PIP VESAC001 Air-Cooled Heat Exchanger Specification (Supplement to API STD 661, 7 th Edition)

Transcription

1 January 2016 Vessels PIP VESAC001 Air-Cooled Heat Exchanger Specification (Supplement to API STD 661, 7 th Edition)

2 PURPOSE AND USE OF PROCESS INDUSTRY PRACTICES In an effort to minimize the cost of process industry facilities, this Practice has been prepared from the technical requirements in the existing standards of major industrial users, contractors, or standards organizations. By harmonizing these technical requirements into a single set of Practices, administrative, application, and engineering costs to both the purchaser and the manufacturer should be reduced. While this Practice is expected to incorporate the majority of requirements of most users, individual applications may involve requirements that will be appended to and take precedence over this Practice. Determinations concerning fitness for purpose and particular matters or application of the Practice to particular project or engineering situations should not be made solely on information contained in these materials. The use of trade names from time to time should not be viewed as an expression of preference but rather recognized as normal usage in the trade. Other brands having the same specifications are equally correct and may be substituted for those named. All Practices or guidelines are intended to be consistent with applicable laws and regulations including OSHA requirements. To the extent these Practices or guidelines should conflict with OSHA or other applicable laws or regulations, such laws or regulations must be followed. Consult an appropriate professional before applying or acting on any material contained in or suggested by the Practice. This Practice is subject to revision at any time. Process Industry Practices (PIP), Construction Industry Institute, The University of Texas at Austin, 3925 West Braker Lane (R4500), Austin, Texas PIP Member Companies and Subscribers may copy this Practice for their internal use. Changes or modifications of any kind are not permitted within any PIP Practice without the express written authorization of PIP. Authorized Users may attach addenda or overlays to clearly indicate modifications or exceptions to specific sections of PIP Practices. Authorized Users may provide their clients, suppliers and contractors with copies of the Practice solely for Authorized Users purposes. These purposes include but are not limited to the procurement process (e.g., as attachments to requests for quotation/ purchase orders or requests for proposals/contracts) and preparation and issue of design engineering deliverables for use on a specific project by Authorized User s client. PIP s copyright notices must be clearly indicated and unequivocally incorporated in documents where an Authorized User desires to provide any third party with copies of the Practice. PUBLISHING HISTORY March 2012 January 2016 Issued Editorial Revision Not printed with State funds

3 January 2016 Vessels PIP VESAC001 Air-Cooled Heat Exchanger Specification (Supplement to API STD 661, 7 th Edition) Table of Contents Introduction... 2 Purpose... 2 Scope... 2 Requirements Scope Normative References Terms and Definitions Preparation for Shipment Supplemental Requirements Annex A Recommended Practices Annex F Quality Overview Plan for Air-Cooled Heat Exchangers General Proposals Documentation Design Materials Fabrication of Tube Bundle Inspection, Examination and Testing Process Industry Practices Page 1 of 23

4 Introduction Purpose This Practice supplements API STD 661, 7 th Edition, July Air-Cooled Heat Exchangers for General Refinery Services. Together, this Practice and API STD 661 provide requirements for providing air-cooled heat exchangers. Scope This Practice and API STD 661 describe minimum requirements for the design, materials, fabrication, inspection, and testing of air-cooled heat exchangers. This Practice describes additions, modifications, and deletions made to API STD 661. In addition, this Practice describes decisions made regarding options offered by API STD 661. This Practice supplements, but does not supersede, API STD 661 and any applicable jurisdictional requirements. Requirements The numbering of the following headings and paragraphs in the Requirements section corresponds to the numbering of API STD 661, which this Practice supplements. The type of revision (i.e., addition, modification, deletion, or new) made to a specified heading or paragraph is described after the heading or paragraph identification. Provisions of API STD 661 that are not revised remain in force. 1 Scope Addition: Supplement as Follows: Equipment that is part of a self-contained package unit (e.g., jacket water and lube oil coolers, integral radiators, humidified exchangers, or exchangers that are part of air-conditioning equipment) is not included. 2 Normative References Addition: Supplement as Follows: Applicable parts of the following Practices, industry codes and standards, and references shall be considered an integral part of this Practice. The edition in effect on the date of contract award shall be used, except as otherwise noted. Short titles are used herein where appropriate. a) Process Industry Practices (PIP) 1) PIP VEFV1100[M] Vessel/S&T Heat Exchanger Standard Details (U.S. Customary Units) [(Metric Units)] i) PIP VEFV1101[M] Vessel Nameplate Bracket ii) PIP VEFV1103[M] Vessel Grounding Lug iii) PIP VEFV1129[M] Vessel Studded Joints 2) PIP VECV1001 Design Criteria and Purchasing Requirements for Vessels; ASME Code Section VIII, Divisions 1 and 2 3) PIP STF05501 Fixed Ladders and Cages Fabrication Details 4) PIP STF05511 Fixed Industrial Stairs 5) PIP VESAC001-T Inspection and Testing Requirements Sheet for Air-Cooled Heat Exchangers Process Industry Practices Page 2 of 23

