Report for CSP Joint Venture Click to edit Master text styles Second level Third level. Fifth level

Transcription

1 Report for CSP Joint Venture Click to edit Master text styles Second level Third level Out of service examination, ultrasonic thickness Fourth survey and level paint evaluation for tanks T221 & T222 Fifth level 19 th March

2 Presentation Title Section 1. Scope Third and Procedures level 2. Executive Summary Table of Contents 6 3. External examination for T221 and T222» Fifth level 4. Internal Examination T Internal Examination T Conclusions and Recommendations 7. Appendix A: UT measurements reports Page

3 Click to edit Master text styles Second level Third level 1. Scope & Procedure Fourth level Fifth level 3

4 Presentation Scope of our Title work and procedures followed The scope of work for this out of service inspection was to evaluate the current condition of the tanks T221 and T222 through visual examination and ultrasonic thickness survey and recommend, if required any rectifying actions to be taken These tanks are coated with epoxy paint and, without removing the paint, MPI and vacuum box testing cannot be performed. However, we have assessed the quality of the paint by carrying out a visual examination and adhesion tests at random location at the bottom» Fifth of both level tanks. Emphasis was given at the areas where paint has failed and rust started to significantly affect the shell plates The procedures followed for the above scope were in accordance with BS EN 12285, EEMUA 159, ISO EN and ISO EN

5 Click to edit Master text styles Second level Third level 2. Executive summary Fourth level Fifth level 5

6 Item Presentation Title Summary of our findings Bund wall area Foundation & Supports External Inspection Internal Inspection Adhesion test UT measurements Other areas of risk Observation Overall found to be in good condition. Erosion observed in North West corner. Wooden ladder leading into area represents a fire hazard and risk for injuries Generally in good condition. Where the steel supports is bolted into the concrete foundation, the concrete sealing has been damaged. Some corrosion was also observed at the points where the steel supports are welded on the tank Paint has failed in a number of areas. There is corrosion in number of places, across the length of the tank. There are also a number of reinforcing plates not properly welded onto the tank which resulted in corrosion initiation» Fifth level There are number of areas where paint has failed and localised corrosion observed. The paint has failed beyond any repair. Severe pitting was also observed in a number of areas, reaching the depth of 5mm (particularly in T221) There are also a number of paint blisters, which represent significant risk to the lifecycle of the tank painting Adhesion test results indicated 100% paint failure i.e. insufficient bonding due to poor initial surface preparation in both tanks T221 & T222 Thickness observed is within the required limits for both tanks Other areas of high risk, for both tanks, are the lack of striking plate for the pontoon leg, improper welding of the striking plate for the measuring ruler, severely corroded internal pipe and the need for adjustment for the floating suction system which is not moving freely Recommendation Repair eroded bund wall and replace wooden ladder by a metallic one Repair the foundation by using appropriate oil resistant sealant Clean, re-evaluate and repair the corroded areas where the steel supports are welded on the tank Clean, repair and test painting where it failed Clean, repair and test corroded areas Remove partially welded reinforcing plates, evaluate condition of shell plate underneath, clean, repair and test Remove paint and evaluate condition of plates and welds Repair all severe pittings by welding lap patch plates and subsequently test the repair works Re-paint, following the correct preparation and painting procedure as per manufacturer s specifications Remove paint, carry out a correct surface preparation and re-paint with appropriate paint as per manufacturer s specifications Introduce striking plate for pontoon leg and test it Repair and test striking plate for measuring ruler Repair, evaluate and test corroded internal pipe Adjust floating suction system 6

7 Click to edit Master text styles Second level Third level 3. External examination for Fourth level T221 and T222 Fifth level 7

8 Presentation The tanks are Titleof a horizontal construction, built in 2001 in accordance to BS 2594:1975 The tanks are of a horizontal welded construction, built in accordance to BS 2594:1975 in 2001 (see photo 1) The tank s main characteristics are:» Fifth level Tank Characteristics Photo 1: Diameter 2.75m Length 9.20m Capacity 55m 3 Product Slop 8

