tanque 1015

ABOVEGROUND TANKS FOR OIL STORAGE IN SERVICE INSPECTION PER API 653

Report TK1015 Page 1 of 78

TK 1015 REFINERIA DE CARTAGENA CARTAGENA - COLOMBIA

April 2009

Contract Nº: NR166001-SC-97300-1040

Job Executed By: Certified By: Approved by:

Jaime Márquez Vega Ever Molina

Edilberto Suarez Jorge Gutiérrez

Jaime Marquez Vega API 653 Certified Inspector,

Certification Nº 26576

Fernando Tovar SGS Project Manager



TABLE OF CONTENT

1. EXECUTIVE SUMMARY 1.1. General Details 1.2. Summary of Findings 1.3. Visual Inspection Photos 1.4. Visual Inspection Check List 2. FOUNDATION 2.1. Tank Settlement Requirements 2.2. Calculation of maximum Permissible out of Planar Deflection 2.3. Tank Settlement 2.3.1. Profile Finding 2.3.2. Illustration 2.3.3. Settlement Calculations 2.3.4. Settlement Graphic 2.4. Conclusions 2.5. Recommendations 3. BOTTOM 3.1. Bottom Projection Plate 3.1.1. Standard and Code References 3.1.2. Ultrasonic Thickness Measurement Finding of Projection Plates 3.1.3. Conclusions 3.1.4. Recommendations 4. SHELL 4.1. Shell Plate 4.1.1. Minimum Thickness Calculation for Tank Shell 4.1.2. Minimum Thickness Calculation for Riveted Tank Shell 4.1.3. Minimum Shell Thickness 4.1.4. Finding And Calculation For Tank Shell Plate 4.1.5. Conclusions 4.1.6. Recommendations 4.2. Shell Nozzle, Manhole and Reinforcement pad 4.2.1. Standard and Code References 4.2.2. Findings of Shell Nozzle, Manhole and Reinforcement Pad 4.2.3. Conclusions 4.2.4. Recommendations 4.3. Plumbness 4.3.1. Acceptance Criteria 4.3.2. Method of Inspection 4.3.3. Plumbness Findings 4.3.4. Plumbness Illustrations by axis



4.3.5. Conclusions 4.3.6. Recommendations 4.4. Tank Roundness 4.4.1. Acceptance Criteria 4.4.2. Method of Inspection 4.4.3. Tank Roundness Findings 4.4.4. Tank Roundness Illustrations by axis 4.4.5. Conclusions 4.4.6. Recommendations 5. ROOF 5.1. Roof Plate 5.1.1. Standard and Code Reference 5.1.2. Ultrasonic Thickness Finding of Roof Plate 5.1.3. Conclusion 5.1.4. Recommendations 5.2. Roof Nozzle 5.2.1. Standard and Code Reference 5.2.2. Ultrasonic Thickness Findings of Roof Nozzle and Reinforcement 5.2.3. Conclusions 5.2.4. Recommendations 6. CATHODIC PROTECTION 6.1. Standard and Code References 6.2. Cathodic Readings 6.3. Tank Grounding 6.4. Recommendations



1. EXECUTIVE SUMMARY 1.1 General Details

GENERAL

TANK NUMBER: 1015

OWNER: REFICAR

TANK LOCATION: AREA 1000, REFINERIA DE CARTAGENA

MANUFACTURER: Unknown

PRODUCT: CRUDE OIL

CATHODIC PROTECTION: Anodes of sacrifice

NAME PLATE CONSTRUCCION PRESENT:

Information not available

SPECIFIC GRAVITY: Water (Assumed for hydrotest)

DIMENSIONS

NOMINAL DIAMETER (ft): 117

ACTUAL EXTERNAL DIAMETER: 117.309

TOTAL CIRCUMFERENCE EXT. (ft): 368’ 6.45”

NOMINAL HEIGHT (ft): 48

ACTUAL HEIGHT (ft): 40’ 4.25’’

MAX. GROSS CAPACITY (ft): NA

FILLING HEIGHT (ft): NA

NOMINAL GROSS CAPACITY (Barrels): 75,000

MATERIALS

SHELL: *First course Information of material is not available Actual thickness: 0,622 Inches

*Second course Information of material is not available Actual thickness: 0,518 Inches

*Third course Information of material is not available Actual thickness: 0,498 Inches

*Fourth course Information of material is not available Actual thickness: 0,439 Inches

*Fifth course Information of material is not available Actual thickness: 0,305 Inches

*Sixth course Information of material is not available Actual thickness: 0,273 Inches

*Seventh course Information of material is not available Actual thickness: 0,276 Inches

*ROOF: Information of material is not available Actual thickness: 0,190 Inches

*BOTTOM PROJECTION: Information of material is not available Actual thickness: 0,417 Inches

NOZZLES: Information of material is not available see nozzles UT measures

JOINTS TYPE

SHELL: First course Butt Joint Riveted

Second course Butt Joint Riveted

Third course Lapped Joint Riveted

Fourth course Lapped Joint Riveted

Fifth course Lapped Joint Riveted

Sixth course Lapped Joint Riveted

Seventh course Lapped Joint Riveted

Between courses Lapped Joint Riveted

SHELL – ROOF: Lapped Joint Welded



ROOF: Lapped riveted joint

SHELL – BOTTOM: Fillet Welded

BOTTOM PROJECTION: Butt Welded joint

APPURTENANCES: MH Riveted, nozzles welded

GEOMETRY:

FOUNDATION: Concrete ring/ partially covered with asphalt

BOTTOM PROJECTION: Butt Welded Joint – Annular ring

SHELL: Riveted

ROOF: Fixed Cone riveted

ACCESS:

TANK: Self access to dike

ROOF: Stairway

COATINGS:

BOTTOM PROJECTION: Paint

SHELL: Paint

ROOF: Paint

OTHERS:

Total Number of anodes installed: Information not available

Date Anodes installed: Information not available

RIVETS DATA:

Geometry: Cone Type

Diameter: 1.575” (First and Second Course) – bottom of cone

Projection: 0.709” (First and Second Course)

Pitch between vertical rivet: 3 ½” for first and second row, 7” for third row, 14” for fourth row (on first course), 3.25 ” for first and second row, 6.5” for third row, 13” for fourth row ( on second course)

Pitch between Horizontal. Rivet: 3 ½”

First course Four vertical rows (72 for first and second row) + (18 for third row)+ (8 for fourth row) =Total 98

Second course Four vertical rows (90) + two vertical rows on each side (24) – Total 114

Third course Four vertical rows – Total 74

Fourth course Three vertical rows – Total 62 (verified)

Fifth course Three vertical rows – Total 74

Sixth course Two vertical rows – Total 74

Seventh course Two vertical rows – Total 74

Between courses Lapped Joint Riveted, one line of riveted

Note: Each vertical butt riveted joint denoted from 10 to 12 rivets seal welded around of it. The strap to bottom projection plate is welded and 7 inches on vertical strap sides .

EXISTING NOZZLES AND APPURTENANCES:

Item LOCATION Diameter Axis (plate) Elevation from the bottom

Course Description

1 Shell 10” 10° 14” 1º Product line


3 Shell 6” 25° 7.5” 1º Product line



4 Shell 20” 105° 6.5” 1º Manhole


6 Shell 2’’ 275° 20 1º Low low level indicator

7 Shell 1” 275° 47” 1º Low level indicator

8 Shell 2’’ 272° 29 1º

9 Shell 20’’ 280° 28 1º Manhole

10 Shell 8” 90°, 210°, 330°

8” from seventh

course top

7º Foam chambers

11 Shell 2” 110° 1’’ from seventh

course top

7º A riveted tread nozzle

12 Shell 1’’ 270° 12’’ from sixth to seventh course

7º High high level indicator, and stair

13 Shell 1’’ 270° 50’’ from seventh

course top

7º High level indicators, and stair

14 Shell 0° 7 course top - 1 course

bottom

7º and 1º Swing guide cable support

15 Roof 24” 359° 715” R12/S1 Manhole

16 Roof 8” 353° 715” R13/S1 Sample hatch

17 Roof 6” 255° 708” R21/S3 Level indicator, and stair

18 Roof 10” 270° 74” R12/S5 Pressure and vacuum valve

19 Roof 10” 92° 74” R10/S5 Pressure and vacuum valve

20 Roof 24” 0° 0” R11/S1, S2 Manhole

21 Roof 1” 359° 715” R12/S1 Swing winch over the manhole cover

EXISTING INSERTS AND PAD PLATES:

Item Location Sheet or Axis Course Dimensions Thickness * Remarks

1 Shell 2 1 59”x21.5” 0,618”

2 Shell 6 1 68.5”x62.5” 0,606”

3 Shell 7 1 68.5”x62” 0,610”

4 Shell 9 1 64”x53” 0,608”

5 Shell 10 1 95.5”X51.5” 6,27”

6 Shell 11 1 77”x59” 0,617

7 Shell 19 1 63’’X 56’’ , 0,583

8 Shell 20 1 94’ X 50’ 0,604

9 Shell 21 1 75’’ X 58’’ 0,616

10 Shell 6 2 137’’ X 32’’ 0,501

12 Shell 15° 7 30’’ X 12’’ unknown

13 Shell 80° 7 35’’ X 12’’ unknown

14 Shell 92° 7 10’’ X 12’’ unknown

15 Shell 130° -135° 7 45’’ X 25’’, y unknown



30” X 12’’

16 Shell 175° -205° 7 400’’ X 50’’ unknown

17 Shell 260° 7 30’’ X 12’’ unknown

18 Shell 290° -320° 7 420’’ X 50’’ unknown

19 Shell 330° 7 12’’ X 12’’ unknown

* The actual thickness UT measures are the AVERAGE Note The insert plates dimensions are on the horizontal then vertical order, the weld spaces were taken from the horizontal and vertical riveted joints axis to horizontal and vertical centerline butt welded joints of insert plates 1.2 Summary of Findings with Recommendations

Item Location Finding Recommendations

1.2.1 Access and dike a) The dike is not well defined. It is not possible to determine the geometry of the dike.

Clean the area, check the design and re-built the dike.

b) The area around the tank has too much vegetation.

