lockhart day 3 training Flashcards

(59 cards)

1
Q

single lap welded joint are allowed?

A
  1. bottom plates

2. roof plates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

min size of fillets? T > 3/16 and t < 3/16

A
  1. t >3/16 = shall be less than 1/3 of thickness of thinner plate and ATLEAST 3/16”
  2. t &laquo_space;3/16 = full fillet
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

when is a lap patch not allowed? what thickness?

A

when t > 1/2”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is min lap patch thickness?

A

3/16” but not greater than 1/2”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Max size for lap patch?

A

48” x 72”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

min size for lap patch

A

4”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

joint efficiency for a lap patch ? (2)

A

0.7 / 0.35

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

lap patch overlap min/ max?

A
min = 1"
max = 8t
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

hot tapping requirements? (3)

A
  1. 3feet below liquid level
  2. <7000 psi
  3. reinforcement thickness = shell thickness
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

hot tapping with unknown metal limitation?

A
  1. limited to 4”
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is hot tapping procedure?

A

API 2201

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

when do you need a reinforcement pad ?

A

when NPS > 2”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

when is hot tap not allowed?

A

not allowed when PWHT is required

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how to calculate hydro pressure?

A

1.5 X 0.433 X liquid height

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

min radius for a lap patch ?

A

2”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

overlap distance requirement for lap patch CROSSES an existing butt weld?

A

6”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

how close can the horizontal weld of a repair plate be to the shell to bottom weld?

A

6”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

min required overlap of a bottom lap patch to cover a corroded area?

A

2”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

min dimension for a welded on patch for the tank bottom that overlaps a 3 lap seam?

A

12”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

max dimension of a bottom lap patch that is within the critical zone

A

24”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

min required distance a bottom lap patch must be from an existing bottom plate weld

A

2”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

max taper for a shell patch

A

1:4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

require shape of a floor patch that is within 6” of a shell

A

tombstone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

max thickness of a lap patch in critical zone

25
min allow roof rim thickness before replacing? new roof thickness?
0.1" / 3/16" + CA
26
when should settlement survey be conducted?
prior to hydro, EXCEPT for tanks with acceptable settlement history.
27
max measurement points OD / ID for bottom settlement
32 feet / 10 feet
28
NDE method for hot tap nozzles?
MT or PT (for all attachment welds)
29
when dismantling a tank, how close to an existing weld can the tank bottom plates be cut if they are going to be reused?
2"
30
when dismantling a tank, how much of the existing weld should be cut out?
lessor of( 1/2" of weld metal width OR 1/4 each side)
31
shell rings maybe be dismantle by cutting a min of what distance form existing welds?
6"
32
when dismantling a tank how should roof plates be cut out?
deseaming 2" away
33
how many set of punch work required to facilitate proper alignment during reconstruction
2 set
34
At what temp is welding not allowed
Less than 0 F
35
when are settlement measurement support to be measure? (2)
1. during filling | 2. when water is 100%
36
Welding consumables conform to which specs?
AWS
37
new material for tank reconstruction shall comply with?
current applicable standards
38
when is it necessary to remove tack welds?
when manual welding process is used
39
When is it not necessary to remove the tank welds?
SAW process (submerged arc process)
40
when to use low h2 electrodes for what materials (2)
1. Group Iv , Iva , v, Vi | 2. group I / II/ III if t > 1/2"
41
max out of plumbess?
1/100 of tank total height MAX - 5"
42
lowest design metal temperature
15 F ABOVE lowest one day mean temp
43
concrete ring wall NOT used out of levelness allowed?
1/8' in any 10 feet circumference and 1/2" of average elevation
44
concrete ring wall IS used out of levelness allowed?
1/8' in any 30 feet circumference and 1/4" of average elevation
45
WPS / PQR is accordance to?
ASME IX, API 653, API650
46
when can preheat or CDW in lieu of PWHT be used for a tank repair?
repairs on nozzles
47
impact test NOT required, preheat requirement applicable to which material?
P1
48
impact test IS required, applicable to which material and use what method?
CDW , P1/P2/P3
49
what welding process can be substitute preheat for the code required PWHT?
SMAW, GMAW, FCAW, GTAW
50
what min require preheat temp and max interpass temp? if impact testing is not required and CDW?
300F / 600 F
51
impact testing is not required (CDW) how far past the weld must preheat be checked?
4" or 4t (greater)
52
NDE method for new/existing penetration
PT or MT
53
projection of the bottom plate beyond the outside toe of the shell to bottom weld shall be at least....
3/8"
54
when can lap patch not be used?
When presence of the produce in the crevice between the lap patch AND shell prevent gas from freeing
55
lap patch repairs should be? (type of welds)
Full fillet welds - (match the thickness of thinner plate)
56
NDe required for (2)existing bottom to shell weld
1. MT or PT for fulling length under a welded on patch plate | 2. additional 6" on each side examined
57
NDe requirement for bottom plate repair?
VI --> MT/PT -->vaccum box and tracer
58
what can lap patches NOT be installed over?
rivets, unrepaired cracks, other lap patches , lap welded seams
59
what is critical zone min thickness requirement?
small of (1/2 t bottom or 50% of tmin of lower shell course), NOT less than 0.1"