooling water service with flange rating 600 # shall be spiral wound graphite filled gasket with external & internal guide rings 3.2 mm thk. For prevention of crushing of gasket. For CW service gaskets for flange rating 150 # compressed fiber gasket type in accordance with ANSI B 16.21 shall be used. Gaskets with flange rating 900 # shall be octagonal ring-joint gasket. Hardness of the gasket shall be 50 BHN lesser than that of the mating flange gasket groove.

4.32 Special flat closures shall normally be furnished with gaskets of one of the following types: i. Double conical - Where double conical gaskets are used, a seating membrane

of graphite tape, 0.25 mm thick, shall be inserted between the joint ring and the conical surfaces on the vessel and the flange. The quality of the graphite tape will be specified by the purchaser.

ii. Welded Diaphragm - Welded diaphragm gaskets shall normally be made of Inconel 600.

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5.0 SCOPE OF SUPPLY 5.1 Unless otherwise specified the complete main equipment and its various components

as specified in specification sheets and enquiry documents shall be included in suppliers scope of supply.

Scope of supply shall included but not be limited to the following: 5.1.1 Cover flanges for manholes, handholes, inspection openings etc. with bolting and

gaskets. 5.1.2 Test blind flanges. (for hydrotesting) 5.1.3 Eye bolts, jack screws, dowel pins and lifting lugs. 5.1.4 Sealing strips for longitudinal baffle. 5.1.5 All external welded attachments like platforms and ladder cleats, insulation supports

and pipe support cleats etc. 5.1.6 Lifting lugs / erection lugs. 5.1.7 Impingement baffle. 5.1.8 Gland packing. 5.1.9 Test rings for removable tube bundle exchanger. 5.1.10 Cleats for earthing connections. 5.1.11 Name plate with bracket. 5.1.12 Foundation / Anchor / Holding down bolts with nuts and washers. 5.1.13 Support stool. 5.1.14 Lapping tool with transportation ring etc. 5.1.15 Welding / wire rods for weld seal gasket. 5.1.16 Special tools / tackles. 5.1.17 Expansion bellows, wherever required. 5.1.18 Internal sliding arrangement for removable tube bundle. 5.1.19 Hydraulic stud tension device. Complete with all accessories and operating manual

for bolt size M52 and above. 5.1.20 Internal sliding arrangement, guide rails, rollers and pulling Yoke for removable tube

bundle exchangers. 5.1.21 Ferrules. 5.1.22 Sight glass with protector glass. 5.1.23 Demister complete with housing and support grid. 5.1.24 Sliding plate, low frictional pads / rollers for free support. 5.1.25 Templates for skirt support of equipment. 5.1.26 Seasoned wooden blocks under support base for LT exchangers with bolting.

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5.1.27 Interconnecting piping for stacked heat exchangers. 5.1.28 Adjustable shim plates between stacked saddle and bolting. 5.1.29 Protection caps for stud ends to be tightened with hydraulic tensioner. 5.1.30 Documents according to clause 10.0. 5.1.31 Spare parts according to clause 5.2.

5.2 The following 2-Years Operation Spares shall be supplied along with the equipment.

i) 200% gaskets for all nozzle connections with blind flange.

ii) 200% gaskets for girth flange.

iii) 200% ring joint gaskets.

iv) 200% 0 ring gaskets for lipseal gasket.

v) 200% graphoil tape / aluminum foil for double conical gasket.

vi) 10% bolts/nuts for each nozzles with blind/companion flanges (min 5 pieces).

vii) 10% bolts/nuts for each body flange joints (min 5 pieces).

viii) 10% internal bolts, nuts & clamps (min 5 pieces of each size).

ix) 200% gland packing.

x) 5% tube plugs for both ends.(Tube plug length equal to tubesheet thickness).

xi) 10% ferrules.

xii) 300% sight glasses and protector glasses.

xiii) 100% demister pad complete with top & bottom grids and fasteners.

