Section 7 — Pressure Vessels

Pressure Vessels for Non-Process Service

IPE Engineering Practice IPE-EP-7-1-2

Document number: IPE-EP-7-1-2 · Section: 7 — Pressure Vessels

SCOPE

• This Practice covers basic requirements for documentation, design, materials, fabrication, inspection, testing and shipping of materials of NEW UNFIRED PRESSURE VESSELS AND SHELL AND TUBE, DOUBLE PIPE AND SPIRAL HEAT EXCHANGERS FOR NON- PROCESS SERVICES. In this Practice, the non-process services are air, water, nitrogen gas, lube and seal oil which satisfy the following criteria. Vessels not satisfying the criteria listed below shall be in accordance with the requirements of EP 7-1-1.
• A maximum design temperature of 650F.
• For lube and seal oil filers and coolers, a design pressure corresponding to a maximum ASME B16.5 flange rating of Class 1500. For all other non-process services, a design pressure corresponding to a ASME B16.5 flange rating of Class 300.
• A maximum vessel wall thickness of one inch.
• Materials used for pressure containing components shall be limited to carbon steel, austenitic or duplex stainless steel, or nickel based alloys.
• Vessel designs that do not have weld alloy strip lining, overlay or cladding.
• Vessel designs that do not have multiple chambers.
• Typical vessels covered by this specification include are air receivers and eliminators, filters, air and gas coolers or dryers, pressure pots for instrument systems, lube and seal oil coolers.
• Supplemental requirements for vessels including the data to be furnished by the Purchaser, the manufacturer's responsibility, documentation, marking, shipping and packaging are covered in EP 7-1-4.
• Any deviation from this practice must be approved by the procedure described in EP 1-1-3.
• An asterisk (*) indicates that a decision by the Owner's Engineer or Owner is required, or that additional information is to be furnished by the Purchaser.
• A revision bar indicates all changes made to this Revision.

2.0 REFERENCES

The latest edition of the following standards and publications are referred to herein.

STANDARDS AND PUBLICATIONS

STANDARDS AND PUBLICATIONS (cont.)

DEFINITIONS

• ASME Code - Refers to the ASME Boiler and Pressure Vessel Code, Section VIII, Division 1 or Division 2, as applicable.
• Contractor - Company or business that agrees to furnish materials or perform specified services at a specified price and/or rate to the Owner.
• Inspector - A IPE Engineering Company appointed engineer or inspector.
• Manufacturer - The recipient of a direct or indirect purchase order for materials and/or equipment. In this context, a direct order is one issued to a manufacturer by a contractor or the Owner. An indirect order is one issued to a manufacturer by a vendor (recipient of a direct order) for materials, fabricated components, or subassemblies.
• Owner – Inflection Point Engineering, LLC.
• Owner's Engineer - A IPE Company appointed engineer.
• Purchase Order - The contractual document given to the Manufacturer to authorize a purchase.
• Purchaser - The party placing a direct purchase order. The purchaser is the Owner's designated representative.

DATA SHEET AND DOCUMENTATION

• (*)The Pressure Vessel or Heat Exchanger Data Sheet (included in EP 7-1-1 DS or in

EP 8-1-1 DS,EP 8-1-5 DS, or EP 8-1-6 DS, as applicable) shall be completed along with a vessel outline drawing by the Owner's Engineer showing the vessel design data, dimensions, schedule of openings, notes and all other requirements necessary to prepare the design and vessel fabrication drawings. The Manufacturer shall use this information to supply with his quotation a completed vessel data sheet containing all the relevant information necessary for appraisal of the mechanical design by the Purchaser.

• Supplemental requirements including documentation for pressure vessels and heat exchangers are stipulated in EP 7-1-4.

5.0 QUALITY ASSURANCE

The Manufacturer shall have as part of his usual business practice an established quality control system. In addition, a quality control plan shall be developed for the manufacture of a new pressure vessel or heat exchanger to insure that all technical requirements are followed. Requirements for this quality control plan are covered in EP 7-1-4.

