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ENGINEERING DESIGN GUIDE FOR STORAGE TANKS

DOC NO 3DG M60 001

BY AMIT KHANNA

04/17/23 2

•DESIGN OF STORAGE TANKS ATMOSPHERIC OIL

STORAGE TANKS AS PER API 650.

WATER STORAGE TANKS AS PER AWWA D 100.

DOME ROOF TANKS AS PER API 620.

OTHERS LIKE BOLTED,FIELD WELDED,SHOP WELDED AS PER API 12B,12D,12F RESPECTIVELY.

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TYPES OF STORAGE TANKS FLOATING ROOF CONE ROOF CONE CUM

FLOATING ROOF

DOME ROOF

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TYPE OF TANKS

FR CRCFR

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SALIENT FEATURES OF API 650 THIS STANDARD COVERS

MATERIAL,DESIGN,FABRICATION,ERECTION,AND TESTING REQUIREMENTS FOR VERTICAL,CYLINDRICAL,ABOVE GROUND, CLOSED –AND OPEN TOP,WELDED STEEL STORAGE TANKS IN VARIOUS SIZES AND CAPACITIES FOR INTERNAL PRESSURES APPROX. ATMOSPHERIC PRESS. (INTERNAL PRESSURE NOT EXCEEDING THE WEIGHT OF ROOF PLATES),EXCEPT THAT A HIGHER INTERNAL PRESSURE IS PERMITTED WHEN THE ADDITIONAL REQUIREMENTS OF APPENDIX F ARE MET.

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SALIENT FEATURES OF API 650 APPENDIX F APPLIES WHEN THE

INTERNAL PRESSURE MULTIPLIED BY THE CROSS SECTIONAL AREA OF THE NOMINAL TANK DIA DOES NOT EXCEED THE NOMINAL WEIGHT OF THE METAL IN THE SHELL, ROOF AND ANY FRAMING SUPPORTED BY THE SHELL OR ROOF FOLLOW REQUIREMENTS IN F.2 THROUGH F.6.

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SALIENT FEATURES INTERNAL PRESSURES THAT

EXCEED THE WEIGHT OF THE SHELL, ROOF AND FRAMING BUT DO NOT EXCEED 2.5 PSIG WHEN THE SHELL IS ANCHORED TO A COUNTER BALANCING WEIGHT,SUCH AS CONCRETE RINGWALL, ARE COVERED IN F.7.

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LIMITATIONS OF API 650

VACUUM PRESSURE LIMITED TO 25MM OF WATER COLUMN.

INTERNAL PRESSURE CAN BE MAXIMUM UP TO 2.5 PSI.

MAX DESIGN TEMP CAN BE UPTO 500 O F.

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LIMITATIONS OF API 620 MAX. INTERNAL PRESSURE CAN BE

UPTO 15 PSI. MAX DESIGN TEMP CAN BE UPTO

250O F.

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DESIGN AS PER API 650 TWO METHODS ARE SPECIFIED

FOR DETERMINING SHELL THICKNESS

ONE FOOT METHOD FOR TANK DIA LESS

THAN 200 FT.

VARIABLE POINT METHOD FOR TANK

GREATER THAN 200 FT DIA.

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  API 650 API620  

 AWWABASIC APP. APP A F 

BASIC APP. APP R Q 

MAX. INT. PR.

ATM ATM 2.5PSI 

15 psi 15 psi 15psi 

ATM. 

MIN. TEMP 

NS -20OF NS 

-50OF - 60OF -270OF 

-55 OF 

MAX TEMP 

500OF 200 O F 500O F 

200OF -40OF -200OF 

RT 

MAX SHELL THK. 

1.75 in 0.50in 1.75 NS NS NS 2 IN a

BRIEF COMPARISION

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MIN. SHELL THK.D < 50FT. 50<D <120FT 120<D <200 FT  D>200 FT 

  01.875 IN 0.25 IN 0.3125IN 0.375 IN

  01.875 IN 0.25 IN 0.3125IN 0.375 IN

  01.875 IN 0.25 IN 0.3125IN 0.375 IN 

MIN ROOF THK. MIN. BOTTOM PLATE THK.

0.1875 IN  0.25 IN+C.A.

NS  NS d

0.1875 IN  NS d

BRIEF COMPARISION

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MIN. TOP ANGLED< 35 FT 35 < D < 60FT D> 60FT

  2 in x 2 in x 3/16 in 2 in x 2 in x 1/4 in 2 in x 2 in x 3/8 in

  NS NS NS

  NS NS NS 

  NS = NOT SPECIFIED, CA = CORR. ALLOW. , RT = ROOM TEMP.  NS d = MIN. THK OF ANY PLATE IS 0.1875 IN. + C.A.

