Third Party Inspection for Reciprocating Compressor - Procedure 

Third Party Inspection for Reciprocating Compressor article provides a sample procedure for reciprocating compressor testing and reciprocating compressor inspection in manufacturing shop. The draft compressor inspection and test plan should be reviewed with this article. 

Third Party Inspection for Reciprocating Compressor

This content guides you through all the necessary stages in the production of the reciprocating compressors, including the examination of material, casing hydrostatic testing, performance test, mechanical run test, final inspection, preservation and packing and dispatch to site.

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

All reciprocating compressor inspections and testing are carried out 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.

Reciprocating 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 reciprocating 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 API 618
  • Other Related API Recommendation Practices

The applicable codes and standards may be based on other international standards such as BS 7322, 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.

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

Third Party Inspection for Reciprocating Compressor - Material Inspection

The first actual inspection work in the reciprocating 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:

Then the inspector witnesses the materials identification on the certificates against materials marking. It is also necessary to check with reciprocating compressor drawing datasheet, material list and other specification 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


Third Party Inspection for Reciprocating Compressor – Fabrication Inspection

When the reciprocating compressor raw 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 reciprocating 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.

The third party inspector checks the following items in the reciprocating compressor fabrication inspection process:

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

Third Party Inspection for Reciprocating Compressor Hydrostatic Test

The compressor and other pressure containing parts are hydrostatically tested. The main items are:

The third party inspector verifies that the correct test pressure has been applied to the relevant parts depending on specification requirements.

Third Party Inspection for Reciprocating Compressor Assembly Test

During compressor assembly and when required by the Purchase order or contract inspection is carried out paying particular attention to the following items:

  • Piston end clearance
  • Crankshaft deflection
  • Run-out check
  • Proper match marking
  • Protection of machined surfaces

Detailed information can be found on reciprocating compressor testing article. 

Third Party Inspection for Reciprocating Compressor Mechanical Running Test

Certain types of compressor may be subjected to a mechanical running test. This particularly applies to skid mounted units.

Where required by the purchase order, the third party inspector checks for the following attributes during the test period:

  • Lubricating oil - temperature, pressure flow rate
  • Cooling water - temperature, pressure flow rate
  • Critical speed
  • Bearing temperatures
  • Vibration
  • Gasket condition/leakage
  • Proper operation of pressure relief valves speed governors and overspeed shutdown devices

For more details, review the Reciprocating Compressor Testing article.

Third Party Inspection for Reciprocating Compressor - Strip Down Inspection

Some purchasers may require a strip down inspection after testing. Where there is an inspection the following points are checked as a minimum by third party inspector:

  • Visual condition of cylinder liner
  • Surface condition of cross head guide piston rods and bearings
  • Valve plates
  • Valve springs
  • Pistons

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

Third Party Inspection for Reciprocating Compressor Final Visual and Dimensional Checking

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 Reciprocating Compressor - Name Plate Checking

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 Reciprocating Compressor Painting and Coating

Surface preparation for painting is checked for the following points, according to specification by third party inspector:

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

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

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

Test marks and tags are checked for correct identification.

Third Party Inspection for Reciprocating 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 reciprocating compressor.

Third Party Inspection for Reciprocating 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 Reciprocating 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 control and packing inspection
  • Pre-assembled systems are marked as required by the specification

Third Party Inspection for Reciprocating 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, Run-test reports, Strip down reports, Final inspection report, Markings, Packing list, Spare parts

2 Free CPD Hours Courses - Completely Free

Enroll, Watch the Video, Take the Test, Download Your Cert and Submit to the API . 2 free courses are availble each with 2 hours credit. (Total 4 hours) - 1) ASME V Articl II , 2) ASME V Article 6 & 7