MATERIALS

• General
• (*)Unless otherwise specified by the Owner's Engineer, materials for pressure vessel construction shall be in accordance with Table 1 of EP 7-1-1. Materials of construction for all vessel components shall be specified by the Owner's Engineer and indicated on the Pressure Vessel Data Sheet, see EP 7-1-1 DS.
• The use of reclaimed materials is prohibited.
• (*)Material substitutions shall not be made without written approval from the Owner's Engineer.
• Material toughness requirements at the specified minimum design temperatures shall be per the ASME Code.
• (*)The use of castings for pressure vessel components shall be limited to return housings for double pipe and multi-tube heat exchangers. The use of castings for other pressure vessel components requires approval of the Owner's Engineer.
• Materials for vessel supports, structural attachments, appurtenances, and lifting lugs shall be in accordance with EP 7-1-7.
• Material Inspection and Testing

Material testing and inspection shall be per manufacturer's standard but shall meet the minimum requirements of the ASME Code.

DESIGN

• Code and Jurisdictional Requirements

• (*)Vessels and their components shall be designed, fabricated, inspected, tested and stamped in accordance with the ASME Boiler and Pressure Vessel Code, Section VIII, Division 1, latest revision, including all addenda officially issued by the ASME as of the date of purchase order award and the requirements of this practice. In addition, all other requirements of local jurisdictions and the Department of Labor, Occupational Safety Health Standards (OSHA) shall be satisfied. All discrepancies between these requirements shall be brought to the attention of the Owner's Engineer for resolution.
• The Manufacturer shall assign and stamp a National Board Registration Number on all vessels manufactured and stamped to the ASME Code.
• In relation to the geometry of pressure containing parts, the scope of the ASME Code shall include all components within the following boundaries. Only these components shall be listed on the ASME Code U-1 (A-1) Form.
• Where external piping is to be connected to the vessel:
• The welding end connection for the first circumferential joint for welded end connections.
• The first threaded joint for screwed connections.
• The face of the first flange for bolted, flanged connections.
• The first sealing surface for proprietary connections or fittings.
• Where non-pressure parts are welded directly to either the internal or external surface of the pressure vessel, the weld attaching the part to the vessel.
• Pressure retaining covers for vessel openings (manhole covers).
• The first sealing surface for proprietary fittings or components for which design rules are not provided by the ASME Code (e.g., pressure gages, instruments, nonmetallic components).

7.2 Design Conditions

7.2.1 (*)Design conditions and minimum design metal temperature (MDMT) shall be in accordance with Section 7.2 of EP 7-1-1. The design conditions and MDMT shall be specified on the Data Sheet of EP 7-1-1 DS, EP 8-1-1 DS, EP 8-1-5 DS, or EP 8-1-6 DS as applicable, by the Owner's Engineer.

• Load Conditions and Combinations

The load conditions and combinations shall be in accordance with Paragraph UG-22 of the ASME Code.

• Component Thickness and Stress Analysis Requirements
• The thickness of all vessel components shall be established based on the design loads and load case combinations stipulated in paragraph 7.3 and the design requirements of the ASME Code.
• All horizontal drums and heat exchangers with a D/t ratio of 100 or greater, on saddle supports shall be investigated for buckling, local circumferential bending and shear stresses. The method of L.P. Zick shall be used for this investigation.
• Corrosion Allowance
• (*)Unless otherwise specified by the Owner's Engineer, the minimum corrosion allowance for all vessels shall be per Table 1.
• (*)Unless otherwise specified by the Owner's Engineer, the corrosion allowance shall not be applied to flange gasket faces.

