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Floating Roof (S.D)FLOATING ROOFS-APPENDIX C .1 - DESIGN DATA .C.3 - DESIGN.C.3.1 GENERAL.The roof and accesories shall be designed and constructed so that the roof is allowed to float to the maximum design liquid level and then return to a liquid level that floats the roof welll below the top of the tank shell without damage to any part of the roof, tank or appurtenances.During such an occurrence , no manual attention shall be required to protect the roof, tank or appurtenances.If a windskirt or top-shell extension is used to contain the roof seals at the highest point of travel, appropiate alarm devices shall be provided to indicate that the liquid level in the tank has risen above the designed capacity height unless the tank shell has been designed for a liquid height to the top of the shell extension.The purchaser shall specify the indicator arrangement suitable for operating purposes.Emergency overflow openings may be provided to protect the tank and floating roof from damage.Design Code .API 650 , 11th Edition.Customer Specification.Design Specific Gravity .G =0.9500Product Specific Gravity.0.9500Tank Internal Diameter ( at V1 ) -D =302.82ft.92.30m.Shell Height .HT =70.21ft.21.40m.Design Height.H =65.85ft.20.07m.Distance between floating roof and shell.9.84in.250.00mm.Width of pontoon.Lw =248.03in.6300.00mm.Number of external compartment.n =44C.3.3 DECKS.C.3.3.1 Roofs in corrosive service , such as covering sour crude oil, should be the contact type designed to eliminate the presence of any air-vapor mixture under the deck.Height of pontoons under the deck level -hp =6.50in.165.00mm.Total height of the pontoons ( external side ) -hpt =41.73in.1060.00mm.C.3.3.2 Unless oteherwise specified by the purchaser, all deck plates shall have a minimum nominal thickness of 5 mm (3/16") - 37,4 kg/m2 - 7.65 lb/ft2 -Maximal height from top of pontoons to top angle.hpta =37.60in.955.00mm.C.3.3.4 Top decks sof double-deck roofs and of pontoon sections, which are designed with a permanent slope for drainage ,shall have a minimum slope of 1 in 64 (3/16" in 12") and shall preferably be lapped to provide the best drainage . Plate buckles shall be kept to a minimum-Weight of floating roof with appurtenances -Wr =1,109,487lb.503,485kg.C.3.4 PONTOON DESIGN .C.3.4.1 Floating roofs shall have sufficient buoyancy to remain afloat on liquid with a specific gravity of 0,7 and with primary drains inoperative for the following conditions:2- FLOATING ROOF BUOYANCY -2.1 - BUOYANCY OF THE SINGLE-DECK FLOATING ROOF.( API 650 Appendix C - C.3.4 ) -The floating roof shall have sufficient buoyancy to remain afloat on a liquid with specific gravity 0,7 , and with primary drains inoperative to the following conditions:1. Simple-deck and any two adjacents pontoon compartments punctured with no water or live load ( C.3.4.1.b ) .2. 10 inches of rainfall in a 24-hour period with the roofs intacts ( C.3.4.1.a ).a - 250 mm (10 in ) of rainfall in a 24-hour period with the roof intact , except for double-deck roofs provided with emergency drains to keep water to a lesser volume that the roof will safely support.Such emergency drains shall not allow the product to flow onto thr roof-b - Single-deck and any two adjacent pontoon compartments punctured in single-deck pontoon roofs and any two adjacent compartments punctured in double-deck roofs, both roof types with no water or live load-c - With agreement by the