9 Presentation The bund wall Titlearea was found to be in good condition with minor repairs required Visual external examination for T221 and T222 Photo 2: a) Bund walls (T221 and T222) The tanks are located within a bund Third wall area. level Overall, the bund walls appear to be in good condition Part of the wall» Fifth at the level north west corner has eroded and needs to be repaired (see photo 2). Access into the bund wall area is via a wooden ladder (see photo 3). This ladder appears to be unstable, represents a fire hazard and risk for injuries and needs to be replaced by a metallic one Photo 3: 9

10 Presentation Tanks supports Title and foundation also require minor repairs Photo 4: b) Tank Supports (T221 & T222) The steel supports have been welded Second the tanks level as shown in picture 4. These supports are supported on concrete stands by Click large bolts as to shown edit in photo 5Master title style The steel supports Fourth are level welded onto a reinforcing plate, and this has prevented» severe Fifth corrosion level on the supports from taking place. However, some areas of corrosion have been identified The concrete foundation however, requires minor repairs, particularly around the steel base (see photo 5), in order to prevent underside corrosion Photo 5: 10

11 Presentation The shells have Title areas of severe localised corrosion c) Shells The shells, both tanks, show signs of localised corrosion, particularly Second in areas level where the paint has failed and where reinforcing plates have not been fully welded on the shells Click Paint failure to has been edit observed Master on numerous locations title on both style tanks, on the Fourth shells and level across welds, which has caused severe localised corrosion (see photos on pages 16 & 17). There are also» a number Fifth level of reinforcing plates on the shells which support the platform. These have not been properly welded onto the shells and have caused severe corrosion. The corrosion around these plates appears to be severe (see photos 6-15 on pages 13-15). We also suspect that there is serious corrosion underneath the plates which is not visible, due to the lack of welding on 2 of the 4 sides of the plates These represent areas of high risk which need to be addressed immediately. For our recommendations, please refer to section 6 11

12 Improper welding Presentation Title of the reinforcing plates has caused extensive corrosion (1 of 3) Photo 6: Photo 7: Click Fourth to edit level Master title style» Fifth level Photo 8: Photo 9: 12

13 Improper welding of the reinforcing plates has Presentation Title caused extensive corrosion (2 of 3) Photo 10: Photo 11:» Fifth level Photo 12: Photo 13: 13

14 Improper welding of the reinforcing plates has Presentation Title caused extensive corrosion (3 of 3) Photo 14: Photo 15:» Fifth level 14

15 Presentation Paint failure Title has initiated serious localised corrosion (1 of 2) Photo 16: Photo 17:» Fifth level Photo 18: Photo 19: 15

16 Presentation Paint failure Title has initiated serious localised corrosion (2 of 2) Photo 20: Photo 21:» Fifth level 16

17 Click to edit Master text styles Second level 4. Internal Third Examination level Fourth T221 level Fifth level 17

18 Presentation There are signs Title of severe internal corrosion, primarily at places where the paint has failed Photo 22 The tank is coated with epoxy paint and the plates are not directly visible However, the paint has failed in a number of places, causing localised corrosion and serious pitting. There is an area of over 0.5m» 2 where the paint has completely failed Fifth exposing level the plates to the stored product (see photo 22) Photo 23 There are also numerous paint blisters in the tank, which represent areas of risk and should be addressed promptly (see photos 23 & 24. Potential further exposure of the shell plate to the stored product, will result in exponential growth of the corroded areas Photo 24 18

19 Severe pitting has reached depths of 5mm Presentation Title As mentioned previously, the paint failure has caused localised corrosion which has Second subsequently level resulted in severe pitting Pitting has reached, in some locations, the depth of over 5mm, which is over half the original shell thickness (see photos 25 & 26)» Fifth level Photo 25: The depth of this pitting is critical and requires immediate remedial work to prevent further localised corrosion, which could result in fuel leakage Photo 26: 19

