Third Party Inspection for Fin Tube Heat Exchanger

The Third Party Inspection for Fin Tube Heat Exchanger article provides you with information about fin tube heat exchangers inspection or air-cooled heat exchanger inspection in a manufacturing shop.

You may need to review this article in conjunction with the following articles:

Fin Tube Heat Exchanger Inspection

Inspection and Test Plan for Fin Tube Heat Exchanger

This content guides you through all the necessary stages in the production of the fin tube heat exchanger, including the raw material, final inspection, preservation and packing, and dispatch to site.

You need to take this point into account: this article is written for a typical fin tube heat exchanger and might not be detailed for special cases.

This content may be useful for second party inspectors, fin tube heat exchanger manufacturer quality control personnel, engineering companies, and purchasers, as well.

All fin tube heat exchanger inspection and testing is done against the approved drawings, purchase order specifications, purchasers or company standards, and within the practices and rules of the country, state or province and any government decrees, laws, ordinance or regulation as may apply.

.The applicable codes and specifications for a fin tube heat exchanger that is under the construction process is:

  • Design code
  • Purchase order specification
  • Purchaser's standards
  • Approved drawings

And the applicable codes and standard are:

  • ASME VIII Division 1 or 2
  • API 661
  • ASME V
  • ASME IX

The applicable codes and standard may be based other international standards, etc. This content is general and can be useful if even the design code is different from ASME and API Code.

Required Documents for Third Party Inspector Review:

The list of documents normally is agreed upon in the Pre-Inspection meeting, which is held several weeks before the actual commencement of the inspection work.

The parties that participate in this meeting are the manufacturer, purchaser and third party inspection agency representatives.

This already explained in the Inspection and Test Plan for fin tube heat exchanger article.

These are the list of documents which are normally agreed to be presented to the inspector:

  • Fin Tube Heat Exchanger Manufacture Quality Control Plan
  • Fin Tube Heat Exchanger Inspection and Test plan
  • Fin Tube Heat Exchanger Data Sheet
  • Fin Tube Heat Exchanger Approved Drawings
  • Fin Tube Heat Exchanger Strength Calculation Sheets
  • Fin Tube Heat Exchanger Material Test Reports
  • Fin Tube Heat Exchanger Test Data for Fans, Fan Motors, Gearboxes etc.
  • Fin Tube Heat Exchanger Welding Specification Procedures (WPS) and Procedure Qualification Records(PQR)
  • Fin Tube Heat Exchanger Welding Map
  • Fin Tube Heat Exchanger Welders Qualifications Reports
  • Fin Tube Heat Exchanger NDE procedures (Radiography, Ultrasonic, Magnetic Particle, Dye Penetration, etc.)
  • Fin Tube Heat Exchanger NDE Personnel Qualifications Reports
  • Fin Tube Heat Exchanger Heat Treatment Procedure
  • Fin Tube Heat Exchanger Calibration Certificates for Test Equipment
  • Fin Tube Heat Exchanger Hydrostatic Testing Procedure and Water Quality Document
  • Fin Tube Heat Exchanger Preparation and Painting Procedure
  • Fin Tube Heat Exchanger Preservation, Packing and Shipping Procedure
  • Fin Tube Heat Exchanger Packing List

Third Party Inspection for Fin Tube Heat Exchanger - Material Inspection

The first actual inspection work on the fin tube heat exchanger is the raw materials inspection. Based on the ASME Code, providing material test reports for fin tube heat exchanger plates is mandatory. For other components, the marking inspection will be enough.

But if the purchase order has mandated the MTR to be provided for all components, such as nozzle pipes, fittings, etc., then the manufacturer needs to provide them as well.

For more details, you may review the the Pressure Vessel Plate article.


As mentioned above, the original or authenticated copies of mill certificates for plates normally are available at the manufacturer's premises.

The third party inspector examines these certificates for compliance with specifications, and where appropriate, drawings.

The review includes checks on:

  • Certificate No.
  • Heat or cast No.
  • Chemical composition.
  • Mechanical properties.
  • Heat treated condition.
  • NDE applied and results.

Then the inspector witnesses the plate material identification on the certificates against the plate marking. It is also necessary to check the identification with the fin tube heat exchanger drawing datasheet, material list and other specifications as appropriate.

The transfer identification to cut off plates also is checked.

Visual inspections for surface finish and probable defects are done and dimensional compliance with specification also needs to be controlled.