Remove the vegetation.

c) The area where the tank is placed has not drain, the rain water stand on. Due to this, the area where the tank is placed show cracks in the soil. On plates 8 and 9 first course the concrete ring is under the dike level

A drain inside the area is required, check the slope of the area

d) The dike permeability is unknown.

Determine the dike permeability

1.2.2 Foundation a) The concrete ring denoted totally underground, some places are below the dike level and do not permit the water drain out off concrete ring

Clean the area in order to expose the bottom support base and improve the dike slope for adequate drain

b) The bottom projection plate to concrete ring seal where inspected, denoted (absent approximately 30% of all perimeter)

Repair the seal.

1.2.3 Bottom Projection Plate a) The bottom projection plate length

is 2’’

b) The bottom projection plate denoted covered by Asphalt on the 15%. of his surface

Remove the asphalt to evaluate the thickness and shell to bottom plate weld size.

c) There are too much trash in the area near to the tank shell.

Clean the area.

1.2.4 Shell

a) Entire Shell external surface noted with coating deteriorated and with de-colorated due to UV rays.

Recoat entire external shell surface.

First course plate 1 b) A 16’’ width by 1/32’’ in depth by 62’’ in height thinning denoted on plate 1 (marked over the plate, numbered by 1). The thinning is

Complete the evaluation




painted First course plate 2 c) The 16’’ nozzle denoted two bolts

no properly installed, deformed flanges, the reinforcement plate do not have wipe hole for pneumatic test, the reinforcement to shell weld denoted undercut on top side, the reinforcement plate to bottom projection plate weld space is ¾’’, and it is near to vertical insert weld (59’’ by 21.5’’) (marked over the plate, numbered by 2 and 3).

The bolts or fasteners shall extend completely through their nuts. The reinforcement do not meet the API 650 figure 5-6, requirements for C and A values. The insert plate do not meet the API 653 fig 9-1 requirements for R Value. Repair the undercut

d) Denoted burrs welds, (marked over the plate, numbered by 2)

Remove by grinding to base metal level, eliminate the raised and sharp edges and test by penetrant testing .

First course plate 3 e) The 6’’ nozzle denoted six bolts no properly installed. (marked over the plate, numbered by 4).

The bolts or fasteners shall extend completely through their nuts.

f) Denoted burrs welds, (marked over the plate, numbered by 5)


First course plate 5 g) The bottom projection plate denoted corrosion and paint failure (marked over the plate, numbered by 6)

Clean and recoat

h) The plate 5 denoted laminations near to horizontal lapped rivet joint, (marked over the plate, numbered by 7)

Evaluate by ultrasonic in order to get the real size and depth.

i) The horizontal lap riveted joint denoted leakage (marked over the plate, numbered by 8).

The horizontal lap riveted joint denoted leakage (marked over the plate, numbered by 8).

j) The vertical welded joints of the insert plate on second course are in line with the vertical welded joints on first course (marked over the plate, numbered by 9).

The insert plate do not meet the API 653 fig 9-1 requirements for V Value. .

First course plate 6 k) The bottom projection plate denoted corrosion and paint failure (marked over the plate, numbered by 10)

Clean and recoat

First course plate 7 l) The bottom projection plate to concrete ring gap is 1 ¼’’ (plates 6 and 7) (marked over the plate, numbered by 11

Cover the gap

First course plate 8 m) The horizontal lap riveted joint denoted leakage (marked over the plate, numbered by 12).

The horizontal lap riveted joint denoted leakage (marked over the plate, numbered by 8).

n) The vertical butt riveted joint denoted leakage (plate 8 – 9)marked over the plate,

Repair by seal weld




numbered by 13). o) Denoted burrs welds, (marked

over the plate, numbered by 14) Remove by grinding to base metal level, eliminate the raised and sharp edges and test by penetrant testing .

First course plate 9 p) The shell to bottom weld joint denoted corrosion and paint failure (marked over the plate, numbered by 15).

Clean and recoat

q) Denoted burrs welds, (marked over the plate, numbered by 16)


r) The 20’’ manhole denoted two bolts no properly installed (marked over the plate, numbered by 17).


First course plate 10 s) Denoted burrs welds, (marked over the plate, numbered by 18)

Remove by grinding to base metal level, eliminate the raised and sharp edges and test by penetrant testing

First course plate 11 t) Denoted burrs welds, (marked over the plate, numbered by 19).

Remove by grinding to base metal level, eliminate the raised and sharp edges and test by penetrant testing.

u) Denoted a 4’’ width welded patch plate around the 77’’ by 59’’ insert plate, the patch plate corners are in straight angle (no rounded) and the patch plate to shell weld denoted undercut, (marked over the plate, numbered by 20). The patch plate thickness is ¾’’

The patch plate do not meet the 9.3.1.2, 3, 4, 5 requirements of API 653. Repair the undercut

v) The grounding cable denoted good connection.

No recommendations

First course plate 12 w) Denoted burrs welds, (marked over the plate, numbered by 21).


First course plate 13 x) The vertical butt riveted joint denoted Leakage, plates 13 and 14, (marked over the plate, numbered 22).

Repair by seal weld

y) The shell to bottom weld joint denoted corrosion and paint failure (marked over the plate, numbered by 23).

Clean and recoat

First course plate 14 z) The vertical butt riveted joint denoted Leakage, plates 13 and 14, (marked over the plate, numbered 24).

Repair by seal weld

aa) Denoted burrs welds, (marked over the plate, numbered by 25).


bb) The 20’’ nozzle denoted 11 bolts no properly installed, the reinforcement plate denoted thinning, the thinning is painted,





(marked over the plate, numbered by 26)

First course plate 15 cc) Denoted burrs welds, (marked over the plate, numbered by 27).


dd) The shell to bottom weld joint denoted 1/16’’ on depth corrosion and paint failure (marked over the plate, numbered by 28).

Clean and recoat.

First course plate 16 ee) The vertical butt riveted joint denoted Leakage, plates 15 and 16, (marked over the plate, numbered 29).

Repair by seal weld.

First course plate 18 ff) The 2’’ nozzle denoted one bolt no properly installed and failure paint, (marked over the plate, numbered by 30)

The bolts or fasteners shall extend completely through their nuts. Recoat

First course plate 19 gg) A 1/16’’ on depth thinning near to shell to bottom weld joint (side shell) on 19 and 20 plates, (marked over the plate, numbered 31).


hh) The 20’’ manhole cover denoted one bolt no properly installed, (marked over the plate, numbered by 32). The manhole is installed on 63’’ by 55’’ insert plate, the horizontal butt welding insert plate to horizontal lapped riveted joint space is 7 ‘’

The bolts or fasteners shall extend completely through their nuts. The insert plate do not meet the API 653 fig 9-1 requirements for H value.

First course plate 20 ii) Denoted burrs welds, (marked over the plate, numbered 33).


jj) Denoted a 94’’ by 50’’ insert plate, the horizontal butt welding insert plate to horizontal lapped riveted joint space is 12 ‘’, the vertical butt welded joint (right side) to radial butt welded joint of annular ring space is ¾’’, (marked over the plate, numbered 34).

The insert plate do not meet the API 653 fig 9-1 requirements for C value.

First course plate 21 kk) Denoted burrs welds, (marked over the plate, numbered 35).


ll) Denoted a 4’’ width welded patch plate around the 78’’ by 55’’ insert plate, the patch plate corners are in straight angle (no rounded) and the horizontal lapped joint of patch plate to horizontal lapped riveted joint space is 4’’, (marked over the plate, numbered by 36). The patch plate thickness is ¾’’

The patch plate do not meet the 9.3.1.2, 3, 4, 5 requirements of API 653. Repair the undercut and do not meet the API 653 fig 9-1 requirements for H value.




mm) The bottom projection plate denoted corrosion and paint failure (marked over the plate, numbered by 37).