purchaser , item b may be replaced by the following for floating roofs 6 m (20 ft) in diametr or less : any one compartment punctured nd flooded in single-deck pontoon roofs or double-deck roofs, both roof types with no water or live load.2.1.1 - SINGLE-DECK AND TWO ADJACENT COMPARTMENTS PUNCTURED.C.3.4.2 The pontoon portions of single-deck pontoon-type roofs shall be designed to have adequate strength to prevent permanent distortion when the center deck is loaded by its design rainwater (C.3.4.1 ,Item a ) or when the center deck and two adjacent pontoons are punctured (C.3.4.1 Item b ) - If calculations are required by the purchaser , the allowable stress and stability criteria shall be jointly established by the purchaser and the manufacturer as part of the inquiry. Alternatively, a proof test simulating the conditions of C.3.4.1 , with the roof floating on water , may be performed on the roof or on one of similar design that is equal or greater diameter -C.3.4.3 Any penetration of the floating roof shall not allow product to flow onto the roof under design conditions-C.3.5 PONTOON OPENINGS-Each compartment shall be provided with a liquid-tight manhole.With agreement by the purchaser , floating roofs 6 m ( 20 ft ) in diameter or less may be designed using a pontoon inspection port in place of a pontoon manhole-Each compartment shall be vented to protect against internal or external pressure. Vents may be in the manhole cover, inspection port cover , or the top deck of the compartment - The vents shall be at an elevation that prevents liquid from entering the compartment under the conditions of C.3.4 and shall terminate in a manner that prevents entry of rain and fire-fighting liquids-C.3.6 COMPARTMENTS -Compartments plates are radial or circumferential dividers forming compartments that provide flotation for the roof (see C.3.4 )- All internal compartment plates (or sheets) shall be single-fillet welded along all of their edges, and other welding shall be performed at junctions as required to make each compartment liquid tight. Each compartment shall be tested for tightness using internal pressure or a cacuum box and a soap solution or penetrating oil-External radius of the floating roof.R1 =150.5906ft.45.9000m.Radius of the single-deck.R2 =129.9213ft.39.6000m.Half-angle of the circular sector of non-punctured external compartment.C.3.7 LADDERS -Unless otherwise specified by the purchaser , the floating roof shall be supplied with a ladder that automatically adjusts to any roof position so that accesss to the roof is always provided. The ladder shall be designed for a full-roof travel , regardless of the normal setting of the roof-leg supports. If a rolling ladder is furnished, it shall have full-length handrails on both sides and shall be designed for a 4450N ( 1000 lbf ) midpoint load with the ladder in any operating position- = (360 - ( 720 / 2 n ))/2 =171.82degree.2.9988rad.Floating surface area.S = x ( R12 - R22 )S =17386.9428ft21615.2998m2C = Center of gravity of the floating surface.C.3.8 ROOF DRAINS -The minimum-size drain shall be capable of preventing the roof from accumulating a water level greater than design at the maximum rainfall rate specified by the purchaser for the roof when the roof is floating at the minimum operating level; however, the drain shall not be smaller than NPS 3 for roof with a diameter less than or equal 36 m ( 120 ft ) , or smaller than NPS 4 for roofs with a diameter greater than 36 