5 b) Industry Codes and Standards 1) American Institute of Steel Construction (AISC) - AISC - Manual of Steel Construction 2) American Petroleum Institute (API) - API RP Steels for Hydrogen Service at Elevated Temperatures and Pressures in Petroleum Refineries and Petrochemical Plants 3) American Society of Mechanical Engineers (ASME) - ASME Boiler and Pressure Vessel Code (Code) Section II - Materials, Parts A, B, C, D Section V - Nondestructive Examination Section VIII - Rules for Construction of Pressure Vessels, Divisions 1 and 2 Section IX - Qualification Standard for Welding and Brazing Procedures, Welders, Brazers, and Welding and Brazing Operators - ASME B1.1 - Unified Inch Screw Threads (UN and UNR Thread Form) - ASME B Pipe Threads, General Purpose (In) - ASME B Pipe Flanges and Flanged Fittings NPS ½ through NPS 24 Metric/Inch Standard - ASME B Factory Made Wrought Buttwelding Fittings - ASME B Forged Fittings, Socket-Welding and Threaded - ASME B Large Diameter Steel Flanges, NPS 26 through NPS 60 - ASME PCC-1 - Guidelines for Pressure Boundary Bolted Flange Joint Assembly - ASME SA-20/SA-20M Specification for General Requirements for Steel Plates for Pressure Vessels - ASME SA-435/SA-435M - Specification for Straight-Beam Ultrasonic Examination of Steel Plates - ASME SA-688/SA-688M - Specification for Welded Austenitic Stainless Steel Feedwater Heater Tubes 4) American Welding Society (AWS) - AWS A2.4 - Standard Symbols for Welding, Brazing, and Nondestructive Examination - AWS D1.1 - Structural Welding Code - Steel 5) Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. (MSS) - SP-43 - Wrought Stainless Steel Butt-Welding Fittings - SP-44 - Steel Pipeline Flanges 6) Tubular Exchanger Manufacturers Association (TEMA) - Standards of the Tubular Exchanger Manufacturers Association Process Industry Practices Page 3 of 23

6 7) Welding Research Council (WRC) - WRC Bulletin Local Stresses in Spherical and Cylindrical Shells Due to External Loadings - WRC Bulletin Precision Equations and Enhanced Diagrams for Local Stresses in Spherical and Cylindrical Shells Due to External Loadings for Implementation of WRC Bulletin 107c) Government Regulations 1) U. S. Department of Labor, Occupational Safety and Health Administration (OSHA) - Occupational Safety and Health Standards (29 Code of Federal Regulations, Part 1910) 3 Terms and Definitions 3.2 Modification: bare tube surface to be defined as follows: total area of the outside surfaces of the tubes, which is the length measured between the airside faces of the header tubesheets minus the portions made inaccessible to cooling air by the tube supports. 3.5 Modification: cyclic service process operation that requires fatigue analysis in accordance with Code Section VIII, Division 2, Section Modification: pressure design code to be defined as follows: also referred to as Code. Code, Section VIII, Division 1 and its referenced sections (e.g., Sections II, V, IX), and Code cases as specified by the Purchaser. PIP VECV1001 supplements the Code Modification: structural code to be defined as follows: ICC IBC 3.34 Addition: New definition: approved equal a substitution to a specified product that has been approved in writing by Purchaser Addition: New definition: construction an all-inclusive term comprising materials, design, fabrication, examination, inspection, testing, certification (Code stamp and Manufacturer s Data Report), and pressure relief Addition: New definition: Designer the party responsible for defining and specifying the mechanical design requirements (e.g., Heat Exchanger Drawing/Data Sheet) consistent with User criteria for use by the Manufacturer. The Designer is frequently an engineering contractor, but could be the User, third party consultant, or the Manufacturer. The Designer is also considered the thermal Designer with respect to heat exchanger design Addition: New definition: Manufacturer the party entering into a contract with the Purchaser to construct a heat exchanger vessel in accordance with the purchase order. In accordance with the Code definition, the Manufacturer is the party that possesses a valid Certificate of Authorization to manufacturer pressure vessels with the ASME Mark Addition: New definition: National Board Process Industry Practices Page 4 of 23

7 the National Board of Boiler and Pressure Vessel Inspectors, an organization comprised of chief inspectors of various governmental jurisdictions in the United States and Canada. Heat exchangers meeting requirements of the Code, except those stamped with the Code UM symbol, may be registered with the National Board Addition: New definition: overlay specification technical requirements that supplement or override the provisions of this document, such as a User specification or a project specification Addition: New definition: Owner the party who owns the facility wherein the heat exchanger will be used. The owner is typically also the User Addition: New definition: Purchaser the party who awards the contract to the Manufacturer. The Purchaser may also be the Owner, User, or the Owner s or User s Designated Agent (e.g., engineering contractor) Addition: New definition: Purchaser s Inspector the person or company authorized by the Purchaser, Owner, and/or User to inspect pressure vessels to the requirements of this Practice and other Purchaser contract requirements Addition: New definition: User the party who establishes construction criteria in accordance with the Code philosophy and service hazards. The User is the operator of the facility wherein the heat exchanger will be installed. 4 General 4.1 Modification: To Read as follows: Pressure components shall be in accordance with Code and the supplemental requirements referenced in this standard. All tube bundles shall be Code stamped. Steam heating coils shall be designed and fabricated to the same requirements as tube bundles. If specified by Purchaser, steam heating coils shall be Code stamped. The edition of the Code to be used for the manufacture of exchangers shall be the edition in effect at time of purchase. Application of Code Cases to the manufacture of exchangers requires approval of the Purchaser and User. 4.8 Addition: New Paragraph: Exchangers shall be designed to minimize field assembly. 4.9 Addition: New Paragraph: Tube bundles shall be three rows deep minimum Addition: New Paragraph: Unless specified as an exception to a specific item in another document, discrepancies between the contract documents shall be submitted to the Purchaser for a written ruling. 5 Proposals 5.1 Addition: Supplement as Follows: Process Industry Practices Page 5 of 23

