Third Party Inspection for Centrifugal Compressor

The Third Party Inspection for Centrifugal Compressor article provides you with information about the centrifugal compressors testing and centrifugal compressor inspection in the manufacturing shop.

Third Party Inspection for Centrifugal Compressor

You may need to review this article along with the following article:

Inspection and Test Plan for Centrifugal Compressor

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

You need to take this point into account: this article is written for a typical centrifugal compressor and might not be detailed for special cases.

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

All centrifugal compressor 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.

Centrifugal compressors by API definition are those compressors for gas or air developing not less than 5 p.s.i. from atmosphere. Currently they range up to machines absorbing 35,000 HP or more within a single case.

Construction of casings is horizontal split or vertical split (barrel) type, single or multiple stages, with or without intercooling. Casings may be cast, forged or fabricated.

Centrifugal compressors are among the most critical items of equipment on a process plant and do not normally have stand by units as is the norm with process pumps.

In consequence absolute integrity of all components is essential. The driver may or may not feature in assembly/tests at the compressor supplier's plant.

The applicable codes and specifications for a centrifugal compressor that is under the construction process is:

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

and the applicable codes and standards are:

  • API 617
  • Other API Recommendation Practices

The applicable codes and standards may be based on other international standards such as BS 2009, etc. This content is general and can be useful even if the design code is different from the 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 is already explained in the Inspection and Test Plan for Centrifugal Compressor article.

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

  • Centrifugal Compressor Purchase Order or Contract
  • Centrifugal Compressor Manufacture Quality Control Plan
  • Centrifugal Compressor Inspection and Test Plan
  • Centrifugal Compressor Data Sheet
  • Centrifugal Compressor Approved Drawings
  • Centrifugal Compressor Material Test Reports
  • Centrifugal Compressor Welding Specification Procedures (WPS) and Procedure Qualification Records(PQR)
  • Centrifugal Compressor Welders Qualifications Reports
  • Centrifugal Compressor NDE Procedures (Radiography, Ultrasonic, Magnetic Particle, Dye Penetration, etc.)
  • Centrifugal Compressor NDE Personnel Qualifications Reports
  • Centrifugal Compressor Heat Treatment Procedure
  • Centrifugal Compressor Calibration Certificates for Test Equipment
  • Centrifugal Compressor Hydrostatic Testing Procedure and Water Quality Document
  • Centrifugal Compressor Impeller Inspection Procedure
  • Centrifugal Compressor Mechanical Running Test and Performance Test Procedure
  • Centrifugal Compressor Preparation and Painting Procedure
  • Centrifugal Compressor Preservation, Packing and Shipping Procedure
  • Centrifugal Compressor Packing List

Third Party Inspection for Centrifugal Compressor - Material Inspection

The first actual inspection work in the Centrifugal Compressor is the raw materials inspection.

The original or authenticated copies of mill certificates of material 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
  • Surface Finish

Then the inspector witnesses the materials identification on the certificates against the materials marking. It is also necessary to check these with the centrifugal compressor drawing datasheet, material list and other specifications as appropriate.

Visual inspection for surface finish and probable defects is done and dimensional compliance with specification need to be controlled, as well.

When 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

When the centrifugal compressor material inspection is carried out, and the results were satisfactory or non-conformities were closed by remedial action, then the compressor manufacturer will start fabrication.

The third party inspector checks the following points on the centrifugal compressor based on the inspection and test plan (ITP), which has already been agreed upon between the purchaser and the Compressor 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 details, review the Inspection and Test Plan for Centrifugal Compressor article. There is a draft of the ITP in this article, which we believe is the best practice for centrifugal compressor inspection.

Third Party Inspection for Centrifugal Compressor - Casing Inspection

The third party inspector checks the following items in the centrifugal compressor casing inspection process:

  • Visual inspection for damage
  • Dimensional check to drawing requirements
  • Witness or review hydrostatic test
  • Witness or review NDE examination
  • Application of test marks
  • Visual examination of welded on connections
  • Review weld qualification and weld procedure records

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 centrifugal compressor manufacturer quality control report in his/her coming visit or on the final inspection day.