m ( 120 ft ) -Distance from C to the center of the roof O : d = (( 2/3 ) * SIN () * (( R13 ) - (R23 ))) / Sd =6.6682ft.2.0325m.Moment of inertia of the ffloating surface / axis YY .Iyy = (R14 - R24) * ( + SIN () * COS ()) / 4Iyy =163867077.20ft41414332.62m4C.3.9 VENTS -Suitable vents shall be provided to prevent overstressing of yhe roof feck or seal membrane. The purchaser should specify liquid withdrawal rates so that the fabricator may size the vacuum vents . Vents, bleeder valves , or other suitable means shall be adequate to evacuate air and gases from under neath the roof during initial filling-Moment of inertia of the floating surface / axis ZZIzz = Iyy - S * ( d2 )Izz =163093963.32ft41407659.89m4C.3.10 SUPPORTING LEGS.C.3.10.1 The floating roof shall be provided with supporting legs. Legs fabricated from pipe shall be notched or perforated at the bottom to provide drainage. The length of the legs shall be adjustable from the top side of the roof. the operating and cleaning-position levels of the sipporting legs shall be as specified on the purchaser order. The manufacturer shall make certain that all tank apputenances , such as mixers , interior piping, and the fill nozzle , are cleared by the roof in lowest position.Plunging of the roof is divided into 2 parts:- Uniform plunging due to the roof weight.- Inclination due to the horizontal excentricity of the center of buoyancy B compared with the center of gravity G - As B is on the same vertical line as C and G as O , the excentricity is equal to "d" calculated above.Uniform submerging :C.3.10.2 The legs and attachments shall be designed to support the roof and a uniform live load of at leat 1,2 kPa ( 25 lbf/ft.2 )- Where possible, the roof load shall be transmitted to the legs through bulkheads or diaphragms. Leg attachments to single decks shall be given particular attention to prevent failures at the points of attachments. Steel pads or other means shall be used to distribute the leg loads on the bottom of the tank. If pads are used, they shall be continuously welded to the bottom.Design specific gravity ( API 650 & C.3.4.1 ) .0.7000Displaced volume :V = Wr / (0.7 * 62.4)V =25400.33ft3719.26m3Volume in pontoons below the level of the deck.V1 = (R1 - R2 ) * ( hp / (12 x 12 x 2 )) * (( 2 * PI* (R1 - (( R1-R2 ) / 3))))V1 =5051.30ft3143.04m3C.3.11 ROOF MANHOLES-At least one roof manhole shall be provided for access to the tank interior and for ventilation when the tank is empty- The number of roof manholes shall be as specified by the purchaser . Each manhole shall have a minimum nominal diameter of 600 mm ( 24 in )-Uniform submerging of roof measured above the deck .C.3.12 CENTERING AND ANTOROTATION DEVICES.Suitable devices shall be provided to maintain the roof in a centered position and to prevent it from rotating. These devices shall capable of resisting the lateral forces imposed by the roof ladder, unequal snow loads , and wind loads.c = ( V - V1 ) / Sc =1.1704ft.0.3567m.Corresponding displaced volume .V2 = V - V1V2 =20349.03ft3576.22m3C.3.13 SEALS-The space between the outer periphery of the roof and the tank shell shall be sealed by a flexible device that provides a reasonably close fit to the shell surfaces.Vertical positon of the metacenter M ( center of rotation ).C.3.14 GAUGING DEVICE -Each roof shall be provided with a gauge hatch or gauge well with a tight cap that complies with the design specified in the purchaser order.z(M) = Izz / Vz(M) =6420.94ft.1957.10m.The