8 If the item has multiple process conditions, the data sheet shall include all design conditions. 5.4 Addition: Supplement as Follows: Alternative methods of fabrication may be proposed; however, alternatives shall be clearly identified and quoted as additions or deductions to the basic proposal Addition: New Paragraph: Proposed platform arrangements and method of unit support shall be clearly specified and, if necessary, drawings shall be provided Addition: New Paragraph: The heat transfer rate shall be calculated for each unit and the quotation shall be based on the minimum surface, air flow, and fan brake horsepower necessary to guarantee that the surface offered is satisfactory for the duty and fouling factors specified. Actual fouling factor available shall be shown on the heat exchanger data sheet. Unless otherwise specified in the contract documents, a complete thermal, hydraulic, and mechanical guarantee shall be provided. 6 Documentation 6.1 Approval Information b) Modification: To Read as Follows: design pressure, maximum allowable working pressure, test pressure, maximum and minimum design temperature, minimum design metal temperature, minimum tube thickness, and corrosion allowance; u) Addition: New paragraph: drawings and completed Motor Design Data Sheets for each size and type of motor in an exchanger; v) Addition: New paragraph: list of nozzle gaskets with the specific manufacturer, style, and type defined; Modification: To Read as Follows: Design calculations shall include relevant formulas and source paragraphs from the Code, values used in the formulas, calculated results, and comparisons with acceptable values. Where calculations are based on formulas other than those in the Code, the source of the formulas shall be referenced. Where calculations are done by a computer program, a program description shall be given, including name and version of the program. If the program is not commercially available to industry, program documentation shall be maintained and provided if requested by Purchaser, Owner, or User. See Cautionary Note in Code Foreword regarding responsibility for the use of computer programs. Calculations shall include: a) Code calculations for pressure components b) Wind and earthquake calculations, as applicable c) Support structure calculations d) Calculations associated with lifting and erection of the heat exchanger Process Industry Practices Page 6 of 23

9 e) Nozzle load analysis for local and gross effect, in accordance with WRC 107 and WRC 537 or other approved method, to the defined external moments and forces in accordance with f) Design of attachments, internal and external, including PIP details or other standard details used g) Fatigue analysis as applicable for fatigue services h) Restraint relief in accordance with Modification: To Read as Follows: Weld maps, all proposed welding procedures, including tube to tubesheet welding procedures, and qualifications, including impact test results, if applicable, shall be submitted to Purchaser for approval before start of fabrication Modification: To Read as Follows: If a hot air recirculation system is utilized for winterization, documents showing duct and plenum sizes, net free flow areas, louver types and arrangement, louver drive location(s), heating coil and heating medium consumption, and control scheme schematic shall be submitted to Purchaser for approval before start of fabrication Modification: To Read as Follows: Documentation as specified in the Documentation Schedule in Appendix D shall be provided Addition: New Paragraph: Manufacturer shall be responsible for the design and construction of the heat exchangers in accordance with this Practice and the documents referenced herein. Review of the documentation (e.g., fabrication drawings or weld procedures) by the Purchaser or User shall not alter this responsibility. 6.2 Final Records g) Modification: To Read as Follows: fan and hub data, including fan ring geometry (particularly fan tip clearance), shaft bore and keyway dimensions, and coupling and sheave data; q) Addition: New Paragraph: certified electrical and instrumentation diagrams. Addition: New Section 6.3: 6.3 Responsibilities Manufacturer shall be responsible for the construction of the exchangers in accordance with this Practice and the documents referenced herein. Review of the documentation (e.g., fabrication drawings, design calculations or weld procedures) by the Purchaser or User shall not alter this responsibility Manufacturer s documents shall be reviewed by Purchaser and comments resolved before start of fabrication unless release to proceed is obtained from Purchaser in writing If an exchanger or exchanger component design is specified on User s design documents, Manufacturer shall not be relieved of any obligations and/or responsibilities to comply with the contract documents Unless approved by Purchaser, welded fabrication shall not be sublet. Process Industry Practices Page 7 of 23

10 7 Design Release for shipment by Purchaser s Inspector shall not relieve the Manufacturer of any responsibility for complying with the Code and contract documents. 7.1 Tube Bundle Design General Modification: To Read as Follows: Unless Purchaser and Manufacturer agree on a different value, provision shall be made for minimum lateral movement of exchanger tube bundles of 19 mm (¾ inch) in both directions or 38 mm (1 ½ inches) in one direction. Unless cold springing is required, bundles shall be centered within the side frames Modification: To Read as Follows: Provision shall be made to accommodate thermal expansion of tubes. Bowed tube design with stresses in the deflected tubes beyond their yield point is not permitted. One header shall be free to move to accommodate thermal expansion and shall have stainless steel or PTFE sliding plates at the moving end on both the structure and bundle Modification: To Read as Follows: Tubes shall be supported to prevent sagging and meshing or deformation of fins. Tube supports shall be spaced less than or equal to 1.83 m (6 ft) from center to center. Tube supports shall be secured to the side frames. The following types of tube supports are permitted: a) For stainless steel tube bundles, aluminum support collars 12.5 mm (½ inch) minimum width b) For other tube bundle metals, cast zinc or aluminum support collars 12.5 mm (½ inch) minimum width c) For all tube bundles, aluminum lock bars 7.25 mm (¼ in) minimum thick Thin aluminum wiggle strips, unattached to the side frames, are not permitted Modification: To Read as Follows: Unless otherwise specified, all tube rows of single pass units and coolers in single phase service, and the last row only of multipass condensers, shall be sloped 10 mm per meter ( 1 / 8 inch per foot) toward the outlet header Addition: Supplement as Follows: If specified in the contract documents, complete drainage shall be provided for special services by sloping successive passes of multipass units in the direction of flow Modification: To Read as Follows: Unless otherwise specified, exchangers shall be designed for a steam-out temperature of 121 C (250 F). Process Industry Practices Page 8 of 23