6.0 FABRICATION 6.1 The manufacturer of the equipment shall comply in all respects with the provisions of

the applicable code/standards and specifications with respect to welding, fabrication, forming of heads, radiography, heat treatment, inspection, testing and quality control etc.

6.2 All welding shall be carried out by qualified welders using approved procedure in compliance with the requirements of code & specifications and duly certified by the inspecting authority. All welding procedure must be got approved from authorized inspecting authority before starting any fabrication job. Welding of all parts must be completed before heat treatment.

6.3 Plates of different thicknesses shall be made flush with the inner surfaces of equipment unless otherwise stated.

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6.4 Top portion of skirt (Minimum 1000 mm skirt) welded with bottom head shall be of same material as that of shell/head. Skirt to head joint shall be full penetration type.

6.5 All conical heads unless otherwise stated shall be of toriconical type. 6.6 Minimum skirt height of dished head shall be 50 mm unless otherwise stated. 6.7 CS / Alloy steel dished end/toriconical head including cone if cold formed or hot

a. In two pieces, with the welding seam included in the middle third and preferably on the centre line.

b. In petal construction, with meridianal seams and a central cap of diameter not larger than 0.75 times the vessel outside diameter.

Formed heads when fabricated in pieces shall be normalized and weld seams radiographed after forming.

6.8 Impact test when required as per code & specifications shall be carried out on parent metal, weld and HAZ.

6.9 In case of CS and low alloy steel expansion bellows, all joints shall be fully radiographed and bellow shall be stress relieved.

6.10 Production control coupons, when required as per code & specifications shall be subjected to impact test, corrosion test etc. in addition to mechanical tests as required. In case of heat treated equipment test coupons shall be given similar heat treatment as for the equipment.

6.11 Each shell section having diameter equal for less than 2 meters to the extent possible, shall be rolled out of a single plate with one longitudinal seam.

6.12 Orientation of longitudinal seams and position of circumferential seams shall be clearly marked in the fabrication drawings. Nozzles, support and other attachments shall be located clear of weld joints.

6.13 The centers of the welded longitudinal joints of adjacent courses shall be staggered or separated by a distance of five times the thickness of the thicker plate or 100 mm whichever is greater.

6.14 All parts involving welding construction including internals and stiffener ring shall have continuous welds unless otherwise stated.

6.15 In case of SS welds, procedure must be qualified to ensure that the weld meets the minimum requirements of C, Cr, Ni and Mo as that of the parent metal. In addition to various tests required as per code, weld procedure shall be qualified for intergranular corrosion test, as per ASTM A 262 practice C/E, if specified. Carbide contamination shall be avoided during welding.

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formed below normalizing temperature shall be subsequently normalized. In case of austenitic SS materials solution annealing shall be carried out if hot worked. Formed ends of vessels with diameters less than 1600 mm shall preferably be made in one piece. Larger heads which can not be formed in one piece shall be fabricated as follows with prior approval from TPI :-



6.16 In case of equipment fabricated of materials SS 316L/ SS 316 for urea service, low ferrite filler material shall be so selected that ferrite content in two subsequent weld pass in contact with process fluid shall be maximum 2% & for equipment fabricated of materials SS 316L urea grade the limitation of ferrite content shall be 1%. The welding not in contact with process fluid may have ferrite content limited to 6%.

6.17 All welds shall be full penetration welds with back chipping and rewelding from the second side. For those joints which are inaccessible for back chipping the root run shall be carried out with TIG process. Single side welding with backing strip is not permitted.

6.18 Due provisions must be kept for venting out entrapped gases during welding of pads, flanges and liner plates etc.

6.19 All nozzle reinforcing pads shall be tested pneumatically at 0.5 Kg/cm2g pressure with soap solution on attachment welds. Vent holes shall be plugged with non hardening mastic to prevent ingress of water.