inclination is given by the equilibrium of moments between weight ( applied in G ) and thrust ( applied in B ).C.4 FABRICATION , ERECTION, WELDING, INSPECTION, AND TESTING.C.4.5 Drainpipe and hose systems of primary drains shall be tested with water at a pressure of 350 kPa ( 50 lbf/in2 ) gauge- During the rotation test, the roof drain valves shall be kept open and observed for leakage of the tank contents into the drain lines.z(M) * SIN(i) = d .SIN (i) =0.0010rad.i =0.0595degree.Maximal submerging of the roof .( hp + c + ( R1 x SIN (i))1.8681ft.0.5694m.Maximal Submerging of the Roof < hpt is OKMinimal submerging of the roof .( measured from the bottom of the pontoon ) .( hp + c - ( R1 x SIN (i))1.5553ft.0.4741m.Minimal Submerging of the Roof > 0 is OK2.1.2 - ROOF INTACT WITH 10 INCHES OF WATER IN THE DECK.Total height of water on the roof .hw =10.00in.0.2540m.Weight of water on the roof .Ww = ( PI() x R22 ) x hw x 62.40Ww =2,757,488lb.1,253,554kg.Displaced Volume .V = ( Wr + Ww ) / ( 0.7 x 62.40 )V =88529.64ft32506.88m3Floating Surface Area .St = PI() x ( R12 )St =71243.51ft26618.74m2.Corresponding height of submerging above the deck.c= ( V - V1 ) / Stc=1.1717ft.0.3571m.Maximal submerging of the roof .( Measured from the bottom of the pontoon ).hp + c1.7131ft.0.5221m.Maximal Submerging of the Roof < hpt is OK2.1.3 - CHECKING OF DESIGN HEIGHT OF LIQUID IN SERVICE.Weight of floating roof with appurtenances.Wr =1109487lb.503485kg.Displaced Volume .V = Wr / ( G x 62.40 )V =18716.04ft3529.98m3Volume in pontoons below the level of the deck.V1 =5051.30ft3143.04m3Floating Surface Area .St =71243.51ft26618.74m2Submerging of roof measured above the deck .c = ( V - V1 ) / Stc =0.1918ft.0.0585m.Submerging of the roof in service .hp + c0.7331ft.0.2235m.Submerging of the roof in service < hpt is OKMaximal height of liquid.64.3322ft.19.6085m.HT - hpta - hpt + ( hp + c )Maximal height of liquid in service < H is OK2.1.4 - CHECKING OF DESIGN HEIGHT IN HYDROSTATIC TEST .Weight of floating roof with appurtenances.Wr =1109487lb.503485kg.Specific gravity for water -Gw =1.0000Displaced Volume .V = Wr / ( 1 x 62.40 )V =17780.23ft3503.48m3Volume in pontoons below the level of the deck.V1 =5051.30ft3143.04m3Floating Surface Area .St =71243.51ft26618.74m3.Submerging of roof measured above the deck .c = ( V - V1 ) / Stc =0.1787ft.0.0545m.Submerging of the roof in service .hp + c0.7200ft.0.2195m.Submerging of the roof in service < hpt is OKMaximal height of liquid.HT - hpta - hpt + ( hp + c )64.3191ft.19.6045m.(condicin)Maximal height of liquid in service < H is OKVERDADEROTHE FLOATING ROOF HAS A SUFFICIENT BUOYANCY3 - FLOATING ROOF SUPPORTS.3.1 - DETERMINATION OF LOADS ON THE LEGS.( As per drawings .)External radius of the floating roof.R1 =150.5906ft.45900mm.Radius of the single-deck.R2 =129.9213ft.39600mm.Radius 8Radius 7Radius 6Radius 5Radius 4Radius 3Radius 2Radius 11 - Support Radius.ft.147.0801133.4646108.484386.843864.484942.844522.998710.0000mm.44,83040,68033,06626,47019,65513,0597,0103,048Rang 8Rang 7Rang 6Rang 5Rang 4Rang 3Rang 2Rang 11 - Support Radius.ft.147.0801133.4646108.484386.843864.484942.844522.998710.0000mm.44,83040,68033,06626,47019,65513,0597,0103,0482 - Supported Section :147.0801133.4646108.484386.843864.484942.844522.998710.0000448304068033066264701965513059701030480.0000150.5906140.2723120.974497.664075.664453.664732.921616.499345900.0042755.0036873.0029768.0023062.5016357.000010034.50005029.00000uter Radius .ft.150.5906140.2723120.974497.664075.664453.664732.921616.4993mm.45,90042,75536,87329,76823,06316,35710,0355,029Inner Radius .ft.140.2723120.974497.664075.664453.664732.921616.49930.0000mm.42,75536,87329,76823,06316,35710,0355,0290Outer Radius - Inner Radius =ft.10.318219.297923.310421.999721.999720.743116.422216.4993mm.3,1455,8827,1056,7066,7066,3235,0065,029Lw =20.6693ft.6300.00mm.Section 8Section 7Section 6Section 5Section 4Section 3Section 2Section 1Roof Areaft140.27129.92mm42,75539,600Deck Areaft120.9797.6675.6653.6632.9216.500.00mm36,87329,76823,06316,35710,0355,02902-1 Roof Area.ft.29428.538786.370.000.000.000.000.000.00m2.875.94816.280.000.000.000.000.000.002-2 Deck Area.ft.20.007052.0116011.2611979.428938.455642.522549.72855.23m.20.00655.151487.491112.92830.41524.21236.8879.453- Uniform live load. ( API 650 & C.10.3.2 ) = 25 lb/ft2 .25 lb/ft2 =1197N.1 Kgf m / seg2 =9.8067Nm.1 N =0.2248lbf.1 kg =2.2046lb.3-1 Roof Area .lb.235713219659000000N.10485059770930000003-2 Deck .lb.01763004002822994862234611410636374321381N.078422317805411332178994005627479283544951064 - Weights. ( As per drawings. )4-1 Roof.lb.272068247824000000N.121021911023750000004-2 Deck.lb.057577130725978077297946069208186983N.025611458149643506832462620492492601310604-3 Roof Stiffeners.lb.00000000N.000000004-4 Deck Stiffeners.lb.00354092036616938120315313765N.001575059059475344535152363434034-5 Rolling Ladder ( Over deck. ).lb.00000000N.000000004-6 Appurtenances .lb.00000000N.00000000Total Weight ( Dead Loads ) .lb.2720683054001661341181738991758099261317748N.12102191358489739001525662399970258439116235344635- Live Loads + Dead Loads.Total Weight.lb.5077817013605664164176593133781991628987429128N.225872431198052519542185784013939758859183997791295696- Number of Supports.444460403224937- Weight of a Support.lb.147147212212212212212212N.6556559459459459459459458- Total Weight. ( Item 5 + ( Item 7 x Item 6 )) .lb.5142607078395791624261573201762042619178629766N.228754431486252576242189564014242159085984082841324049- Total Load per Support.lb.1168816087965310654100068511101989922N.5199071560429374739144507378584536544135Maximum load on a pontoon support :MLP =16087lb.71560N.Maximum load on a deck support :MLD =10654lb.47391N.3.2 - CHECKING OF DECK SUPPORTS.Checking of the legs in compression.The checking is made in compression as per API 650 & AISC .Material for Column.API 5L BSupporting Leg.3"stdDiameter .D =3.50in.88.90mm.Thickness ( ordered ).0.2160in.5.49mm.Corrosion.CA =0.0000in.0.00mm.Minimal Thickness in Operation.t =0.2160in.5.49mm.Section .S =2.2300in21438.71mm2Moment of Inertia.3.0200in41257018.91mm4Radius of Gyration.r =1.1600in.29.46mm.Tensile Strength of Column @ ambient Temperature.TS =60000lb/in2413.69Mpa.Yield strength of Column @ ambient Temperature.YS =35000lb/in2241.32Mpa.(API STD 650 -Item 3.10.3.4)Cc = (( 2 x PI2 x E ) / YS) 0.5Cc =127.45( Table B5.1 AISC )Description of Element :( Circular hollow sections in axial compression )Width thickness ratio = D / t .D / t =16.20Limiting Width-Thickness Ratio.3300 / ( YS / 1000 )94.29THE COLUMN IS NOT A SLENDER ELEMENT.Maximal Length of Leg ( 100 mm in the 4" pipe included ).L =45.4724in.1155.00mm.Effective Length Factor . K .K =2.10( Table C-C2.1 AISC )Slenderness Ratio.( K x L ) / r =82.32Cc > ( K x L / r ) IS OKAPI 650 - Item 3.10.3.3 - Maximum Slenderness Ratio-For columns , the value L/r shall not exceed 180.THE SLENDERNESS RATIO IS RESPECTEDElasticity Modulus at Ambient Temperature.E =28800000lb/in2198569.06Mpa.