BRIEF COMPARISION

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GENERAL DATASERVICE ITEM NO.ROOF TYPE OPERATING CAPACITYNO. REQUIRED INTERNAL FLOATING ROOFHAZARD CATEGORY SIZE-DIAMETER/HEIGHT(NOM)

NET CAPACITY

PROCESS DATACONTENTS AMBIENT TEMP: MAX/MINLIQUID SPECIFIC GRAVITY @OPR. TEMP(MIN.) BLACK BULB TEMP.LIQUID VISCOSITY @OPR. TEMP(MIN.) STORAGE TEMPO MAX/MINFLASH POINT ALTITUDE ABOVE LAT.VAPOUR PRESSUE @ 20 O C RAINFALLCORROSIVITY PRESSURE: MIN/NORM/MAXTOXICITY TANK HEATING TYPEFILLING RATE HEAT LOAD NORM/MAXEMPTYING RATE OPERATING LEVEL MIN/MAXEVOLVED VAPOUR TANK MIXERS TYPE/NO.PURGE GAS:INERT / NAT. GAS WATER DRAW SUMPMOLE WT. VAPOUR/OURGE GAS GAUGINGDESIGN LIQ. DENSITY KG/M3 DESIGN TEMP.

DATA SHEET FOR TANKS

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MECHANICAL DETAILSDESIGN & CONSTRUCTION CODE INSULATION TYPE/THKSHELL DESIGN METHOD PAINT ROOFDESIGN PRESSURE MIN/MAX PAINT SHELLDESIGN WIND SPEED PAINT BOTTOMSEISMIC CODE/FACTOR WEIGHT FOUNDATION OPERATINGCORR. ALLOW HYDROTESTTHK SHELL INSULATION TYPE/THKROOF (DEPENDING ON TYPE) ROOFBOTTOM ANNULAR/SKETCH ACCESS(EXTERNAL) STAIRCASE TYPEJOINT EFFICENCY EARTHING BOSSBASE HANDRAILINGMAX. ALLOWABLE SOIL LOADING CLEAN OUT DOORPRESS. VAC RELIEF TYPE DIP HATCHESSTIFFENING RINGS FIRE PROTECTION /CONTROLCATHODIC PROTECTION MANHOLESINSP[ECTION SURFACE PREPN.

DATA SHEET

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MATERIALSSHELL HEATING COILSHELL LINING BOLTSANNULAR PLATE NUTSSKETCH PLATE WELDING FITTINGSROOFPLATE (DEPENDING ON TYPE) GASKETSROOF LINING INSULATION SUPPORTSFLOATING ROOF SEAL STAIRS,HANDRAILS,PLATFORMSNOZZLE FLANGES EARTHING BOSSNOZZLE NECKS RADIOGRAPHYNOZZLE/MANWAY LINING STRESS RELIEVINGSTRUCTURAL STEEL OTHER NDT

DATA SHEET

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Dome roof tank with external structure

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INPUT DATA FOR DESIGN AS PER API 650

DIA• HT.

•NET CAPACITY.

•GROSS CAPACITY.

• DESIGN WIND VELOCITY.

•SESIMIC ZONE

•INTERNAL PR.

PUMPING DATAINFLOW RATE

OUTFLOW RATE

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CONTD. HORIZONTAL ACCEL FACTOR. SOIL DATA. SITE COEFF. VAC. PR. TYPE OF TANK. SPECIFIC GRAVITY OF THE LIQUID STORED. DESIGN TEMPERATURE. CORR. ALLOWANCE.

Rainfall data in mm/hr

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Design as per API 620 OTHER THAN WHAT IS ALREADY

GIVEN FOR API 650 ADDITIONALY YOU SHOULD HAVE :

VAPOUR PRESSURE OF THE LIQUID WHICH NEEDS TO BE STORED.

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APPLICABLE CODES & STDS. WELDING QUALIFICATION/DETAILS

ASME SEC IX. FILLER METALS ASME SEC II PART C. NON DESTRUCTIVE TESTING ASME

SEC V. RADIOGRAPHY ACCEPTANCE ASME

SEC VIII DIVN 1 UW51.

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CONE ROOF TANKS THEIR ROOF CAN BE ANY OF THE

FOLLOWING DEPENDING ON THE DIAMETER OF TANK

COLUMN SUPPORTEDRAFTER/TRUSS SUPPORTED

SELF SUPPORTED

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Typical cone roof tank

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Floating roofs

FLOATING ROOFS ARE PRIMARILY OF THE TYPES AS MENTIONED BELOW.

