BP OIL CO.

RP 4-2-2
FOUNDATIONS FOR
ATMOSPHERIC Page 1 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

TABLE OF CONTENTS

PAGE

1.0 SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2.0 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

3.0 DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

4.0 SUBSURFACE INVESTIGATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

5.0 SITE IMPROVEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

6.0 TANK FOUNDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

6.1 Earth Pads and Gravel Ringwalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
6.2 Pile Foundation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.3 Concrete Ringwalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.4 Foundation Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

7.0 LEAK DETECTION, CATHODIC PROTECTION, AND RELEASE PREVENTION BARRIER

SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

8.0 TANK SETTLEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

8.1 Shell Settlement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.2 Bottom Settlement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

9.0 HYDROTESTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

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 BP OIL CO. RP 4-2-2
FOUNDATIONS FOR
ATMOSPHERIC Page 2 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

1.0 SCOPE

1.1 This Practice covers general requirements for the design and construction of foundation pads for
atmospheric storage tanks.

1.2 This Practice does not apply to tanks used for storage of acids or other corrosive chemicals, or to
refrigerated tanks.

1.3 Any deviation to this Practice must be approved by the procedure described in RP 0-1-3 .

1.4 An asterisk (*) indicates that a decision or approval by the Owner or the Owner’s Engineer is required,
or that additional information is furnished by the Purchaser.

1.5 A Revision Bar indicates all changes made to this Practice.

1.6 Documentation required for atmospheric storage tank foundations in accordance with this Practice is
given in Table 3.

2.0 REFERENCES

The latest edition of the following standards and publications are referred to herein, and shall be used
with this Practice.

STANDARDS AND PUBLICATIONS

BP Oil Refining Practices

RP 0-1-3 Deviations to BP Oil Refining Practices
RP 4-2-1 Foundation Types and Selection Criteria
RP 4-6-1 Concrete Design
RP 4-6-2 Concrete Construction Requirements
RP 11-1-1 Atmospheric Storage Tanks
RP 14-4-2 Cathodic Protection for Tank Bottoms

ASTM Standards
D693 Crushed Stone, Crushed Slag, and Crushed Gravel for Bituminous Macadam
Base and Surface Courses of Pavements
D1556 Density of Soil in Place by the Sand–Cone Method
D1557 Moisture–Density Relations of Soils and Soil–Aggregate Mixtures Using 10–lb.
(4.54kg) Hammer and 18 in. (457 mm) Drop
D2167 Density of Soil in Place by the Rubber–Balloon Method
D2922 Density of Soil and Soil–Aggregate in Place by Nuclear Methods (Shallow Depth)
D2937 Density of Soil in Place by the Drive–Cylinder Method
D4253 Maximum Index Density of Soils Using a Vibratory Table
D4254 Minimum Index Density of Soils and Calculation of Relative Density

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 BP OIL CO. RP 4-2-2
FOUNDATIONS FOR
ATMOSPHERIC Page 3 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

3.0 DEFINITIONS

3.1 Contractor – Company or business that agrees to furnish materials or perform specified services at
a specified price and/or rate to the Owner.

3.2 Earth Pad – The soil used to elevate tank above surface grade.

3.3 Geotechnical Engineer – A BP Oil Company engineer or designated representative appointed to carry
out soil testing and field inspection.

3.4 Inspector – A BP Oil Company appointed engineer or inspector.

3.5 Owner – BP Company.

3.6 Owner’s Engineer – A BP Company appointed engineer.

3.7 Pile – Structural member of timber, concrete, and/or steel, used to transmit surface loads to lower
levels in the soil mass.

3.8 Ringwall – Foundation provided under the shell to minimize shell settlement caused by the shell cutting
into the soil.

4.0 SUBSURFACE INVESTIGATION

* 4.1 An accurate determination of the geotechnical conditions at the tank sites including, but not limited to
a program of soils borings, laboratory testing and engineering analysis shall be carried out for all new
tank foundations, by a Geotechnical Engineer approved by the Owner.