11 Horizontal partitioning in outlet headers shall be drainable by weep holes of the largest diameter in accordance with good thermal and mechanical design practice. The return header of even pass units shall include DN 40 (NPS 1 ½) LWN nozzles to facilitate venting and draining. For odd pass arrangements, DN 40 (NPS 1 ½) LWN nozzles shall be properly located in both headers to facilitate venting and draining. Special consideration shall be given to draining units with split headers or full vertical partitioning where isolated chambers exist Addition: New Paragraph: Unless otherwise specified by Purchaser, exchangers shall be thermally designed using Heat Transfer Research Institute (HTRI) or Heat Transfer and Fluid Flow Services (HTFS Addition: New Paragraph: Unless otherwise specified by Purchaser, tube-to-tubesheet joints shall be expanded Addition: New Paragraph: Unless approved by Purchaser and User, proof testing shall not be permitted Addition: New Paragraph: Weighted mean temperature difference (MTD) shall be used in the design only if Purchaser provides heat release curves or tables Addition: New Paragraph: Unless approved by Purchaser, tube inserts for turbulence promotion and heat transfer enhancement shall not be used. If tube inserts are offered for Purchaser's consideration, all essential data on the proposed tube inserts, including any test data that substantiates enhanced performance shall be provided in the proposal Addition: New Paragraph: Fouling factors shown on Purchaser s data sheet are net. Tubeside values shall be multiplied by the ratio of the outside to inside surface area Addition: New Paragraph: Services requiring multiple bays shall be provided with an even number of bundles to facilitate even flow distribution. For services with two phase inlet conditions, the number of bundles shall be selected to permit a symmetrical piping arrangement to equalize flow into each bundle. Symmetrical piping requires the number of bundles to be any number in the following progression: 1, 2, 4, 8, 16, 32, 64, 128, etc Heating Coils Modification: To Read as Follows: The tube pitch of the heating coil shall not exceed the smaller of 1.5 times the tube pitch of the tube bundle or 4.75 times the nominal heating coil tube diameter. Process Industry Practices Page 9 of 23

12 Modification: To Read as Follows: If steam is used as heating fluid, heating coils shall be single row straight tube design sloped 10 mm per meter (1/8 inch per foot) toward the outlet header. Standard header size (i.e., non-as stamped coils) shall be DN 80 (NPS 3) pipe fabricated of SA-106, Grade B carbon steel material. Nozzle size and rating for all coil connections shall be DN 80 (NPS 3) ASME Class 300, Raised Face. Prime tube size shall be 25.4 mm (1 in), 12 BWG minimum wall, fabricated of SA-214 welded grade carbon steel. Fins shall be aluminum with a standard outside diameter of 57 mm (2 ¼ inches) and a density of 4.4 fins per cm (11 fins per inch). Tube pitch shall be a maximum of twice the process bundle pitch or 127 mm (5 inches), whichever is less. Tube length shall be maximized in accordance with the main coil tubing dimensions. Fin type shall be in accordance with the individual item requisition sheet Design Temperature Modification: To Read as Follows: For pressure parts, the maximum and minimum process design temperatures, the maximum and minimum ambient temperatures, and the minimum design metal temperature (MDMT) shall be as specified on the data sheet Modification: To Read as Follows: Finned tubes shall be in accordance with Annex A-1, Section A Design Pressure Modification: To Read as Follows: The design pressure(s) shall be as specified by the Purchaser on the data sheet. The maximum allowable working pressure (MAWP) shall be calculated for both the cold and uncorroded condition and the hot and corroded condition. The hot and corroded condition shall be stamped on the nameplate. The MAWP shall not be limited by the nozzle reinforcement Headers General Addition: Supplement as Follows: Tube-wall temperature differences between passes in the same row or between adjacent rows shall not lead to overstressing due to tension, bending or shear. Bowed-type designs are not permitted ) Modification: To Read as Follows: Stress caused by temperature and pressure Modification: To Read as Follows: The lateral velocity in the header shall not be greater than the velocity in the nozzle or the tubes. Multiple nozzles or an increased header cross-sectional area may be required. Process Industry Practices Page 10 of 23