Clean and recoat.

nn) The cables for cathodic protection and grounding denoted no connected, (marked over the plate, numbered 38).

Connect properly the cables

First course plate 22 oo)Denoted burrs welds, (marked over the plate, numbered by 39).


pp) The foam piping support denoted with no proper plumbness, and the pipe is not properly supported (marked over the plate, numbered by 40).

Adequate the support .

From second to seventh courses

qq) Buckling: 130° – 150° Buckled in seventh course,


rr) Insert Plates 15° a 30’’by 12’’ patch plate seventh course, 70°-80° axis a 137’ by 32’ insert plate on second course and on seventh course a 35’’ by 12’’insert plate, 92° axis 10’’ by 12’’ patch plate on seventh course, 130°- 135° axis a 45’’ by 25’’ insert plate on seventh course and 10’’ by 12’’ patch plate on seventh course, 175°- 205° axis a 400’’ X 50’’ insert plate on seventh, 260° axis 30’’ by 12’’ patch plate on seventh course, 300° axis a 420’’ X 50’’ insert plate on seventh course from 290° to 320°, 330° axis 12’’ by 12’’ patch plate on seventh course,


ss) Burrs welds: 10° axis burrs welds on third course, 160°, 350° axis burrs welds on second and five course.


tt) Leakage: 140° axis vertical butt riveted joint second course, 280° axis vertical butt riveted joint second course, 290° axis vertical lapped riveted joint third course.

Repair by seal weld

uu) Nozzles: 110° axis a 2’’ riveted thread nozzle on seventh course


vv) Thinning: 50° axis A 10’’ BY 10’’ thinning on seventh course, 65° axis A 12’’ BY 12’’ thinning on five course, 300° axis near to horizontal lapped riveted joint five to sixth and sixth to seventh course

Complete the evaluation and recoat the corrosion areas




denoted thinning with severe corrosion and paint failure,

ww) Others: 270° axis the high high level indicator stair denoted corrosion and paint failure,

Recoat and replace the stair

1.2.5 Roof 359° and 0° (roof center)

a) The (two) manholes cover bolts denoted severe corrosion and paint failure, the manhole denoted reinforcement

Replace the bolts and recoat

353° b) The sample hatch cover is in carbon steel and do not have gasket for spark prevent when it operate, denoted holes and do not have chain, the sample hatch nozzle denoted reinforcement.

Replace the sample hatch

0° c) The roof denoted absence of handrail, only denoted handrail near to stairway (and it is corroded and denoted paint failure).

Install the handrail on all roof, repair and Recoat the actual section of handrail

d) The roof denoted sagging on all plates.

Review the roof supports

80% of all perimeter e) The top angle denoted severe corrosion on 80% of all perimeter

Change the top angle

92° y 270° f) The (two) 10’’ nozzles for pressure and vacuum valves denoted severe corrosion and paint failure on bolts and flanges

Clean and recoat

R2,S1/ R3,S1/ R6,S5/ R7,S2/ R14,S1/ R16, S1,

g) The roof denoted 7 holes (from ¼’’ to 2’’ in diameter)

Change the roof plates

R1, S2, S3/ R2,S5/ R3,S4/ R6,S4/ R8,S4/ R10,S8/ R11, S2, S7, S8/ R12,S5/ R13,S4/ R15,S4/ R19,S1,S2

h) The roof denoted 21 patch plates Change the roof plates

330° i) The chamber foam denoted six holes

Change the camber foam

1.2.6 Accessories a) The flanged foam chamber to shell joint (330°) denoted paint failure and corrosion.


1.2.7 Handrails and stairs a) The stair rest on concrete block, the middle stair support denoted corrosion, and are partially underground.

Clean the middle stair support to evaluate for corrosion and anchored bolts

b) The stair handrail is 2’’ by 2’’ by 3/16’’ angle carbon steel and denoted paint failure.

Recoat.

c) The ninth thread (from down to up) denoted a crack.

Change the tread.

d) The handrail supports denoted thinning, corrosion and paint failure.

Change the handrail supports

e) The thread supports bolts The bolts or fasteners shall extend completely




denoted no properly installed through their nuts. Recoat f) The stair to shell grounding cable is

absent. Install the cable.

g) The stair to shell support pad denoted corrosion and paint failure.

Change the support stair

h) The stairway safety chain is absent.

Install the safety chain



1.3 Visual Inspection Photos

General view of the tank Vegetation on dike

The dike permeability is unknown Concrete ring below the dike level

The bottom projection plate covered by asphalt Gap on the bottom projection plate to concrete ring



1/32’’ Thinning on plate 1 ( 16’’ by 65’’) The reinforcement in over the insert plate and do not have

wipe hole for pneumatic test

The 16’’ nozzle denotes two bolts no properly installed Burrs welds first course plate 2

Insert plate on plate 2 first course denoted burrs welds and

the corners are on straight angle The 16’’ nozzle flange denoted deformed, plate 1



The weld on 16’’ reinforcement plate denoted undercut,

plate 2 course 1 (close up) The weld on 16’’ reinforcement plate denoted

undercut, plate2 course 1

The flange denoted 6 bolt no properly installed plate 3

course 1 (close up) The flange denoted 6 bolt no properly installed

plate 3 course 1



The concrete ring denoted underground Burrs welds on first course plate 3

The dike denoted at same level than the bottom projection

plate (plate 5 course 1) The bottom projection plate denoted corrosion and paint

failure (plate 5 course 1)

Denoted lamination on plate 5 course 1 Area with desalinations plate 5 course 1



Denoted leakage on rivets on horizontal joint course 1 and 2 The vertical welded joints of the insert plate on second course

are in line with the vertical welded joints course 1 (plate 6)

(Close up) The vertical welded joints of the insert plate on

second course are in line with the vertical welded joints course 1 (plate 6)

The bottom projection plate denoted corrosion and paint failure plate 6 course 1

The bottom projection plate to concrete ring gap is 1 ¼’’

(plates 6 and 7) The horizontal lap riveted joint denoted leakage plate 7-8

course 1



The vertical butt riveted joint denoted leakage (plate 8 – 9)

course 1 Denoted burrs welds, plate 8 course 1

The shell to bottom weld joint denoted corrosion and paint

failure Burrs welds on first course plate 9

The 20’’ manhole denoted two bolts no properly installed

plate 9 course 1 The 20’’ manhole denoted two bolts no properly installed,

First course plate 9 (close up)



Burrs welds on first course plate 10 Burrs welds on first course plate 11

Denoted a 4’’ width welded patch plate around the 77’’ by 59’’ insert plate, the patch plate corners are in straight angle

(no rounded) and the patch plate to shell weld denoted undercut, plate 11 course 1

(close up) Denoted a 4’’ width welded patch plate around the 77’’ by 59’’ insert plate, the patch plate corners are in straight angle (no rounded) and the patch plate to shell weld denoted

undercut, plate 11 course 1

The grounding cable denoted good connection Burrs welds on first course plate 12



Leakage on vertical butt joint, plates 13 and 14 course 1 The shell to bottom weld joint denoted corrosion and paint

failure, plate 13 course 1

The vertical butt riveted joint denoted Leakage, plates 13 and

14 course 1 Burrs welds on first course plate 14

The 20’’ nozzle denoted 11 bolts no properly installed, the reinforcement plate denoted thinning, the thinning is painted,

plate 14 course 1

(Close up),The 20’’ nozzle reinforcement plate denoted thinning, the thinning is painted plate 14 course 1



Burrs welds on first course plate 15 The shell to bottom weld joint denoted 1/16’’ on depth

corrosion and paint failure, plate 15 course 1

Leakage on vertical butt riveted joint, plate 16 first course The 2’’ nozzle denoted one bolt no properly installed and

failure paint, plate 18 course 1

A 1/16’’ on depth thinning near to shell to bottom weld joint (side shell) on 19 and 20 plates

(Close up) A 1/16’’ on depth thinning near to shell to bottom weld joint (side shell) on 19 and 20 plates



The 20’’ manhole cover denoted one bolt no properly

installed,). The manhole is installed on 63’’ by 56’’ insert plate, plate 19 course 1

(General view) The 20’’ manhole cover denoted one bolt no properly installed,). The manhole is installed on 63’’ by 56’’

insert plate, plate 19 course 1

Burrs welds on first course plate 20 Denoted a 94’’ by 50’’ insert plate, the vertical butt welded

joint (right side) to radial butt welded joint of annular ring space is ¾’’ (the red arrows are over the vertical and radial

weld) course 1 plate 20



Burrs welds on first course plate 20 Denoted a 4’’ width welded patch plate around the 75’’ by

58’’ insert plate, the patch plate corners are in straight angle, course 1 plate 21