4.2 The number of borings and the scope of testing and analysis will vary with the number and size of tanks,
the soils characteristics and the amount of historical settlement data from tanks within the Refinery.
For guidelines on soils borings and sampling refer to RP 4-2-1 .

4.3 The results of a geotechnical investigation shall include an evaluation of foundation stability (general
bearing capacity, local shear and potential for plastic or lateral flow) and estimates of foundation
settlement at 10 and 25 years. These results shall be documented in a report which shall be part of
the tank’s permanent records.

5.0 SITE IMPROVEMENT

* 5.1 If the results of the soils investigation indicate that calculated safety factors against foundation failures
are less than 1.5 or if estimated future tank shell settlements are likely to exceed 12 inches the following
site improvements shall be performed, unless otherwise approved by the Owner:

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 BP OIL CO. RP 4-2-2
FOUNDATIONS FOR
ATMOSPHERIC Page 4 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

1. Removal of soil which contributes most to the tank instability and settlement, and replacing it with
well compacted fill. This is usually viable if total excavation depth require to remove weak soils
does not exceed 10 to 15 ft. Consideration shall be given to the effect such excavation and fill will
have on the water table.

* 2. Preloading of the soils under the tank site (surcharge) by placing an earth mound on the site and
waiting until sufficient consolidation has taken place to permit tank erection, Normally, a preload
equal to 1-1/2 to 2 times the full service load of the tank is adequate to achieve the necessary
consolidation. Sand drains are sometimes installed to increase consolidation rates and thereby
reduce preload in-place time. Preloading can also be achieved by filling the tank with water in
increments and allowing the soil to consolidate under each increment until the full load is applied.
Releveling of the tank shall be done after water preloading. The method of preloading shall be
approved by the Owner.

3. Densification of loose granular soils responsible for the instability or settlement problems by vibro
compaction techniques.

6.0 TANK FOUNDATIONS

6.1 Earth Pads and Gravel Ringwalls

* 1. Steel storage tanks shall be supported on raised compacted earth pads with gravel ringwalls
under their shells, unless conditions specified in Paragraph 6.2 or 6.3 exist. For details of gravel
ringwalls, see Figures 1 through 4. Earth pad foundations without gravel ringwalls shall not be
used without the approval of the Owner’s Engineer.

2. The predicted settlements from the geotechnical investigation shall be used in establishing final
foundation pad elevations.

* 3. Any crushed stone or crushed gravel with a maximum size of 1-1/2 in. and which meets the
requirements of ASTM D 693 and Figure 21 shall be used to construct the gravel ringwall.
Proposal to use other materials shall be approved by the Owner. Ringwall material shall be
compacted to 70% relative density in accordance with ASTM D 4253 and D4254. Limestone shall
not be used without the approval of the Owner’s Engineer.

4. The general fill used to construct the pad shall be a non-corrosive, cohesive or cohesionless soil.
The cohesive soil shall be compacted to a dry density equivalent to 90% of the maximum dry
density obtained in ASTM D 1557. The cohesionless soil shall be compacted to 70% relative
density in accordance with ASTM D 4253 and ASTM D 4254.

5. In-place density shall be determined by one or more of the methods given by ASTM D 1556,
ASTM D 2167, ASTM D 2922 and ASTM D 2937.

6. The area surrounding a tank shall be graded to provide adequate drainage.

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 BP OIL CO. RP 4-2-2
FOUNDATIONS FOR
ATMOSPHERIC Page 5 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

* 6.2 Pile Foundation

1. A pile or other deep foundation shall be used only with the approval of the Owner’s Engineer when,

a. The tank site is underlain by deep soil deposits which are too weak to support the loads
imposed by the tank.
b. Expected settlements are too large and cannot be reduced to tolerable limits by methods
given in Paragraph 5.1.
c. Construction of a viable lead containment and detection system using any other foundation
system is precluded due to soil conditions.