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Floating roofs

SINGLE PONTOON TYPE IDEAL FOR DIA MORE THAN 17.5 MTR DIA TO 65.0 MTR DIA.

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Typical view of top of FR.

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Floating roofs

DOUBLE DECK ARE IDEAL FOR TANK DIA LESS THAN 17.5 M AND MORE THAN 65.0MTR.

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Floating roofs

HOWEVER FOR CFR TANKS WE CAN ALSO USE ALUMINUM FLOATING ROOF AS PER REQUIREMENT OF CODE AS PER APPENDIX H. HOWEVER THEY HAVE A LIMITATION AS THEY CAN BE USED FOR SMALL DIA TANKS ONLY.

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Aluminum floating roof

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ALUMINIUM FLOATING ROOF

APPENDIX H : THIS PROVIDES MINIMUM REQUIREMENTS THAT APPLY TO THE FLOATING ROOF OF A TANK WITH A FIXED ROOF AT THE TOP OF THE TANK SHELL. PLASTIC CAN BE USED FOR THE CORE AND SKIN MATERIAL PER REQUIREMENTS OF [H3.4]. ALL CONDUCTIVE PARTS OF THE INTERNAL FLOATING ROOF SHALL BE ELETRICALL INTERCONNECTED [H.4.2.4]. THE INTERNAL FLOATING ROOF SHALL BE DESIGNED TO SAFELY SUPPORT AT LEAST TWO MEN [H.4.2.5]. ALL DESIGN CALCS SHALL BE BASED ON SG OF 0.7 [H.4.2.6]. METALLIC INTERNAL FLOATING ROOF SHALL BE BUOYANT ENOUGH TO SUPPORT AT LEAST TWICE ITS DEAD WEIGHT AND SHALL BE CAPABLE OF FLOATING AFTER TWO OF ITS COMPARTMENTS ARE PUNCTURED [H.5.1.2].

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FLOATING ROOFS

FOR A ROLLING LADDER TO BE ACCOMMODATED THE DIA. OF THE TANK SHOULD BE AT LEAST 2.5 TO 3.0 MTR MORE THAN THE HEIGHT OF THE TANK.

ROLLING LADDER SHOULD BE SELF ADJUSTABLE TYPE.

HOWEVER CFR TANKS CAN HAVE A HANG SAFE LADDER ONLY OR ALTERNATIVE ARRANGEMENT CAN BE MADE.

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Rolling ladder

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ECONOMICS IN DESIGN THOUGH THE DIA & HT OF THE TANK

WILL DEPEND ON VARIOUS PARAMETERS LIKE PROCESS REQUIREMENT,TYPE OF SOIL ETC.

THE MOST ECONOMICAL DESIGN CAN HAVE HT. SLIGHTLY MORE THAN THE DIA TO GIVE MOST OPTIMUM DESIGN.e.g. 16 m dia x16.5 mtr ht.

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MATERIAL OF CONSTRUTION API 650 ALLOWS TO USE MATERIAL

LISTED IN CODE AS PER THEIR GROUP NO.

MOST COMMONLY USED MOC ARE 283 GRC,A36,516 GR60,70,A537 CL1.

537 CL11 INVOLVES SPECIAL WELDING SKILLS AND IS NORMALLY AVOIDED.

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MOCPLATES : PLATES SHALL CONFORM TO THE LATEST EDITION OF ONE OF THE SPECIFICATIONS REFERRED BELOW ASTM STANDARDS [2.2.2 ]CSA STANDARDS [2.2.3 ]ISO STANDARDS [2.2.4 ]NATIONAL STANDARDS [2.2.5 ]SHELL PLATES ARE LIMITED TO A MAXIMUM THICKNESS OF 1.75" UNLESS A LESSER THICKNESS IS SPECIFIED. PLATES THICKER THAN 1.5"SHALL BE NORMALIZED OR QUENCH TEMPERED, KILLED, MADE TO FINE GRAIN PRACTICE AND IMPACT TESTED [2.2.1.4]

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WELDING AS PER ASME SEC IX WELDING ELECTRODES : FOR THE

WELDING OF MATERIALS WITH A MINIMUM TENSILE STRENGTH LESS THAN 80 KIPS PER SQUARE INCH, MANUAL ARC-WELDING ELECTRODES SHALL CONFORM TO THE E60 AND E70 CLASSIFICATION SERIES.

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SHELL DESIGN AFTER CAREFULLY SELECTING THE MOC

THE THK. SHOULD BE WORKED OUT AS PER ALLOWABLE STRESS OF THE MOC GIVEN IN CODE.

CHECK FOR REQUIREMENT OF STRESS ANALYSIS, KILLED OR SEMI KILLED MATERIAL.

