API 653 Chap 9 Flashcards
All repair work must be authorized by?
AI OR Engineer
Alteration must be approved by?
Engineer
Can AI approved alteration?
No, only limited or routine repair (anything work that WILL NOT require hydro)
What is Annex F of API653? and can it be used alone?
NDE requirement summary, and no, must use other section 1-12
What should replacement shell plate be accordance with?
as-built standard
What should the thickness be of the replacement shell?
shall not be less than the greatest nominal thickness of any plate in the same course adjoining the
replacement plate except where the adjoining plate is a thickened insert plate.
What is the min dimension of replacement shell plate?
Greater ( 12 or 12t)
What is the min spacing requirements for t
R=6" B=6" H=3" V=6" A=12" C= Great (3" or 5t)
Prior to welding the new vertical joints, what needs to be done? (3)
(1) .the existing horizontal welds shall be cut for a minimum distance of 12 in. beyond the new vertical joints.
(2) The cut shall extend past or stop short of existing bottom plate welds by at least 3 in. or 5t.
(3) Weld the shell- to-bottom weld last
What is the min spacing requirements for t > 0.5”
Greater R=6" or 6t B=10" or 8t H=10" or 8t V=10" or 8t A=12" or 12t C= (3" or 5t)
What should shell replacement plates be welded with?
butt joints with complete penetration / complete fusion
What are the acceptable lapped patch shell repairs (3)?
- butt welded
- lap welded
- riveted tank shells
Could lapped patch repair be considered as permanent repairs?
Yes, subject to an ongoing inspection and maintenance
When can lapped patch shell repairs not be used?
When t > 1/2” and not to replace door sheets or shell plates
What are the requirements of the repair plate for closure of holes? (5)
- t < 1/2”
- 3/16 «_space;tpatch«_space;1/2” or thickness of shell plate adjacent to the repairs
- min R = 2” min
- overlap of 1” & 8t max
- D» 2”
- E=.7
When can lapped patch repairs be used ? (2)
- removal of existing shell openings
2. removal of severely corroded areas
What is the max vertical/horizontal dimension of a repair plate? and min?
48” x 72” , 4”
When can lapped patch repair not be used on? (4)
- lap welded shell seams
- riveted shell seams
- lapped patch repair plates.
- distorted areas
What are the requirements of the repair plate for severely corroded area (5)
- t < 1/2”
- 1/8»_space; tpatch«_space;1/3 ts
- overlap of 1” & 8t max
- E=.35
- no less than 3/16” and no more than 1/2”
With lapped welded joints repair plate when is the E used for?
To determine the hydrostatic pressure load.
What are repair methods? (4)
- grind with smooth contour
- localized depositions
- replacement plates
- lap welded patch plates
when is it not necessary to remove existing weld reinforcement?
when existing tank with satisfactory service history
New Penetrations larger than NPS 4 shall be installed with the use of an insert plate or thickened insert plate, in what scenario? (2)
(1) shell plate thickness is greater than 1/2 in.
(2) the shell plate material does not meet the current design metal temperature criteria.
The existing reinforcing plate may be removed and a new reinforcing plate added except that reinforcement plate replacement is not permitted on
existing stress relieved assemblies. What is not known?
If it is not known whether the assembly was thermally stressed relieved, then the alteration shall meet the
requirements of API 650, Section 5.7.4.