13 Modification: To Read as Follows: For all materials, the minimum tubesheet and plug sheet thicknesses shall be 25 mm (1 inch) including any corrosion allowance Modification: To Read as Follows: Pass partitions used as stay plates for the tubesheet and plug sheet shall be made of one integral plate. Horizontal partition plates shall be provided with a 6 mm (¼ inch) hole for drainage and venting Removable Cover Plate and Removable Bonnet Headers Modification: To Read as Follows: Bolted joints shall be designed using through bolts with confined gaskets. Unconfined full-face gasket joint designs are not permitted. Stud bolt construction may be used if approved by the Purchaser. Gasket contact surfaces on cover plates, matching header box flanges, and tubesheets shall be machined. The surface finish shall be appropriate for the type of gasket (See A.3.12). Typical constructions are shown in Figure 4,). The design of the joint, including cover plate, shall include seating the pass partition rib(s) gasket Addition: Supplement as Follows: Studs shall be in accordance with PIP VEFV Addition: New Paragraph: Removable cover plates are not permitted in hydrogen service Plugs for Tube Access Modification: To Read as Follows: Threads of plugs having nominal diameters 30 mm (1¼ inch) and less shall be fine series threads in accordance with ASME B Addition: New Paragraph: Plugs shall be coated with thread lubricant suitable for the design conditions of the exchanger Nozzles and Other Connections Modification: To Read as Follows: Unless otherwise specified on the data sheet, all nozzles shall be flanged. Flanges less than and equal to DN 600 (NPS 24) shall be in accordance with ASME B16.5. Unless otherwise specified, flanges greater than DN 600 (NPS 24) shall be in accordance with ASME B ASME Class 400 flanges are not permitted Modification: To Read as Follows: Flanged nozzles less than and equal to DN 250 (NPS 10) shall be either fabricated from seamless pipe with weld neck flanges or long weld neck type. Flanges greater than DN 250 (NPS 10) shall be weld neck or slip-on flanges. Process Industry Practices Page 11 of 23

14 Use of slip-on flanges shall be limited to design temperatures of 260 C (500 F), and a maximum corrosion allowance of 3 mm ( 1 / 8 inch). Slip-on flanges shall be of the same material as the nozzle neck, and double welded. Cast pieces are not permitted Addition: Supplement as Follows: Connections in cast transitions are not permitted in any service Modification: To Read as Follows: Connections to the header or header nozzles shall be flanged, and not less than DN 25 mm (NPS 1). This includes auxiliary connections such as vents, drains, instrument connections, and chemical cleaning connections Deletion: Delete in Entirety Modification: To Read as Follows: For header nozzles greater than or equal to DN 100 (NPS 4), DN 40 (NPS 1½) flanged thermowell connections shall be provided. For header nozzles less than DN 100 (NPS 4), flanged thermocouple connections shall be provided on the adjacent piping as close as possible to the nozzles. One thermowell connection each shall be provided on one inlet nozzle and one outlet nozzle of each bundle. Thermowell connections shall be horizontal and shall be size DN 25 (NPS l), ASME Class 6000 forged steel couplings. For all exchangers in hydrogen service and/or for all nozzles that have ASME Class 900 or greater flanges, flanged thermowell connections shall be provided Deletion: Delete in Entirety Modification: To Read as Follows: Chemical cleaning connections, if specified, shall be provided as follows: a) For inlet and outlet nozzles less than or equal to DN 100 (NPS 4), DN 50 (NPS 2) flanged connections b) For inlet and outlet nozzles greater than or equal to DN 150 (NPS 6), DN 100 (NPS 4) flanged connections c) For bundles in series or series-parallel arrangements, one chemical cleaning connection in the inlet nozzle and one in the outlet nozzle of each series group Modification: To Read as Follows: Instrument and chemical cleaning connections shall be located in a minimum of one inlet and outlet nozzle per bundle. Instrument and chemical cleaning connections shall not be provided in intermediate nozzles of stacked bundles Deletion: Delete in Entirety Modification: To Read as Follows: Flanged vent, drain, temperature, pressure, chemical cleaning and inspection openings shall be provided with blind flanges, gaskets, and all stud bolts and nuts suitable for the specified operating conditions Deletion: Delete in Entirety. Process Industry Practices Page 12 of 23

15 Addition: New Paragraph: Slip-on flanges shall not be used in vacuum service.[es1] Addition: New Paragraph: Nozzles shall not project past the inside surface of the header box. Nozzles shall be designed to avoid impingement on tube ends, restriction of flow, and uneven flow distribution Addition: New Paragraph: Bolt holes shall straddle the horizontal and vertical centerlines Addition: New Paragraph: Weld neck flanges shall have the same inner diameter as the nozzle necks Addition: New Paragraph: Nozzle projections shall be sufficient to permit bolt removal Addition: New Paragraph: Flanged process nozzles shall not be less than DN 50 (NPS 2) Addition: New Paragraph: Integrally reinforced nozzles shall be provided if any of the following conditions exist: a) Cyclic services b) Carbon steel with header plate thickness 40 mm (1 ½ inches) and greater c) Alloy steel with header plate thickness 25 mm (1 inch) and greater d) Exchangers are in hydrogen service e) If 100% radiography of nozzles is specified Addition: New Paragraph: Nozzles on weld overlaid or integrally clad vessels shall be integrally clad or weld overlaid. Sleeve lined nozzles are not permitted. Clad or overlaid protection shall extend through the nozzle neck and cover the gasket face of the nozzle flange Addition: New Paragraph: The thickness of reinforcing pads shall not be greater than header thickness Addition: New Paragraph: Heat affected zones from nozzle welds and header welds shall not overlap Addition: New Paragraph: All nozzle welds, including neck welds, shall be full-penetration welds Addition: New Paragraph: Nozzles shall be in accordance with the following industry standards, as applicable. a) ASME B16.5 b) ASME B16.9 Process Industry Practices Page 13 of 23