• Shells, Heads, Transitions and Stiffening Rings
• All heads shall conform with the ASME Code requirements and with additional requirements listed below:
• All heads shall preferably be of one-piece construction.
• Ellipsoidal heads shall have a ratio of the inside major axis to the inside minor axis of 2:1.
• The minimum thickness of vessel shells and heads, not including corrosion allowance, shall be 1/4 inch.
• For jacketed vessels, both the vessel and jacket shall be designed in accordance with this Practice and the ASME Code regardless of the design pressure. No credit for pressure or vacuum in the jacket shall be taken to reduce the pressure for which the vessel is to be designed.
• (*)The use and design of flexible shell elements (i.e., an expansion joint in the shell of a TEMA type BEM heat exchanger) are subject to the approval of the Owner's Engineer.
• Nozzles
• (*)Nozzles for process connections and pressure relief valves shall be specified by the Owner's Engineer. In this Practice, the term "nozzle" is used to encompass process connections, vents, boots, manways, or any other pressure vessel openings. Supplemental requirements for manways, handholes, instrument connections, drains, vents and steamout connections are covered in paragraph 7.9.
• (*)Connections shall be flanged using a minimum nozzle size of NPS 1 inch. Full couplings may be used for connection size NPS 3/4 inch. If threaded couplings are used, seal welding requirements shall be provided by the Owner's Engineer. Nozzle sizes of NPS 1-1/4, 2-1/2, 3- 1/2 and 5 inches shall not be used.
• The nozzle and reinforcing pad, if required, shall be fabricated from a material with the same P- Number as the vessel shell to which they are attached.
• Nozzle necks shall be made from forgings, from seamless pipe or from rolled plate using full penetration welds. The bore of weld neck flanges and the nozzle necks for which they are attached shall be the same.
• The minimum nozzle wall thickness shall be per Table 2.
• (*)Unless otherwise specified by the Owner's Engineer, all nozzles not directly connected to internals shall be flush with the inside surface of the vessel wall.
• Reinforcing pads shall be provided with a NPT 1/4 inch ventilation hole to permit an air-leakage test of the attachment welds. The ventilation holes shall be left open during welding, and for post-weld heat treatment. Where a reinforcing pad consist of two or more plates welded together after fitting to the vessel, a ventilation hole shall be provided for each sealed section. Where vessels are insulated for hot service, the ventilation holes shall be fitted with vent lines projecting beyond the surface of the insulation. Where vessels are insulated for cold service, vent lines shall not be fitted.

• (*)Unless otherwise specified by the Owner's Engineer, nozzles NPS 12 inches and smaller shall have a minimum projection of 8 inches, whereas nozzles NPS 14 inches and larger shall have a minimum projection of 10 inches (all measured on the short side). However, nozzle projection shall be increased as necessary to permit stud removal from the back-side of the flange without interference from the insulation. All flanged connections shall be dimensioned from the centerline of the vessel to the extreme face of the flange on the fabricator's drawing.
• Nozzles adjacent to shell girth flanges or horizontal vessel saddles shall be located with adequate clearance such that bolt tightening equipment can be used on the girth flange bolts. Adequate clearance in the form of additional saddle height shall be proved such that bolts between connecting nozzles of stacked heat exchangers can be removed without moving the heat exchangers.
• Nozzle Flanges
• The nozzle flange shall be fabricated from a material with the same P-Number as the nozzle neck to which it is attached.
• All nozzle flanges shall be designed for through bolting. Additional requirements for flange rating, facing, gasketing and bolting shall be in accordance with EP 5-2-2.
• Manways and Instrument Connections
• Design requirements for manways, handholes and instrument connections shall conform to the requirements of Sections 7.7 and 7.8.
• For vessels, excluding heat exchangers, with an inside diameter of less than 36 inches, handholes or flanged heads or both shall be provided as follows.
• (*)When personnel access is not mandatory, manways are not required. However, an adequate number of inspection openings shall be provided. These may be NPS 8 inch or larger nozzles that are required for piping, etc. or 8-inch minimum inside diameter handholes. For vessels with an inside diameter less than NPS 24 inches, inspection openings shall be specified by the Owner's Engineer.
• When personnel access is mandatory, it shall be provided by manways or flanged vessel sections.
• Vessels, excluding heat exchangers, with an inside diameter of 36 inches and larger shall have at least one manway. Additional manways shall be provided as required to permit access to internals such as entrainment screens, filter beds, etc.
• (*) All manway blind flanges shall be furnished with davits in accordance with EP 7-1-7.

Hinged manway covers may be substituted for vertical manway covers based on approval of the Owner's Engineer.

• The minimum inside diameter for manways shall be large enough to permit entry and exit of personnel wearing fresh air equipment, and personnel safety baskets. In no case shall the inside diameter be less than 20 inches.
• (*)Unless otherwise specified by the Owner's Engineer, connections for internal-displacement liquid level devices shall be NPS 4 inch, with ASME/ANSI class 300 flanges minimum. A NPS 4 inch stilling well shall be provided for the float.
• (*)Unless otherwise specified by the Owner's Engineer, connections for external-displacement liquid level devices shall be NPS 2 inch, with ASME/ANSI Class 300 flanges minimum.