6.20 Pads for supports and external cleats etc. shall be of same material as that of shell. 6.21 All sharp corners shall be rounded off with smooth radius. Inside edge of manhole

and hand hole at the internal surface shall be rounded to min. radius 5 mm. 6.22 Unless otherwise stated all nozzle flanges shall be weld neck type. For nozzle flange

size 24 dimensions shall conform to ASME ANSI B16.5 and nozzle flange size >24 NPS dimensions shall conform to ASME ANSI B16.47 (Series - B). All welding neck flanges shall be bored to suit nozzle I.D. Flange facings shall have suitable serrations for gasket seating in case of plain, male/female and raised.

6.23 Unless otherwise stated all girth flange joins shall be confined type. Minimum depth of gasket facing for girth flanges shall be 5 mm for compressed fiber gaskets and 6 mm for spiral wound / metal jacketed gaskets.

6.24 All internals fabricated in pieces shall be shop assembled and properly match marked for easy assembly at site.

6.25 Each partition plate shall be welded to channel for their full length with full penetration welds.

6.26 Each partition plate shall be provided with 3 mm dia drainage hole located as far from the tubesheet as possible

6.27 Procedure shall be qualified for tube to tubesheet joint. Mock-up test shall be carried out to establish all the requirements to the satisfaction of inspector.

6.28 In case of equipment to be assembled at site trial assembly in shop shall be carried out and match marked for proper assembly at site.

6.29 Equipment shall be provided with suitable bracings/stiffeners to avoid any damage during transportation and erection at site.

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6.30 In case of equipment involving site assembly/fabrication, the entire site job including

fabrication, radiography, heat treatment, inspection, testing and transportation to site shall be in suppliers scope of works at his cost.

6.31 All flange bolts & skirt-bolts shall straddle centre line unless otherwise stated. 6.32 Flange gasket contact surface shall not exceed 125 in roughness. In case of

metallic gasket the side wall surface of the gasket groove shall not exceed 63microns.

6.33 All nozzles less than or equal to NPS 65 shall be stiffened with three equispaced plate ribs of the same material as that of shell.

6.34 External bolting for gasketed flanges shall always be stud bolts and nuts. Bolt threads shall be in accordance with ANSI B1.1 (UNC for dia. 1, 8 UN for dia.> 1). Threads of bolts and nuts shall be coated before installation with lubricant to prevent galling of the threads.

6.35 Tubes holes in tube sheets of high alloy steel exchanger shall be finished to the diameter and tolerances as special close fit specified in TEMA.

6.36 Tubes shall be flush with or extend by 3 mm beyond the face of each tube sheet, except that tubes shall be flush with the top tube sheet in vertical exchangers unless otherwise specified.

6.37 Bent portion of C-Mo, Cr-Mo U-tubes shall be heat treated after bending. Non ferrous tubes shall be annealed.

6.38 Tubes in exchangers having design pressure less than 60 Kg/cm2g shall be rolled in grooved holes in tube sheets and seal welded. Weld shall be DP checked. Tubes in exchangers having design pressure equal to or more than 60 Kg/cm2g shall be expanded in plain holes in tube sheets and strength welded in minimum 2 runs. Each pass DP checked. All welding of tube to tubesheet joint shall be done using TIG method.

6.39 In case of overlayed tubesheet three grooves shall be made out of which one groove shall be in overlayed thickness.

6.40 In case of lip seal gasket, lip shall be welded after successful hydraulic test. Lip seals shall preferably be of hollow type and shall be furnished with O ring groove to facilitate hydrotesting at work. O ring shall be removed after hydrotesting.

6.41 Unless otherwise specified minimum thickness of undiluted weld overlay on tubesheet shall be 10 mm and flange face 5 mm.

6.42 In case of nozzle with butt-end construction, extra length shall be provided to facilitate hydraulic testing and subsequently cutting and edge preparation as per ANSI B 16.25 to suit piping welding at site.

6.43 All nozzle necks, nozzle flanges and blind flanges shall be of weld deposit construction for clad equipment. Loose liners are not permitted.

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7.0 INSPECTION AND TESTING 7.1 All raw materials shall be inspected at source by authorized inspection agency and

test certificates with due identification shall be submitted.