16 c) ASME B16.11 d) ASME B Maximum Allowable Moments and Forces for Nozzles and Headers Modification: To Read as Follows: Each nozzle in the corroded condition shall be capable of withstanding the simultaneous application of two times the moments and forces described in Figure 6 and Table 4. The impact of these loads shall be incorporated into the design of the header boxes, side frames, header box supports, and the exchanger support structure Tubes Addition: Supplement as Follows: Minimum fin tip thickness for integral or extruded fins shall be 0.2 mm (0.008 inch). For fins wrapped under Addition: New Paragraph: The number of fins shall not be greater than 4.4 fins per cm (11 fins per inch) Addition: New Paragraph: Minimum clearance between tips of fins on adjacent tubes shall be 3 mm ( 1 / 8 inch) Addition: New Paragraph: Unless approved by Purchaser, serrated fins are not permitted Addition: New Paragraph: Circumferential welding of tubes is not permitted Addition: New Paragraph: Unless otherwise approved by Purchaser, tube sizes and spacings shall be uniform throughout bundles in the same exchanger unit. 7.2 Air-side Design General Addition: Supplement as Follows: design exposure temperature (including for steam-out) for mechanical components Addition: New Paragraph: All fans, drive trains, and drivers shall be interchangeable within each exchanger unit Addition: New Paragraph: Motors and the drivers for hot-air recirculation units shall not be exposed to heated recirculated air Addition: New Paragraph: Gear box vents, oil filters, and sight glasses shall be located outside the plenums. Process Industry Practices Page 14 of 23

17 Addition: New Paragraph: For multiple bay applications, the exchanger shall be designed to ensure that hot air recirculation cannot occur that can detrimentally affect performance Fans and Fan Hubs b) Modification: To Read as Follows: The pneumatic actuator shall be provided with a positioner e) Modification: To Read as Follows: Unless otherwise specified on Purchaser s data sheet, if control air pressure fails, fan blades shall automatically adjust to maximum pitch f) Addition: New Paragraph: Forced draught exchangers shall have adequate clearance in the plenum to permit removal of the actuator without removing the autovariable hub or fan Addition: New Paragraph: Attachments to fan orifice rings, for reducing fan tip clearances, shall be bolted Addition: New Paragraph: Mounting and bearing arrangement of induced draught fans shall permit removal and reinstallation of the fan and hub without exposing personnel to discharge air streams of neighboring fans, and without disturbing the tube bundle Fan Shafts and Bearings Modification: To Read as Follows: Shaft bearings shall have a calculated rating life, L 10, of 100,000 hours at maximum load and speed in accordance with ISO 281 and/or ISO 76, where L 10 is the number of hours at rated bearing load and speed that 90% of a group of identical bearings completes or exceeds before the first evidence of failure Modification: To Read as Follows: Bearings shall be suitable for exposure to the maximum expected air temperature determined in accordance with paragraph If the maximum expected air temperature is greater than 127 C (260 F), the following shall be provided: a) Tapered roller type bearings, heat stabilized to 232 C (450 F) b) High-temperature seals c) Adequate internal clearances for high temperature duty Maximum bearing temperature shall be determined for each fan individually. Lubricants shall be suitable for the design exposure temperature and temperatures from friction and loading Addition: New Paragraph: Thrust bearings shall be located at the lower end of shafts and mounted in a manner that permits removal without disturbing shafts or hubs. Process Industry Practices Page 15 of 23

18 Addition: New Paragraph: Top and bottom fan shaft bearing assembly alignment shall be maintainable. Structural features (e.g., a rugged shaft tube or other structural detail) shall be provided to maintain bearing pedestal alignment Addition: New Paragraph: Drive shaft shall not permit the maximum operating speed to be greater than 60% of the first critical shaft speed Fan Guards Modification: To Read as Follows: Removable steel fan guards shall be provided for both forced- and induceddraught exchangers Addition: New Paragraph: Guards on forced draught fans shall provide containment for fan blades and hubs in the event of a fan or hub failure Drivers General Addition: New Paragraph: Drivers shall be arranged and mounted in a manner that provides ready and complete access for service Electric Motor Drivers Modification: To Read as Follows: Shaft-up design shall be used only if approved by the Purchaser. If the motor is mounted in the shaft-up position, the belt sheave shall be designed as a shield to prevent water from accumulating and being directed down the motor shaft while the motor is either idle or running. Alternatively, an external conical slinger may be fitted to the shaft to prevent water from entering the housing along the shaft Couplings and Power Transmissions General Modification: To Read as Follows: Fan shaft and gear shaft couplings shall be of the non-lubricated flexible type, and shall have a minimum service factor of Belt Drives Modification: To Read as Follows: Belt drives shall be either banded type V-belts or high-torque type positive-drive belts Modification: To Read as Follows: Belt drives shall be provided with jack screws or an equivalent means of initial belt-tensioning and/or re-tensioning. Belt tensioning Process Industry Practices Page 16 of 23

19 devices shall be easily accessible from maintenance area, without removing fan guards Modification: To Read as Follows: V-belts shall have a minimum service factor of 2.0 based on driverrated horsepower Addition: New Paragraph: Belts shall be anti-static Addition: New Paragraph: Unless approved by the Purchaser, belt drives in a heated air stream (e.g., top-mounted drives) are not permitted. If belt drives in a heated air stream are approved, the following shall apply: a) The belt design temperature shall be the greater of the maximum air temperature near the belt or the maximum belt temperature that can be caused by radiation under all conditions. b) Decreased fan efficiency shall be considered. c) The method for suspending the driver shall be approved by the Purchaser. d) Driver shall not be located in the heated air stream. See paragraphs and e) Automatic belt tensioners shall be provided for belts located in hot air recirculation Mechanical Power Transmission Guards Addition: New Paragraph: Guards shall be in accordance with OSHA 1910 requirements Vibration Cut-Out Switches Modification: To Read as Follows: A readily accessible, double-throw, two-contact vibration cut-out switch shall be provided for each fan driver unit Addition: New Paragraph: Vibration cut-out switches shall be the acceleration sensitive type Addition: New Paragraph: Vibration switches shall be installed in housings suitable for the electrical classification of the area Louvers Modification: To Read as Follows: If used for automatic control, louver actuators shall operate with a 20 to 100 kpa gauge (3 to 15 psig) pneumatic control signal. If supplied with design motive-air pressure, actuators shall be sized to supply at least 200% of the Process Industry Practices Page 17 of 23

