lockhart day 2 training Flashcards
What are 2 NDE methods that are normally used to determine tank bottom corrosion?
- UT and MFL
Min required thickness of the projection of the bottom plate outside the bottom to shell weld ?
0.1”
How far must the plate extend past the bottom to shell per API653?
3/8”
require interval and who for routine inspection
monthly/operator
require interval and who for external inspection
5 years or RCA/4N (lessor) / AI
require interval and who for UT if CR is known
15 years or RCA/2N (lessor) / (not specified)
require interval and who for UT if CR is not known
5 years
require interval and who for internal inspection
10 years w/o safeguard or RPS
initial internal inspection max ?
- 10 years w/o safe guard or RPB
- 20 years with safe guard but no RPB
- 30 years with RPB
subsequent internal intervals?
- 10 years w/o safe guard or RPB
- 20 years with safe guard but no RPB
- 30 years with RPB
When is brittle not a concern? at what stress?
when less than 7000 KSI , no brittle concern
what temp is brittle not a concern?
greater 60F
What thickness is brittle not a concern
less than 1/2”
API651
cathodic protection
Require inspection interval for cathodic?
annually
Required inspection interval for impressed current?
at least 2 months
when can an on stream inspection be performed in lieu of visual internal inspection?
when the inspection is being performed to determine the condition of the tank bottom
By what date must owner/operator comply with API653?
1/2012
when can pitted corrosion be ignored (2)
- 8” length total pitting length cannot exceed 2”
2. tremaining»_space; 50% of tmin
tank with highly viscous material which will solidify below what temp is not required to meet max internal inspection interval requirement?
110F
how often must RBI assessment be reviewed?
10 years or sooner
when is it allow to not scan the tank bottom during an internal inspection?
when the bottom thickness can be determine by external means
What must be done if material is unknown?
Chemical analysis, charpy V , tension test
when is CR subtracted to liquid height calculation
when Height of product is needed (not done for height for hydro) and only for uniform corrosion (NOT LTA)
for height calculation if given t1 and t2, what do you use?
t1 - average thickness
material spec for structural material code?
a36 or a992
records should be maintained by owner? (3)
- construction records
- inspections
- repair history
when is alternative internal inspection permitted?
when size is limited for entry