FOR LOW TEMP CHECK FOR IMPACT TESTING AS GIVEN IN CODE.

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FORMULA USEDT = 2.6 D (H-1) * G + C.A. Sd OR St.

WHERE T = THK. OF SHELL CORSE IN INCHES.

WHERE D = DIAMETEROF THE TANK IN FEET.

WHERE H = HEIGHTOF THE TANK IN FEET.

WHERE G = SP. GRAVITY.

WHERE SD=DESIGN STRESS IN PSI.

WHERE ST = HYDROSTATIC STRESSIN PSI.

WHERE C.A.= CORROSION ALLOWANCE IN INCHES.

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•SHELL DESIGN : THE REQUIRED SHELL THICKNESS IS DEFINED AS THE GREATER OF THE DESIGN SHELL THICKNESS, INCLUDING ANY CORROSION ALLOWANCE, OR THE HYDROSTATIC TEST SHELL THICKNESS. THE SHELL THICKNESS SHALL NOT BE LESS THAN THE FOLLOWING

NOMINAL TANK DIA IN FT.

NOMINAL PLATE THK. IN INCHES

< 50 

50 TO <120 

120 TO 200 

>200 

3/16 ¼ 

5/16 

3/8

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Shell design

•Guidelines for computing the design shell thickness and hydrostatic shell thickness are given. •The permissible plate materials and maximum allowable product design stress, Sd are covered in [Table 3-2 ].

The design stress basis Sd shall be the lesser of two-thirds the

yield strength or two-fifths the tensile strength.

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SHELL DESIGN CONTD THE VACUUM SHOULD BE ADDED

IN THE WIND PRESSURE TO DETERMINE SHELL THK.

INTERNAL PRESSURE TO BE TAKEN BY INCREASING THE HT. OF THE TANK EQUIV. TO INT. PR. WATER COLUMN.E.

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SHELL PLATE ERECTION

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WIND GIRDERS

•TOP AND INTERMEDIATE WIND GIRDERS: AN OPEN TOP TANK SHALL BE PROVIDED WITH STIFFENING RINGS TO MAINTAIN ROUNDNESS WHEN TANK IS SUBJECTED TO WIND LOADS. TYPES OF STIFFENING RINGS, RESTRICTIONS ON STIFFENING RINGS, STIFFENING RINGS AS WALKWAYS, SUPPORTS, CALCULATION OF SECTION MODULUS FOR TOP AND INTERMEDIATE WIND GIRDERS ARE ADDRESSED IN SECTION 3.9.

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WIND GIRDER DESIGN TO BE CALCULATED USING THE

TRANSPOSED WIDTH METHOD. IF EXPERIENCING MORE NO OF

WIND GIRDERS THEN INCREASE THE SHELL THK. MARGINALLY .

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WIND GIRDER DESIGN FLOATING ROOF TANKS INVARIABLY

WILL HAVE ONE PRIMARY WIND GIRDER WHICH IS USED AS A WALK WAY ALSO.

THE SIZE OF SECONDARY WINDGIRDER. SHOULD BE SUCH THAT IT DOESNOT

INTERFERE WITH THE STAIRWAY. SO IDEALLY THE WIDTH OF THE WEB SHOULD BE LESS THAN 200 mm.

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BOTTOM PLATE THE NOMINAL THK SPECIFIED IN

THE CODE IS 6 MM. HOWEVER ANNULAR PLATE THK

NEEDS TO BE SIZED IN TERMS OF WIDTH AND THK.

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ROOFS• ROOFS [3.10]: ALL ROOF PLATES SHALL BE DESIGNED TO SUPPORT DEAD LOAD PLUS A UNIFORM LIVE LOAD OF NOT LESS THAN 25 PSF. MINIMUM NOMINAL THICKNESS OF 3/16 IS SPECIFIED FOR ROOF PLATES. DESIGN REQUIRED FOR FRANGIBLE ROOF TO SHELL DESIGN ARE LISTED IN [3.10.2.5.1]. FAILURE OF THE ROOF TO SHELL JOINT IS USUALLY INITIATED BY BUCKLING OF THE TOP ANGLE AND FOLLOWED BY TEARING OF THE 3/16 INCH CONTINUOUS WELD OF THE PERIPHERY OF THE ROOF PLATES [3.10.2.5.1]. IN CASE THE ROOF TO SHELL JOINT IS NOT FRANGIBLE THEN EMERGENCY VENTING DEVICES IN ACCORDANCE WITH API 2000 SHALL BE PROVIDED BY THE PURCHASER.

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ROOF PLATE THE NOM. THK SPECIFIED IN THE

CODE IS 5 MM. IF CORR. ALLOW. IS ADDED TO

THIS THEN THE SPACING BETWEEN THE RAFTERS CAN BE INCREASED .