20 necessary force for full-range louver blade travel. Unless otherwise specified, design motive-air pressure shall be 410 kpa gauge (60 psig) Modification: To Read as Follows: Unless otherwise specified, louvers shall open if control-air pressure fails Addition: New Paragraph: Outlet louver shall be designed to prevent recirculation of hot air through idle fan Addition: New Paragraph: 7.3 Structural Design General louvers shall not be located under bundles, or above induced draught fans Modification: To Read as Follows: Structural steel design, fabrication, and erection shall be in accordance with the Structural Code and AISC Manual of Steel Construction Modification: To Read as Follows: Weld-metal design stress shall be in accordance with AWS D1.1, Section Addition: New Paragraph: All platforms, ladders, cages, and stairs shall be in accordance with OSHA 1910 requirements Vibration Testing Modification: To Read as Follows: A shop test shall be performed to verify compliance with the vibration limits. For multi-bay exchanger units, 10% of the bays shall be shop tested, with a minimum of one bay per exchanger unit Plenums Modification: To Read as Follows: The thickness of steel sheet material used for ducts and plenums shall be a minimum of 3.6 mm (10 gauge USS) (0.141 inch) flat or 2.7 mm (12 gauge USS) (0.106 inch) ribbed Modification: To Read as Follows: Fan decks shall be designed for a live load of 2500 N/m 2 (50 lbf/ft 2 ) with a minimum thickness of 4.4 mm (8 gauge USS) (0.173 inch) for induced draught units and 3.6 mm (10 gauge USS) (0.141 inch) for forced draught units Addition: New Paragraph: Plenum welds shall be continuous seal welds Addition: New Paragraph: Inlet or outlet bells shall be provided in accordance with the following: a) For forced draught units with box-type plenums, both inlet and outlet bells shall be provided. Process Industry Practices Page 18 of 23

21 b) For forced draught units with transition plenums, inlet bells shall be provided. c) For induced draught units with box-type plenums, inlet bells shall be provided Mechanical Access Facilities d) Addition: New Paragraph: Lifting Devices Ladders and cages shall be in accordance with PIP STF Addition: Supplement as Follows: Lug or eye design shall be based on a total load equal to twice the weight of the lift. Lifting lugs and side frames shall be designed for an impact factor of 1.5. If frame lugs cannot be used for lifting, Purchaser shall be notified in writing of the intended method of unit lift Addition: New Paragraph: A hoisting beam shall be provided in the plenum chamber to lower motors, fan shafts, fan blades, etc. The beam shall be designed to carry twice the weight of the heaviest component to be lifted. Addition: New Section: Section Grounding Lugs Each bay shall be provided with a grounding lug connection welded to the support in accordance with detail PIP VEFV Materials 8.1 General Modification: To Read as Follows: Cast iron shall not be used for pressure components for any service Addition: New Paragraph: Welding, forming, or other operation injurious to galvanizing shall not be performed after galvanizing. All connections required after galvanizing shall be bolted Addition: New Paragraph: Attachments welded to pressure retaining components shall be of the same nominal chemical composition as the component Addition: New Paragraph: Hardened washers shall be provided under nuts for all bolts having diameters of 32 mm (1 ¼ inches) or greater. The washers shall be 6 mm (¼ inch) thick minimum. 8.2 Requirements for Carbon Steel in Sour or Wet Hydrogen Sulfide Service Addition: New Paragraph: Materials for exchangers in hydrogen service shall be selected in accordance with API RP 941 using a value for the hydrogen partial pressure 10% greater than the design partial pressure and a temperature of 30 C (54 F) greater than the design metal temperature. Process Industry Practices Page 19 of 23

22 8.4 Louvers Modification: To Read as Follows: Steel louver blades, frames, and linkages shall be galvanized. If mill-galvanized material is used, all cut and punched edges shall be protected by a zinc-rich coating. 8.5 Other Components Addition: New Paragraph: Slide plates shall be stainless steel or PTFE. Carbon steel slide plates are not permitted. 9 Fabrication of Tube Bundle 9.1 Welding General Modification: To Read as Follows: Welding procedures and welders shall be qualified in accordance with the pressure design code. Welding shall be performed in accordance with the pressure design code. Welding procedures, qualifications, and weld maps shall be submitted to the Purchaser for approval before start of fabrication in accordance with paragraph Addition: New Paragraph: The layout of header plates shall be made in such a manner that nozzles and their reinforcement are not located within weld seam heat affected zones. 9.2 Post-Weld Heat Treatment Addition: New Paragraph: If PWHT is specified for process conditions, Code exemptions for PWHT are not permitted Addition: New Paragraph: Post-weld heat treatment shall follow all welding and repairs but shall be performed before hydrostatic testing or other load tests. 9.3 Tube-to-Tubesheet Joints Tube-Hole Grooving Addition: New Paragraph: Tube-hole grooves shall be in the base material and not in any applied cladding. 9.6 Alignment and Tolerances Addition: New Paragraph: For completely field or module yard assembled units, proper fit-up and match tolerance of the complete structure, including all components (e.g., columns, fan ring, and plenum), for each size provided shall be demonstrated before shipment. If all bays are fabricated using the same drilling templates and punch guides, the fit-up of only one unit of a multiple bay unit is required before shipment. Process Industry Practices Page 20 of 23

