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  1. KiwiTanks

    Expected Earthquake damage for IFR

    HI IFR, (and anyone else interested) Just an update to the above thread... The accellerations encountered in the Feb 2011 Christchurch earthquake were in the order of 1:2500 yrs, which is well above the normal design quake of 1:500 yrs. The IFR has sustained very little damage, as you had...
  2. KiwiTanks

    Expected Earthquake damage for IFR

    As some of you may be aware, a very destructive earthquake has hit near Christchurch in NZ. The epicentre was almost in the Port of Lyttelton. We have recently built a 30m diameter tank, 16m high, which has been fitted with an Internal Floating Roof (IFR). At the time of the quake, the tank was...
  3. KiwiTanks

    Weld Efficiency determination

    Thanks for your comments. We have taken these samples from a single plate about 500x700 cut out of a vertical weld. We are going to pick some of the worst looking welds, perform more radiography, cut out some more coupons from the worst places, and get them tested too. I think that the info...
  4. KiwiTanks

    Weld Efficiency determination

    We have taken a coupon out of a tank to determine the weld efficiency to use in the calculations and have the following test results: 508 MPa - UTS Parent metal (both Long and Trans) 410 MPa - UTS Weld 1 417 MPa - UTS Weld 2 375 MPa - UTS Weld 3 The cross sectional area of the test specimen are...
  5. KiwiTanks

    API 653 Plumbness Criteria

    You are right that it only refers to reconstructed tanks. We regularly assess tanks to the tilt clause that you are referring to, just to see how they stack up. (along with a floor plate projection settlement survey) If we find the tank is beyond this limit, we have performed calculations to...
  6. KiwiTanks

    API 653 Plumbness Criteria

    You are right that it only refers to reconstructed tanks. We regularly assess tanks to the tilt clause that you are referring to, just to see how they stack up. (along with a floor plate projection settlement survey) If we find the tank is beyond this limit, we have performed calculations to...
  7. KiwiTanks

    API 653 Lap patch maximum size restrictions?

    I understand that the code doesn't allow this, but is there any technical reason for not allowing this type of arrangement? For example in a seismic event will it promote buckling in the area above the band to a greater extent than if it weren't there? or will the additional heat from welding...
  8. KiwiTanks

    Hyrdotesting after painting.

    I am looking for people's opinions on the practice of painting a tank prior to the hydrotest. I remember seeing a thread on this before, but can't seem to locate it again. Due to the onslaught of winter, we have a contractor who would like to internally line the floor and first strake of a new...
  9. KiwiTanks

    Shell thickness to API653

    I have been inspecting a tank which used to have an external pressuriser roof, which has a water trough over the top strake. We have taken some thickness readings on the inside of the tank (the only way to get the actual tank shell thickness readings in this area) and found readings between 2.9...
  10. KiwiTanks

    Repair of lamination in plate corner

    Thanks Bonswa, I have found a copy of the report, which showws it is up to 2.5mm deep, but may be corroding inside the lamination. Grind and paint sounds like the best option, as it is high up ion the tank, in a low stress area. The main lamination is only 40mm x 50mm, but the surrounding plate...
  11. KiwiTanks

    Repair of lamination in plate corner

    I'm pretty sure it's external. I'm going to go back to the NDT company for a copy of the results as I can't find mine easily - as I said I'm just going from memory from the external insepection performed a while ago.
  12. KiwiTanks

    Repair of lamination in plate corner

    Going from memory here - the lamination is in 6mm plate, with an area of about 300mm square. The lamination comes to the surface and up to about 2mm deep. There may be minor internal corrosion, but nothing significant at this stage.
  13. KiwiTanks

    Repair of lamination in plate corner

    We have a tank due to come out of service shortly for an internal inspection. During the external inspection (and NDT) we found that there was a lamination in the corner of one of the plates - ie above a horizintal weld, and to the right of a vertical. Although it is up in the 2nd-to-top...
  14. KiwiTanks

    Hydrotest of repairs to API653

    Thanks for your input guys. We have now filled the tank beyond the safe fill level for product, and as high as the floating suction arm will allow us. The arm is actually tied down to the bottom of the floor, but no one is certain why. (Can anyone shed some light on this?) The arm is long...
  15. KiwiTanks

    Hydrotest of repairs to API653

    API653 Section 12.3 relates to the hydrotesting of a tank after major repiars and states "A full hydrostatic test, held for 24 hours, shall be performed...." What is the definition of a "Full Hydrostatic test". I have a client who just wants to go for the minimum possible. The only references I...
  16. KiwiTanks

    Rim Seal Foam Dam

    My questions are in 2 parts... We are constructing a 32m dia floating roof tank to API650, with fire protection to NFPA11. Part 1 NFPA11 Table 5.3.5.3.1 indicates spacing between the foam discharge outlets depending on the 'foam dam'. It is not clear if the measurements for the foam dam are...
  17. KiwiTanks

    Allowable Dimensions for Flush Type Cleanout under API 650

    Carrying on from this theme, our client has specified "a 750mm flush clean-out" (30") for their tank. From the clause in 5.7.7.1 mentioned above by jeap, we have to use the dimensions as if it were a 900mmx1200mm (36"x48") ("...shall conform to the next larger opening listed..." In this case...
  18. KiwiTanks

    API653 - Low Nozzle Problems.

    Thanks for all your advice. We are removing the low nozzle altogether. We have a door sheet and 2 strake plates also to be replaced.. Cheers
  19. KiwiTanks

    API653 - Low Nozzle Problems.

    The details are not in compliance with a flush-clean-out type fitting. It is a simple 6" nozzle stabbed in at the very bottom of the shell, (ie touching the floor plates) but has been reinforced by the 25mm doubler (Shell strake thickness is only 17mm). The tank is 19m diameter, 17m tall and the...
  20. KiwiTanks

    API653 - Low Nozzle Problems.

    I have a tank which has a very low nozzle which I have been asked to inspect to API653. It has never been inspected before, and the drawings have some references to API650. This is a 6" nozzle, which has been installed touching the floor to shell joint. The strake is 17mm thick, and the nozzle...
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