The bottom projection plate denoted corrosion and paint

failure course 1 plate 21 The cables for cathodic protection denoted no connected,

course 1 plate 21



Denoted burrs welds first course plate 22 The foam piping support denoted with no proper plumbness,

and the pipe is not properly supported, course 1 plate 22

Denoted burrs welds, 10° course 3 15° a 30’’ by 12’’ patch plate seventh course

The top angle denoted corrosion and paint failure 9seven

course (80% 0f al top angle) 65° axis A 12’’ BY 12’’ thinning on five course



70°-80° axis a 137’ by 32’ insert plate on second course 92° axis 10’’ by 12’’ patch plate on seventh course

110° axis a 2’’ riveted thread nozzle on seventh course 130° – 150° Buckled in seventh course

130°- 135° axis a 45’’ by 25’’ insert plate on seventh course

and 10’’ by 12’’ patch plate on seventh course, Leakage on 140° axis, vertical butt riveted joint second

course



175°- 205° axis a 400’’ X 50’’ insert plate on seventh (begin) 175°- 205° axis a 400’’ X 50’’ insert plate on seventh (end)

260° axis 30’’ by 12’’ patch plate on seventh course 260° Vegetation on top seventh course

270° axis the high high level indicator stair denoted corrosion

and paint failure seventh course Leakage on 280° axis vertical butt riveted joint second course



Leakage on 290° axis vertical lapped riveted joint third

course 300° axis near to horizontal lapped riveted joint five to sixth

and sixth to seventh course denoted thinning with severe corrosion and paint failure,

300° axis a 420’’ X 50’’ insert plate on seventh course from

290° to 320° axis 330° axis 12’’ by 12’’ patch plate on seventh course,

350° axis burrs welds on second course. Stairway on 360° axis



General view of roof (denoted lapped riveted joint) The sample hatch cover is in carbon steel and do not have

gasket for spark prevent when it operate, denoted holes and do not have chain

359° The manhole cover bolts denoted severe corrosion

and paint failure, the manhole denoted reinforcement 0° (roof center) The manhole cover bolts denoted severe

corrosion and paint failure, the manhole denoted reinforcement



The roof denoted absence of handrail, only denoted handrail

near to stairway ( and it is corroded and denoted paint failure).

The roof denoted absence of handrail, only denoted handrail near to stairway ( and it is corroded and denoted paint

failure).

The top angle denoted severe corrosion on 80% of all

perimeter The roof denoted sagging on all plates.

The roof denoted 21 patch plates The roof denoted 7 holes (from ¼’’ to 2’’ in diameter)



10’’ nozzles for pressure and vacuum valves denoted severe corrosion and paint failure on bolts and flanges

(general view) 10’’ nozzles for pressure and vacuum valves denoted severe corrosion and paint failure on bolts and

flanges

The chamber foam denoted six holes (330° axis) The flanged foam chamber to shell joint (330°) denoted

paint failure and corrosion.

The high level indicator stair denoted severe corrosion and

the safety chain is absent General view of stairway



The stairway rest on concrete block The middle stairway support denoted corrosion, and are

partially underground.

The stairway handrail is 2’’ by 2’’ by 3/16’’ angle carbon steel The ninth thread (from down to up) denoted a crack.

The handrail supports denoted thinning, corrosion and paint

failure. The thread supports denoted holes and corrosion



The stairway to shell support denoted severe corrosion and

paint failure. (Close up) The stairway to shell support denoted severe

corrosion and paint failure

The stairway safety chain is absent.



1.3 Visual Inspection Checklist

IN SERVICE INSPECTION CHECK LIST API 653 STANDARD, APPENDIX C

Description COMPLETED

√ COMMENTS

C.1.1 FOUNDATION Measure foundation levelness and bottom elevations (see Appendix B for extent of

measurements). √

See the settlement results. The tank has a tilt with angle 1.36° 0.79’’

C.1.1.1 Concrete Ring a. Inspect for broken concrete, spalling, and cracks, particularly under backup bars used in

welding butt-welded annular rings under the shell. √

The concrete ring denoted totally underground.

b. Inspect drain openings in ring, back of water draw basins and top surface of ring for indications of bottom leakage.

√ There are not any type of drain in the concrete ring.

c. Inspect for cavities under foundation and vegetation against bottom of tank. √ Denoted vegetation near to concrete ring d. Check that runoff rainwater from the shell drains away from tank. √ The tank has not any system to runoff the rainwater.

e. Check for settlement around perimeter of tank. √

Per API 653 formulas the maximum calculated settlement is 1.544”, settlement obtained is 0.79”, and settlement actual is 2.48”. Per API 653 the settlement is in tolerance.

C.1.1.2 Asphalt a. Check for settling of tank into asphalt base which would direct runoff rain water under the

tank instead of away from it. √

The tank denoted underground concrete ring.

b. Look for areas where leaching of oil has left rock filler exposed, which indicates hydrocarbon leakage.

√ The area where the tank is located has too much vegetation and rocks

C.1.1.3 Oiled Dirt or Sand Check for settlement into the base which would direct runoff rain water under the tank

rather than away from it. √

The settlement shows that the water may runoff under the tank.

C.1.1.4 Rock Presence of crushed rock under the steel bottom usually results in severe underside

corrosion. Make a note to do additional bottom plate examination (ultrasonic, hammer testing, or turning of coupons) when the tank is out of service.

√ Complete the evaluation.

C.1.1.5 Site Drainage a. Check site for drainage away from the tank and associated piping and manifolds. √ Denoted evidence of stand water.





√ COMMENTS

b. Check operating condition of the dike drains. √ Denoted stand water evidences C.1.1.6 Housekeeping Inspect the area for buildup of trash, vegetation, and other inflammables buildup. √ There are too much trash, vegetation C.1.1.7 Cathodic Protection Review cathodic protection potential readings.

√ Readings of cathodic protection were taken. The result are in this report

C.1.2 SHELLS C.1.2.1 External Visual Inspection a. Visually inspect for paint failures, pitting, and corrosion. √ The paint is decorated due to UV rays. b. Clean off the bottom angle area and inspect for corrosion and thinning on plate and weld.

√ Partially covered with asphalt, denoted some places with paint failure and corrosion

c. Inspect the bottom-to-foundation seal, if any. √

Where inspected the bottom to foundation seal denoted absent, and in some places is evident a 1 ¼ gap

C.1.2.2 Internal (Floating Roof Tank) Visually inspect for grooving, corrosion, pitting, and coating failures. NA C.1.2.3 Riveted Shell Inspection a. Inspect external surface for riveted and seam leaks.

√ Some rivets have leakages, see in the photographs the location

b. Locate leaks by sketch or photo (location will be lost when shell is abrasive cleaned for painting).

√ See in the photographs and findings the locations of the leakages.

c. Inspect rivets for corrosion loss and wear. √ The rivets do not have loss of material due corrosion. d. Inspect vertical seams to see if they have been full fillet lap-welded to increase joint

efficiency. √ The vertical butt riveted joint denotes from 4’’ to 7’’ welded near to bottom plate in some joints and some rivets welded round it.

e. If no record exists of vertical riveted seams, dimension and sketch (or photograph) the riveted pattern: number of rows, riveted size, pitch length, and note whether the joint is butt-riveted or lap-riveted.

√ See Executive Summary.

C.1.2.4 Wind Girder (Floating Roof Tanks) a. Inspect wind girder and handrail for corrosion damage (paint failure, pitting, corrosion NA





√ COMMENTS

product buildup), especially where it occurs at tack-welded junction, and for broken welds. b. Check support welds to shell for pitting, especially on shell plates. NA c. Note whether supports have reinforcing pads welded to shell. NA C.1.3 SHELL APPURTENANCES C.1.3.1 Manways and Nozzles a. Inspect for cracks or signs of leakage on weld joint at nozzles, manways, and reinforcing

plates. √

There is not cracks or sign of leakage in these places.

b. Inspect for shell plate dimpling around nozzles, caused by excessive pipe deflection. √ There is not dimpling. c. Inspect for flange leaks and leaks around bolting. √ The flanges denoted absence of leakages. d. Inspect sealing of insulation around manways and nozzles. NA e. Check for inadequate manway flange and cover thickness on mixer manways. √ OK, see the thickness report in this document. C.1.3.2 Tank Piping Manifolds a. Inspect manifold piping, flanges, and valves for leaks. NA b. Inspect fire fighting system components. √ The foam chamber are corroded and denoted some holes c. Check for anchored piping which would be hazardous to the tank shell or bottom

connections during earth movement. NA

d. Check for adequate thermal pressure relief of piping to the tank. NA e. Check operation of regulators for tanks with purge gas systems. NA f. Check sample connections for leaks and for proper valve operation. NA g. Check for damage and test the accuracy of temperature indicators. NA h. Check welds on shell-mounted davit clips above valves 6 in. and larger. NA C.1.3.3 Autogauge System a. Inspect autogauge tape guide and lower sheave housing (floating swings) for leaks. √ The tank does not have autogauge tape guide b. Inspect autogauge head for damage. √ OK, there is not any damage c. Bump the checker on autogauge head for proper movement of tape. √ OK, the autogauge head has proper movement d. Identify size and construction material of autogauge tape guide (floating roof tanks). NA e. Ask operator if tape tends to hang up during tank roof movement (floating roof tanks). NA f. Compare actual product level to the reading on the autogauge (maximum variation is 2

in.). √

The actual level was not measured





√ COMMENTS

g. On floating roof tanks, when the roof is in the lowest position, check that no more than two ft of tape are exposed at the end of the tape guide.