23 9.7 Assembly Addition: Supplement as Follows: Field assembled components shall be match marked. 10 Inspection, Examination and Testing 10.1 Quality Control Addition: New Paragraph: The edges of carbon steel and low-alloy steel plates equal to or greater than 25 mm (1 inch) thick shall be wet florescent magnetic particle tested for linear discontinuities. Defects shall not be greater than the limits shown in ASME SA-20. Plate edge laminations revealed by magnetic particle testing shall be completely removed and repaired Addition: New Paragraph: If full radiographic examination of the nozzle attachment weld is specified, the attachment details shall be in accordance with Code Section VIII, Division 1, Figures UW 16.1 type (f-1), (f-2), (f-3), or (f-4) only Addition: New Paragraph: Before final inspection and pressure testing, the inside and outside of exchangers shall be thoroughly cleaned of all slag, scale, dirt, grit, weld spatter, paint, oil, etc Addition: New Paragraph: Eddy-current testing of tubes shall be in accordance with ASME SA M Pressure Test Addition: Supplement as Follows: If specified by Purchaser, liquids other than water may be used for hydrostatic testing in accordance with the Code Addition: New Paragraph: Welded attachments provided with telltale holes shall be pneumatically tested at 100 kpa gauge (15 psig) before pressure testing an exchanger unit. Telltale holes shall not be plugged during pressure testing of an exchanger unit Shop Run-In Modification: To Read as Follows: For units that are shipped completely shop-assembled, a shop run-in test shall be performed for the driver, drive assembly, and fan for a period equal to or greater than 30 minutes. Louver operators shall be assembled, mounted, tested for free movement from full open to full closed, and then removed and packed for shipment Nameplates Modification: To Read as Follows: Nameplates shall be in accordance with PIP VEFV1101 with the bracket welded to the top of the header. Addition: New Section: Section Inspections Process Industry Practices Page 21 of 23

24 Purchaser s inspection and associated documentation requirements shall be in accordance with Purchaser s PIP VESAC001-T Inspection and Testing Requirements Sheet. See Annex F. If inspection by the Purchaser is specified in the contract documents, the Purchaser s Inspector shall contact the Manufacturer to schedule inspection visits. The Purchaser shall be notified five working days minimum before an inspection is scheduled A complete set of fabrication drawings reflecting all Purchaser s comments shall be provided to the Purchaser s Inspector at the time inspection activities are being performed If major components or services are obtained from sub-suppliers, the Purchaser s Inspector shall be notified and given the option of inspecting those items at their point of manufacture. The Manufacturer is responsible for including the Purchaser s quality surveillance and notification requirements in suborders. The Manufacturer is also responsible for arranging for certified drawings for use by the Purchaser s Inspector at the sub-supplier s location The Manufacturer retains overall responsibility for ensuring, either directly or through sub-suppliers, that the inspections required by Purchaser are performed. The performance of quality surveillance by the Purchaser s Inspector does not relieve the Manufacturer or sub-suppliers of responsibility for meeting the specification requirements. 11 Preparation for Shipment 11.1 General Addition: New Paragraph: Exposed fin tube sections shall be protected from mechanical damage during shipment and construction Addition: New Paragraph: Tell-tale holes shall be packed with grease Surfaces and Finishes Addition: Supplement as Follows: Except for surfaces of tubes and gasket contact surfaces, all exposed ferrous surfaces not otherwise coated shall be given one coat of the Manufacturer's standard shop primer before shipment Addition: New Paragraph: All PWHT exchangers shall have the following notice painted on two sides of the header and insulation covering, if present, in three-inch high letters visible in the shipping position from grade: POSTWELD HEAT TREATED - DO NOT BURN OR WELD Process Industry Practices Page 22 of 23

25 12 Supplemental Requirements 12.3 Examination Addition: Supplement as Follows: Examination and acceptance standards shall be in accordance with Code Section V, Specification SA-435. Annex A Recommended Practices A.3.3 Tubes and Finning Guidance to A Addition: New Paragraph: If specified, embedded finned tubes shall be subjected to a pull test, either before purchase or at time of inspection. If specified, a pull test shall consist of the following: a) One out of 100 tubes shall be tested at two points not less than 3 m (10 ft) apart. b) Fins shall be cut leaving a pie-shaped section embedded with a root length of about 12 mm (½ inch). c) The pie-shaped sections shall be clamped and a force of 22.5 N (5 lb-force) shall be applied slowly and held for one minute minimum to pass the test. d) The sections shall then be pulled out and the root lengths measured. If a root length is greater than 12 mm (½ inch), the force required to pull the fin out divided by the actual root length shall be greater than 3.53 N/mm (20 lbforce/in). e) If a tube fails either c) or d) above, the tube shall be subjected to a similar test not greater than 1 m (3 ft) away from the point that failed. If the tube passes the second pull test, the tube is considered acceptable. If the tube fails the second pull test, two pull tests shall be performed on another tube of the same lot of 100 tubes. If the second tube fails either of the two pull tests the lot of 100 tubes shall be rejected. Annex F Quality Overview Plan for Air-Cooled Heat Exchangers Addition: New Form: PIP VESAC001-T Inspection and Testing Requirements Sheet for Air-Cooled Heat Exchangers Process Industry Practices Page 23 of 23