HOW TO INSPECT PRESSURE VESSEL

 

HOW TO INSPECT THE PRESSURE VESSEL…?

 

·         Pressure vessel should be inspect as per manufacturer approved QAP.

·         In QAP various stages are there we will discuss those stages in brief.

MATERIAL INSPECTION

·         Raw material inspection is the actual first step of the inspection.

·         At the time of actual material inspection manufacturer should give original material test certificate for all pressure and non-pressure parts.

·         Inspector should note the following information from actual material and matches those information with MTC (material test certificate).

·         Heat or cast number

·         Manufacturer

·         Plate number

·         Size etc.

·         Inspector should check all test certificates with standard values of chemical composition and mechanical strength.

·         If raw material like higher thickness plate which is having NDT of Ultrasonic test then those reports are also mandatory.

·         Inspector should check the heat number transfer overall length of the plate.

·         After checking of raw material inspector should transfer his stamp (stamp is normally short letters or symbol of company from which inspector is belongs) of inspection on material.

·         After completion of inspection inspector should make an inspection visit report with supplier or manufacturer for the inspection record purpose.

·         In his reports he should mentioned about following items,

·         Confirmation of satisfactory documents review and material witness.

·         Records of endorsement of certification review or witnessed.

·         Whatever non conformity observed during inspection.

·         If any test is witnessed then also mention it in the inspection report.

INSPECTION OF FABRICATION WORKS

·         After confirmation of raw material manufacturing engineer is taking this material for the cutting.

·         He is marked layout by pencil on the plates which are taken for cutting.

·         Those marking should be check by manufacturing quality engineer and only after that give the clearance for the cutting to avoid unusual mistakes by worker.

WELDER QUALIFICATIONS

·         Inspector or MQC (manufacturing quality engg.) should check welder qualification documents before commencing the welding.

·         As per required thickness and material the approved WPS should be there and as per WPS the welder should have qualification under his WPQ.

·         Needs to check welder presence in the company at the time of inspection as mentioned in WPQ.

·         Review the WPS, PQR and WPQ.

·         After all documents found satisfactory then give permission to do further work.

FIT-UP OR SET UP INSPECTION

·         During fit-up inspection all required dimensions as per drawing should be checked thoroughly.

·         V-groove preparation should be checked by weld gauge as per WPS and given approved drawing.

·         All tack welds should free from defects.

·         After checking whole fit-up give the permission to further work.

IN-PROCESS WELDING CONTROL

·         During welding needs to check preheat temperature, welding consumable storage and temperature of the oven at the time welding rods are taken from it.

·         Welding position and welding method or process should be checked before starting welding.

·         During root run welding all tack welds should be grind off in such a way that minimum strength is available in tacking to hold material in round condition.

·         Root run penetration should be available for sound weld quality.

·         If penetration is not getting then welding should be done with back gauging.

·         Back gauging is a process of grinding of welding on other side of root run and produce a finish welding run on this side to assure better strength of welding.

VISUAL INSPECTION

·         After completion of full welding there should be visual inspection done before starting any NDE on weld joints.

·         In visual inspection all spatters, arc strikes, penetration, surface porosity and other defects which can detect visually should be clear before NDE.

NDE (NONDESTRUCTIVE EXAMINATION)

·         NDE is performed by worker having ASNT level 1 qualification or having proper training of NDE and examine by ASNT level II personnel qualification.

·         In NDE there are various methods applied as per requirements such as PT, RT, MT etc.

·         If root run of the welding required DP test then must be done after complete root run.

·         Also for final weld DP test is carried on after completing final weld run.

·         All dye check material should not be expired before examination.

·         All NDE material test certificates must be review during inspection.

WELD REPAIR INSPECTION

·         All repairs on pressure vessel should be performed as per approved weld repair procedure and WPS.

·         All repairs must be retested accordingly by using NDE.

·         Radiography should be done on weld repair to ensure soundness of weld.

·         All repairs should be approved before doing any heat treatment after welding that is PWHT.

PWHT

·         Inspector must review the heat treatment documents such as Stress relieving report and temperature graph also see the applied temperature range, normalizing report and same all temperature graph for each process.

·         Also every heat treatment process should have approved procedure.

DIMENSIONAL MEASUREMENT AND VISUAL

·         All major dimensions should be checked as per approved GAD (general arrangement drawing).

·         In dimensions mostly length and diameter of the shell, nozzle orientation and elevation, all other attachments to pressure vessel as per drawing, grouting etc. needs to be cover.

·         In addition full visual examination from inside and outside of the vessel needs to be checked.

AIR TIGHT TEST OR PNEUMATIC TEST

·         Pneumatic test is for all pressure parts of pressure vessel like closed shell, RF (reinforcement) pad of nozzles, skid piping etc. carried out with approved low pressure.

·         Leak test of each weld joint is carried out during pneumatic test by using soap solution.

HYDRO STATIC INSPECTION

·         Before start the hydrostatic testing kindly confirm the proper calibration of gauges and equipment.

·         Water is being used for hydro test should be tested for its Ph value.

·         For hydro testing is recommended for minimum two pressure gauges are required on vessel.

·         Adequate provision for venting of high points and draining is provided.

·         Test pressure should applied as per given approved procedure and standard code.

·         During increasing pressure Outer circumference of vessel should be check time to time.

·         Hydro pressure needs to increase gradually.

·         All time, pressure, temperature, ocf and other important parameters during testing should be recorded.

·         After hydro test all water should be drained properly, clean and dried out all the inside surfaces in such a way that corrosion should not be started after drained.

·         If required any coating to inside surface for corrosion resistance then check properly coating has done or not, if inside blasting is there then there is no require for coating.

BLASTING & PAINTING INSPECTION

·         First check the approved procedure for blasting & painting.

·         Blasting is checked by profile gauge of blasting.

·         For stainless steel vessel there should be checked salt contamination test for blasting.

·         Then as per given paint specification match the paint shade with standard painting shade card.

·         Check the dry film thickness (DFT) of paint coat should be within acceptable limit of paint specifications.

·         Scratch test or pill off test or adhesion test is carried out to check paint adhesion property.

·         Overall visual inspection of paint should be done for all possible defects like blow hole, pin hole etc.

NAME PLATE

·         Name plate also very important part of pressure vessel.

·         It should be as per approved drawing.

·         All the necessary information like project name, project number, client, manufacturer, code of construction, date of manufacturing, design pressure etc.

INSPECTION RELEASE NOTE

·         After manufacturer MRB and Quality dossier reviewed inspector is released the inspection Note for further packing and dispatch activity.

·         The same IRN will forwarded to client also for confirmation of inspection only.

INSPECTION OF PACKING, MARKING AND SHIPPING

·         Check for cleanliness and dryness of pressure vessel during packing.

·         All necessary marking should be done for proper assembly on site.

·         Packing should as per approved procedure in such a way that it could not damage the equipment during transport.

·         In packing all required manuals, bought out manuals and all required tags should be there like Caution and all.

END OF THE INSPECTION