Joint Efficiencies/ hydro (Chap 4-5 / A-2.3.9.12)

Question 1

What is joint efficiencies?

Answer 1

strength of the weld/strength of the base material

Question 2

With is E for new tanks and reconstructed tank

Answer 2

E=1

Question 3

What is E for full penetration butt welds

Answer 3

E=1

Question 4

Joint efficiency 2 traits?

Answer 4

1. Type of welds

2. Extent of NDE

Question 5

when evaluating the retirement thickness in a corroded plate, when away from welds or joints by at least the greater of 1 in. or twice the plate thickness

Answer 5

E = 1.0 (6” or more for rivet and 1” or more for welds)

Question 6

What to use when E is unknown?

Answer 6

API 653 table 4.2 (has to be 1” or less)

Question 7

When to use E?

Answer 7

When obtain tmin for shell course, AND when determining the max level of water to be used during hydro test for a test.

Question 8

What is the formula for hydro test?

Answer 8

Ht = StETmin/2.6D + 1 (for entire shell course)

Ht=StETmin/2.6D (for area)

Question 9

What is joint efficiencies for riveted joint

Answer 9

See API653 table 4.3, (only if 6” or less)

Question 10

API 650 5.1.5 - says what about vertical / horizontal joint

Answer 10

must be butt joints with complete penetration.

Question 11

What is the formula for fill Height?

Answer 11

H=SEtmin/2.6DG (local area)

H=SEtmin/2.6DG + 1( for who shell course)

Question 12

what can pitting corrosion be ignored?

Answer 12

1. sum of their dimension of any vertical lines does not exceed 2” in any 8” length
2. no pit depth cannot be less than 1/2 of the tmin (exclude CA)

Question 13

Existing shell tmin?

Answer 13

tmin = 2.6DG(H-1)/SE = (entire shell)
tmin = 2.6DGH /SE = local area