Structural support, pass partition, stiffener, plug, Louvre blade pivot pins, Louvre bearings,

Steel louver blades and frames, fin, Fan blades, Plenums, fan decks, partitions, platforms and fan rings and Metal gasket materials are selected and inspected based of requirements of API 661 Clause 8.

When the third party inspector carries out the material inspection, then provides the inspection visit report (IVR), the report contains the following items:

  • Confirmation of satisfactory document review
  • Record of the endorsement of certification reviewed/witnessed
  • Record of all non-conformities
  • Record of any tests witnessed and the result

Third Party Inspection for Fin Tube Heat Exchanger - Fabrication

When the fin tube heat exchanger raw material inspection is carried out, and the results were satisfactory or non-conformities were closed by remedial action, then the fin tube heat exchanger manufacturer will start fabrication.

The third party inspector checks the following points on the fin tube heat exchanger based on the inspection and test plan (ITP), which has already been agreed upon between the purchaser and the fin tube heat exchanger manufacturer.

The inspection scope is determined in the ITP. Some purchasers prefer to have stringent controls and assign the TPI for more “hold or witness points” for inspection and test activities, and some others prefer less “hold or witness points” and assign the TPI much more work in the “review document.”

This depends in the inspection budget, which purchasers assign for inspection. Much more inspection will have a much larger cost and less risk, and conversely, less inspection will have less cost but more risks.

For more detail, review the Inspection and Test Plan for fin tube heat exchanger article. There is a draft of the ITP in this article, which we believe is the best practice for fin tube heat exchanger inspection.

Third Party Inspection for Fin Tube Heat Exchanger - Preparation for Welding:

The third party inspector carries out the visual and dimensional check to ensure compliance with WPS and other specifications. Where specified, weld bevels are examined by the required code method after grinding/machining.

It is necessary that the edges and weld bevels are clean, dry and free from surface defects, laminations, cracks, voids, notches, etc.

They are causes for rejection unless suitable/satisfactory remedial action can be taken.

Weld repairs are carried out in accordance with the code requirements and approved by the client before welding proceeds and serious or excessive defects normally are reported.

Fabrication tolerances and requirement are controlled as per API 661 Clause 9.

If the third party inspector is not in the hold or witness point in the ITP for this inspection stage, then he/she will review the fin tube heat exchanger manufacturer quality control report in his/her coming visit or on the final inspection day.

Third Party Inspection for Fin Tube Heat Exchanger - Fit-Up Inspection

Shapes and dimensions are checked in accordance with the approved WPS and drawing.

Tack welds are produced using the applicable WPS conditions, and it is necessary to be visually free from defects.

Magnetic Testing (MT) or Penetration Testing (PT) may be performed in accordance with the code requirement.

Similarly, If the third party inspector is not in the hold or witness point in the ITP for this inspection stage, then he/she will review the fin tube heat exchanger manufacturer quality control report in his/her coming visit or on the final inspection day.

Third Party Inspection for Fin Tube Heat Exchanger - Monitoring of Weld Conditions

The third party inspector controls preheat heat temperature and method, interpass temperatures, weld material control, welder and process qualifications for conformity to the code requirements.

Similarly, If the third party inspector is not in the hold or witness point in the ITP for this inspection stage, then he/she will review the fin tube heat exchanger manufacturer quality control report in his/her coming visit or on the final inspection day.

Third Party Inspection for Fin Tube Heat Exchanger - Back Gouging Inspection:

The third party inspector controls the shape and dimensions of the back gouged groove for conformity to the WPS requirement.

It is necessary that the visual appearance is clean and free from defects. NDE examination is done in accordance with the code requirement.

Similarly, If the third party inspector is not in the hold or witness point in the ITP for this inspection stage, then he/she will review the fin tube heat exchanger manufacturer quality control report in his/her coming visit or on the final inspection day.

Third Party Inspection for Fin Tube Heat Exchanger - Inspection of Completed Weld

After completion of all welding and grinding operations, a visual examination confirms there are no harmful defects such as cracks, lack of fusion, surface porosity or exposed slag inclusions, incomplete penetration, incorrect profile of the weld, lack of leg length and overlap.

Temporary attachments are removed, ground smooth, and the areas are checked for defects by MP or PT for defects.

Similarly, If the third party inspector is not in the hold or witness point in the ITP for this inspection stage, then he/she will review the fin tube heat exchanger manufacturer quality control report in his/her coming visit or on the final inspection day.