7.2 All equipment shall be inspected during various stages of manufacture starting from identification of raw materials to completion. The equipment shall be considered acceptable for dispatch only after final certification for acceptance is issued by the inspector.

7.4 Inspection by third party, if specified, shall be arranged by the supplier. It shall be the responsibility of the supplier to make available to the inspector all the new/revised drawings, calculations and other enquiry documents.

7.6 For equipment coming under IBR preview, the items shall be inspected during various stages of fabrication and testing by an inspecting authority acceptable to IBR. For list of inspection authorities recognized under IBR, reference shall be made to appendix C of IBR. It is the responsibility of the supplier to get the fabrication drawings and design calculations approved by IBR authority in India before the start of fabrication.

7.7 For equipment coming under the purview of IBR, the inspection by local IBR authorities shall have to be arranged by the supplier and all cost borne by the supplier.

7.8 In case of site fabricated/assembled equipment same inspection agency shall be responsible for inspection, testing at site.

7.9 In case of castable refractory, 3 Nos. slab of each size shall be cast at site before application and tested to meet the refractory specification in the presence of the inspector.

7.10 Unless otherwise stated gaskets used during testing shall be same as specified for operating conditions. After testing, gaskets used during testing shall be replaced by new gaskets.

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In case of equipment under TPI inspection, imported raw materials will be procured under third party inspection, unless otherwise specified.

7.3 Bought out items or items sub-contracted to other sub-suppliers shall also be inspected at the sub-suppliers works. However, standard items like bolts, nuts, ordinary gaskets etc. may be exempted from the inspection with specific approval from TPI.

7.5 Inspection order on third party shall also include specific instructions for marking copies of all correspondence from inspecting authorities to TPI and reporting monthly progress of the order to TPI. Complete responsibility of getting approval of drawings/calculations and documents from inspecting authority shall be that of the supplier.



7.11 The following NDT requirements are mandatory in addition to the requirements of

code/specifications :

a) Ultrasonic Examinations i. Butt weld in thickness 50 mm as supplement to radiography. ii. Full penetration welds of nozzle attachments on equipment shell/head

of thickness 50 mm as substitute for radiography. iii. Weld overlay on tube sheet. iv. All forgings

b) Magnetic particle / Liquid penetrant examination i. All edges of plates and openings in shell of C.S. having thickness 40 mm

and low alloy steel / S.S. having thickness > 25 mm and alloy steel of all thickness.

ii. Root-run and final layer of all butt welds. iii. All welds having thk. > 50 mm, all welds of low alloy steels and all

materials with UTS 52 Kg/mm2. iv. Fillet welds of 3% nickel and SS. v. Each layer of weld deposit in case of SS / inconnel weld overlay, cladding

& lining. vi. Each passes of tube to tubesheet joint. vii. Knuckle surface of dished ends / toriconical sections, pipe bends and

expansion bellow. viii. Bent portion of all U-tubes. ix. Skirt to head joint. x. All welds of SS and non ferrous materials and welds for vessels with

design temp. (-) 45OC and below after hydrotesting. xi. All weld surfaces after PWHT. xii. All welds of SS over thk. after hydrotesting. xiii. All forgings after machining.

c) Radiography i. Radiography when called for shell is applicable to all pressure welds i.e.

longitudinal & circumferential. ii. In case heads are formed of welded plates / petal construction, all the weld

seams prior to forming and after forming. iii. Circumferential joint of shell to dished head. iv. All T-weld joints.