• Vents, Drains, and Steamout Connections
• Design requirements for vents, drains, and steamout connections shall conform to the requirements of Sections 7.7 and 7.8.
• Adequate nozzles and/or manholes shall be provided to meet all venting requirements (including OSHA) for gas freeing vessels and ventilation for mechanical work such as welding or burning. Manways for horizontal drums, and bottom manways on the side of vertical vessels shall be located as near to the vessel tangent line as practicable (without encroaching on knuckle area) to facilitate ventilation of vessels. A minimum of one NPS 6 inch opening shall be provided at or near the highest point of all vessel compartments that have manways. The vent(s) may be another manway or a flanged process nozzle which can be disconnected at the vessel, provided the adjacent piping contains a break out spool. On horizontal vessels, the vent(s) and access manway shall be on opposite ends of the vessel.
• Requirements for vents, drains and steamout connections for vessels, excluding heat exchangers, are shown in Table 3. Vents shall be located at the highest point at one end of each compartment. Steamout connections(s) shall be located at the end opposite the vent in horizontal vessels, and near the bottom of vertical vessels. The steamout connection shall be independent of the drain from the vessel and shall be provided with a blind for positive isolation.

• Vents and drains for heat exchangers shall be per Table 4.
• Flanged Shell Girth Joints
• Girth flanges shall be designed per the ASME Code and shall satisfy the following requirements:
• Girth flanges shall be fabricated from a material with the same P-Number as the shell to which they are attached.
• Girth flanges shall be designed for through-bolting. All flanges, excluding blind flanges, shall have a weldneck configuration.
• The gasket contact surface shall be in accordance with EP 5-2-2. The allowable flatness tolerances of gasket contact surfaces, after PWHT if required, shall be as shown in Table 5 designated service condition.
• For tongue and groove type joint construction (peripheral gasket confined on OD):
• When a tongue and groove design is used for main body flange, the tongue shall be on the removable vessel section.
• The clearance between flanges after assembly shall be not less than 3/16 inch. This clearance shall extend from the periphery of the flange to within the bolt circle.
• (*)Nubbins shall not be used unless approved by Owner's Engineer. If provided, nubbins shall be located on the female (grooved) flange.
• Girth flanges designed with spiral wound gaskets shall include provisions to prevent over- compression of the gasket.
• (*)Unless otherwise approved by the Owner's Engineer, girth flange gaskets shall be solid flat metal, metal jacketed or spiral wound, and shall be in accordance with EP 5-2-2.
• Girth flange bolting shall satisfy the following requirements:
• Girth flange bolting shall be per EP 5-2-2, except that the bolt material specifications shall be in accordance with the ASME Code, Section II.

• The maximum and minimum bolt spacing for vessel girth flanges shall be TEMA paragraph RCB-11.2.
• Vessels Supports, Structural Attachments and Lifting Lugs
• Vessels shall be designed to be self-supporting. The type and location of vessel supports shall be as specified on vessel drawing(s). The supports shall be continuously welded to the vessel.
• Requirements of non-mandatory Appendix G of the ASME Code shall be regarded as mandatory.
• Vessel-supports, structural attachments, and lifting lugs attached directly to the vessel shall be fabricated from a material with the same P-Number as the vessel to which they are attached.
• (*)The number and size of anchor bolts required shall be as shown on vessel drawing(s). Unless otherwise specified by the Owner's Engineer, anchor bolts shall be designed in accordance with Section 5.0 of EP 4-2-3.
• (*)Support skirts for vertical vessels shall be in accordance with EP 7-1-7. Skirts that exceed 3/4 inch thickness at their point of attachment shall be in accordance with EP 7-1-3. Details of the skirt to vessel weld shall be shown on the vessel drawings and shall be subject to approval by Owner's Engineer.
• Leg supports shall be in accordance with EP 7-1-7.
• Saddle supports for horizontal vessels and heat exchangers shall be in accordance with EP 7- 1-7. Saddle supports shall not be attached to vessel girth flanges.
• Wearplates and reinforcing pads for internal or external structural attachments to vessels hells shall be provided with a 1/4 inch diameter vent hole for the enclosed space between welds. External vent holes shall be vented per paragraph 7.7.7.
• (*)Lifting lugs shall be provided for all shop-fabricated vertical vessels and shall be in accordance with EP 7-1-7. Use of vessel tailing lugs is subject to approval by the Owner's Engineer. The design of tailing lugs shall be in accordance with EP 7-1-7. A minimum factor of safety of 1.5 applied to the maximum permissible load shall be used to design all lifting lugs. The location and type of lifting lugs attached to the vessel shall be subject to approval by the Owner's Engineer and the erection contractor.
• Lifting lugs shall be provided for all removable heads and covers such as shell and tube exchanger channel, shell and floating head covers and spiral exchanger end covers. These lugs shall be located vertically above the cover centroid and shall be designed to support twice the dead load. The lugs shall have an opening not less than 2 inches in diameter.
• The design of supports shall be arranged to ensure that the temperature of any supporting concrete will not exceed 100F. For low temperature vessels, this temperature shall be such that no condensation will occur under normal operating conditions. The mechanical design should provide for insulation sealing, adequate surface protection and prevention of condensate-collecting areas.
• Vessel Internals