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SESIMIC DESIGN SHALL BE DONE AS PER APPENDIX E. CHECK FOR TANK STABILITY WITH RESPECT

TO WIND MOMENT AND SESIMIC MOMENT. IF UNSTABLE DO EITHER OF THE

FOLLOWING: INCREASE SHELL THK OR ANNULAR PLATE

THK OR ANCHOR THE TANK AS PER CODE.

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CURB ANGLE CURB ANGLE SIZE IS DEFINED IN

THE CODE FOR DIA OF THE TANK. CHECK FOR FRANGIBILITY. IF SHELL TO ROOF JOINT IS NOT

FRANGIBLE PROVIDE EMERGENCY VENT DEVICE.

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ANCHOR CHAIR AND BOLT

ANCHOR CHAIR DESIGN IS GIVEN IN API 620.

THE CODE SPECIFIES THE SPACING TO BE KEPT FOR DIFFERENT DIAMETERS.

ANCHOR BOLT LENGTH SHALL BE DEPENDENT ON BOND STRESS OF CONCRETE OR ALTERNATIVELY THE LENGTH CAN BE REDUCED BY PROVIDING ANCHOR AT THE BASE OF THE PLATE.

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TANK VENTING VENTING IS THE MOST IMPORTANT PART

IN TANK DESIGN AS NO. OF FAILURES HAVE BEEN EXPERIENCED ON ACCOUNT OF THESE.

THE CODE TO BE FOLLOWED IS API 2000.

THE VENT MUST ALSO BE CHECKED BY THE PROCESS ENGINEER FOR THE PRESSURE DROP ACROSS IT.

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FLOATING ROOF

•APPENDIX C- ADDRESSES MINIMUM REQUIREMENTS OF EXTERNAL FLOATING ROOFS. MINIMUM THICKNESS OF DECK PLATES SHALL HAVE A NOMINAL THICKNESS OF 3/16 INCH [C3.3.2]. TOP DECK OF DOUBLE DECK ROOFS AND OF PONTOON SECTIONS WHICH ARE DESIGNED WITH PERMANENT SLOPE , SHALL HAVE A MINIMUM SLOPE OF 3/16 INCH IN I FOOT [C3.3.4].

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FLOATING ROOFS

•FLOATING ROOFS SHALL HAVE SUFFICIENT BUOYANCY TO REMAIN AFLOAT.ON LIQUID WITH SG OF 0.7 AND WITH PRIMARY DRAINS INOPERATIVE [C3.4.1]. EACH COMPARTMENT OF THE PONTOON OPENING SHALL BE PROVIDED WITH A LIQUID-TIGHT MANHOLE [C3.5].

•THE FLOATING ROOF SHALL BE SUPPLIED WITH LADDER THAT AUTOMATICALLY ADVANCES TO ANY ROOF POSITION [C.3.7].

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FLOATING ROOF DESIGN FOR A SINGLE DECK PONTOON

TYPE THE MOST IMPORTANT ASPECT IS ITS WIDTH ,OUTER RIM HEIGHT AND THE INNER RIM HEIGHT.

FLOATING ROOFS ARE SUBJECTED TO EITHER OF THE FOLLOWING DESIGN CONDITIONS.

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FLOATING ROOF DESIGN 10 INCHES OF RAINFALL WATER

ACCUMULATION OR PUNCTURED DUCK WITH TWO ADJACENT COMPARTMENTS PUNCTURED.

IT IS PREFERRED THAT THE OUTER RIM SUBMERGENCE SHOULD NOT BE MORE THAN 65 % FOR A CONSERVATIVE DESIGN.

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LEG SUPPORTS THE FLOATING ROOF IS DESIGNED FOR

OPERATING LEVEL AND MAINTENANCE LEVEL.THE NORMAL INDUSTRY PRACTICE IS TO HAVE 1200 MM AS OPERATING LEVEL AND 1800MM AS MAINTENANCE LEVEL.

CARE SHOULD BE TAKEN TO DESIGN THE LEG SUPPORTS AS A VERY HEAVY LEG SUPPORT IS A PROBLEM FOR THE OPERATIONS TEAM.

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LEG SUPPORTS IDEALLY WE USE EITHER 80 NB WITH A

SLEEVE OF 100 NB OR 100 NB WITH A SLEEVE OF 125NB.

NORMALLY THE RADIAL DISTANCE BETWEEN THE LEG SUPPORTS SHOULD NOT BE MORE THAN 5 MTRS FOR DECK THK OF 5 MM.