2. Pile foundations shall comply with RP 4-3-1 .

6.3 Concrete Ringwalls

* 1. Unless otherwise approved by the Owner’s Engineer, a concrete ringwall shall be used only in
firm soils where settlement at the tank center is expected to be less than 6 inches, and edge
cutting settlement is a concern. For details of concrete ringwalls see Figure 5 through 8.

2. Concrete ringwall design and construction shall comply with RP 4-6-1 and RP 4-6-2 .

6.4 Foundation Details

1. Figures listed in Table 1 shall be used in the design of tank foundations.

2. As-built plan, elevation and section drawings required in the construction of the tank’s foundation
shall be included in the tank’s permanent records.

7.0 LEAK DETECTION, CATHODIC PROTECTION, AND RELEASE PREVENTION

BARRIER SYSTEMS

* 7.1 Unless otherwise specified by the Owner, new tanks shall have a leak detection and release prevention
barrier system which as a minimum shall consist of:

1. An impermeable membrane installed immediately below a layer of fine gravel or sand placed
under the tank. The membrane shall be a coated fabric with a minimum thickness of 40 mils (1
mm). The membrane shall be protected against puncturing as recommended by the
manufacturer, and shall be compatible for the type of product stored in the given tank.

2. A leak detection system consisting of plastic pipes, placed on top of the membrane. The number
of pipes for cone-up tanks shall be obtained by dividing the tank diameter, in feet, by 10. For
cone-down tanks, a minimum of one leak detection pipe, from the center sump, shall be required.

3. Details for leak detection system shall be per Figures 3, 4 , 7 , 8 , 11 , 12 , and 15 through
21 .

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 BP OIL CO. RP 4-2-2
FOUNDATIONS FOR
ATMOSPHERIC Page 6 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

7.2 The leak containment and detection system specified above shall be designed to take into account
expected settlements that may affect the integrity of the impermeable membrane. Slip joints, such as
folds, are required to avoid rupturing the membrane.

7.3 Cathodic protection systems shall be designed in accordance with RP 14-4-2 .

7.4 As-built plan, elevation and details of leak detection, cathodic protection and release prevention
barriers shall be included in the tank’s permanent records.

* 7.5 Field test and inspection records for impermeable membranes shall be recorded on RP 4-2-2 IC or
an alternative acceptable to the Owner’s Engineer.

7.6 Where appropriate, manufacturer’s installation, calibration and maintenance recommendations shall
be documented in the tank’s permanent records.

8.0 TANK SETTLEMENT

When dealing with tank settlement, it is important to distinguish between shell and bottom settlement.
The following types of settlement shall be considered in the design of atmospheric storage tank
foundations:

8.1 Shell Settlement

Shell settlement is categorized into four groups.

1. Uniform shell settlement – The shell can settle uniformly so that the structure remains level.
Uniform settlement of this type does not introduce high stresses in the tank shell and the tank
should not need correction. It is usually easier and safer to adjust piping to accommodate the tank
shell settlement.

2. Uniform tilt – The shell can also settle unevenly so that tilting occurs across the tank diameter,
with the bottom of the shell remaining in a flat plane. Settlement of this type is called planar tilt
and does not affect the integrity of the tank. It is conceivable that tilting could promote operating
problems, loss of capacity and inhibited floating roof travel. However, experience indicates that
planar tilting of up to 12 to 24 inches has not affected operability in large diameter tanks (up to
200 ft diameter).

3. Differential shell settlement – The shell settles unevenly so that it does not remain either level or
in a tilted planar condition. If large enough, this type of settlement can cause ovalization of the
tank shell. With floating roof tanks, shell ovalization can cause windgirder distortion, binding of
the roof or loss of seal between shell and roof. With cone roof tanks, excessive differential shell
settlement could cause flat spots or wrinkles in the thinner top courses of the tank shell and at
the roof to shell junction.

