GP Exxon Civil

 

GP 04-08-01

Tank Foundations

March 2005

Tank Foundations GP 04-08-01 Scope [I] This Global Practice (GP) covers the design and construction of foundations for atmospheric storage tanks, refrigerated storage tanks, and carbon steel tanks in sulfuric acid service. [I] An asterisk (*) indicates that additional information information is required. If a job is contracted, this information is furnished in the Job Specification.

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GP 04-08-01

Tank Foundations

March 2005

Table of Contents Table of Figures ......................... ................................................... .................................................... .................................................... ............................... ..... 3 1.

Required References ....................... ................................................ .................................................. ............................................ ................... 4

1.1. 2.

Global Practices–ExxonMobil Engineering Practices ........ ................ ................ ................. ........... .. 4

Additional References ......................... .................................................. .................................................. ........................................ ............... 4

2.1.

Global Practices–ExxonMobil Engineering Practices ........ ................ ................ ................. ........... .. 4

2.2.

AASHTO–American Association of State Highway Transportation Officials 4

2.3.

ACI–American ACI–Ame rican Concrete Institute ....................... ............................................... .......................................... .................. 5

2.4.

API–American API–Ame rican Petroleu Petroleum m Institute........... Institute.................................... ................................................... ............................ .. 5

2.5.

ASTM–American Society for Testing and Materials ........ ................ ................ ................ ............. ..... 5

3.

General ....................... ................................................. ................................................... ................................................... ......................................... ............... 5

4.

Pad Construction for Atmospheric Storage Tanks ...................... ............................................ ...................... 6

5.

Foundations for Refrigerated Storage Tanks ......................... ................................................... .......................... 10

6.

Foundations for Carbon Carbon Steel Tanks in Sulfuric Acid Service ................... ........................ ..... 14

Record of Change ......................................................................... ................................................................................................... .............................. .... 17 Attachment: Purpose Codes Definitions ......................... .................................................. ......................................... ................ 18

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GP 04-08-01

Tank Foundations

March 2005

Table of Figures Figure 1: Pad Construction Apex-Up Cone Bottom Tanks Ta nks ...................... ....................................... ................. 8 Figure 2: Pad Construction Apex-Down Cone Bottom Tanks Ta nks .................... .................................. .............. 9 Figure 3: Concrete Ringwall Details .................................. ........................................................... ....................................... .............. 10 Figure 4: Zinc Reference Electrode Installation ............................ .................................................... .......................... .. 10 Figure 5: Ringwall Foundation for Cylindrical Refrigerated Tank........................ Tank.......................... .. 12 Figure 6: Elevated Pile Foundation for Cylindrical Refrigerated Tank .................. 13 Figure 7: Foundation for Carbon Steel Tanks in Sulfuric Acid Service ................. 15

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GP 04-08-01

1.

Tank Foundations

March 2005

Required References

1) [I] This Section lists lists the Practice that is referenced and assumed to be a part of this document. Unless otherwise specified herein, use the latest edition. 2) * [I] Local codes and standards standards may be substituted substituted for the ones referenced herein provided the following provisions are met: a) The resultant resultant design design meets the safety safety and serviceabil serviceability ity criteria criteria attained attained through through this practice. practice.  b) Substitution is accepted by the authorities authorities where the facility is to be located located and by the Owner's Engineer.

1.1.

2.

Global Practices–ExxonMobil Engineering Practices GP 04-01-03

Design Loads for Structures

GP 04-09-01

Site Preparation and Earthwork

Additional References

1) * [I] The following following Practice Practicess and Standards Standards shall shall be used with this this Practice Practice as applicable. applicable. 2) * [I] Local codes codes and standards standards may be substitu substituted ted for the ones referenc referenced ed herein provid provided ed the following provisions are met: a) The resultant resultant design design meets meets the safety safety and serviceabil serviceability ity criteria criteria attained attained through through this this GP.  b) Substitution is accepted by the authorities authorities where the facility is to be located located and by the Owner's Engineer.

2.1.

Global Practices–ExxonMobil Engineering Practices GP 04-01-01

Concrete Design and Construction

GP 04-06-01

Reinforced Concrete Foundations, Anchor Bolts and Grout

GP 04-07-01

Piles and Sheet Piling

GP 09-06-01

Refrigerated Storage Tanks

GP 19-05-01

Cathodic Protection

2.2.