THE MAX LOAD CARRYING CAPACITY OF INDIVIDUAL LEG SUPPORT IS LIMITED BY L/R RATIO WHICH SHOULD NOT EXCEED 180.

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TANK BOTTOM VIEW

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ANTIROTATIONAL DEVICE SIZING OF ANTIROTATIONAL

DEVICE NEEDS TO BE DONE FOR RESTRICTING THE MOVEMENT OF THE TANK IN SWAYING IN ANY DIRECTION CIRCULARLY.

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FLOATING ROOF SEALS PRIMARY SEALS ARE THE FIRST DEFENSE

AGAINST PRODUCT EVAPORATION AND VAPOR EMISSIONS. MOST GOVERNMENT REGULATIONS REQUIRE PRIMARY SEALS ON ALL FLOATING ROOFS. THE OPTIMAL SEAL HAS INSULATED STAINLESS STEEL HANGERS WITH 316L STAINLESS STEEL COILSPRINGS. GALVANIZED OPTIONS ARE AVAILABLE, SOME ADVANTAGES ARE:

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FLOATING ROOF SEALS REDUCE RISK OF RIM FIRES

INSTALLATION OR MAINTENANCE WITH TANK IN SERVICE

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FLOATING ROOF SEALS UNIFORM CENTERING FORCES AT

LOW STRESS LEVELS DESIGNED FOR INTERNAL AND

EXTERNAL FLOATING ROOF TANKS STANDARD DESIGN FOR 8 IN. (+/-

4 IN.) RIM SPACE – ALTERNATE DESIGNS ARE AVAILABLE

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Double wiper type seal

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Single wiper type

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SECONDARY SEAL

• TO FURTHER REDUCE PRODUCT LOSS AND VAPOR EMISSIONS, A SECONDARY SEAL IS ADDED ABOVE THE PRIMARY SEAL. MOST REGULATIONS REQUIRE THESE SEALS ON EXTERNAL FLOATING ROOFS. SOME ADVANTAGES ARE:

•SEGMENTAL COMPRESSION PLATE DESIGN WITH 2 IN. LAP SEAL •INSTALLATION OR MAINTENANCE WITH TANK IN SERVICE •INSTALLATION ON VERTICAL OR HORIZONTAL RIM •INDIVIDUAL COMPRESSION PLATES MAY BE REMOVED WITHOUT AFFECTING PRIMARY SEAL •STANDARD DESIGN FOR 8 IN. (+/- 4 IN.) RIM SPACE – ALTERNATE 12 IN.

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FLEXIBLE DRAIN ARRANGEMENT

ARTICULATE DRAIN SYSTEM IS REQUIRED FOR FLOATING ROOF TANKS TO CATER FOR RAIN WATER BEING REMOVED FROM DECK TOP.

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TYPICAL ARRANGEMENT OF COFLEXIP ROOF DRAIN

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OTHER VENTS FLOATING ROOF SHALL BE PROVIDED

WITH BLEEDER VENT AND RIM VENTS TO TAKE CARE OF ANY VACUUM BEING CREATED DURING PUNPING CONDITIONS.

STANDARD PRACTICE IS TO PROVIDE MIN. TWO RIM SEAL OR ALTERNATIVELY AT EVERY 50 MTRS OF TANK CIRCUMFERENCE.

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HEATING COILS CERTAIN TANKS STORING CLASS C

PETROLEUM WILL BE PROVIDED WITH FLOOR COIL HEATERS TO HELP REACH STORED LIQUID TO ITS POUR POINT.

HOWEVER IT IS USED FOR CRUDE OIL TANKS ALSO.

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HEATING COILS CLASS C IS WITH FLASH POINT

GREATER THAN 65 O C.

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HEATING COILS SIZING OF FLOOR HEATERS IS DONE BY

PROCESS ENGINEER TAKING INTO CONSIDEARTION THE TIME REQUIRED FOR HEATING THE TANK CONTENTS .

TO AVOID IBR REGULATIONS IT IS DESIRED THAT WE USE SATURATED STEAM WITH PRESS. LESS THAN OR EQUAL TO 3.5BAR (G)BECAUSE OF ITS HIGH OVERALL HEAT TRANSFER COEFFICIENT .

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Appurtenances TANKS SHALL BE PROVIDE WITH

THE FOLLOWING: SHELL: MANHOLES ( 1 FOR 0-60’) 2 FOR 60’-120’ 3 FOR 120’-200’

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Appurtenances 4 OVER 200’ INLET OUTLET DRAW OFF SUMP ROOF DRAIN (FOR F.R.)

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Appurtenances ROOF: MANHOLE VENT WITH FLAME ARRESTOR RIM VENTS GAUGE HATCH LEVEL

MEASUREMENT DEVICES

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INSULATION TANKS WITH HEATING COILS ARE

PROVIDED WITH INSULATION AT SHELL AND ROOF TOP.

