ABS-108-NOTICE-1-2004.pdf

ABS GUIDE FOR BUILDING AND CLASSING MEMBRANE TANK LNG VESSELS . 2002 1 GUIDE FOR BUILDING AND CLASSING MEMBRANE TANK LNG VESSELS OCTOBER 2002 NOTICE NO. 1 23 August 2004 SECTION 2 DESIGN CONSIDERATIONS AND GENERAL REQUIREMENTS (Reduce the NDCV in pipe duct space except for the same in way of the tank boundary. Revise Section 2, Figure 1 accordingly:) FIGURE 1 Nominal Design Corrosion Values (23 August 2004) Trunk Deck Plate: 1.5 mm in Void Space Deck Transverse and Deck Girder: 1.0 mm in Void Space Upper Deck Plate: Watertight: 2.0 mm Weathertight: 1.5 mm Nontight: 1.5 mm Transverse Bulkhead Plate (Wing): 1.5 mm in Ballast Tank 1.0 mm within Void Spaces Side Stringer: in Tank: WT: 2.0 mm NT: 1.5 mm in Void Space: WT: 1.5 mm NT: 1.0 mm Longitudinals and Stiffeners: in Tank: Vertical Element: 1.0 mm (2.0 mm for Splash Zone* and within Double Bottom) Non Vertical Element: 2.0 mm in Pipe Duct Space: All Elements: 1.0 mm in Void Space outside Double Bottom: All Elements: 1.0 mm Side Transverse: 1.5 mm in Tank (2.0 mm for Splash Zone) 1.0 mm in Void Space Side Shell Plate: 1.5 mm Bottom Shell Plate: 1.0 mm Floor, Girders and Transverses: 2.0 mm in Tank 1.5 mm in Pipe Duct or Void Space including watertight bottom girder as duct keel tank boundary Webs on Cargo Transverse Bulkhead: where a space between trans. bulkheads is ballast tank: Vertical Web: 1.5 mm (2.0 mm for Splash Zone) Horizontal Web: 2.0 mm where a space between trans. bulkheads is void space: Vertical Web: 1.0 mm Horizontal Web: 1.5 mm Inner Bottom Plate: 1.0 mm (2.0 mm for Tank Top)* Transverse Bulkhead Plate: 1.0 mm in Cargo Tank Inner Deck Plate: 1.0 mm Inner Skin Bulkhead Plate: 1.0 mm *Splash Zone is 1.5 m below Tank Top. *Tank Top is considered in case double bottom has the separate ballast tank with outboard watertight double bottom girders. Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:45:24 MDTNo reproduction or networking permitted without license from IHS -,-,- Notice No. 1 23 August 2004 2 ABS GUIDE FOR BUILDING AND CLASSING MEMBRANE TANK LNG VESSELS . 2002 (Add new Note 9 and revise the entries “Longitudinals and Stiffeners” and “Longitudinals and Stiffeners within Pipe Duct Space in Section 2, Table 1 as follows:) TABLE 1 Nominal Design Corrosion Values (1) (2) (23 August 2004) Nominal Design Corrosion Values in mm (in.) Structural Element/Location in Tank in Void Space Trunk Deck Plating N.A. 1.0 (0.04) Watertight 2.0 (0.08) Upper Deck Plating Weathertight 1.5 (0.06) Nontight 1.5 (0.06) Inner Deck Plating 1.0 (0.04) Side Shell Plating 1.5 (0.06) Bottom Plating 1.0 (0.04) Inner Bottom Plating 1.0 (0.04) (3) 1.0 (0.04) Longitudinal Bulkhead Plating 1.0 (0.04) Transverse Bulkhead Plating in Wing Spaces 1.5 (0.06) 1.0 (0.04) (8) in Cargo Tanks 1.0 (0.04) Deck Transverse and Deck Girder N.A. 1.0 (0.04) (8) Double Bottom Floor and Girder (9) 2.0 (0.08) 1.5 (0.06) (8) Side Transverse 1.5 (0.06) (4) 1.0 (0.04) Side Stringer Watertight 2.0 (0.08) 1.5 (0.06) (8) Nontight 1.5 (0.06) 1.0 (0.04) Webs on Cargo Transverse Bulkhead Vertical Web 1.5 (0.06) (4) 1.0 (0.04) (8) Horizontal Web 2.0 (0.08) 1.5 (0.06) (8) Longitudinals and Stiffeners Vertical Element (5) 1.0 (0.06) (7) 1.0 (0.04) Non Vertical Element (6) 2.0 (0.08) 1.0 (0.04) Longitudinals and Stiffeners within Pipe Duct Space N.A. 1.0 (0.04) Longitudinals and Stiffeners in Void Spaces outside Double Bottom N.A. 1.0 (0.04) Notes 1 It is recognized that corrosion depends on many factors including coating properties, cargo composition and temperature of carriage, and that actual wastage rates observed may be appreciably different from those given here. 2 Pitting and grooving are regarded as localized phenomena and are not covered in this table. 