AASHTO–American Association of State Highway Transportation Officials AASHTO T166

RFCH, PL Page 4 of 18

Standard Method of Test for Bulk Specific Gravity of Compacted Bituminous Mixtures Using Saturated Surface-Dry Specimens

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ACI–American Concrete Institute ACI 318/318R 

2.4.

Building Code Requirements for Structural Concrete (ACI 318-02) and Commentary (ACI 318R-02)

API–American Petroleum Institute API STD 650

Welded Steel Tanks for Oil Storage

API STD 650, 650, App. B

Recommendations for Design and Construction of Foundations for Aboveground Oil Storage Tanks

API STD 650, 650, App App.. E

Seis Se ismi micc Des Desig ign n of St Stor orag agee Tan Tanks ks

API STD 650, 650, App. I

Undertank Leak Detection and Subgrade Protection

2.5.

3.

Tank Foundations

ASTM–American Society for Testing and Materials ASTM B 418

Standard Specification for Cast and Wrought Galvanic Zinc Anodes

ASTM C 192/C 192M

Standard Practice for Making and Curing C uring Concrete Test Specimens in

ASTM D 448

the Laboratory Standard Classification for Sizes of Aggregate for Road and Bridge Construction

ASTM D 693

Standard Specification for Crushed Aggregate for Macadam Pavements

ASTM D 1556

Standard Test Method for Density and Unit Weight of Soil in Place by the Sand-Cone Method

ASTM D 1557

Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft3 (2,700 kN-m/m3))

ASTM D 2167

Standard Test Method for Density and Unit Weight of Soil in Place by the Rubber Balloon Method

ASTM D 2922

Standard Test Methods for Density of Soil and Soil-Aggregate in Place  by Nuclear Methods (Shallow (Shallow Depth)

ASTM D 2937

Standard Test Method for Density of Soil in Place by the Drive-Cylinder Method

General

1) [R] Earth subgrad subgradee preparation, preparation, placement placement of fill, fill, and compaction compaction requirem requirements ents shall shall be per GP 0409-01.. 09-01 2) [R] Where concrete ringwalls ringwalls are provided under the shell, they they shall be designed designed in accordance with API STD 650, 650, Appendix B, and ACI 318/318R , taking into consideration predicted settlements. RFCH, PL Page 5 of 18