20 Presentation The paint adhesion Title results indicate a poor paint bonding strength Photo 27: We have carried out a paint adhesion test to evaluate the quality of the paint s Second bonding strength level (see photos 27 & 28) The results of the test have shown that the paint bonding strength is extremely low and the paint failure is beyond repair» Fifth level Primary reason for this appears to be poor initial surface preparation prior to the initial painting This needs to be addressed promptly to ensure the tanks integrity is maintained. The paint provides protection to the shell plates and further paint failure could result in product leakage The results of paint failure are already evident in areas where the lack of paint has caused pitting of 5mm depth Photo 28: 20

21 Presentation Other areas Title of risk include lack or poor welding of striking plates We asasastext have also identified a styles number of other areas which pose significant risk and need to be addressed in order to Second ensure the tanks level integrity. These are the: Lack of striking plate for the pontoon leg (see photo Fourth 29) level Improper welding of the striking plate for the measuring» ruler, Fifth which level allows the product to penetrate underneath it. We suspect the area underneath is not coated, and this could potentially result in significant material loss of the shell course underneath (photo 30) Severely corroded pipe, which requires immediate repair (see photo 31) The floating suction system is not moving freely and requires adjustment Photo 29 Photo 30 Photo 31 21

22 Presentation Ultrasonic thickness Title measurements were taken as per BS EN We have taken ultrasonic thickness measurements from the inside of the tanks, as per EN at approximately every 0.3m length Third at level the locations shown on the right» Fifth level The measurements indicate that the shell plates are in good condition (with the exception of the localised pitting described in section 3) and average thickness above the minimum required Measurement positions Detailed results of the ultrasonic thickness measurements can be found in the corresponding report in Appendix A 22

23 Click to edit Master text styles Second level 5. Internal Third Examination level Fourth T222 level Fifth level 23

24 Presentation There are signs Title of corrosion inside the shell, primarily at places where the paint has failed Photo 32 The tank is coated with epoxy paint and the plates are not directly visible. However, the paint has failed in number of places, and there Third is decolourisation level of the paint on the side of the tank Pitting has also initiated at a number of places» Fifth level There are also numerous paint blisters in the tank, which represent areas of risk and should be addressed promptly. Potential further exposure of the plate to the stored product, will multiply the localised corroded areas. There are also areas of paint discolourisation inside the tank, indicating an area where paint has started to fail Area covered in paint blisters Photo 33 Photo 34 Paint discolourisation 24

25 Presentation The poor condition Title of the paint is evident in number of places Photo 35: Photo 36:» Fifth level Photo 37: Photo 38: 25

26 Presentation Other areas Title of risk include lack or poor welding of striking plates We have also identified a number of other areas which pose significant risk and need Second to be addressed level in order to ensure the tanks integrity. These are the: Lack of striking plate for the pontoon leg (see photo 39) Improper welding of» the Fifth striking level plate for the measuring ruler, which allows the product to penetrate underneath it. We suspect the area underneath is not coated, and this could potentially result in significant damage to the shell (photo 40) Severely corroded pipe, which requires immediate repair (see photo 41) The floating suction system is not moving freely and requires adjustment Photo 39 Photo 40 Photo 41 26

27 Presentation The paint adhesion Title results indicate a poor paint bonding strength Photo 42 We have carried out a paint adhesion test to evaluate the quality of the paint s bonding strength The results of the test have shown that the paint bonding strength is extremely low and the paint failure is beyond repair» Fifth level Primary reason for this appears to be poor initial surface preparation prior to the initial painting This needs to be addressed promptly to ensure the tanks integrity is maintained. The paint provides protection to the shell plates and further paint failure could result in catastrophic failure Photo 43 27

28 Presentation Ultrasonic thickness Title measurements were taken across the length of the tank Measurement positions We have taken ultrasonic thickness measurements from the inside of the tanks as per EN 12819, at approximately every 0.3m Second length at the level locations shown on the right The measurements indicate that the shell plates are in good condition» Fifth (with level the exception of the localised pitting described in section 3) and average thickness above the minimum required Detailed results of the ultrasonic thickness measurements can be found in the corresponding report in Appendix A 28

29 Click to edit Master text styles Second level 6. Conclusions Third level and Recommendations Fourth level Fifth level 29