4. Edge cutting – The shell settles as much as a foot more than the bottom within several feet of the
shell. This type settlement can be avoided with a properly designed ringwall.

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 BP OIL CO. RP 4-2-2
FOUNDATIONS FOR
ATMOSPHERIC Page 7 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

8.2 Bottom Settlement

Experience shows that tank bottom settlement can be more critical to the structural integrity of a tank
than shell settlements. When a tank bottom settles evenly and is supported adequately by the
foundation, membrane stresses in the bottom plates are very low. However, when localized uneven
or differential bottom settlement occurs, it can cause extremely high membrane stresses in the fillet
welded bottom plates. This can result in weld failures which in turn can cause progressive washout
for a poorly designed/constructed foundation.

9.0 HYDROTESTING

For requirements for hydrotesting of atmospheric storage tanks, refer to RP 11-1-1 .

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 BP OIL CO. RP 4-2-2
FOUNDATIONS FOR
ATMOSPHERIC Page 8 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

TABLE 1
TANK FOUNDATION
FIGURE NUMBERS

TYPE OF TANK BOTTOM

TYPE OF MEMBRANE SYSTEM
FOUNDATION CONE-UP CONE DOWN DETAILS
Stone Ringwall 1 (3) 2 (4) (17, 21)
Concrete Ringwall 5 (7) 6 (8) (18, 19, 21)
Piles/Slab 9 (11) 10 (12) (20)
No Ringwall 13 (15) 14 (16) (17, 21)

NOTE:
(2) With leak detection and release prevention listed in ( ). Notes to figures listed in Figure 21.

TABLE 2
PHYSICAL PROPERTIES OF LINER MATERIALS

Property ASTM Value

Procedure

Grab Tensile Strength D751 1000 lbs.

Strip Tensile Strength D751 750 lbs.
Tongue Tear Strength D751 50 lbs.
Hydrostatic Resistance D751 – Method A 500 psi – 5 min.
Low Temperature Strength D-2136, 4hrs, 25°F No cracking, 1/8” mandrel
Dimensional Stability D-1204, 1hr, 212°F 4% max
Thickness (1) D-751 As specified "0.002 in
Chemical Resistance (1) As specified As specified
Moisture Absorption D-471, 7 days, 70°F 5% max

NOTE:
To be specified by the Owner’s Engineer.
* (1)

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 BP OIL CO. RP 4-2-2
FOUNDATIONS FOR
ATMOSPHERIC Page 9 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

TABLE 3
DOCUMENTATION REQUIREMENTS
FOR FOUNDATIONS FOR ATMOSPHERIC STORAGE TANKS PER RP 4-2-2

Item Description Format As-Built

1 Geotechnical Engineer’s Report in accordance with Text N/A
Paragraph 4.3.
2 Plan, elevation and section drawings of AST CALS G4 TIFF Yes
foundation. (Compressed)
3 Plan, elevation and detail drawings of leak detection, CALS G4 TIFF Yes
cathodic protection and/or release prevention systems (Compressed
in accordance with Paragraph 7.4.
4 Field test and inspection records for impermeable Text Yes
membranes.
5 Manufacturer’s installation, calibration and Text N/A
maintenance data for leak detection systems, where
appropriate.

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 BP OIL CO. RP 4-2-2
FOUNDATIONS FOR
ATMOSPHERIC Page 10 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

FIGURE 1
CONE – UP, GRAVE RINGWALL, NO MEMBRANE

L
C

5
1/120 SLOPE

1/120 SLOPE

4
2 FT.-6 IN.

10 FT.-6 IN. MIN.

12 IN. 18 IN. MIN.

2 FT.-6 IN. (TYPE)

4 IN.

1 IN.
3 FT.-6 IN.

NOTE For Notes see Figure 22.

1/24 SLOPE

1.5
3

GRADE

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FOUNDATIONS FOR
ATMOSPHERIC Page 11 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

FIGURE 2
CONE – DOWN, GRAVEL RINGWALL, NO MEMBRANE

L
C

5
1/120 SLOPE

1/120 SLOPE

4
2 FT.-6 IN.