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March 2005

Pad Construction for Atmospheric Storage Tanks

1) [O], [R] Pad construction construction shall be per Figure 1, Figure 2, or Figure 3. If flush type nozzles nozzles are used, there shall be a minimum 2 in. (50 mm) clearance beneath the flange of the nozzle. 2) * [I] Predicted settlement settlement to be used in establishing establishing foundation pad height height will be specified. specified. 3) [R] Pads equipp equipped ed with a ringwall ringwall are are required required for the follow following ing conditi conditions: ons: a) Tan Tanks ks large largerr than than 120 ft (36.5 (36.5 m) m) in diame diameter ter  b) Tanks higher than 48 ft (14.6 (14.6 m) with diameters of 100 ft (30 m) or larger c) When a cohesionl cohesionless ess soil will will be used as general general fill, the minimum minimum size size tank requiring requiring a ringwall ringwall will be specified. 4) [R] Acceptable Acceptable material materialss for stone ringwall ringwall constru construction ction,, below the top 4 in. (100 (100 mm) zone of graded crushed stone or crushed gravel, include any crushed stone or crushed gravel size numbers 2, 24, 3, 357, 4 or 467 (ASTM ( ASTM D 448) 448) that meets the requirements of ASTM D 693 for 693 for crushed aggregate. Proposals to use other gradations or materials shall be approved by the the Owner’s Engineer. Crushed slag shall not be used. 5) [R] A reinforced reinforced concrete ringwall ringwall is acceptable, provided provided a tank shell settlement settlement of 2 in. (50 mm) or less is expected and details details in Figure 3 are applied. If site-specific experience has demonstrated demonstrated satisfactory performance of concrete ringwalls for larger shell settlements, then the use of concrete in lieu of crushed stone can be considered in these cases as well. 6) [O], [R] The average elevation elevation of finished finished pads, measured at the the tank shell, shell, shall be within a tolerance of 1 in. (25 mm) of that shown on the construction drawings. 7) [O], [R] Tank pad elevation elevation differences, measured measured at the the shell, shall shall not exceed any of of the following: following: a) 1:7 1:720 20 in any any dist distanc ancee of 30 ft ft (10 m) m) or more. more.  b) 1 in. (25 mm) between the highest highest and lowest elevation points. points. To achieve these tolerances, it may be helpful to either choke surface voids in a crushed stone ringwall with fine aggregate of gradation Size No. 10 (ASTM (ASTM D 448), 448), or excavate a portion of the crushed stone and place a layer of unreinforced or fiber-reinforced mortar having maximum dimensions of 1 ft (300 mm) wide by 2 in. (50 mm) thick. 8) [O], [R] Deviations Deviations from the specified slope of the the pad within within the tank shell shall not exceed 1:720 in a horizontal distance of 30 ft (10 m) or more. 9) [O] Apex-down Apex-down cone cone bottom bottom tanks shall shall have a drain pipe install installed ed to remove rainwate rainwaterr during construction. The pipe shall empty into into a water drawoff manhole, rainwater sump, sump, or other location as specified. The inlet to the drain shall be per API STD 650. 650. 10) [O], [E] Bottom leak detection facility: facility: All new tank tank pads shall be be equipped with with a bottom leak detection facility consisting of a synthetic membrane, a collection sump, and a drain pipe, and specified in accordance with API STD 650, 650, Appendix I. a) The requiremen requirementt for a leak detectio detection n system may may be waived waived if the tank contain containss clean water, water, a  product not fluid at ambient ambient temperature, or if the temperature of the the tank is sufficiently high high to  jeopardize the integrity integrity of the membrane.

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Tank Foundations

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 b) The membrane shall be High Density Density Polyethylene sheet, sheet, 80 mil thickness, unless unless the stored  product necessitates the the use of another material. c) The membrane membrane shall shall be furnis furnished hed with with factory factory sealed sealed seams seams if practical practical.. If field field seams are are used, these shall be made using the extrusion extrusion welding or or hot wedge methods. Seams shall be 100  percent tested using the vacuum vacuum box method and any leaks leaks shall be repaired. d) Where permitt permitted, ed, a concrete pad may may be used under small small tanks instead instead of a synthetic synthetic membrane membrane for leak detection subject to the following: i)

A cont continu inuous ous sla slab b may may be be used used for clo closel sely y spac spaced ed tan tanks. ks.

ii)

The concr concrete ete pad pad or slab shall shall be struc structur turall ally y designe designed d to preven preventt concre concrete te cracki cracking. ng.

iii)

The concr concrete ete pad or slab shall have no join joints ts under the tank. If a join jointt cannot cannot be avoide avoided, d, then a waterstop shall be provided to permanently seal the joint.

iv)

The pad pad or slab slab shal shalll be provi provided ded with with gro groves ves or or slots slots in the the top top of the the slab/p slab/pad ad or equivalent means to allow a leak to flow quickly out from under the tank and be detected. A sump shall not be placed under the tank.

11) [R] Permanent zinc zinc reference electrode: electrode: All tanks shall be provided provided with with a permanent zinc reference electrode installed per Figure Figure 4. The zinc anode shall be per ASTM B 418, 418, Type II composition. Where an impermeable membrane is used per Item (10) above, the electrode shall be installed above the membrane.

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Tank Foundations

March 2005

Figure 1: Pad Construction Construction Apex-Up Cone Cone Bottom Tanks Tanks (Stone Ringwall Construction Shown)(1) C L TANK

2 ft - 6 in.

3 ft - 6 in. 3 ft

NOTE 4

NOTE 2 12 in.

NOTE 3

 APEX

1

SLOPE 1/120

2

SLOPE 1:12 6 3 in. GRADE

3

1 1.5

2 ft MIN.