NA

h. Inspect condition of board and legibility of board-type autogauges. √ OK the boar denoted legible i. Test freedom of movement of marker and float. √ OK C.1.3.4 Shell-Mounted Sample Station The tank has not shell-mounted sample station a. Inspect sample lines for function of valves and plugging of lines, including drain or return-

to-tank line. NA

b. Check circulation pump for leaks and operating problems. NA c. Test bracing and supports for sample lines and equipment. NA C.1.3.5 Heater (Shell Manway Mounted) The tank has not heater Inspect condensate drain for presence of oil indicating leakage. NA C.1.3.6 Mixer a. Inspect for proper mounting flange and support. NA b. Inspect for leakage. NA c. Inspect condition of power lines and connections to mixer. NA C.1.3.7 Swing Lines: Winch Operation a. Nonfloating. Raise, then lower the swing line with the winch, and check for cable tightness

to confirm that swing line lowered properly. √

The device working properly.

b. Floating. With tank half full or more, lower the swing line, then let out cable and check if swing has pulled cable tight, indicating that the winch is operating properly.

√ The device working properly

c. Indicator. Check that the indicator moves in the proper direction: Floating swing line indicators show a lower level as cable is wound up on the winch. Non-floating swing line indicators show the opposite.

√ The device working properly

C.1.3.8 Swing Lines: External Guide System Check for leaks at threaded and flanged joints. √ OK, the swinging lines has not flanged joints C.1.3.9 Swing Lines: Identify Ballast Varying Need Check for significant difference in stock specific gravity. NA C.1.3.10 Swing Lines: Cable Material and Condition a. For non stainless steel cable, check for corrosion over entire length. √ The cable is OK





√ COMMENTS

b. All cable: check for wear or fraying. √ The cable is OK C.1.3.11 Swing lines: Product Sample Comparison Check for water or gravity differences that would indicate a leaking swing joint. √ There is not leakage C.1.3.12 Swing Lines: Target Target should indicate direction of swing opening (up or down) and height above bottom

where suction will be lost with swing on bottom support. √

OK

C.1.4 ROOFS C.1.4.1 Deck Plate Internal Corrosion For safety, before accessing the roof, check with ultrasonic instrument or lightly use a ball

peen hammer to test the deck plate near the edge of the roof for thinning. (Corrosion normally attacks the deck plate at the edge of a fixed roof and at the rafters in the center of the roof first.)

√

Before access to the roof the deck plate was checked by hammer, edge and center of the roof. The UT readings were taken

C.1.4.2 Deck Plate External Corrosion Visually inspect for paint failure, holes, pitting, and corrosion product on the roof deck. √ The paint denoted corrosion products and holes C.1.4.3 Roof Deck Drainage Look for indication of standing water. (Significant sagging of fixed roof deck indicates

potential rafter failure. Large standing water areas on a floating roof indicate inadequate drainage design or, if to one side, a non level roof with possible leaking pontoons.)

√ The roof denoted sagging on all plates.

C.1.4.4 Level of Floating Roof At several locations, measure distance from roof rim to a horizontal weld seam above the

roof. A variance in the readings indicates a non level roof with possible shell out-of-round, out-of-plumb, leaking pontoons, or hang-up. On small diameter tanks, an unlevel condition can indicate unequal loading at that level.

NA

C.1.4.5 Gas Test Internal Floating Roof Test for explosive gas on top of the internal floating roof. Readings could indicate a leaking

roof, leaking seal system, or inadequate ventilation of the area above the internal floating roof.

NA

C.1.4.6 Roof Insulation The roof has not insulation. a. Visually inspect for cracks or leaks in the insulation weather coat where runoff rain water NA





√ COMMENTS

could penetrate the insulation. b. Inspect for wet insulation under the weather coat. NA c. Remove small test sections of insulation and check roof deck for corrosion and holes near

the edge of the insulated area. NA

C.1.4.7 Floating Roof Seal Systems a. Inspect the condition of the seal, measure and record maximum rim spaces and seal-to-

shell gaps around the full roof circumference at the level of inspection (Note: Inspection of the seal and measurement of the rim spaces and seal-to-shell gaps at more than one level may be necessary to more fully determine if any problems exist at other levels of tank operation)

NA

b. Measure and record annular space at 30-ft spacing (minimum of four quadrants) around roof and record. Measurements should be taken in directly opposite pairs. 1. _______ _______ Opposite pair 1. 2. _______ _______ Opposite pair 2.

NA

c. Check if seal fabric on primary shoe seals is pulling shoes away from shell (fabric not wide enough).

NA

d. Inspect fabric for deterioration, holes, tears, and cracks. NA e. Inspect visible metallic parts for corrosion and wear. NA f. Inspect for openings in seals that would permit vapor emissions. NA g. Inspect for protruding bolt or riveted heads against the shell. NA h. Pull both primary and secondary seal systems back all around the shell to check their

operation. NA

i. Inspect secondary seals for signs of buckling or indications that their angle with the shell is too shallow.

NA

j. Inspect wedge-type wiper seals for flexibility, resilience, cracks, and tears. NA C.1.5 ROOF APPURTENANCES C.1.5.1 Sample Hatch a. Inspect condition and functioning of sample hatch cover.

√ The sample hatch cover denoted holes, do not have chain, the cover is in carbon steel.





√ COMMENTS

b. On tanks governed by Air Quality Monitoring District rules, check for the condition of seal inside hatch cover.

√ Denoted absence of seal or gasket

c. Check for corrosion and plugging on thief and gauge hatch cover. √ OK d. Where sample hatch is used to reel gauge stock level, check for marker and tab stating

hold-off distance. √

There is not reel gauge.

e. Check for reinforcing pad where sample hatch pipe penetrates the roof deck. √ The sample hatch has reinforcing pad f. On floating roof sample hatch and recoil systems, inspect operation of recoil reel and

condition of rope. NA

g. Test operation of system. √ The system works properly h. On ultra clean stocks such as JP4, check for presence and condition of protective coating or

liner inside sample hatch (preventing rust from pipe getting into sample). √

The storage product is crude oil.

C.1.5.2 Gauge Well a. Inspect visible portion of the gauge well for thinning, size of slots, and cover condition. NA b. Check for a hold-off distance marker and tab with hold-off distance (legible). NA c. On floating roofs, inspect condition of roof guide for gauge well, particularly the condition

of the rollers for grooving. NA

d. If accessible, check the distance from the gauge well pipe to the tank shell at different levels.

NA

e. If tank has a gauge well washer, check valve for leakage and for presence of a bull plug or blind flange.

NA

C.1.5.3 Fixed Roof Scaffold Support Inspect scaffold support for corrosion, wear, and structural soundness. √ There is not this element C.1.5.4 Autogauge: Inspection Hatch and Guides (Fixed Roof) a. Check the hatch for corrosion and missing bolts. √ It was checked, it does have cover with bolts b. Look for corrosion on the tape guide’s and float guide’s wire anchors. √ Denoted corrosion where inspected C.1.5.5 Autogauge: Float Well Cover The tank has not float well cover a. Inspect for corrosion. NA b. Check tape cable for wear or fraying caused by rubbing on the cover. NA C.1.5.6 Sample Hatch (Internal Floating Roof)





√ COMMENTS

a. Check overall conditions. NA b. When equipped with a fabric seal, check for automatic sealing after sampling. NA c. When equipped with a recoil reel opening device, check for proper operations. NA C.1.5.7 Roof-Mounted Vents (Internal Floating Roof) Check condition of screens, locking and pivot pins. NA C.1.5.8 Gauging Platform Drip Ring On fixed roof tanks with drip rings under the gauging platform or sampling area, inspect

for plugged drain return to the tank. √

The tank has not gauging platform

C.1.5.9 Emergency Roof Drains Inspect vapor plugs for emergency drain: that seal fabric discs are slightly smaller than the

pipe ID and that fabric seal is above the liquid level. √

The tank has not emergency roof drains

C.1.5.10 Removable Roof Leg Racks Check for leg racks on roof. √ The tank has not removable roof leg racks C.1.5.11 Vacuum Breakers Report size, number, and type of vacuum breakers. Inspect vacuum breakers. If high legs

are set, check for setting of mechanical breaker in high leg position. √

Two, 10” Diameter

C.1.5.12 Rim Vents a. Check condition of the screen on the rim vent cover. NA b. Check for plating off or removal of rim vents where jurisdictional rules do not permit

removal. NA

C.1.5.13 Pontoon Inspection Hatches a. Open pontoon inspection hatch covers and visually check inside for pontoon leakage. NA b. Test for explosive gas (an indicator of vapor space leaks). NA c. If pontoon hatches are equipped with locked down coves, check for vent tubes.