Third Party Inspection for Fin Tube Heat Exchanger - Non-Destructive Examination

NDE is performed by qualified personnel by the approved techniques.

NDE technique and scope is based of clause 10.2 of API 661and acceptance criteria for any indication are based ASME Code Section VIII Div 1 or 2

The third party inspector checks that the correct method has been used and verifies the approved status of both the technique and the personnel.

Similarly, If the third party inspector is not in the hold or witness point in the ITP for this inspection stage, then he/she will review the fin tube heat exchanger manufacturer quality control report in his/her coming visit or on the final inspection day.

Third Party Inspection for Fin Tube Heat Exchanger - Weld Repair

The fin tube heat exchanger weld repairs are completed using an approved WPS method and retested accordingly.

It is necessary that all repairs are approved before any post weld heat treatment is carried out.

Third Party Inspection for Fin Tube Heat Exchanger - Post Weld Heat Treatment

The third party inspector reviews the post weld heat treatment record of the temperature and time in accordance with the approved code/procedure.

The results of hardness tests are reviewed in accordance with the code requirements.

Third Party Inspection for Fin Tube Heat Exchanger - Mock-Up Test of Tube to Tubesheet Weld

Mock-up test is made when required by purchase order or contract. Identification, visual appearance and dimensions, weld control, PT, section of weld, Macro-observation, hardness check of weld metal and heat affected zone are checked as required.

Third Party Inspection for Fin Tube Heat Exchanger - Visual and Dimensional Inspection of Tubes, Tube Bundle, Cover Plate, Bonnet, Plug Sheet, Top and Bottom Plate and End Plate

The third party inspector carries out following controls:

  • Tube sheet and baffle plate, including tube hole, heads, flanges, tubes, flange facing finish.
  • Tubes after bending for thinning particularly on the back of bends.
  • Finned tubes are visually inspected to confirm that the type of finning is in accordance with the contract requirement and to ensure that assembled tubes have no damage in the finned areas. It is necessary damaged tubes to be rejected for straightening or correction before final test.
  • Cover plate, top and bottom plates, tubesheet, pass partition, side frame, tube spacers, tube keepers, tube supports, nozzles and tubes assembly in Removable cover-plate header type air cooled heat exchanger.
  • Bonnet, top and bottom plates, end plates, stiffeners, tubesheet, pass partition, side frame, tube spacers, tube keepers, tube supports, nozzles and tubes assembly in Removable Bonnet header type air cooled heat exchanger.
  • Plug sheet, top and bottom plates, tubesheet, pass partition, side frame, tube spacers, tube keepers, tube supports, nozzles and tubes assembly in plug headers type air cooled heat exchanger.
  • Direction and orientation of nozzle, lugs and external, internal fittings are checked.
  • Lengths, wall thickness, straightness of header box are checked.
  • Expansion ratio of tube ends is checked. Tubes are checked for thinning after expansion.
  • U-tubes are formed from a single length having no circumferential welds, and flattening is not exceeding 10% of the nominal OD of tubes.
  • Tube sheet flatness on gasket contact surface is checked as required.

Similarly, If the third party inspector is not in the hold or witness point in the ITP for this inspection stage, then he/she will review the fin tube heat exchanger manufacturer quality control report in his/her coming visit or on the final inspection day.

Third Party Inspection for Fin Tube Heat Exchanger Bundle Insertion

Tube bundle insertion is checked as required. Cleanliness, insertion without binding, contact of tube sheet and shell flange and gasket used is confirmed.

Similarly, If the third party inspector is not in the hold or witness point in the ITP for this inspection stage, then he/she will review the fin tube heat exchanger manufacturer quality control report in his/her coming visit or on the final inspection day.

Third Party Inspection for Fin Tube Heat Exchanger - Fan Test

After installation each fan is tested to ensure that it is correctly installed (correct direction of rotation) and can rotate freely without fouling any part of the surrounding structure.

Similarly, If the third party inspector is not in the hold or witness point in the ITP for this inspection stage, then he/she will review the fin tube heat exchanger manufacturer quality control report in his/her coming visit or on the final inspection day.

Third Party Inspection for Fin Tube Heat Exchanger - Pneumatic Test

The third party inspector witnesses low pressure pneumatic test for nozzle reinforcing pads, support saddles or other attachments when specified by approved low pressure pneumatic test procedure using soapy water as the indicating medium.

A minimum of 1 gauge with correct working ranges as described by the code is used.