5

1 1.5

4 GENERAL FILL

 AS REQUIRED REQUIRED (MIN.=0) (MIN.=0) RINGWALL

SUBGRADE NOTES: (1) For tanks not not requiring ringwalls, ringwalls, all other details remain the same, except general general fill replaces the the ringwall material material and starts at pit grade level. (2) For tanks less less than 30 ftft diameter and 30 ft high, high, the berm width shall be decreased to 2 ft. (3) The crushed stone stone or gravel gravel (2 in. Legend) Legend) should extend extend outward past the annular annular ring through through water test. test. The necessary amount may be removed to apply the impermeable sand-asphalt mix after the water test. (4) 1/2 in. (13 mm) mm) thick (min.) (min.) asphalt-impregnated asphalt-impregnated board board required when when oiled sand or or permeable asphalt subbase subbase is used. LEGEND: 1

 

 

With cathodic protection, protection, one of the following subbases should be specified specified (listed in order of preference). The subbase thickness requirement is dependent on the anode configuration. • Dry Clean Clean Sand: 4 in. minimum thickness below the tank bottom if used in conjunction conjunction with a galvanic (sacrificial) anode cathodic protection system. system. 8 in. minimum thickness if used in conjunction with an impressed current cathodic protection system. • Fine Crushed Crushed Stone Stone (gravel/limesto (gravel/limestone): ne): Size Size number number 9 (ASTM (ASTM D448 Table Table 1) crushed stone shall be be used. The thickness requirements requirements are similar to those required of the dry clean sand. Without cathodic protection, one of the following subbases should be specified (listed in order of preference). • Oiled Sand: The sand shall entirely pass the 3/8 in. (9.5 mm) sieve, almost almost entirely pass the No. 4 (4.75 mm) sieve, and have no more more than 10% passing the No. 200 (0.074 mm) sieve. The oil used shall be a low corrosivity oil such as 18 gravity railroad railroad fuel oil or 11.5 minimum gravity Bunker C. A satisfactory mix of oil and sand shall maintain its shape when pressed pressed into a vertical plane. In general, 5 to 10% oil by weight should suffice. The oiled sand shall be compacted by rolling or tamping. Low viscosity asphalt may may be substituted for the oil; however, care should be taken taken to ensure that the resulting mix is suitable for cold placement. placement. Oil may also be spray-applied to the sand, provided oil penetration through the full depth of the sand is demonstrated with a test application. The minimum thickness thickness shall be 2 inches. • Permeable Asphalt: Aggregate shall have have gradation gradation No. 8 or 89 (ASTM (ASTM D448) D448) or equivalent, asphalt cement type AC-20 AC-20 or equivalent at 2 to 4% by weight. Compact using light, walk-behind walk-behind equipment if the pad is equipped with a leak detection membrane. membrane. AASHTO T166 should be used to assess the permeability of the asphalt.

 

The minimum air void percentage should be 8% for a 9.5 mm mix, 6% for a 12.5 mm mix, and 5% for a 19 mm mix. The minimum thickness shall be 2 inches. 2 3 4 5 6

4 in. of well graded crushed stone or crushed gravel, size number number 7 (ASTM D448 Table 1). Size numbers 6, 56, or  67 are also acceptable, provided that tank pad elevation differences can be met. 1 in. minimum thickness impermeable sand-asphalt sand-asphalt mix. Terminate at the outer edge of the annular plate. Cohesive or Cohesionless compacted fill. 12 in. minimum after settlement. Leak Detection Membrane in accordance with Section 4, Item (10).

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Tank Foundations

March 2005

Figure 2: Pad Construction Construction Apex-Down Cone Bottom Tanks Tanks (Stone Ringwall Construction Shown)(1) 3 ft - 6 in.

2 ft - 6 in.

C L TANK

NOTE 5

3 ft NOTE 2 SLOPE 1:12

3 in. GRADE

3

12 in.

NOTE 4

5

1 1.5

1/48 SLOPE NOTE 3

1

2 ft MIN.

 APEX 2

1

4 1.5

 AS REQUIRED REQUIRED (MIN. = 0) RINGWALL

GENERAL FILL 8 in. MIN.