ES 3201



v. Radiography examination of welds in C-1/2 Mo and Cr-Mo steel shall

preferably be carried out after heat treatment. If radiography is carried out Prior to heat treatment the welding and adjacent areas of base metal shall be examined by MPT/LPT after heat treatment.

d) Hardness i. Weld and Heat Affected zone (HAZ) of all pressure bearing welds in

Cr-Mo steel vessels shall be tested after final heat treatment using a portable hardness tester. Hardness value shall not exceed 215 HB for steel having Cr < 2% and 240 HB for steel having Cr 2%.

ii. Four opposite points of U-tube bent portion. 7.12 All completed equipment shall be tested hydraulically as per the requirements of

specification/codes in presence of the inspecting authority. Pneumatic test of completed equipment shall be carried out only when specially mentioned in the specification sheets. Chloride content in water used for testing shall not exceed 30 ppm for SS equipment and 40 ppm for CS and low alloy steel equipment. Duration of test shall be 1 hour minimum.

7.14 Tube to tube sheet joints shall be leak tested with air and soap solution at a pressure of 2.0 Kg/cm2g. When specified leak testing with Halogen shall be carried out.

7.15 Stacked exchangers shall be hydraulically tested as a combined unit. 7.16 After bending of U-tubes, each tube shall be tested hydraulically at 70 bars.

8.0 CLEANING, PAINTING AND DESPATCH 8.1 After hydraulic testing, the equipment shall be dried, thoroughly cleaned from inside

and outside and shall be free from all shop dirt, loose scale, grease etc. 8.2 All external surfaces of CS including internal surface of skirt to be painted shall be

degreased and all rust and mill scale removed. 8.3 i) Austenitic stainless steels and non-ferrous materials shall not be painted.

ii) The equipment shall be shot/grit blasted (min SA 2.5 ISO 8501-1) before the primer coat is applied on external surfaces. Primer shall be compatible to succeeding painting.

iii) In general, uninsulated equipment working below 94C, alkyd high build primer of thickness 50 microns DFT shall be applied.

iv) For Uninsulated equipment above 94C to 204C working temperature, aluminum paint of 30 microns DFT shall be applied.

v) For uninsulated equipment upto 420C working temp. inorganic zinc silicate of 50 microns zinc silicate shall be applied.

ES 3201

7.13 When required as per specification / code, strain gauge measurements shall be carried out on outside circumference during hydrostatic testing. The results shall be plotted both during pressurizing and depressurizing and procedure to such strain measurements shall have prior approval of TPI.



vi) For insulated equipment up to 94C, primer painting shall be of alkyd high build epoxy primer of 50 microns DFT shall be applied.

vii) For insulated equipment temperature exceeding 94C, primer shall be aluminum paint of 30 microns DFT.

viii) Thermo-indicative paint (three colour phases) shall be applied on refractory lined equipment to give warning of insulation/refractory failure. Paint manufacturers recommendation shall be followed.

ix) All flange faces, bolting and other machined surfaces shall be painted with an easily removable rust-preventive coating.

All machined surfaces, boltings and flange faces shall be properly protected from rust and mechanical injury during transit and storage.

8.4 Nozzles shall be sealed suitably. Threaded connections and beveled openings shall be suitably protected.

8.5 Name and code number of equipment shall be painted on each equipment at a conspicuous place in letters 150 mm high.

8.6 After hydraulic testing, all SS parts of equipment shall be pickled and passivated as per the following procedure :

a) Cleaning Clean surface and remove all extraneous matter with a hard fiber brush or SS

wire brush. M.S. wire brush shall not be used. All organic materials shall be removed with any paint remover like light solvent naphtha or benzene or equivalent. Motor petrol shall not be used.

b) Pickling Aqueous pickling solution shall be as follows: Nitric acid (Tech. grade) 10 to 25% plus Hydrofluoric acid 1 to 8% (to be used

only for stabilized SS grades). Temperature 50 to 60C for 10% Nitric acid and 20C for 25% Nitric acid. When size and shape of product permit, total immersion in the pickling solution is preferred. Where immersion is impractical, pickling may be accomplished by wetting the surface by:-

1) Swabbing or spraying. 2) By partial filling the item with pickling solution and rotating or rocking so that

all the surface receive the required chemical treatment. The maximum period for which the pickling solution shall be allowed to remain

on the surface is 30 minute. During pickling removal of oxides may be hastened by brushing with a hard fiber or SS wire brush. Over pickling shall be avoided.