3 2.0 mm (0.08 in.) for tank top. 4 2.0 mm (0.08 in.) for Splash Zone (1.5 meters down from tank top). 5 Vertical elements are defined as elements sloped at an angle greater than 25° to the horizontal line. 6 Non vertical elements are defined as elements sloped at an angle less than 25° to the horizontal line. 7 2.0 mm (0.08 in.) for Splash Zone and within double bottom. 8 When plating forms a boundary between a tank and a void space, the plating NDCV is determined by the tank type. 9 (23 August 2004) 1.5 mm (0.06 in.) for duct keel tank boundary girder. Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:45:24 MDTNo reproduction or networking permitted without license from IHS -,-,- Notice No. 1 23 August 2004 ABS GUIDE FOR BUILDING AND CLASSING MEMBRANE TANK LNG VESSELS . 2002 3 SECTION 3 LOAD CRITERIA 11 Sloshing Loads 11.5 Sloshing Pressures 11.5.1 Nominal Sloshing Pressure (23 August 2004) (Equations for “htb” and “htub” to read as follows:) htb = 0.0055bCtb (es + 35) (es)1/2cos2u m (ft) htub = 0.007 tb Cb (es + 35) (es)1/2 sin2u m (ft) 11.5.2 Additional Nominal Sloshing Pressure for Low-Filling Resonance (23 August 2004) (Revise first paragraph as follows:) When the natural periods at the filling level higher than 1.13hd or 0.17h, whichever is less, and at filling level lower than 0.2l or 0.2b, whichever is higher, are at least 20% greater or smaller than that of the relevant ships motion, the nominal sloshing pressure for low-filling resonance, pi, should be used for the lower filling level in lieu of the nominal pressure given in 3/11.5.1 (See 3/Figure 11) unless the vessel loading manual indicates that the filling level higher than 1.13hd or 0.17h, whichever is less, and lower than 0.2l or 0.2b, whichever is higher, are avoided. (Revise Section 3, Figure 9 (“hl” to read “hd”) as follows:) FIGURE 9 Definition of Tank Geometry (23 August 2004) l bt bf b do h hu hd u b Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:45:24 MDTNo reproduction or networking permitted without license from IHS -,-,- Notice No. 1 23 August 2004 4 ABS GUIDE FOR BUILDING AND CLASSING MEMBRANE TANK LNG VESSELS . 2002 (Revise Section 3, Figure 11 (“0.2dl” to read “dl”) as follows:) FIGURE 11 Vertical Distribution of Nominal Slosh Pressure Head, hi for Low-Filling Resonance (23 August 2004) he dm hi dl 1.0 m Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:45:24 MDTNo reproduction or networking permitted without license from IHS -,-,- Notice No. 1 23 August 2004 ABS GUIDE FOR BUILDING AND CLASSING MEMBRANE TANK LNG VESSELS . 2002 5 SECTION 4 INITIAL SCANTLING CRITERIA (Revise footnote at bottom of Section4, Figure 3 as follows:) FIGURE 3 Effective Breadth of Plating be (23 August 2004) For bending at endsat midspan For bending Longitudinal Mx l M lc s = spacing of longitudinals lc o lw a) For bending at midspan c o l/s 1.5 2 2.5 3 3.5 4 4.5 and greater be/s 0.58 0.73 0.83 0.90 0.95 0.98 1.0 b) For bending at ends cl/s 1 1.5 2 2.5 3 3.5 4.0 be/s 0.25 0.35 0.43 0.5 0.55 0.6 0.67 (23 August 2004) a) is for strength evaluation and b) is for fatigue strength assessment. 