(*)Vessel internals shall be per Manufacturer's standard and subject to the approval of the Owner's Engineer. Recommended materials, corrosion allowances and design are given in EP 7-2-1.

• Insulation, Refractory and Fireproofing
• Insulation for pressure vessels shall be designed per EP 11-3-1. Installation requirements for insulation are covered in EP 11-3-3.
• Design and installation of vessel fireproofing shall be in accordance with EP 11-2-1.
• Vessel attachments required for support of insulation and fireproofing shall be supplied and installed by the vessel manufacturer. Materials for refractory anchors are covered in EP 11-1-
• Materials for insulation and fireproofing supports shall be as follows:
• Support clips welded to the vessel shall be fabricated from the same material as the vessel.

• Insulation support ring materials shall be as follows:
• Carbon steel for carbon steel vessels.
• Austenitic stainless steel for all other cases.
• (*)Installation of insulation, refractory and fireproofing shall be by others, unless otherwise noted by the Owner's Engineer on the vessel drawing(s) or in the applicable specifications.
• Vessel Appurtenances
• Davits shall be provided for handling equipment weighing more than 150 lbs., such as safety valves and manway covers, which are subject to periodic removal for repair, replacement, or for access purpose. Davit designs shall be in accordance with EP 7-1-7. The davits shall be designed to swing equipment clear of the vessel to facilitate lowering to grade. Davit supports welded to the vessel shall be designed to minimize localized stresses at the attachment point.
• Use of hinged, manway cover designs for vertical manway covers shall be subject to approval

of the Owner's Engineer. Hinged manway cover designs shall be in accordance with EP 7-1-7.

FABRICATION

• General
• (*)Fabrication shall be in accordance with the ASME Code and the additional requirements of this Practice. In case of conflict among these requirements, the most stringent requirements, as determined by the Owner's Engineer, shall govern.
• (*)Written approval shall be obtained from the Owner's Engineer before any welding, preparation for welding fabrication, or forming, including bending and rolling, is subcontracted to another shop or supplier.
• When this Practice or an ASME Specification requires normalized plate, the manufacturer shall not destroy the normalized properties of the plate during fabrication.
• Welding
• Welding of pressure vessels shall be per this Practice and EP 7-1-5.