The pickling agent shall be washed off with plenty of water so as to leave no trace behind.

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c) Passivation

After pickling and water rinsing, an aqueous caustic permanganate solution containing NaOH 10 weight % and KMnO4 4 weight % shall be used for neutralizing pickling solution. This shall be followed by thorough water rinsing.

Water used for pickling and washing shall not have chloride contents exceeding 30 ppm.

8.7 Equipment intended for transportation by ship shall be kept in hatch of the ship. Suitable seaworthy packing/painting shall be applied to avoid any damage during transshipment.

8.8 The responsibility of transport, packing and forwarding of the equipment shall be of the supplier. In case of inland transportation equipment shall be properly lashed, fixed on to the wagon/trailer to avoid any damage due to shocks in transport. In case of ODC movement, ODC sanctions for movement either by rail/road shall be arranged by the supplier from appropriate authorities in advance to meet the scheduled delivery. Supplier shall have to arrange the chasers.

8.9 All spares shall be properly packed, marked and sent separately along with equipment.

8.10 When specified equipment shall be dispatched with N2 filling. In case of equipment assembled and welded at site, it shall be filled with N2 after testing at site. Dry Nitrogen shall be filled at a pressure of 0.5 Kg/cm2g and equipment shall be fitted with a pressure gauge and valve.

9.0 GUARANTEE 9.1 The supplier shall guarantee equipment and their components against faulty design

with regard to mechanical adequacy, improper material of construction and poor workmanship for the specified period.

9.3 Should any repair or replacement be necessary owing to any type of failure on account of design, material or workmanship of the equipment, the supplier shall by dint of this guarantee, be bound to replace the same either in part or in entirety, without additional cost, at site. Repaired or replaced parts shall be covered by same guarantee as in case or main supply.

9.4 In case process design is also in suppliers scope, guarantee shall include process guarantee also in addition to above. All special instruments required to verify the guarantee, fixtures as outlined in the equipment specification shall have to be brought by the supplier on draw-back basis.

ES 3201

9.2 Approval of detailed shop drawings by TPI, will not in any way absolve the supplier from his responsibilities to supply the equipment in accordance with order specification.



10.0 DOCUMENTATION 10.1 Detailed fabrication drawings shall be prepared by supplier clearly indicating all

10.3 In case of vessels under the purview of IBR, complete responsibility of getting approval of drawings and design calculations etc. from concerned IBR authorities of state of manufacture and state of installation shall be with the supplier at his cost.

10.4 For equipment requiring statutory approval from Inspector of Explosives, it will be the responsibility of the supplier to get the fabrication drawings of equipment approved at his cost, wherever required.

10.5 All drawings shall be drawn in CAD to scale. Subsequent revisions/incorporation of comments shall also be made in CAD. Manual drawing shall not be accepted.

10.7 After approval one set of drawings / documents shall be given to the inspector by the supplier.

10.10 Payment against submission/approval of drawing if applicable shall be made after approval of drawing under Code 1.

10.11 All documents / drawings shall be in English language and in Metric system. 10.12 All documents required as per IBR code for approval must be supplied on IBR

Performa. 10.13 All final documents indicated against Sl.No.8 to 31 shall be properly arranged,

indexed and bound in one folder. The document as marked (**) are to be approved by authorized inspecting agency.

ES 3201

design data, nozzle data, details of all parts with tolerances, all welding joints details and detailed bill of materials etc. Location of weld seams, construction notes, welding processes, detailed specification of electrodes including NDT tests etc. as applicable shall be clearly indicated in the drawing. Drawing submitted for approval must be complete in all respects and thoroughly checked and approved by suppliers competent authority before submitting to TPI. Drawings without such information are likely to be rejected and any delay on this account shall be attributable to the supplier.

10.2 Before starting any fabrication, drawings must be got approved from TPI. Any comments marked on fabrication drawings shall have to be incorporated and decision of TPI in this regard shall be considered as final.