9 Side Shell and Deck 9.7 Deck and Side Longitudinals (23 August 2004) (The cap of “fb” is increased from 0.4Smfy to 0.6 Smfy as follows:) fb = permissible bending stresses, in N/cm2 (kgf/cm2, lbf/in2) for inner deck longitudinals in load case 5-“a” in 3/Table 3 = (1.0 0.822SMRD/SMD)Sm fy 0.60Sm fy for upper deck longitudinals Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:45:24 MDTNo reproduction or networking permitted without license from IHS -,-,- Notice No. 1 23 August 2004 6 ABS GUIDE FOR BUILDING AND CLASSING MEMBRANE TANK LNG VESSELS . 2002 11 Side Shell and Deck Main Supporting Members 11.3 Deck Transverses 11.3.2 Web Thickness of Deck Transverses (23 August 2004) (The additional note to the equation for “t1” to read as follows:) t1 = F1/(k1 dt fs) mm (in.) but need not be taken less than 9.0 mm (0.35 in.) SECTION 5 TOTAL STRENGTH ASSESSMENT 5 Failure Criteria Buckling and Ultimate Strength 5.1 General 5.1.1 Approach (23 August 2004) (Add new sentence to the end of Subparagraph 5/5.1.1 to read as follows.) The strength criteria given here correspond to either serviceability (buckling) state limits or ultimate state limits for structural members and panels, according to the intended functions and buckling resistance capability of the structure. For plate panels between stiffeners, buckling in the elastic range is acceptable provided that the ultimate strength of the structure satisfies the specified design limits. The critical buckling stresses and ultimate strength of structures may be determined based on either well-documented experimental data or a calibrated analytical approach. When a detailed analysis is not available, the equations given in Appendix 2 (A2) may be used to assess the buckling strength. However, for plate panels on which insulation systems are installed, the maximum deflection of the plate panel is not to be greater than 4.6 mm (0.18 in.) in the elastic buckling range. SECTION 6 HULL STRUCTURE BEYOND 0.4L AMIDSHIPS 1 General Requirements (Add two new sentences to the end of Paragraph 6/1.1 to read as follows.) 1.1 General (23 August 2004) The structural configurations, stiffening systems and design scantlings of the hull structures located beyond 0.4L amidships, including the forebody, aft end and machinery spaces, are to be in compliance with this Section and 5-2-2/17 of the Rules. In accordance with 3-2-2/5.1 of the Rules, the thickness of the plating between the amidship 0.4L and the end 0.1L may be gradually tapered. However, the thickness need not be greater than the thickness required for the side shell plating amidships. Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:45:24 MDTNo reproduction or networking permitted without license from IHS -,-,- Notice No. 1 23 August 2004 ABS GUIDE FOR BUILDING AND CLASSING MEMBRANE TANK LNG VESSELS . 2002 7 3 Forebody Side Shell Structure 3.1 Side shell Plating 3.1.1 Plating Forward of Forepeak Bulkhead (23 August 2004) (Specify “p” in various locations in lieu of one location as follows:) p = nominal pressure |pi pe|, in N/cm2 (kgf/cm2, lbf/in2), as specified in 3/Table 3 at the lower edge of each plate amidships with the following modifications (Notes i) to iii) remain unchanged.) 3.1.2 Plating between Forepeak Bulkhead and 0.125L from FP (23 August 2004) (The permissible stresses “f1”and “f2” are increased as follows:) f1 = permissible bending stress in the longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2) = 0.60Sm fy , for L 190 m (623 ft) = 0.60 + 0.10 (190 L)/40 Sm fy , for L 190 m (623 ft) f2 = 0.85Sm fy , in N/cm2 (kgf/cm2, lbf/in2) in the transverse (vertical) direction Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:45:24 MDTNo reproduction or networking permitted without license from IHS -,-,-