6

7 SUBGRADE

NOTES: (1) For tanks not not requiring ringwalls, ringwalls, all other details remain the same, except general general fill replaces the the ringwall material material and starts at pit grade level. (2) For tanks less less than 30 ftft diameter and 30 ft high, high, the berm width shall be decreased decreased to 2 ft. (3) Specified bottom plate plate slope (1:48) does not apply for tanks tanks less than than 20 ftft in diameter. diameter. (4) The crushed stone or gravel gravel (2 in Legend of Figure 1) should extend extend outward past the annular ring ring through water water test. The necessary amount may be removed to apply the impermeable sand-asphalt mix after the water test. (5)

1/2 in. (13 mm) thick (min.) asphalt-impregnate asphalt-impregnated d board required required when oiled sand sand or permeable permeable asphalt subbase subbase is used.

LEGEND: 1 For Legend Notes 1 through 5, see Figure 1 - Legend 6 8 in. minimum, increased by predicted differential settlement settlement between the center and the shell of the tank. Increase this dimension as required when a leak detection system is specified, to ensure that the drain pipe slopes for drainage. 7 Leak Detection Membrane in accordance with Section 4, Item (10).

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Tank Foundations

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Figure 3: Concrete Ringwall Details

5

4 3

1 2

REINFORCED CONCRETE RINGWALL RI NGWALL

1 1.5 NATURAL SOIL OR GENERAL FILL

L EGEND: 1 and 2 Materials and bottom slopes per Figures Figures 1 3 Leak detection detection mem membrane. brane. Attached to ringw all. 4 5

and 2 as applicable. Cushion top and and bottom w ith non-w oven geotextile geotextil e w here in contact w ith materials materials that could cause punctures. Compacted crushed stone 1 in. (25 mm) maximum size, gravel, or clean sand backfill. 3 in. (75 mm mm) chamfer at 45 degrees. Cham hamfer fer may be reduced if there is satisf satisfactory actory s ite specific specif ic experience w ith smaller smaller chamfer chamfer s.

Figure 4: Zinc Reference Reference Electrode Installation TEST STATION

CL

JUNCTION BOX

GRADE

RINGWALL

SUBGRADE

PROTECTIVE SLEEVE

5.

TANK BOTTOM

GENERAL FILL ZINC REFERENCE CODE

Foundations for Refrigerated Storage Tanks

1) [R] Refrigerated storage tanks shall be supported on either a ringwall ringwall foundation foundation per Figure Figure 5, or an elevated pile supported foundation foundation per Figure 6. Proposals to use alternative foundation foundation design shall  be submitted to Purchaser Purchaser for approval by the Owner’s Engineer. Engineer. 2) [S] [S],, [R] Founda Foundatio tions ns shall shall be be design designed: ed: a) To restrain restrain the tank shell shell against against lifting lifting forces forces resulting resulting from internal internal pressure pressures. s.  b) For full hydrostatic testing, testing, in which the fill height height equals the design liquid liquid height. RFCH, PL Page 10 of 18

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3) [S] [S],, [R] For pile pile suppor supported ted found foundati ations ons:: a) The pile pile cap shall be be designed designed to withstand withstand the the total total loss of any any single single pile.  b) Supports shall be designed designed to withstand thermal thermal effects of a spill of the full tank tank contents. 4) * [R] Heating and/or and/or insulation insulation systems systems shall be designed to prevent ground freezing freezing if specified. 5) [R], [M] If specified, ringwall foundations shall be provided with one one of the following following electrical heating systems: a) Elect Electrical rical resistan resistance ce coils with with separate separate temperature temperature sensing sensing elements elements and and controls controls  b) Self-limiting heater cables All heating elements and temperature sensing elements shall be installed in conduits and be readily accessible for inspection and replacement. 6) [R] Tank Tank bottom bottom settle settlement ment criteri criteriaa shall shall be as specif specified ied in GP 09-06-01. 09-06-01.