Check that vent tubes are not plugged up. Inspect lock-down devices for condition and operation.

NA

C.1.6 Accessways See Tank Out-of-Service Inspection Checklist, item C.2.12. C.2.12 ACCESS STRUCTURES





√ COMMENTS

C.2.12.1 Handrails a. Identify and report type (steel pipe, galvanized pipe, square tube, angle) and size of

handrails. √

Handrail is 2’’x 2’’ x 3/16’’ carbon steel angle.

b. Inspect for pitting and holes, paint failure. √ Denoted paint failure c. Inspect attachment welds. √ A crack denoted on stair handrail to roof handrail weld d. Identify cold joints and sharp edges. Inspect the handrails and midrails.

√ The handrail and midrail denoted corrosion and paint failure.

e. Inspect safety drop bar (or safety chain) for corrosion, functioning, and length. √ Denoted safety chain absent f. Inspect the handrail between the rolling ladder and the gauging platform for a hazardous

opening when the floating roof is at its lowest level. NA

C.2.12.2 Platform Frame a. Inspect frame for corrosion and paint failure. √ Denoted paint failure. b. Inspect the attachment of frame to supports and supports to tank for corrosion and weld

failure. √

Denoted severe corrosion and paint failure

c. Check reinforcing pads where supports are attached to shell or roof. √ There are corrosion evidence. d. Inspect the surface that deck plate or grating rests on, for thinning and holes. √ Denoted thinning and holes e. Check that flat-surface-to-flat-surface junctures are seal-welded. √ One plate only C.2.12.3 Deck Plate and Grating a. Inspect deck plate for corrosion-caused thinning or holes (not drain holes) and paint

failure. √

Denoted paint failure, thinning and holes

b. Inspect plate-to-frame weld for rust scale buildup. √ Denoted corrosion products c. Inspect grating for corrosion-caused thinning of bars and failure of welds. √ Denoted plate with holes and thinning d. Check grating tie down clips. Where grating has been retrofitted to replace plate, measure

the rise of the step below and above the grating surface and compare with other risers on the stairway.

√ Denoted plate with holes and thinning

C.2.12.4 Stairway Stringers a. Inspect spiral stairway stringers for corrosion, paint failure, and weld failure. Inspect

attachment of stairway treads to stringer. NA

b. Inspect stairway supports to shell welds and reinforcing pads. √ The stairway is supported on seventh course, denoted





√ COMMENTS

severe corrosion c. Inspect steel support attachment to concrete base for corrosion.

√ The middle stairway support denoted thinning and partially underground, the stairway rest over the concrete block

C.2.12.5 Rolling Ladder a. Inspect rolling ladder stringers for corrosion. NA b. Identify and inspect ladder fixed rungs (square bar, round bar, angles) for weld attachment

to stringers and corrosion, particularly where angle rungs are welded to stringers. NA

c. Check for wear and corrosion where rolling ladder attaches to gauging platform. NA d. Inspect pivot bar for wear and secureness. NA e. Inspect operation of self-leveling stairway treads. NA f. Inspect for corrosion and wear on moving parts. NA g. Inspect rolling ladder wheels for freedom of movement, flat spots, and wear on axle. NA h. Inspect alignment of rolling ladder with roof rack. NA i. Inspect top surface of rolling ladder track for wear by wheels to assure at least 18 in. of

unworn track (track long enough). NA

j. Inspect rolling ladder track welds for corrosion. NA k. Inspect track supports on roof for reinforcing pads seal-welded to deck plate. NA l. Check by dimensioning, the maximum angle of the rolling ladder when the roof is on low

legs. Max. angle ____________ .

NA

m. If rolling ladder track extends to within 5 ft of the edge of the roof on the far side, check for a handrail on the top of the shell on that side.

NA

Notes: the access to the roof shall be carefully, the roof structure shall be checked internally.



2 FOUNDATION

2.1 Tank Settlement Requirements

Settlement of a tank is the result of either one, or a combination of the following three settlement components.

a. Uniform settlement

It may vary in magnitude, depending on the soil characteristics. Uniform settlement of a tank does not induce stresses in the tank structure. However, piping, tank nozzles, and attachments must be given adequate consideration to prevent problems caused by such settlement.

b.

. This component often can be predicted in advance, with sufficient accuracy from soil tests.

Rigid body tilting of a tank (planar tilt). This component rotates the tank in a tilted plane. The tilt will cause an increase in the liquid level and, therefore, an increase in the hoop stress in the tank shell. Also, excessive tilting can cause binding of peripheral seals in a floating roof and inhibit roof travel. This type of settlement could affect tank nozzles that have piping attached to them. Figure B-3 shows that the settled location of the tank shell, after rigid body tilt, can be represented by either a cosine or sine wave with respect to its original position in a horizontal plane.

c. Out-of-plane settlement (differential settlement)

Where:

S = Deflection, in ft (out of plane distortion), L = Arc length between measurement points, in ft, Y = Yield strength, in Ibf /in², For Unknown material – 30,000Ibf/in², E = Young’s modulus, in Ibf /in ², - ASME II Part A - 30,000,000Ibf/in², H = Tank height, in ft.

If out-of –measured out-of-plane settlement exceeds the limit above using the optimum cosine curve method, a more rigorous evaluation may be performed in lieu of repairs. This evaluation must be done by an engineer experienced in tank settlement analysis.

. Due to the fact that a tank is a rather flexible structure, chances are great that the tank shell will settle in a nonplanar configuration, inducing additional stresses in the tank shell.

The out-of-plane settlements at the bottom edge lead to a lack of circularity at the top of the tank, and in the case of a floating roof tank, the extent of the induced ovality may impede the proper functioning of the floating roof in such a way that re-leveling is required. Also, such settlements may cause flat spots to develop in the tank shell. This type of settlement could affect tank nozzles that have piping attached to them.

d. While uniform settlement and rigid body tilt of a tank may cause problems as described above, the out-of-plane settlement is the important component to determine and evaluate in order to ensure the structural integrity of the shell and bottom. Based on this principle, a common approach is to determine the magnitudes of the uniform and rigid body tilt component (if any) for each data point on the tank periphery. Once this is carried out, the plane of rigid tilt is then important as a datum from which to measure the magnitudes of the out-of-plane settlements.

2.2 Calculation of Maximum Permissible Out Of Planar Deflection.

To determine the maximum out-of-plane deflection for shell settlement, the following formula can be used to calculate the maximum permissible out-of plane deflection as per API 653, Appendix B.3.2.

2.3 Tank Settlement

2.3.1 Profile Find

{ }H*E*211*Y*L

S2

≤



SETTLEMENT PROFILE TANK 1015

Point Height (inch) 1 0.000

2 2.480

3 2.126

4 2.165

5 1.496

6 1.063

7 0.709

8 0.787

9 0.551

10 0.276

11 0.551

12 -0.315

2.3.2 Illustration



SKETC 3D



2.3.3 Settlement calculations

Smax = Max. calculated out-of-plane settlement from the data in inches. Tilt = Rigid Body Rotation of tank in degrees. Rigid = Rigid body settlement of tank from a Body datum in inches. Phase = Phase angle in degrees of the tilt plane from station 1.



2.3.4 Settlement Graphic

2.4 Conclusions

The survey found the tank is within API 653 requirements. API 653; maximum deflection permitted for this tank is calculated to be 1,541” and the deflection calculated from measurement is 0.79”.

The tank has a rigid body tilting settlement (planar tilt).

2.5 Recommendations

To make a study of soil in order to have clear type of soil and it characteristics



3 BOTTOM

3.1 Bottom Projection Plate

A total of 2 points were taken at each axis marked for the settlement along the entire circumference of the Bottom projection plate. A point was taken near the toe of the weld and the other was taken at the edge of the projection.

3.1.1 Standard and Code Reference

Standard API 653, Clause 4.4.7.7: “The thickness of the projection of the bottom plate beyond the shell as measured at the toe of the outside bottom-to-shell fillet weld shall not be less than 0.1 in. The projection of the bottom plate beyond the outside toe of the shell-to-bottom weld shell shall be at least 3/8 in..

3.1.2 Ultrasonic Thickness Measurement Findings of projection plates (inches)

Point Axis Average

0°

Bottom Projection plate Edge 0.439 0.451 0.451 0.447

Near toe 0.444 0.448 0.461 0.451

Point

Axis Average

90°


Near toe 0.445 0.474 0.475 0.465

Point

Axis Average

180°


Near toe 0.451 0.461 0.433 0.448

Point

Axis Average

270°


Near toe 0.469 0.467 0.468 0.468

Point Point Axis

Average 170°


Near toe 0.389 0.387 0.382 0.386



Point Point Axis

Average 210°


Near toe 0.307 0.289 0.297 0.298

3.1.3 Conclusions

Bottom Projection Plates is 2” on width, this is within API 653 Tolerance. The thickness average for bottom projection plate is 0,416”.