IN THIS TANK THE SPIRAL STAIRWAY SHALL BE 200 MM AWAY FRO THE TANK AND SHALL BE STRINGER TYPE.

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INSULATION SUITABLE PROVISION AT TANK TOP IS

TO BE MADE FOR ACCESS TO NOZZLES.

NORMALLY LRB MINERAL WOOL IS USED AS INSULATION MATERIAL WITH ALUMINUM CLADDING.SUITABLE PROVISION IS TO BE PROVIDED ON THE TANK FOR HOLDING THE SAME.

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MIXERS THIS NOZZLE/FLANGE MAY

REQUIRE SPECIAL SIZING TO MATCH THE MIXER SUPPLIER SPECIFICATION. SUPPORTS FOR THE MIXER SHALL BE SUPPLIED AND INSTALLED BY THE TANK CONTRACTOR.

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STANDARD TANK EQUIPMENTS LEVEL INDICATOR LEVEL TRANSMITTER TEMP GAUGE LEVEL SWITCHES

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Cooling & foam system COOLING SYSTEM AND FOAM

SYSTEM ARE TO PROVIDED IF REQUIRED AS PER NFPA CODE.

FOAM POURERS ARE TO BE PROVIDED WITH DEFLECTOR PLATES FOR EXTERNAL FLOATING ROOF TANKS.

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Cooling & foam system RIM SEAL PROTECTION FOR

FLOATING ROOF. FOAM DAM SHALL BE PROVIDED

TO ACCUMULATE THE FOAM BEING POURED FROM THE POURER.

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CORROSION PROTECTION THE STORAGE TANK STEEL

SURFACES ARE TO BE PROTECTED FROM EXTERNAL AND INTERNAL CORROSION.

THIS WILL DEPEND ON SITE CONDITIONS AND PRODUCT TO BE STORED.

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CORROSION PROTECTION Internal Coating.   TANKS MAY BE COATED

INTERNALLY WITH PAINTS OR EPOXY LININGS FOR PROTECTION FROM CORROSION BY STORED FLUIDS. ALL SUPPORTS INSIDE INCLUDING STRUCTURALS UNDER THE ROOF SHALL BE COATED..

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CORROSION PROTECTION   SPECIAL ATTENTION SHALL BE

GIVEN TO SURFACE PREPARATION FOR INTERNAL COATING,AND TO CURING REQUIREMENTS OF THE COATING. CORROSION PROTECTION

NACE REQUIREMENTS SHALL BE SPECIFIED PER THE PROJECT SPECIFICATIONS FOR INTERNAL COATING.

EXTERNAL PAINTING.

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CORROSION PROTECTION EXTERNAL PAINTING. SPECIFY THE TYPE OF PRIMER AND

FINISH COATS OF PAINT INCLUDING DRY FILM THICKNESS REQUIRED PER THE PROJECT PAINTING SPECIFICATION. USUALLY THE TANK CONTRACTOR'S SCOPE WILL INCLUDE SURFACE PREPARATION AND PRIMER APPLICATION, WHILE THE FINISH COAT WILL BE APPLIED BY OTHERS.

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CORROSION PROTECTION STRUCTURAL ATTACHMENTS

NORMALLY ALL LADDERS, PLATFORMS, STAIRS, RAILINGS AND CAGES ARE TO BE HOT DIP-GALVANIZED. ALL OTHER ATTACHMENTS WELDED TO THE SHELL SHALL BE PAINTED TO THE PROJECT PAINT SPECIFICATION FOR THE TANK EXTERIOR.

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CORROSION PROTECTION BOTTOM PLATE COATING. THE BOTTOM PLATE MAY BE

COATED ON THE UNDERSIDE WITH EPOXY PER SPECIFIED REQUIREMENTS. AN ADDITIONAL 1/16" CORROSION ALLOWANCE MAY BE SPECIFIED FOR THE UNDERSIDE OF THE BOTTOM, WITH OR WITHOUT THE BOTTOM COATING.

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FOUNDATION DESIGN TYPICALLY FLAT BOTTOM TANKS

ARE INSTALLED ON RINGWALL FOUNDATIONS. SMALL TANKS (15'-20' DIA) AND THOSE REQUIRING LEAK DETECTION MAY BE INSTALLED ON CONCRETE SLAB FOUNDATION.

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FOUNDATION DESIGN FOR TANKS STORING

PRODUCTS LIKE CHLORINE, ACIDS AND HAZARDOUS CHEMICALS, THE FOUNDATION MAY BE COVERED WITH A PROTECTIVE COATING.