10 FT.-6 IN. MIN.

12 IN. 18 IN. MIN.

2 FT.-6 IN. (TYPE)

4 IN.

1 IN.
3 FT.-6 IN.

NOTE For Notes see Figure 22.

1/24 SLOPE

1.5
3

GRADE

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 BP OIL CO. RP 4-2-2
FOUNDATIONS FOR
ATMOSPHERIC Page 12 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

FIGURE 3
CONE-UP, GRAVEL RINGWALL MEMBRANE – ANCHOR SYSTEM 1

L
C

5
1/120 SLOPE

1/120 SLOPE

SEE ANCHOR SYSTEM 1 DETAIL A

15
1
2
2 FT.-6 IN.

12 IN. 18 IN. MIN.

10 FT.-6 IN. MIN.
4 IN.
2 FT.-6 IN. (TYPE)
3 FT-6 IN.

3
5 FT.

7
1/24 SLOPE

NOTE For Notes see Figure 22.

(SEE NOTE 4)

2 FT.
8

3 FT.

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REFINING PRACTICE

3 FT.-6 IN.

2 FT.-6 IN. (TYPE) 2 FT.-6 IN.

8 IN. TO 4 IN.
8 16 IN. 3 C
1/48 SLOPE L
(SEE NOTE 4)
1/24 SLOPE

1
1/48 SLOPE

2 FT.
1 4
2 6
FIGURE 4

3 IN.
15

18 IN. MIN. 12 IN.

ATMOSPHERIC
STORAGE TANKS
FOUNDATIONS FOR

7 5
1/48 SLOPE SEE ANCHOR SYSTEM 1 DETAIL B

10 FT.-IN. MIN.

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SEE CENTER
SUMP DETAIL
NOTE: For Notes see Figure 22.
Rev. 4

CONE – DOWN, GRAVEL RINGWALL MEMBRANE – ANCHOR SYSTEM

RP 4-2-2
Page 13 of 32

June 1996
 BP OIL CO. RP 4-2-2
FOUNDATIONS FOR
ATMOSPHERIC Page 14 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

FIGURE 5
CONE-UP, CONCRETE RINGWALL, NO MEMBRANE

CL

1
1
1/120 SLOPE

1/120 SLOPE

9
10

7 FT.
2 IN.

B (NOTE 1)
CL
CL

11
4 IN.

2 FT.

NOTE: For Notes see Figure 22.

1 FT.

A (NOTE 1)
9

1
1

(NOTE 1)
C

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FOUNDATIONS FOR
ATMOSPHERIC Page 15 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

FIGURE 6
CONE-DOWN, CONCRETE RINGWALL, NO MEMBRANE

CL

1
1
1/120 SLOPE

1/120 SLOPE

9
10

7 FT.
2 IN.

B (NOTE 1)
CL
CL

11
4 IN.

2 FT.

NOTE: For Notes see Figure 22.

1 FT.

A (NOTE 1)
9

1
1

(NOTE 1)
C

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FOUNDATIONS FOR
ATMOSPHERIC Page 16 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

FIGURE 7
CONE-UP, CONCRETE RINGWALL, MEMBRANE – ANCHOR SYSTEM 2

CL

6
1
1
SEE ANCHOR SYSTEM 2 DETAIL

1/120 SLOPE

1/120 SLOPE

9
10

15 IN.
1

7 FT.
6 IN.
3 IN.

B (NOTE 1)
CL
CL

11
4 IN.

NOTE: For Notes see Figure 22.

3 FT.

SLOPE
7

1/12

2 FT.

1 FT.
(SEE NOTE 4)

4 FT. 6 IN.
A (NOTE 1)
9

1
1

(NOTE 1)
C

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FOUNDATIONS FOR
ATMOSPHERIC Page 17 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

FIGURE 8
CONE-DOWN, CONCRETE RINGWALL MEMBRANE – ANCHOR SYSTEM 3

CL

SEE CENTER
SUMP DETAIL
6
1

1
SEE ANCHOR SYSTEM 3 DETAIL

1/48 SLOPE

1/48 SLOPE

9
10

7 FT.
2 IN.

B (NOTE 1)
CL
CL

11

NOTE: FOr Notes see Figure 22.