Similarly, If the third party inspector is not in the hold or witness point in the ITP for this inspection stage, then he/she will review the fin tube heat exchanger manufacturer quality control report in his/her coming visit or on the final inspection day.

Third Party Inspection for Fin Tube Heat Exchanger - Hydro-static Testing

The third party inspector witnesses tube side hydrostatic testing, the test is done based requirements of API 661 clause 10.3 and following points is taken in account.

  • Calibration status and correct working ranges of gauges. A minimum of 2 pressure gauges are attached to item under test.
  • Adequate provision for venting of high points and draining is provided.
  • Test pressure is applied as directed by procedure or code until test limiting pressure is reached. During hold period, a methodical check for leaks is conducted.
  • Test pressures, metal and water temperatures are recorded.
  • Water quality is as specified.

Special requirements of the purchaser's specification for deflection or strain gauges or pressure/time/temperature recordings are examined by the inspector and records verified.

For more detail in hydrostatic testing, review the Vessel Pressure Testing article.

Third Party Inspection for Fin Tube Heat Exchanger - Performance Testing

Where specified by the contract or purchase order the third party inspector witnesses a full performance test of the Air Cooled Heat Exchanger package including:

  • Air flow through the exchanger
  • Pressure drop test
  • Flow test
  • Power consumption
  • Noise level test

Third Party Inspection for Fin Tube Heat Exchanger - Final Inspection

After hydrostatic testing, the fin tube heat exchanger is thoroughly drained and dried out by approved methods.

All internal fittings, attachments, coatings or other requirements are completed.

Specified post hydrostatic test NDE is completed and the heat exchanger closed.

All Fin Tube Heat Exchangers are checked for cleanliness and dryness by an approved method.

The third party inspector rechecks nozzle, saddle and bracket locations and orientations against assembly drawings.

Third Party Inspection for Fin Tube Heat Exchanger - Name Plate

The content of the marking is checked in accordance with approved drawing and specifications by the third party inspector. It is necessary name plate to be mounted on bracket welded to shell at the height specified.

Third Party Inspection for Fin Tube Heat Exchanger - Painting and Coating Inspection

Surface preparation for painting is checked for the following points and meets the requirements of API 661 clause 11.2 by third party inspector:

  • Cleaning method (Blast or scraping and wire brushing)
  • Preparation grades
  • Freedom from weld spatter, blow-holes and other defects
  • Dry film thickness is checked according to specification

Surface condition needs to be free from pin-holes, runs damage and other discontinuity.

Third Party Inspection for Fin Tube Heat Exchanger - Spares and Accessories:

The third party inspector controls spares, tools and accessories and makes visual and dimensional inspection for materials, workmanship and quantity according to the purchase order specification and packing list.

The marking and/or tag is checked for identification.

Third Party Inspection for Fin Tube Heat Exchanger - Reporting:

The third party inspector provides an Inspection Visit Report (IVR) after each visit, as well as a final report summarizing the activities carried out during the fin tube heat exchanger production in accordance with the contract requirements and circulated within the time limits specified in the contract.

The report is in the format required by the client and clearly indicates final acceptance or rejection of the fin tube heat exchanger.

Third Party Inspection for Fin Tube Heat Exchanger - Release Note:

When required by the contract or purchase order, a release note is issued by the third party inspection agency and given to the manufacturer when the fin tube heat exchangers have been accepted.

Third Party Inspection for Fin Tube Heat Exchanger Packing, Marking and Shipping:

The following points are checked by the third party inspector:

  • Cleanliness and dryness of Fin Tube Heat Exchangers
  • Rust prevention for all machined surfaces
  • Protection for cover for all opening and protruding parts
  • Packing style and suitably for overseas transportation
  • Shipping marks and other markings and notificationof welding prohibited, etc.
  • Where nitrogen purge is specified the gas pressure is checked and the presence of warning notices checked.

Third Party Inspection for Fin Tube Heat Exchanger - Final Book (Dossier)

The following final documents are reviewed and signed off by the third party inspector:

As built, drawings if required, Manufacturer's data reports, Material certificate or certified mill test reports for all pressure parts, Material list or map, Welder record for each seam or map, Heat treatment records (Temperature-time record chart during PWHT), Dimensional record, NDE records, Production test record/mock test record, Alloy verification records, (if required), Hydrostatic test record, Pneumatic test record, Hardness test record, Tube expansion record, if required, Post weld heat treatment NDE, if specified, Name plate or other marks, Packing list, Spare parts and tool list

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