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Figure 5: Ringwall Foundation Foundation for Cylindrical Cylindrical Refrigerated Tank Tank SINGLE WALL TANK TANK SHELL (OR OUTER SHELL OF DOUBLE WALL TANK) TANK SHELL INSULATION SYSTEM DOUBLE WALL TANK  ANNULAR SPACE SPACE INSULATION INSULATION

STRAP  ALTERNATE DESIGN DESIGN DETAIL

INNER TANK SHELL INNER TANK BOTTOM TANK BOTTOM TANK BOTTOM INSULATION

STRAP  ATTACHED BY CONTINUOUS FILLET WELD TO SHELL 6

1 2

5

3 6 in. MIN. (150 mm)

COMPACTED

6 in. MIN. (150 mm)

SAND FILL

1

GRADE

4 7

COMPACTED CRUSHED STONE 1 in. (25 mm) MAXIMUM SIZE OR GRAVEL BACKFILL

1 1.5

BOTTOM FACE BELOW FROSTLINE REINFORCED CONCRETE RINGWALL

NATURAL SOIL OR GENERAL FILL

LEGEND: 1 Clean, dry, sand layer, 1 in. (25 mm). 2 Insulation, foam glass block. 3 Vapor Barrier, polyethylene sheet 0.015 in. (.375 mm) thick, factory sealed joints or 6 in. (150 mm) min overlap. 4 Galvanized carbon steel conduit for Electric Heating Elements and Sensors, with sleeved opening through concrete walls. 5 Hardwood block: kiln dried, < 10% moisture, coated coated all sides with elastomeric elastomeric vapor barrier. barrier. Alternatively, a load bearing insulating concrete block, similarly coated is acceptable. 6 Metal jacket insulation covering shall be extended to lap over the top of the Ringwall, with joints lapped and sealed against entrance of water. 7 Layer of non-woven geotextile.

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Figure 6: Elevated Pile Foundation Foundation for Cylindrical Cylindrical Refrigerated Tank Tank SINGLE WALL TANK TANK SHELL (OR OUTER SHELL OF DOUBLE WALL TANK) TANK SHELL INSULATION SYSTEM DOUBLE WALL TANK  ANNULAR SPACE SPACE INSULATION INSULATION

STRAP  ALTERNATE DESIGN DESIGN DETAIL

INNER TANK SHELL INNER TANK BOTTOM

STRAP  ATTACHED BY BY CONTINUOUS FILLET WELD TO SHELL

TANK BOTTOM

TANK BOTTOM INSULATION 5

1 2

4

3 PILE CAP

36 in. (1 m) MIN.

1

FOUNDATION PILES

GRADE

LEGEND: 1 Clean, dry, sand layer, 1 in. (25 mm). 2 Insulation, foam glass block. 3 Vapor Barrier, polyethylene sheet 0.015 0.015 in. (.375 mm) thick, factory sealed joints or 6 in. (150 mm) min overlap. 4 Hardwood block: kiln dried, < 10% moisture, coated coated all sides with elastomeric elastomeric vapor barrier. barrier. Alternatively Alternatively,, a load bearing insulating concrete block, similarly coated is acceptable. 5 Metal jacket insulation covering shall be extended to lap over the top of the Ringwall, with joints lapped and sealed against entrance of water.

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Foundations for Carbon Steel Tanks in Sulfuric Acid Service

1) [M] Special Special requireme requirements nts for the the design design of foundatio foundations ns shall shall be per Figure Figure 7. 2) [M] Drain requirements. Drains shall shall consist of an elbow set set flush in the concrete and piped to an acid sump or sewer. sewer. Each drain shall be equipped with with a strainer. Elbow, pipe, and strainer shall be be of an acid resistant material. 3) [R], [M] Protecti Protection on of concrete concrete against against acid acid spillage spillage shall shall be per the followi following: ng: a) Two coats coats of Coal Tar Epoxy Epoxy or Epoxy Epoxy Mastic Mastic applied applied on all expose exposed d concrete concrete surfaces surfaces after after suitable surface preparation, including the outer vertical surface of the foundation extending about 12 in. (300 mm) below finished grade.  b) When specified, areas around connections connections (e.g., takeoff, sampling) sampling) shall be faced with acid resistant tile and mortar.

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Figure 7: Foundation for for Carbon Steel Tanks in Sulfuric Sulfuric Acid Service

FOUNDATION FOUNDA TION TO BE SY MM MMETR ETRICAL A BOUT CENTER CENTER LINE  .   n    i      6

 A

 A

SLOPE 1:50

DRAINAGE GUTTER

DRAIN TANK DIAMETE TER R + 3 ft - 0 in. PLAN

 ACID  ACI D TANK CURB

 .   n    i      8

6 in.

20 in. MIN. CI

8 in.