4 IN.
3 FT.

2 FT.
7

1 FT.
(SEE NOTE 4)

A (NOTE 1)
6 IN.
8

APPROX 3 FT.-6 IN.

9

(NOTE 1)
C

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REFINING PRACTICE

3 FT.

CL
3 4 IN.
1/120 SLOPE
1/24 SLOPE

1 (NOTE 2) 1/120 SLOPE

1

12 (NOTE 3)
5
FIGURE 9

5
13
ATMOSPHERIC

OTHER PILES
STORAGE TANKS

NOT SHOWN
FOUNDATIONS FOR

CONE-UP, PILES/SLAB, NO MEMBRANE

BPOUS Engineering Services – Cleveland, Ohio

NOTE: For Notes see Figure 22.
(See Notes for channels in
concrete slab, design of R/C
Rev. 4

slab and pile data).

RP 4-2-2
Page 18 of 32

June 1996
 BP OIL CO.

REFINING PRACTICE

3 FT.

CL
3 4 IN.
1/120 SLOPE
1/24 SLOPE

1 (NOTE 2) 1/120 SLOPE

1

12 (NOTE 3)
5
FIGURE 10

5
13
ATMOSPHERIC

OTHER PILES
STORAGE TANKS

NOT SHOWN
FOUNDATIONS FOR

BPOUS Engineering Services – Cleveland, Ohio

CONE – DOWN, PILES/SLAB, NO MEMBRANE

NOTE: For Notes see Figure 22.

(See Notes for channels in
concrete slab, design of R/C
Rev. 4

slab and pile data).

RP 4-2-2
Page 19 of 32

June 1996
 BP OIL CO.

3 FT.
REFINING PRACTICE

8 (SEE NOTE 4)

4 IN. SEE ANCHOR SYSTEM 4 DETAIL CL

3

3 FT.
1/24 SLOPE 1/120 SLOPE

1 (NOTE 2) 1/120 SLOPE

1

12 (NOTE 3) 6

6 IN.
7
FIGURE 11

5
5
ATMOSPHERIC
STORAGE TANKS

13 OTHER PILES
FOUNDATIONS FOR

NOT SHOWN

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NOTE: For Notes see Figure 22.
(See Notes for channels in
concrete slab, design of R/C
Rev. 4

slab and pile data).

CONE-UP, PILES/SLAB, MEMBRANE – ANCHOR SYSTEM 4
RP 4-2-2
Page 20 of 32

June 1996
 BP OIL CO.

3 FT.
REFINING PRACTICE

8 (SEE NOTE 4)

4 IN. SEE ANCHOR SYSTEM 4 DETAIL CL

3

3 FT.
1/24 SLOPE 1/120 SLOPE

1 (NOTE 2) 1/120 SLOPE

1

12 (NOTE 3) 6

6 IN.
7
FIGURE 12

5
5
ATMOSPHERIC
STORAGE TANKS

13 OTHER PILES
FOUNDATIONS FOR

NOT SHOWN

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NOTE: For Notes see Figure 22.
(See Notes for channels in
concrete slab, design of R/C
Rev. 4

slab and pile data).

CONE – DOWN, PILES/SLAB, MEMBRANE – ANCHOR SYSTEM 4
RP 4-2-2
Page 21 of 32

June 1996
 BP OIL CO. RP 4-2-2
FOUNDATIONS FOR
ATMOSPHERIC Page 22 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

FIGURE 13
CONE-UP, EARTH PAD, NO MEMBRANE

CL

1/120 SLOPE

1/120 SLOPE

5
14
1 IN.
4 IN.
3 FT.-6 IN.
4 FT.-6 IN.