Third Party Inspection for Centrifugal Compressor - Impeller Inspection

The third party inspector checks the following items in the centrifugal compressor casing inspection process:

  • Witness or Review Run Out Test
  • Witness or Review Dynamic Balance Test
  • Witness or Review Over Speed Test
  • Review NDE Examination Results

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 centrifugal compressor manufacturer quality control report in his/her coming visit or on the final inspection day.

Third Party Inspection for Centrifugal Compressor Mechanical Running Test

After complete assembly, the centrifugal compressor is submitted to a mechanical running test. The test is conducted within the contract and code requirements. The third party inspector witnesses the following items:

  • Collection of test data
  • Preparation of test curves
  • Rated speed
  • Check bearings for overheatin
  • Noise test
  • Vibration test

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 centrifugal compressor manufacturer quality control report in his/her coming visit or on the final inspection day.

For more details, review the Centrifugal Compressor Testing article.

Third Party Inspection for Centrifugal Compressor Performance Test

When required by the contract or purchase order, the compressor is subjected to the performance test and 5 points as minimum including of surge and overload need to be taken at normal speed. It is necessary the performance test to be done based instruction outlined in the ASME PTC 10.

The parameters stated in this standard need to be measured and recorded.

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 centrifugal compressor manufacturer quality control report in his/her coming visit or on the final inspection day.

For more detail, review the Centrifugal Compressor Testing article.

Third Party Inspection for Centrifugal Compressor – Strip Down Inspection

A strip down inspection may be required by the contract and it may be limited to the checking of bearings and seals or may require the complete dismantling of the unit.

The inspector checks, as necessary, to ensure that no damage has occurred during tests, and the necessary care is taken during re-assembly, including rust preventative procedures when necessary.

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 centrifugal compressor manufacturer quality control report in his/her coming visit or on the final inspection day.

Third Party Inspection for Centrifugal Compressor Final Visual and Dimensional Control

After completion of all of the manufacturing and tests, the third party inspector carries out a final inspection of the compressor with paying particular attention to:

  • Main dimensions to drawing requirements
  • Base plate dimensions
  • Size rating and position of flanged connections
  • Size and type of threaded connection
  • Inspection for workmanship, defects and damage
  • Check on installed condition of parts, assemblies

Third Party Inspection for Centrifugal Compressor Name Plate Check

The third party inspector checks the content in accordance with the approved drawings and specifications and make sure it is stamped in accordance with the code requirements.

Third Party Inspection for Centrifugal Compressor Painting and Coating

Surface preparation for painting is checked for the following points, according to specification 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

It is necessary that surface condition is free from pin-holes, runs damage and other discontinuity

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 centrifugal compressor manufacturer quality control report in his/her coming visit or on the final inspection day.

Third Party Inspection for Centrifugal Compressor Spare Parts, Loose Items and Accessories

Spare parts, loose items and accessories are checked visually for their dimensions, materials, workmanship and quantity, according to the purchase order specification.

Test marks and tags are checked for correct identification.

If Third party inspector is not in hold or witness point for this inspection stage in project ITP, then will review the centrifugal compressor manufacture quality control report in his/her coming visit or in final inspection day.

Third Party Inspection for Centrifugal Compressor - 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 compressor 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 Centrifugal Compressor.

Third Party Inspection for Centrifugal Compressor - 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 compressors have been accepted.

Third Party Inspection for Centrifugal Compressor Packing, Marking and Shipping:

The following points are checked by the third party inspector:

  • All exterior machined surfaces are coated with rust preventative
  • All internal surfaces that are susceptible to corrosion are coated with rust preventative
  • All flanged openings are fitted with metal protectors in accordance with the specification
  • All threaded connections are provided with steel plugs
  • Exposed shafts and shaft couplings are covered with waterproof material and sealed
  • Check manuals and instructions are included to the specification requirements
  • Packing style and suitability for overseas shipment
  • Shipping marks are correct
  • Pre-assembled systems are marked as required by the specification

Third Party Inspection for Centrifugal Compressor Final Book (Dossier)

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

Manufacturer's data reports, Material certification, Dimensional record, NDE reports, Hydrostatic test reports, Performance test report, Run-test reports, Strip down inspection reports, Final inspection report, Marking Inspection Report, Packing list, Spare parts list

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