4 in. MAX. 2 in. MIN.

(TYP.)

 .   n    i      4    2

6 in.

PROTECTIV PROTEC TIVE E COA COATING TING

FOUNDATION SECTION A-A

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FIN. 6 in. AT GRADE HIGH PT. OF SLAB

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GP 04-08-01

Tank Foundations

March 2005

Table 1: Acceptable Metric Metric Equivalents Equivalents for Figures Figures in.

mm

1

25

2

50

3

75

4

100

6

150

8

200

12

300

24

600

28

700

30

750

36

900

42

1050 Tank Diameter

RFCH, PL Page 16 of 18

20 ft

6m

30 ft

9m

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Record of Change Version 1.0.0 Location

Action

Date: 02/02

Description

Initial Publish.

Version 1.1.0 Section 2

Modifications

Date: 06/02

Minor reference mnemonic updates.

Version 1.1.0

Date: 11/03

Global Practice version number and format updated to comply with new  process; however, original publish date remains, and and no content was modified.

Version 1.2.0

Date: 03/05

Section 1.1

Addition

Added GP 04-01-03 as a reference.

Section 2.2

Addition

Added AASHTO T166 reference.

Section 2.4

Addition

Added API STD 650 Appendix E and Appendix I references

Section 2.5

Addition

Added ASTM D 693 as a reference.

Section 4, Item (1)

Addition

Added rationales for subbase requirements clarification made in Figures 1 and 2.

Section 4, Item (9)

Modification

Replaced reference to Figure 4 with reference to API STD 650.

Section 4, Item (10)

Deletion

Deleted reference to detail connecting the membrane to the sump in Section III of the Civil Engineering Design Guide.

Section 4, Item (11)

Deletion

Deleted Item (11) and renumbered Item (12).

Figure 1

Revision

Revised Figure to clarify subbase requirements dependent on cathodic  protection requirements. requirements.

Figure 2

Revision

Revised Figure to clarify subbase requirements dependent on cathodic  protection requirements. requirements.

Figure 4

Deletion

Deleted figure, which was duplicated in API STD 650, and renumbered remaining figures.

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Attachment: Purpose Codes Definitions Code

Description

C

Assigned to paragraphs containing specifications whose primary purpose is reduced costs. Reduced cost in this context refers to initial investment cost and does not include Life-Cycle cost considerations. considerations. Life-Cycle cost considerations considerations are captured under reliability, reliability, maintainability, or operability purpose codes.

E

Assigned to paragraphs containing specifications whose primary purpose is driven by environmental considerations. considerations. Environmental considerations considerations typically include specifications specifications intended to protect against emissions/leakage emissions/leakage to the air, water, and/or soil. Deviations from the specifications contained in such paragraphs require formal review and approval according to local environmental policy.

I

Assigned to paragraphs that provide only clarifying information such as Scope statements, definitions of terms, etc.

M

Assigned to paragraphs containing specifications whose primary purpose is to provide for maintainability equipment on equipment or systems. Maintainability Maintainabilit y provisions are thoseorthat facilitate  performance of of maintenance equipment/systems equipment/systems either during downtimes during during on- the onstream operations.

O

Assigned to paragraphs containing specifications whose primary purpose is to assure operability of equipment or systems. Operability is the ability of the equipment/system equipment/system to  perform satisfactorily even though though conditions conditions are off-design, such as during startups, process swings, subcomponent malfunction, etc.

R

Assigned to paragraphs containing specifications whose primary purpose is to improve or assure the reliability of equipment equipment or systems. Reliability is a measure of the ability ability of equipment/systems to operate without malfunction or failure between planned maintenance interventions.

S

Assigned to paragraphs containing specifications whose primary purpose is avoidance of  personnel or operational operational safety incidents. Any deviation from the the specifications contained contained in such designated paragraphs requires formal review and approval according to local safety  policy. Personnel Safety:

Operational Safety:

RFCH, PL Page 18 of 18

Refers to the avoidance of recordable personnel injuries; i.e., burns, cuts, abrasions, inhalation, or exposure to dangerous substances, etc., that could result in medical treatment, restricted work, lost-time incidents, or fatalities. Refers to the prevention and control of process releases, fires, explosions, etc.

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