1/24 SLOPE

NOTE: For Notes see Figure 22.

3

1
1

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FOUNDATIONS FOR
ATMOSPHERIC Page 23 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

FIGURE 14
CONE – DOWN, EARTH PAD, NO MEMBRANE

CL

1/120 SLOPE

1/120 SLOPE

5
14
1 IN.
4 IN.
3 FT.-6 IN.
4 FT.-6 IN.

1/24 SLOPE

NOTE: For Notes see Figure 22.

3

1
1

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FOUNDATIONS FOR
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REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

FIGURE 15
CONE-UP, EARTH PAD, MEMBRANE – ANCHOR SYSTEM

CL

1/120 SLOPE

1/120 SLOPE

SEE ANCHOR SYSTEM 1 DETAIL A

14

12 IN.
4 IN.
4 FT.-6 IN.

3
4 FT.

NOTE: For Notes see Figure 22.

1/24 SLOPE
2 IN.
(SEE NOTE 4)

1
1
8

2 FT.

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FOUNDATIONS FOR
ATMOSPHERIC Page 25 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

FIGURE 16
CONE – DOWN, EARTH PAD, MEMBRANE – ANCHOR SYSTEM 1

CL

SEE CENTER
SUMP DETAIL
1/48 SLOPE

1/48 SLOPE

SEE SNACHOR SYSTEM 1 DETAIL B

14

12 IN.
4 IN.

7
4 FT.

3
4 FT.-6 IN.

NOTE: For Notes see Figure 22.

1/48 SLOPE
1/24 SLOPE
2 IN.
(SEE NOTE 4)

6 IN.
1
8

2 FT.

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 BP OIL CO.

REFINING PRACTICE

4 TO 4 TO
8 IN. 4 IN. 8 IN. 4 IN.
NOM. NOM.
1 IN. 3 1 IN.
3
TANK BOTTOM TANK BOTTOM

6 IN.
17 17 6 IN.

9 IN.
7

12 IN.
12 IN.
1 1

18 IN.
18
FIGURE 17

16 6 2 6
ATMOSPHERIC
STORAGE TANKS

2
FOUNDATIONS FOR

ANCHOR SYSTEM 1 DETAILS

DETAIL A DETAIL B
CONE – UP CONE – DOWN

BPOUS Engineering Services – Cleveland, Ohio

Rev. 4

NOTES:
1. For Notes see Figure 22.
.

2. Continuous fillet wel between tank chime and item 18

RP 4-2-2
Page 26 of 32

June 1996
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FOUNDATIONS FOR
ATMOSPHERIC Page 27 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

FIGURE 18
ANCHOR SYSTEM 2 DETAIL

6
1/120 SLOPE
1/12 SLOPE

9
10

APPROX. 3 FT.

15 IN.
NOTE: For Notes see Figure 22.
6 IN.
15

3 IN.
11

1/12 SLOPE

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FOUNDATIONS FOR
ATMOSPHERIC Page 28 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

FIGURE 19
ANCHOR SYSTEM 3 DETAIL

1/48 SLOPE

6
12 IN. 9
10

NOTE: For Notes see Figure 22.

6 IN.
15

3 IN.
11

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FOUNDATIONS FOR
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REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

FIGURE 20
ANCHOR SYSTEM 4 DETAIL

1/120 SLOPE

12 IN.
1/12 SLOPE

APPROX. 3 FT.

NOTE 2

C (NOTE 1)
NOTE: For Notes see Figure 22.

B (NOTE 1)

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FOUNDATIONS FOR
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REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

FIGURE 21
CENTER SUMP DETAIL

6
12 IN. NOM.

5
TANK BOTTOM

20
21

24 IN. DIA.
1
CL

12 IN. NOM.
SEAM
19
10
1

NOTE: For Notes see Figure 22.