( Table M-2 API 650 )AISC - E.2 DESIGN COMPRESSIVE STRENGTH FOR FLEXURAL BUCKLING.Gross Area of Members.Ag =2.2300in21438.71mm2Specified Yield Stress.Fy =35.00ksi.241.32Mpa.Modulus of Elasticity.E =28800ksi.198569.06Mpa.Effective Length Factor.K =2.10Laterally Unbraced Length of Member.l =45.4724in.1155.00mm.Governing Radius of Gyration about the Axis of Buckling.r =1.1600in.29.46mm.(E2-4)(( K x l ) / ( r x PI )) x( ( Fy / E )05) =0.91350.8344( E2-2) , ( E2-3)Fcr =24682lb/in2170.18Mpa.Allowable Stress in CompressionFa =46786lb.208113N.( Fa = Ag x Fcr x 0.85 )Fa > MLD ; LEG IS OK.Checking of the fillet welds at pipe supporting plates .Length of weld of pipe 3" on pipe 4". ( As per drawing. )Lw =10.9956in.279.29mm.Fillet weld size ( leg dimension )Ws =0.1969in.5.00mm.Shear Stress :( MLD / (( Ws / 20.5 ) x Lw ))Ss1 =6961lb/in2Ss1 < 18000 psi- WELD IS OKLength of weld of gussets on pipe 4" ( As per drawing. )Lw =76.5354in.1944.00mm.Fillet weld size ( leg dimension )Ws =0.1969in.5.00mm.Shear Stess :( MLD / (( Ws / 20.5 ) x Lw ))Ss2 =1000lb/in2Ss2 < 18000psi - WELD IS OKLength of weld of plate on deck ( As per drawing ).Lw =33.7795in.858.00mm.Fillet weld size ( leg dimension )Ws =0.1969in.5.00mm.Shear Stress :( MLD / (( Ws / 20.5 ) x Lw ))Ss3 =2266lb/in2Ss3 < 18000 psi - WELD IS OK3.3 - CHECKING OF PONTOON SUPPORTS .The checking is made in compression as per API 650 & AISC .Material for Column.API 5L BSupporting Leg.3" Std.Diameter .D =3.50in.88.90mm.Thickness ( ordered ).0.2165in.5.50mm.Corrosion.CA =0.0000in.0.00mm.Minimal Thickness in Operation.t =0.2165in.5.50mm.Section .S =2.2300in21438.71mm2Moment of Inertia.3.0200in41257018.91mm4Radius of Gyration.r =1.1600in.29.46mm.Tensile Strength of Column @ ambient Temperature.TS =60000lb/in2413.69Mpa.Yield strength of Column @ ambient Temperature.YS =35000lb/in2241.32Mpa.(API STD 650 -Item 3.10.3.4)Cc = (( 2 x PI 2 x E ) / YS) 0.5Cc =127.45( Table B5.1 AISC )Description of Element :( Circular hollow sections in axial compression )Width thickness ratio = D / t .D / t =16.16Limiting Width-Thickness Ratio.3300 / ( YS / 1000 )94.29THE COLUMN IS NOT A SLENDER ELEMENTMaximal Length of Leg ( 100 mm in the 4" pipe included ).L =0.0000in.0.00mm.Effective Length Factor . K .K =2.10( Table C-C2.1 AISC )Slenderness Ratio.( K x L ) / r =0.00Cc > ( K x L / r) IS OKAPI 650 - Item 3.10.3.3 - Maximum Slenderness Ratio-For columns , the value L/r shall not exceed 180.THE SLENDERNESS RATIO IS RESPECTEDElasticity Modulus at Ambient Temperature.E =28800000lb/in2198569.06Mpa.( Table M-2 API 650 )AISC - E.2 DESIGN COMPRESSIVE STRENGTH FOR FLEXURAL BUCKLING.Gross Area of Members.Ag =2.2300in.21438.71mm2Specified Yield Stress.Fy =35.00ksi.241.32Mpa.Modulus of Elasticity.E =28800ksi.198569.06Mpa.Effective Length Factor.K =2.10Laterally Unbraced Length of Member.l =0.0000in.0.00mm.Governing Radius of Gyration about the Axis of Buckling.r =1.1600in.29.46mm.(E2-4)(( K x l ) / ( r x PI )) x( ( Fy / E )05) =0.00000.0000( E2-2) , ( E2-3)Fcr =35000lb/in2241.32Mpa.Allowable Stress in CompressionFa =66343lb.295106N.( Fa = Ag x Fcr x 0.85 )Fa > MLP ; LEG IS OKChecking of the fillet welds at pipe supporting plates .Length of weld of pipe 4" on reinforcing plate - ( As per drawing. )Lw =49.5276in.1258.00mm.Fillet weld size ( leg dimension )Ws =0.1969in.5.00mm.Shear Stress :MLP / (( Ws / 20.5 ) x Lw )Ss =2334lb/in2Ss < 18000 psi - WELD IS OK

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