• Full penetration double butt welds are required for all shell and head seams, except small diameter vessels or closing seams that are not accessible from the backside. Closing seams that require welding from one side only shall have the root pass deposited with the GTAW or GMAW process. All double welded groove joints shall be backgouged to clean metal and inspected per paragraph 9.4.4.
• All nozzles shall be attached to the vessel with full penetration welds. The inside circumference of reinforcing pads shall be attached to the vessel and nozzle using full penetration welds. All required welding details shall be in accordance with the ASME Code.
• All skirt butt welds shall be full penetration. Skirt attachment welds to the vessel and the base ring, and all other attachment welds shall be continuous and have complete fusion for the full length of the weld. In addition, these welds shall be free from unacceptable undercut, overlap, or abrupt ridges or valleys. Attachment welds may be submerged arc welded provided that the first pass is made with the shielded metal arc process.
• Arc strikes on the pressure shell shall be minimized. When they occur, the surface shall be properly conditioned to eliminate surface stress concentrations. Such surfaces shall be examined in accordance with paragraph 9.4.5. Any defects found shall be removed and the surface repaired or reexamined.
• Forming of Vessel Components
• When a difference in thickness exists between shell sections or shells and heads, the inside surface shall be aligned.
• Welds subject to severe working shall be inspected per paragraph 9.2.2.
• The maximum allowable gap between nozzle reinforcing pads and the curvature of the shell to which they are attached shall not exceed 1/8 inch.
• Forgings
• Forgings shall be per Manufacturer's standard.
• Heat Treatment
• (*)Carbon steel vessels shall be post-weld heat treated (PWHT) when required by the ASME Code or when specified by the Owner's Engineer. PWHT shall be in accordance with EP 7-1- 5.
• (*)All heat treatment to be performed on the vessel, including intermediate and final post weld treatment temperatures and times shall be submitted to the Owner's Engineer for approval before starting fabrication.
• On vessels to be postweld heat treated, lifting attachments, insulation support clips, as well as all other external shell attachments shall be welded to the vessel before the final heat treatment. The PWHT sequence for ferritic vessels with welded ferritic internal attachments shall be complete welding of attachments to shell, followed by PWHT.
• (*)Local postweld heat treatment shall not be performed without advance written approval from the Owner's Engineer.
• (*)The proposed postweld heat treatment for welds between ferritic and austenitic steels shall be reviewed by the Owner's Engineer.

• (*)Temperatures during furnace post weld heat treatment (PWHT) shall be recorded using thermocouples attached to the vessel. At least one thermocouple is required for each head and one for each shell course randomly distributed around the circumference. Vessels larger than 144 inches nominal diameter shall have at least two thermocouples for each shell course. Additional thermocouples are required for field or localized PWHT. The number and location of these thermocouples shall be subject to the approval of the Owner's Engineer.
• Machined surfaces and flange facings shall be protected against oxidation and scaling during heat treatment.
• Carbon steel plate, seamless heads, parts of built-up heads, and similar pressure retaining parts subjected to cold or hot bending and forming shall be heat treated as follows:
• As required by the applicable code and the applicable material specification.
• If the material temperature at the completion of forming is within that temperature range that would be utilized for normalizing of the material in question, then this may be considered as an acceptable normalizing treatment.
• Where the code or specification requires normalizing, the hot-formed parts which do not meet the requirements of subparagraph (b) above, shall be normalized after forming.
• Plate material which is formed at less than 1100F shall be heat treated when the resulting extreme fiber elongation is more than 5% from the as-rolled condition. The extreme fiber elongation shall be computed using the formula in paragraph USC-79 of the ASME Code.
• Nameplate
• All vessels shall be furnished with a stainless steel nameplate. Required markings shall not be stamped directly on the vessel. Nameplates shall be installed on the Manufacturer's standard nameplate holder of sufficient length to project at least 1 inch beyond the vessel insulation or fireproofing, as applicable. The letters and figures shall be at least 5/32 inch high. A drawing of the nameplate shall be included in the Manufacturer's vessel drawings.
• The nameplates of vertical vessels shall be located on the shell above the lowest manhole. On horizontal vessels, they shall be located in the center of a head or above a manhole in a head. The nameplate location shall be shown on the Manufacturer's drawings.
• Dimensional Tolerances
• Dimensional tolerances shall be per the Manufacturer's standard.
• Vessels that will contain cartridge or pedestal tray assemblies shall be check with a template to ensure that the assemblies can be inserted and withdrawn without interference or binding. The diameter of the template shall be no smaller than the specified inside diameter of the vessel minus 1/4 inch.

INSPECTION AND TESTING

• General
• (*)Inspection and testing shall be in accordance with the ASME Code and the requirements of this Practice. In case of conflict among the requirements of these documents, the most stringent requirements, as determined by the Owner's Engineer, shall govern.