2 IN.
1/48 SLOPE

3 IN.
1/48 SLOPE
1/48 SLOPE

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FOUNDATIONS FOR
ATMOSPHERIC Page 31 of 32
REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

NOTES TO FIGURES 1 THRU 21

LEGEND:
* 1. Clean, dry sand, pea gravel, or well-graded crushed stone or crushed gravel per ASTM D 693. Size
Number 6, as specified by the Owner’s Engineer. Size Numbers 7, 56, or 57 are also acceptable,
provided the fine grading requirement to meet dimensional tolerances for the tank pad elevations can
be met.
2. Crushed stone or gravel per Paragraph 6.1.3.
3. 1 in. minimum thickness, impermeable sand-asphalt mix (apply after wet test).
4. Cohesive or cohesionless fill compacted to densities per Paragraph 6.1.5.
5. Undisturbed sub-grade.
* 6. Impermeable membrane, thickness and type to be specified by Owner’s Engineer. Physical properties
of the liner shall comply with the requirements of Table 2, as a minimum. Seams are to be tested per
RP 4-2-6 Paragraph 8.1.6.
* 7. 1 1/2 to 2 in. diameter SCH 40 PVC pipe, slotted and capped at one end, teed into tell-tale pipe at
opposite end. Length, actual diameter, slots, expansion loop and spacing to be specified by Owner’s
Engineer. Hardware to to be specified by Vendor.
8. 2 in. diameter SCH 40 PVC tell-tale pipe, capped both ends (top cap removable), teed into 7.
9. Clay fill compacted to density per Paragraph 6.1.5.
* 10. 12 in. clean, dry sand fill unless otherwise specified.
* 11. Reinforced concrete ringwall – reinforcing steel design to be specified by Owner’s Engineer. Tolerances
to comply with API 653.
* 12. Reinforced concrete mat. Reinforcing steel and drainage channels to be specified by Owner’s Engineer.
* 13. Piles to be specified by Owner’s Engineer.
* 14. Earth pad per Paragraph 6.1. Height above original grade to be specified by Owner’s Engineer.
* 15. 3/8 in. diameter x 3 in. long imbedded anchor – stainless steel – with washer and nut 3/16 in. thick x
2 in. wide continuous stainless steel clamping plate. Anchor spacing to be specified by Owner’s
Engineer.
16. C. S. channel, angle or plate – continuous with spacer, if required welded to top flange 7/16 in diameter
holes required for item 17.
* 17. S.S. or galvanized studs per item 16 dimensions, with second nut and washer 1/4 in. thick x 2 in wide
S.S. or galvanized clamping plate. Anchor spacing to be specified by Owner’s Engineer. See also
Note 6.
18. C.S. channel angle or plate – continuous with spacer, if required, welded to top flange. 7/16 in diameter
holes required for item 17.
* 19. Angle 8x4x1/2 CS, with 3/8 in diameter C.S. bolt, nut and washer, or equivalent. Spacing of holes to
be specified by Owner’s Engineer
20. 1/2 in. thick C.S. pan includes angle 4x4x1/2 with holes for 19.
21. Geotextile to hold sand, if required.

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REFINING PRACTICE
STORAGE TANKS Rev. 4 June 1996

NOTES TO FIGURES 1 THRU 21

NOTES:
* 1. Dimensions A, B, and C for concrete ringwall designs to be furnished by Owner’s Engineer.
2. 3 in. minimum depth of sand between tank bottom and sloped concrete mat over pile foundation.
* 3. Thickness of concrete mat over piles to be specified by Owner’s Engineer.
* 4. If specified by the Owner’s Engineer, tell-tale well pipes shall be eliminated and replaced by a valve,
normally closed in service. A concrete manhole, size to be specified by the Owner’s Engineer shall be
constructed around the valved end of the leak detection pipe(s).
* 5. 12 in. unless otherwise specified by Owner’s Engineer.
* 6. Embedded polymeric anchors welded to the flexible liner may be used if approved by the Owner’s
Engineer.
3

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