Maximum Interval Inspection as Per API 653 is 20 Years for known corrosion rates.

Recommended to do next interval inspection before or within 20 years.

3.1.4 Recommendations

To perform the evaluation to bottom internally.

4. SHELL

4.1 Shell Plate

4.1.1 Minimum Thickness Calculation for Tank Shell

According with Standard API 653, Section 4.3.3.1, the minimum acceptable shell plate thickness for tanks with diameters equal to or less than 200 ft shall be calculated as follows:

a. When determining the minimum acceptable thickness for an entire shell course, tmin is calculated as follows:

Where:

tmin = the minimum acceptable thickness, in in. for each course as calculated from the above formula; however, tmin shall not be less than 0.1 in. for any tank course,

D = nominal diameter of tank, in ft.,

H = height from the bottom of the shell course under consideration to the maximum liquid level when evaluating an entire shell course, in ft; or

= height from the bottom of the length L (see 4.3.2.1) from the lowest point of the bottom of L of the locally thinned area to the maximum liquid level, in ft; or

= height from the lowest point within any location of interest to the maximum liquid level, in ft,

G = Highest specific gravity of the contents,

S = maximum allowable stress in lbf/in.2; use the smaller of 0.80Y or 0.429T for bottom and second course; use the smaller of 0.88Y or 0.472T for all other courses.

E*SG*D*1)-2.6(H

min =t



Allowable shell stresses are shown Table 4-1 for materials listed in the current and previous editions of API Std 12C and Std 650.

Y = specified minimum yield strength of the plate; use 30,000 lbf/in.2 if not known.

T = the smaller of the specified minimum tensile strength of the plate or 80,000 lbf/in.2; use 55,000 lbf/in.2 if not known,

E = original joint efficiency for the tank. Use Table 4-2 if original E is unknown. E = 1.0 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.

4.1.2 Minimum Thickness Calculation For Riveted Tank Shell

According with Standard API 653, Para. 4.3.4.1: “The minimum acceptable thickness for riveted tank shells shall be calculated using the formula of 4.3.3.1 except that the following allowable stress criteria and joint efficiencies shall be used:

S = 21,000 lbf/in2

E = 1.0 for shell plate 6 in. or more away from riveted.

See Standard API 653, Table 4-3 for joint efficiencies for locations within 6 in. of riveted.”

Standard API 653, Table 4-3

On API 653 standard, Para. 4.3.4.2: “The riveted joint efficiencies given in Table 4-3 are conservative minimums for riveted tank construction details and are included to simplify riveted tank evaluations. However, in some cases it may be advantageous to calculate the actual riveted joint efficiencies using computational methods applicable to lap and butt type riveted joints. When this alternative of calculated joint efficiencies is used, the following maximum allowable stresses shall apply:

a. For the maximum tensile stress in net section of plate, use the lesser of 0.80Y or 0.429T; use 21,000 lbf/in.2 if T or Y is unknown.

b. For the maximum shear in net section of riveted, use 16,000 lbf/in2.

c. For the maximum bearing stress on plates or rivets, use 32,000 lbf/in2 for rivets in single shear, and 35,000 lbf/in2 for rivets in double shear.



On API 653 standard, Para. 4.3.4.3: “For tanks with riveted joints, consideration shall be given to whether, and to what extent, corrosion affects such joints. If calculations show that excess thickness exists, this excess may be taken as corrosion allowance.”

Non-liquid loads (see 4.3.3.5) shall also be considered in the analysis of riveted tanks.

4.1.3 Minimum Shell Thickness

The minimum shell thickness shall be according with next information extracted from Standard API 650:

4.1.4 Finding And Calculation For Tank Shell Plate

Calculations are based on Section 4.3.3.1 of Standard API 653, no corrosion allowance was considered

GENERAL DETAIL OF TANK SHELL PLATE YEARS IN SERVICE: (Assumed) >70 PRODUCT: Crude oil SG (for Hydrotest): Water DIAMETER (ft): 117.287 HEIGHT (ft): 40.322 MATERIAL: UNKNOWN PLATE WIDHT (ft): 5,282 (First Course) 6,332 (Second Course)

ALLOWABLE PRODUCT STRESS (lbf/in2): 21.000 For two course below 21.000 For upper course

ALLOWABLE HYDROSTATIC STRESS (lbf/in2): 21.000 For two course below 21.000 For upper course

JOINT EFFICIENCY, E: Table 4-3 API 653 NUMBER OF STATION POINT: 12



Findings of Shell Plate are shown in next table:

TK 1015

SHELL READINGS FIRST COURSE (INCHES)

Point Axis Average

0°

First Course

Down 0.632 0.634 0.634 0.633

Middle 0.630 0.635 0.635 0.633

Top 0.630 0.630 0.631 0.630

Point Axis

Average 90°

First Course

Down 0.620 0.622 0.620 0.621

Middle 0.626 0.627 0.626 0.626

Top 0.620 0.618 0.617 0.618

Point Axis

Average 180°

First Course

Down 0.621 0.619 0.618 0.619

Middle 0.619 0.622 0.622 0.621

Top 0.611 0.609 0.610 0.610

Point Axis

Average 270°

First Course

Down 0.616 0.621 0.619 0.619

Middle 0.629 0.630 0.630 0.630

Top 0.608 0.606 0.609 0.608



TK 1015 SHELL READINGS INCHES (Manual or Crawler) 2 TO 7 COURSE

Point Axis

Average

5°

Second Course

Down 0.519 0.520 0.520 0.520

Middle 0.513 0.520 0.519 0.517

Top 0.519 0.519 0.511 0.516

Third Course

Down 0.500 0.498 0.501 0.500

Middle 0.490 0.499 0.500 0.496

Top 0.492 0.502 0.497 0.497

Fourth Course

Down 0.427 0.436 0.432 0.432

Middle 0.444 0.439 0.438 0.440

Top 0.440 0.443 0.448 0.444

Fifth Course

Down 0.294 0.292 0.308 0.298

Middle 0.322 0.321 0.318 0.320

Top 0.297 0.297 0.296 0.297

Sixth Course

Down 0.265 0.270 0.270 0.269

Middle 0.271 0.282 0.282 0.278

Top 0.272 0.271 0.271 0.272

Seventh Course

Down 0.276 0.278 0.276 0.277

Middle 0.279 0.276 0.275 0.277

Top 0.267 0.286 0.274 0.276



TK 1015

OTHER INDICATIONS SHELL READINGS (INCHES)

Item Description Dimensions Location Point 1 2 3 Average

1 INSERT PLATE 59" X 21,5" COURSE 1 SHEET

2 DOWN 0.624 0.626 0.624 0.625

TOP 0.614 0.609 0.609 0.611

2 INSERT PLATE 68,5" X 62" COURSE 1 SHEET

6 DOWN 0.601 0.607 0.602 0.603

TOP 0.606 0.611 0.611 0.609

3 INSERT PLATE 68,5" X 62" COURSE 1 SHEET

7 DOWN 0.608 0.600 0.599 0.602

TOP 0.615 0.621 0.619 0.618

4 INSERT PLATE 64" X 53" COURSE 1 SHEET

9 DOWN 0.596 0.603 0.594 0.598

TOP 0.618 0.620 0.619 0.619

5 INSERT PLATE 95,5" X 51,5" COURSE 1 SHEET

10 DOWN 0.622 0.627 0.623 0.624

TOP 0.630 0.630 0.629 0.630


11

DOWN 0.617 0.620 0.630 0.622

TOP 0.612 0.608 0.611 0.610

PAD 0.616 0.618 0.620 0.618


19 DOWN 0.550 0.571 0.512 0.545

TOP 0.621 0.622 0.620 0.621


20 DOWN 0.582 0.600 0.587 0.590

TOP 0.617 0.619 0.617 0.618


21 DOWN 0.617 0.619 0.622 0.619

TOP 0.613 0.612 0.613 0.612


6 DOWN 0.504 0.507 0.507 0.506

TOP 0.495 0.499 0.494 0.496



Calculation For Tank Shell Plate TANK COURSE 1 2 3 4 5 6 7

Original Thickness (inch) (Unknown, same value obtained for tmin per API 653 was assumed)

0.762

0.660

0.537

0.456

0.337

0.254

0.115

Minimum Thickness Measured (Inch)

0º 0.630

90º 0.617

180º 0.609

270º 0.606

0.511

0.490

0.427

0.292

0.265

0.267

Average Thickness (Inch) 0.622

0.518

0.498

0.439

0.305

0.273

0.276

Corrosion Rate per Year (inch/Year)

0.002

0.0007

0.0002

0.0003

0.0006

Inspection Interval (Years) 5 5 5 5 5 5 5 Minimum Acceptable Thickness (“)

0.762

0.660

0.537

0.456

0.337

0.254

0.115

Maximum Height allowed for Hydrostatic test with actual thickness (ft)

33.139

27.739

26.693

22.142

15.669

12.271

12.414

Remaining Life (Years)

Maximum Height allowed for Hydrostatic test is taken from API 653, 3TH Edition, Addendum 2, November 2005, Clause 4.3.3.2:

Servicein Yearscourseper thicknessAverage- thicknessPlate Original

=ateCorrosionR

RateCorrosion Required Thickness Minimum- courseper thicknessAverageRe =emainingLif



See the next sketch for Ultrasonic Thickness Measurements locations on Shell Plates



4.1.5 Conclusions

Shell thicknesses are not within stipulated requirements of API 653 because the minimum required thickness is bigger than actual thickness.