• Fabrication drawings of the vessel shall be available to the inspector at the time of the inspection. Surfaces shall not be painted nor the vessel shipped until the Owner's inspection is complete. In addition to any required code inspection, all materials, fabrication and methods of shipping shall be subject to inspection by the Inspector. Rejections by the Inspector are final. The inspection does not relieve the Manufacturer of his responsibility for complying with this Practice.
• Prior to final inspection and hydrostatic test, the inside and outside of the vessel shall be thoroughly cleaned and shall be free from all slag, scale, dirt, grit, weld splatter and pieces of metal, paint, oil, etc. All welds shall be free of slag, oil, grease, paint and other foreign substances which might prevent proper interpretation of the required tests.
• Positive Materials Identification (PMI) shall be in accordance with EP 15-1-4.
• The Manufacturer shall submit for Purchaser's approval, a detailed plan of applicable examinations and tests required for the individual components and weldments of each vessel.
• The responsibility for examination rests with the Manufacturer. However, the Purchaser shall at all times have access to the shop of any Manufacturer engaged in supplying material or in fabricating the vessel for the purpose of inspecting and, if necessary, rejecting such material and work which does not meet with the applicable requirements of this Practice.
• (*) "Dead space" in a vessel shall not be closed off until the inspector has had an opportunity to inspect the area and give his approval.
• Radiographic Examination
• All vessels constructed to the ASME Code, Section VIII, Division 1, shall be spot radiographed unless full radiography is required by the Code or is stipulated on the Vessel Data Sheet.
• All welds, including weld repairs, placed in any part (regardless of the materials, thickness or service) before the part is subjected to severe working (ratio of thickness to local radius greater than 5 percent) by any means (including spinning, pressing and rolling) shall be given a complete radiographic and either magnetic particle or liquid penetrant examination after the completion of the severe working and before further fabrication is performed.
• Manual "stringer bead" or irregular surface welds shall be flat-topped prior to radiography to remove surface ripples which may obscure internal indications.
• Radiographs disclosing defects shall be followed by tracer radiographs until the extent of the defect is determined, or the entire weld shall be removed and rewelded. All tracer radiographs and subsequent weld repair shall be at the contractor's expense.
• All repair films and the corresponding original films of defective welds shall be retained for review by the Inspector.
• Ultrasonic Examination

Ultrasonic (UT) examination shall be per Manufacturer's standard.

• Magnetic Particle and Liquid Penetrant Examination
• Magnetic particle examination (MT) and acceptable criteria shall be per the ASME Code Appendix 6.

• Liquid penetrant examination (PT) and acceptable criteria shall be per the ASME Code Appendix 8.
• For examination of magnetic materials, either the MT or PT method may be used. For non- magnetic materials, the PT method shall be used for all examinations.
• All welds made from two sides, i.e. back welded or double welded groove joints, shall be backgouged to clean metal and MT or PT inspected before welding of the second side.
• The following welds and areas of vessels shall be inspected as indicated using the magnetic particle method or liquid penetrant method. Any defects found shall be repaired in accordance with the procedures of Section 10.0.
• The attachment welds of all vessel lifting lugs.
• All attachment welds for reinforcing pads and vessel internal and external attachments (e.g., tray support rings, insulation clips, platform clips, etc.)
• All areas on the vessel subject to arc strikes.
• The skirt to shell weld; examination shall be before and after hydrotest.
• Welds subject to severe working, see paragraph 9.2.2.

REJECTION AND REPAIR

• Defects that are outside the limits of the codes, project specifications, or other requirements stated on the Purchase Order shall be cause for rejection. The Contractor or Manufacturer shall take such remedial action as is necessary to secure acceptance. The cost of the remedial action shall be defrayed by the Contractor or Manufacturer.
• (*)Repairs of major defects and all repairs in plate or forgings require prior approval by the Owner's Engineer. Repairs of weld defects are considered major when the defect size exceeds 3/8 inch in depth or one-half the wall thickness of the component, whichever is less; or when the defect resulted in leakage during a hydrostatic test. The repair procedure shall be in writing and shall include information on methods used for defect removal, inspection of cavity, welding procedures, post weld heat treatment (if required for original) and details of non-destructive examination of the repaired area.
• (*)All welds that are found by inspection to be unsound, or that are deposited by procedures differing from those properly qualified, shall be rejected. They shall be completely removed from the equipment and replaced in accordance with approved procedure or shall be repaired subject to approval by the Owner's Engineer.
• Removal of defects by chipping, grinding or gouging shall be done in such a manner as to avoid reducing the adjacent base material thickness. If the adjacent material thickness is reduced below acceptable limits, it shall be restored to its original design condition. complete removal of defects shall be verified by nondestructive examination before repair is started. Repair welding shall be performed only by qualified welders using qualified procedures, see EP 7-1-5.

