Dimensions

Question 1

Linings – typically anchor profile of steel surface required for the installation of a tank bottom lining

Answer 1

1.5 - 4.0 mils

Question 2

Welds – maximum undercut of a vertical weld and nozzle weld

Answer 2

1/64”

Question 3

Welds – maximum undercut of a horizontal weld

Answer 3

1/32”

Question 4

Welds – maximum diameter of a surface porosity cluster

Answer 4

3/32”

Question 5

Weld qualification – max allowed discontinuity in a bend test

Answer 5

1/8”

Question 6

Nameplates – minimum size of nameplate letters

Answer 6

5/32”

Question 7

Bottoms – minimum external projection of bottom plate on an existing tank (from toe of shell-to-bottom FW)

Answer 7

3/8”

Question 8

Reconstruction – max amount of peaking allowed in vert welds

Answer 8

1/2”

Question 9

Shell Calcs - when calculating tmin for shell LTA, minimum distance away from a weld where “E” is always 1.0

Answer 9

> 1” or 2t

Question 10

Shell patch - minimum overlap of shell lap-patch used to cover a hole (edge of hole to edge of patch)

Answer 10

1”

Question 11

NDE - When performing a PT examination, minimum distance to clean beyond the area to be examined

Answer 11

1”

Question 12

NDE - When performing a MT examination, minimum distance to clean beyond the area to be examined

Answer 12

1”

Question 13

Reconstruction - Maximum amount of banding allowed in a horizontal welds

Answer 13

1”

Question 14

Bottoms - Minimum overlap required for single-welded lap joints

Answer 14

1”

Question 15

Bottoms - Minimum external projection of bottom plate on a new tank

Answer 15

2”

Question 16

Vacuum Box - Minimum overlap of previously test surfaces when using a vacuum box

Answer 16

2”

Question 17

Bottom Patch - Minimum overlap of bottom lap-patch used to cover corroded area (edge of corrosion to edge of patch)

Answer 17

2”

Question 18

Bottom Patch - Minimum distance bottom lap-patch fillet weld to the nearest existing bottom weld

Answer 18

2”

Question 19

Shell Patch - Minimum radius of a shell lap-patch

Answer 19

2”

Question 20

Reconstruction - If reusing bottom plates, min distance to cut from existing bottom welds (if plates are not deseamed)

Answer 20

2”

Question 21

Reconstruction - If reusing roof plates, min distance to cut from existing roof welds (if plates are not deseamed)

Answer 21

2”

Question 22

Shell Pitting - Maximum allowed vertical length of pits on a tank shell

Answer 22

2” in 8” line

Question 23

Bottom Pitting - Maximum allowed length of pits in the critical zone that can be repaired by weld-buildup

Answer 23

2” in 8” arc

Question 24

Bottoms - Radial length of critical zone measured from shell

Answer 24

3”

Question 25

Bottoms – Suggested pad thickness

Answer 25

3-4"

Question 26

Welds - Min distance between clusters of surface porosity

Answer 26

4"

Question 27

Shell Patch - Minimum dimension of a shell lap-patch

Answer 27

4"

Question 28

Shell Patch - Minimum radius of a shell flush-patch

Answer 28

6"

Question 29

Shell Calcs – When calculating tmin for shell LTA, minimum distance away from a rivet where “E” is always 1.0

Answer 29

6"

Question 30

Bottom Patch - Minimum size of bottom lap-patch that does NOT cross a bottom seam

Answer 30

6"

Question 31

Bottom Patch - Minimum distance between a bottom lap-patch and the shell for patches that do NOT extend to the shell

Answer 31

6"

Question 32

Reconstruction - If reusing shell plates, min distance to cut from existing shell welds (if plates are not deseamed)

Answer 32

6"

Question 33

RT - Minimum diagnostic length of a RT for vertical or horizontal welds

Answer 33

6"

Question 34

Weld Qualification - Minimum length of RT when qualifying a welder with RT using a coupon or 1st production weld

Answer 34

6"

Question 35

Weld Qualification - Minimum length of RT when qualifying a welding operator with RT of a test coupon

Answer 35

6"

Question 36

Shell Patch – Minimum distance to overlap a shell weld when using a lap-patch

Answer 36

6"

Question 37

Corrosion – Area to dig when checking for soil-to-air corrosion

Answer 37

6-12"

Question 38

NDE – Distance of eye-to-part to count as a Visual Exam

Answer 38

6-24"

Question 39

Vacuum Box - Typical size of a vacuum box

Answer 39

6" x 30"

Question 40

Shell Patch - Minimum dimension of a shell flush-patch

Answer 40

12"

Question 41

Bottoms - Minimum dimension that a 3-lap joint can be from: other 3-laps, the shell, or annular plate joints

Answer 41

12"

Question 42

Bottom Patch - Minimum dimension of bottom lap-patch that crosses a bottom seam

Answer 42

12"

Question 43

Foundations - Suggested height above grade for new tank bottoms

Answer 43

12"

Question 44

Shell Patch - When adding a shell flush-patch that extends to a horizontal shell weld, minimum distance to cut the horizontal weld past the new vertical welds

Answer 44

12"

Question 45

Shell Patch - Dimension of a shell flush-patch that is considered either a major repair or alteration

Answer 45

> 12"

Question 46

Definition - Dimension of a shell vertical weld if repaired or replaced is considered a major repair or alteration

Answer 46

> 12"

Question 47

Bottom Patch – Max width of bottom patch in the critical zone

Answer 47

24"

Question 48

Bottoms - Minimum radial width of annular plate (distance between shell and nearest bottom fillet weld)

Answer 48

24"

Question 49

NDE – Max distance of eye-to-part to count as a Visual Exam

Answer 49

24"

Question 50

Hot Tap - Minimum height of liquid above new nozzle during the hot tap operation

Answer 50

36"

Question 51

Weld Qualification - Minimum length of RT when qualifying a welding operator with RT of first production weld

Answer 51

36"

Question 52

NDE - Length of sweep board used when checking for banding or peaking

Answer 52

36"

Question 53

Welds - Maximum distance between welder ID stamps on a tank weld

Answer 53

36"

Question 54

Shell Patch - Maximum size of shell lap-patch (vertical & horizontal dimensions)

Answer 54

48" x 72"

Question 55

Settlement - Maximum distance between tank settlement survey points across the inside of the tank

Answer 55

10'

Question 56

Roofs – Maximum shunt spacing on floating roof

Answer 56

10'

Question 57

Settlement - Maximum distance between tank settlement survey points around the outside diameter of the tank

Answer 57

32'

Question 58

NDE - Maximum distance between RT’s in horizontal welds when welding to existing shell plates

Answer 58

50'

Question 59

CP – Typical tank size for Galvanic CP systems

Question 60

Shell Calcs - Tank diameter when variable point design method should always be used to calc shell minimum thickness

Answer 60

> 200'

Question 61

Shell – Minimum offset between vertical welds in adjacent courses

Answer 61

5t

Question 62

Bottoms – Minimum size of bottom welds

Answer 62

Full Fillet

Question 63

Definitions – length of Shell–to–bottom weld that if repaired is considered a major repair or alteration

Answer 63

> 0"