It is not possible determine the interval of inspection and remaining life because the actual thicknesses are out of tolerance according to standard API 653.


Change the design criteria according with these results of thickness data or improve the efficient joint. The maximum height shall be changed.



4.2 Shell Nozzle, Manhole and Reinforcement Pad

4.2.1 Standard and Code Reference

Table 5-4b - API 650



Table 5-6b - API 650



4.2.2 Findings of Shell Nozzle, Manhole and Reinforcement Pad.

4.2.3 Conclusions

All nozzles (except manholes and a 2’’ nozzle on 265° and 270°) do not comply to API 650 Requirements. For this case this standard employs the principles of API Standard 650, (API 653, Clause 1.1.3).


According to the standard and code for the acceptance criteria, the nozzles shall be changed except (except manholes and a 2’’ nozzle on 265° and 270°), because the thicknesses are below the values allowed by the API 650 standard.

4.3 Plumbness

4.3.1 Acceptance Criteria

Standard API 653, Clause 10.5.2.1: “The maximum out-of-plumbness of the top of the shell relative to the bottom of the shell shall not exceed 1/100 of the total tank height, with a maximum of 5 in. The 1/100 criteria, with a maximum of 5 in., shall also apply to fixed roof columns. For tanks with internal floating roofs, apply the criteria of this section or API Std 650, Appendix H, whichever is more stringent.”



Standard API 653, Clause 10.5.2.2: “The out-of-plumbness in one shell course shall not exceed the values specified for mill tolerances in ASTM A 6 or A 20, whichever is applicable.

4.3.2 Method of Inspection

Optical measurement offsets were carried out using a topography equipment Sokkia, Model 630 RK. The tank was surveyed with product (in service).

The total number of stations to be carried out was taken in the same axis established for settlement.

Each tank will be strapped with calibrated steel strapping tape for the outside circumference at the first course of each tank. The outside circumference will be then divided by 30 for the total number of stations required.

4.3.3 Plumbness Findings

Height of the tank: 40.354 ft

API 653 Acceptable Limit: 1/100 of height, maximum 5”

Maximum out-of-Plumbness tolerance: 4.842’’

API 650 Acceptable Limit: 1/200 of height

Maximum out-of-Plumbness tolerance: 2.421”



Axis

Maximum Deviation Vertically

(inch)

Deviation of top of the

shell (inches)

Acceptable Limit API 653 (1/100 TANK

HEIGHT) inches

Acceptable Limit API 650 (1/200 TANK

HEIGHT) inches

Criteria

API 653 API 650

Station 1 (0º) -2.929 -2.677 4.842 2.421 ACCEPTABLE REJECTED

Station 2 (30º) -2.452 -2.066 4.842 2.421 ACCEPTABLE ACCEPTABLE










Station 12 (330º) -2.441 -1.917 4.842 2.421 ACCEPTABLE ACCEPTABLE 4.3.4 Plumbness Illustrations by axis



4.3.5 Conclusions

The Plumbness meet the requirements of API 653.

The axis 0° , 60, 90° ,150, 180, 240°, 270° , 300° do not meet the Plumbness requirements of API 650.


The axis 0° , 60, 90° ,150, 180, 240°, 270° , 300° require to be repair in order to meet the API 650 requirements for plumbness. Evaluate if the new purpose service require floating roof

4.4 Tank Roundness

4.4.1 Acceptance Criteria

Standard API 653, Clause 10.5.3: “Radii measured at 1 ft above the shell-to-bottom weld shall not exceed the tolerances shown in Table 10-2.

Radius tolerances measured higher than one foot above the shell-to-bottom weld shall not exceed three times the tolerances given in Table 10-2.”

4.4.2 Method of Inspection

Optical measurement offsets were carried out using a topography equipment Sokkia, Model 630 RK. The tank was surveyed with product (in service).

The total number of stations to be carried out was taken in the same axis established for settlement.

Each tank will be strapped with calibrated steel strapping tape for the outside circumference at the first course of each tank. The outside circumference will be then divided by 30 for the total number of stations required.

4.4.3 Tank Roundness Findings

The roundness values were taken on same axis where plumbness measured recorded in 4.3.4

4.4.4 Tank Roundness Illustrations



The roundness at 1 ft of the tank is showed in next illustration.





The roundness at the middle of the tank is showed in next illustration.





The roundness at the middle of the seventh course of the tank is showed in next illustration.





4.4.5 Conclusions

The 1, 2, 5, and 7 roundness measures axis at 1 ft high do not meet the API 653 Table 10-2 requirements

The 3 roundness measures axis at middle high (20.243 ft)do not meet the API 653 Table 10-2 requirements

The 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 roundness measures axis at top high (37.510 ft)do not meet the API 653 Table 10-2 requirements


This result should be taken account if the installation of floating roof is considered in the future.

5. ROOF

5.1. Roof Plate

5.1.1. Standard and Code Reference

TK 1015

Tank Roof Evaluation - API 653, Section 4.2.1.2:

“Roof plates corroded to an average thickness of less than 0.09 in. in any 100 in.2 area or roof plates with any holes through the roof plate shall be repaired or replaced.”

5.1.2. Ultrasonic Thickness Findings of Roof Plate

ROOF READINGS (INCHES)

Point Axis Average

0°

Center 0.184 0.188 0.189 0.187

1 0.192 0.191 0.179 0.187

2 0.209 0.206 0.205 0.206

3 0.166 0.194 0.181 0.180

4 0.219 0.220 0.222 0.220

5 0.186 0.160 0.170 0.172

6 0.179 0.182 0.176 0.179



Point Axis

Average 90°

Center 0.184 0.188 0.189 0.187

1 0.175 0.184 0.175 0.178

2 0.181 0.188 0.193 0.187

3 0.201 0.200 0.197 0.199

4 0.195 0.197 0.202 0.198

5 0.180 0.187 0.172 0.180

6 0.179 0.180 0.181 0.180

Point Axis

Average 180°

Center 0.184 0.188 0.189 0.187

1 0.214 0.211 0.219 0.215

2 0.216 0.216 0.212 0.214

3 0.195 0.197 0.202 0.198

4 0.215 0.209 0.209 0.211

5 0.205 0.193 0.194 0.197

6 0.175 0.179 0.172 0.175

Point Axis

Average 270°

Center 0.184 0.188 0.189 0.187

1 0.187 0.185 0.185 0.186

2 0.189 0.187 0.186 0.188

3 0.192 0.186 0.189 0.189

4 0.183 0.188 0.186 0.186

5 0.185 0.183 0.183 0.184

6 0.180 0.184 0.188 0.184

5.1.3. Conclusions

The present average thickness in the roof is 0,190”; roof plates comply with the requirements of API 653.

5.1.4. Recommendations

Change The roof because it denoted sagging on all plates, 7 holes, 21 patch plates and the top angle denoted severe corrosion and paint failure.



5.2 Roof Nozzles

Ultrasonic Thickness measurement taken on four places around nozzle and reinforcement pad.

5.2.1. Standard and Code Reference

API 650 Section 5.8.4, 5.8.5 and Table 5-13a & b:

Reinforcement plates and nozzles attached to the roof shall be confirm to the requirements of API 650, section 5.8.4 and section 5.8.5.

“Pipe may be used for neck, providing the minimum nominal wall thickness is 6 mm (1/4 in.).”

5.2.2. Ultrasonic Thickness Findings of Inserts Roof, Roof Nozzles and Reinforcement



5.2.3. Conclusions

The N1 , N3 8’’ and 10’’ nozzles reinforcement thickness attached to the roof are not conform to the requirements of API 650, figure 5.19.

5.2.4. Recommendations

Replace the N1 , N3 8’’ and 10’’ nozzles reinforcement

6 CATHODIC PROTECTION

6.1 Standard and Code References

Standard API RP 651 – “Cathodic Protection of Aboveground Petroleum Storage Tanks”

6.2 Cathodic Readings



6.3 Tank Grounding According with Standard API 653, Clause 6.3.2.3 Tank grounding system components such as shunts or mechanical connections of cables shall be visually checked.

The tank has 3 connection for grounding system one properly connected and two no connected

6.4 Recommendations

Perform the activities according with Standard API 653, Clause 6.3.4:

Documents

tanque 1015