PRESSURE TEST REQUIREMENTS AND NOZZLE PAD TESTING

• All ASME Code stamped vessels shall be hydrostatically pressure tested in accordance with provisions of the ASME Code and this Practice.
• The Vessel Manufacturer shall take all necessary precautions to avoid brittle fracture of vessels during the pressure test. The minimum vessel metal temperature shall be 30F above the specified minimum design temperature MDMT or 60 °F, whichever is higher. Only water shall be used for hydrostatic testing. Heating of the vessel wall by direct flame impingement to increase the water temperature is strictly prohibited. It is the primary responsibility of the vessel Manufacturer to avoid brittle fracture of vessels, and the vessel manufacturer shall note that the hydrotest temperatures discussed above are minimum required values.
• To prevent chloride stress cracking, vessels fabricated, lined or welded with austenitic stainless steels, e.g., AISI Type 300 Series, shall be tested with water that has a maximum chloride content not exceeding 50 ppm. In addition, maximum vessel metal temperature during test shall not exceed 120F. The vessel shall be drained immediately after testing until all standing water is removed and then dried by blowing air through the vessel.
• The test pressure shall be maintained for a minimum of one hour per inch of thickness. A minimum of two test gauges shall be provided for testing of vessels.
• Vessels with linings which may be damaged by water shall be hydrostatically tested prior to installation of such linings. Alternatively, a pneumatic test may be used, see paragraph 11.12 of EP 7-1-1.
• If a shop tested vessel is damaged during shipment, the vessel shall be retested to at least the shop test pressure after repairs, if the Owner's Engineer judges that the nature of the repairs so warrant.
• All pressure tests shall be made in the presence of the Inspector and with his approval. Vessels shall not have been previously tested by the vessel Manufacturer prior to this witnessed hydrotest.
• The gaskets, joint rings and bolting, used on all flanged connections during pressure testing shall be of identical material and dimensions as those specified for the operating duty unless otherwise approved by the Owner's Engineer. Following the pressure test, if flanged connections are opened for access, the gaskets used during the hydrotest shall be replaced with new service gaskets. This requirement only applies to gaskets that are being furnished to the Owner by the Manufacturer.
• Each nozzle and structural reinforcing pad or each segment there of shall be tested at 15 psig with dry air and a soap solution before hydrotest.

PAINTING AND INTERNAL LININGS

• Vessels shall be painted in accordance with EP 10-3-1. Machined surfaces shall not be painted.
• Internal linings, if specified by the Owner's Engineer, shall be per EP 10-3-7.

• (*) Austenitic alloy steel and nickel-iron-chromium alloy material parts with design metal temperatures above 750 F shall be kept free of paint to avoid the possibility of corrosion at elevated operating temperatures. All traces of paint that accidentally spatter on such parts shall be promptly removed. These vessels may require painting with special paints, when specified by the Purchaser.

13.0 ERECTION PLANS AND DRAWINGS

Erection plans and drawings shall be per Manufacturer's standard.

14.0 TABLES

TABLE 1

MINIMUM VESSEL CORROSION ALLOWANCE

TABLE 2

MINIMUM NOZZLE THICKNESS

TABLE 3

VENTS, DRAINS AND STEAMOUT CONNECTIONS FOR VESSELS

NOTES:

(1) Vent size shown is minimum for operation. If a vent is required per the criteria of paragraph 7.10.2, this connection may be used to satisfy venting requirements for operation.

TABLE 4 REQUIREMENTS FOR VENTS AND DRAINS

FOR HEAT EXCHANGERS IN NON-PROCESS SERVICES

TABLE 5

FLATNESS TOLERANCES OF GASKET CONTACT SURFACE

NOTES:

(1) The total tolerance on the peripheral gasket contact surface shall not occur in less than a 20 degree arc.

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