30 Presentation The bund wall Titlearea appears to be in good condition with minor repairs required 1. Bund wall area The bund wall area was found to be in good condition, with the exception of the NW corner and the wooden ladder used to enter the area a) We recommend to repair the area where the wall has eroded. Bund wall area needs to be in good condition to ensure it holds any spillage» Fifth level b) We also recommend to replace the existing unstable, wooden ladder that leads into the bund wall with a metallic one, as it represents both a fire hazard and a Health and Safety risk. This will limit the fire risk and the risk of injuries of people entering the bund wall 30

31 Presentation Foundations Title and supports of the tanks also require some repairs 2. Foundations and supports The foundations and supports were also found to be, generally, in good condition, with the exception Third level of a few areas where corrosion has initiated, and where the supports sealing Fourth needs level to be repaired» Fifth level a) We recommend to clean and repair the paint at the areas on the steel supports where paint has failed and corrosion initiated. This will ensure that further corrosion in this critical area is prevented b) At the area where the steel supports are bolted into the concrete foundation, the concrete used to seal the gap between the steel support and the concrete foundation, has failed in number of places and there is a risk of underside corrosion. We recommend to remove any remaining of this concrete layer and seal all supports for both tanks with oil resistant sealant 31

32 Presentation Externally, the Titleseverely corroded areas require immediate attention 3. External Examination The external shells of both T221 and T222 show signs of corrosion, particularly around the reinforcing plates which have been partially welded on the tanks. There are also other areas where the paint has failed and corrosion has initiated a) We recommend that the externally corroded areas are cleaned, reevaluated» and Fifth repaired level accordingly. Similarly, all areas where the paint has failed should also be repaired b) The partially welded reinforcing plates have to be removed and the condition of the shell underneath them to be inspected and evaluated. Depending on the inspection results, the shells will need to be repaired appropriately and any reinforcing plates should be welded properly on the tank shell and tested 32

33 The Presentation paint has Title failed in numerous places within both tanks leading to localised corrosion 4. asasastext Internal examination: styles During our internal examination of both T221 and T222 tanks we have observed the following: The overall thickness of the plates appears to be satisfactory based on the ultrasonic Third level thickness measurements taken across both tanks, which showed low level Fourth of overall level corrosion The plates are painted with epoxy paint and therefore MPI and Vacuum box testing» Fifth could not level be performed However, there are areas where that paint has failed and localised corrosion observed. There are also numerous paint blisters, which represent significant risk to the lifecycle of the paint the tank The paint strength has also proved to be very poor in both tanks as they 100% failed the adhesion test Pitting, which represent areas of high risk, was also observed in both tanks Tank T221 in particular, has areas of significant pitting, reaching, in some cases, the depth of 5mm There are other areas of risk which need to be addressed and include the lack of striking plate for the pontoon leg, a semi-welded striking plate for the measuring ruler, a severely corroded internal plate and lack of adjustment for the floating suction system 33

34 Presentation We recommend Title to address all issues identified to ensure the tanks integrity We therefore recommend the following measures to be taken: As the paint s condition is poor, we recommend to initially completely remove the paint internally This will enable further inspection of the tank s plates through full visual, vacuum box and MPI testing in order to establish the actual condition of the entire tanks Click and of to the welds edit Master title style The identified Fourth damaged level and corroded areas can then be repaired, ensuring the tanks are fit to return to service and prolong their lifetime. This should» also Fifth include level the repair of the semi-welded striking plate for the measuring ruler and of the severely corroded internal pipe The shells should subsequently be properly be painted, ensuring correct surface preparation is followed, in line with the manufacturer s specifications. This will avoid any paint blisters which will speed up paint failure and localised corrosion Additionally, striking plate for the pontoon should be added, after carefully cleaning and evaluating the area The floating suction system should be adjusted appropriately to enable it to move freely Prepared by: C.Kallis, CEng, Mins NDT, Tank Integrity Assessor 02/ATC5E/010 S.Kallis, MEng, CEng, Tank Integrity Assessor 09/11L1/84 34

35 Click to edit Master text styles Second level APPENDIX Third levela UT measurements Fourth levelreports Fifth level 35