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FOUNDATION DESIGN SOIL CONDITIONS WHICH

PRODUCES UNUSUAL SETTLEMENT OF FOUNDATIONS SHALL BE GIVEN TO THE TANK CONTRACTOR IN CONSULTATION WITH THE CIVIL GROUP. THE LATTER MAY REQUIRE TANKS TO BE KEPT FILLED WITH WATER AFTER HYDROTEST FOR A LONGER PERIOD TO MONITOR GRADUAL SETTLEMENT, PRIOR TO MAKING PIPING CONNECTIONS.

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LIGHTNING PROTECTION/GROUNDING LUGS

THESE LUGS ARE SUPPLIED AND INSTALLED BY THE TANK CONTRACTOR. REVIEW THE ELECTRICAL SPECIFICATION FOR THEIR DETAILS INCLUDING LOCATION AND QUANTITY.

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INSPECTION & TESTING UNLESS OTHERWISE SPECIFIED BY

THE CLIENT, ALL INSPECTION AND TESTING SHALL BE PER API STANDARDS.

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INSPECTION & TESTING THE INSPECTION DEPARTMENT

SHALL PREPARE AN INSPECTION PLAN FOR SHOP FABRICATED TANKS AND SHOP FABRICATED COMPONENTS OF FIELD ERECTED TANKS PER PROJECT SPECIFICATIONS/ GUIDELINES, AND THE VESSEL ENGINEER SHALL REVIEW THE SAME. THIS PLAN WILL BE PART OF THE TANK CONTRACT.

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INSPECTION & TESTING FIELD INSPECTION OF TANK

ERECTION AND TESTING SHALL BE ADMINISTERED BY THE GENERAL CONSTRUCTION CONTRACTOR/CLIENT.

TESTING. PRESSURE TESTS.

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INSPECTION & TESTING HYDROSTATIC TESTING SHALL BE

SPECIFIED IN THE MECHANICAL DATA SHEET OF STAINLESS STEEL TANKS REVIEW THE CHLORIDE CONTENT OF THE TEST WAT. THE TEST WATER SHALL BE CLEAN AND FREE OF SILT OR ANY SUSPENDED SOLIDS. IN CASE ER AVAILABLE AT THE SITE. THE CHLORIDE CONTENT SHALL NOT EXCEED THE MAXIMUM PERMISSIBLE LIMIT.

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INSPECTION & TESTING ALL HYDROSTATIC OR

PNEUMATIC TESTS SHALL BE PER API STANDARDS.

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INSPECTION & TESTING NON-DESTRUCTIVE

EXAMINATIONS.

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INSPECTION & TESTING RADIOGRAPHY AND ANY

OTHER NON-DESTRUCTIVE EXAMINATION SHALL BE SPECIFIED PER API STANDARDS AND/ OR PROJECT REQUIREMENTS.

VACUUM TESTS.

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INSPECTION & TESTING VACUUM BOX TESTING SHALL

BE SPECIFIED FOR BOTTOM JOINTS, BOTTOM TO SHELL JOINTS AND ROOF PLATE JOINTS PER API STANDARDS.

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APPENDICESAPPENDIX A – OPTIONAL DESIGN BASIS FOR SMALL TANKS.APPENDIX B – RECOMMENDATIONS FOR DESIGN & CONSTRUCTION OF FOUNDATIONS.APPENDIX C – EXTERNAL FLOATING ROOFS.APPENDIX D – TECHNICAL INQUIRIES.

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APPENDICES

APPENDIX E – SEISMIC DESIGN.APPENDIX F – DESIGN FOR SMALL INTERNAL PRESSURES.APPENDIX G – STUCTURALLY SUPPORTED ALUMINIUM DOME ROOFS.APPENDIX H – INTERNAL FLOATING ROOG ROOFS.

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APPENDICES APPENDIX I – UNDERTANK LEAK

DETECTION. APPENDIX J – SHOP ASSEMBLED

STORAGE TANKS. APPENDIX K – SAMPLE CALCULATION

ON VARIABLE DESIGN. APPENDIX L – API 650 DATA SHEETS.

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APPENDICESAPPENDIX M – FOR ELEVATED TEMPERATURES.APPENDIX N – USE OF NEW MATERIALS.APPENDIX O – RECOMMENDATIONS FOR UNDER BOTTOM CONNECTIONS.APPENDIX P – ALLOWABLE EXTERNAL LOADS ON TANK SHELL OPENINGS.APPENDIX S – AUSTENTIC STAINLESS STEEL DESIGN.

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EXTERNAL FLOATING ROOF

04/17/23 106NOZZLE ORIENTATION

04/17/23 107CONE ROOF TANK