10.6 It will be preferable, if the soft copy along with 4 prints is brought to TPIs design office for getting approval. Supplier shall depute the concerned engineers & draftsmen with prior intimation and agreed date for deciding and incorporating the various agreed comments during their stay. Same procedure shall be followed for the approval of subsequent revisions, if any. Revisions shall also be entered in CAD file. Manual revision in drawing shall not be accepted.

10.8 Approval / comments on various documents shall be given by TPI within 3 weeks of the receipt of the same, mailing time excluded.

10.9 Turn around time for submission of revised drawings / documents based on TPIs comments shall be two weeks. Any delay in approval on account of delay in submission of revised drawings / documents shall be attributable to the supplier.



10.14 The number of copies of documents and required delivery time in weeks from date of

letter of intent / order for each document is given below.

Sl. No.

Description Reqd. with bid

Required after purchas

Copies Copies Days 1 2 3 4 5

1. Out line sketch showing thickness of main parts, weight & anchorage details (Refer Clause 10) 6 -- --

2 List of items likely to be subcontracted with probable vendors

6 -- --

3 Details of demister (i.e. make and model no. free volume, wire dia, surface area, density of material and separation efficiency)

6 -- --

4 Based on delivery stipulations a time bar chart indicating time required for material procurement, fabrication, testing, transportation and site assembly as required

6 -- --

5 Billing Schedule 6 -- --

6 Reference list of similar equipment, supplied indicating various parameters & material of construction. 6 -- --

7 Description of present shop load and spare load available for this job and annual turn over. 6 -- --

8 List of drawings -- 6 7

9 Final civil load data including details of foundation/anchor bolts

-- --

4 30

13 Welding procedure and performance records approved by inspecting authority ( ** )

-- 6 30

14 Procedure for hydraulic test and heat treatment ( ** ) -- 6 60

15 Procedure for tube to tubesheet joint (**) -- 6 60 16 Procedure for site jobs like assembly, heat treatment,

testing etc. -- 6 60

17 Detailed manufacturing schedule CPM/PERT & progress report to be submitted every month ( ** ) -- 8 30

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10 Design calculations -- 6 30 11 shop drawings/Detail fabrication drawing 8 30 12 Spare parts list -- 6 30



Sl. No.

Description Reqd. with bid Required after purchase order

Copies Copies Days from L/I

1 2 3 4 5

18 Procedure for removal & reassembly of weld seal gasket. Procedure of repair of damaged tubes. -- 12+ 2 RTF After dispatch of equipment

19 Operating/maintenance manual wherever required -- 12 180

20 Records of NDT tests e.g. radiography, UT, MP/PT, hardness etc. ( ** ) -- 12 After dispatch of equipment

21 Materials test certificates duly stamped by inspecting authority ( ** ) -- -do- After dispatch of equipment

22 PWHT Charts ( ** ) -- -do- After dispatch of equipment

23 Test on production test coupons ( ** ) -- -do- After dispatch of equipment

24 Corrosion test reports including C, Cr, Ni, Mo and ferrite contents report of raw materials, weldments, HAZ etc. ( ** )

-- -do- After dispatch of equipment

25 Hydraulic / pneumatic test reports ( ** ) -- -do- After dispatch of equipment

26 Strain gauge measurement ( ** ) -- -do- After dispatch of equipment

27 Inspectors final certificate ( ** ) -- -do- After dispatch of equipment

28 Suppliers guarantee certificate -- 12 + 2 RTF After dispatch of equipment

29 Transportation drawing showing overall dimension, C.G. weight and handling instructions duly approved by appropriate authority.

-- 8 120

30 All final as built shop drgs & calculations duly certified by inspecting authority( ** ) -- 12 +RTF + 2CD ROM containing editable soft files

After dispatch of equipment

31

For equipment coming under IBR purview all certificates required as per IBR code in IBR Performa and CIB approved and stamped copy of drawings.

-- 12 After approval of CIB

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