ANNEX 18. RESOLUTION MSC.362(92) (Adopted on 14 June 2013) REVISED RECOMMENDATION ON A STANDARD METHOD FOR EVALUATING CROSS-FLOODING ARRANGEMENTS

Transcription

1 MSC 92/26/Add. Annex 8, page ANNEX 8 RESOLUTION MSC.362(92) (Adopted on 4 June 203) REVISED RECOMMENDATION ON A STANDARD METHOD FOR EVALUATING CROSS-FLOODING ARRANGEMENTS THE MARITIME SAFETY COMMITTEE, RECALLING Article 28(b) o the Convention on the International Maritime Organization concerning the unctions o the Committee, RECALLING ALSO resolution A.266(VIII), by which the Assembly, at its eighth session, adopted the Recommendation on a standard method or establishing compliance with the requirements or cross-looding arrangements in passenger ships, RECALLING FURTHER resolution MSC.245(83), by which it, at its eighty-third session, adopted the Recommendation on a standard method or evaluating cross-looding arrangements, NOTING that the above Recommendation on a standard method or evaluating cross-looding arrangements needed to be revised and improved, based on recent research results regarding cross-looding, RECOGNIZING the need to establish a methodology or evaluating cross-looding arrangements on ships subject to the applicable subdivision and damage stability requirements o SOLAS chapter II- to ensure uniorm treatment o cross-looding and equalization arrangements, HAVING CONSIDERED, at its ninety-second session, the Revised Recommendation on a standard method or evaluating cross-looding arrangements, prepared by the Sub-Committee on Stability and Load Lines and on Fishing Vessels Saety, at its ity-ith session,. ADOPTS the Revised Recommendation on a standard method or evaluating cross-looding arrangements, the text o which is set out in the annex to the present resolution; 2. INVITES Governments to apply the annexed Revised Recommendation to ships constructed on or ater 4 June 203 and to bring it to the attention o all parties concerned; 3. NOTES that calculations to evaluate cross-looding arrangements perormed beore 4 June 203 remain valid. * * * I:\MSC\92\26-Add-.doc

2 MSC 92/26/Add. Annex 8, page 2 ANNEX REVISED RECOMMENDATION ON A STANDARD METHOD FOR EVALUATING CROSS-FLOODING ARRANGEMENTS Table o contents Deinitions 2 Formulae 3 Air pipe venting criteria 4 Alternatives Appendix Appendix 2 Appendix 3 Examples or treatment o heel angles and water heads at dierent stages o cross-looding Friction coeicients in cross-looding arrangements Example using igures or a passenger ship I:\MSC\92\26-Add-.doc

3 MSC 92/26/Add. Annex 8, page 3 Deinitions : Sum o riction coeicients in the considered cross-looding arrangement. s (m 2 ): Cross-section area o the cross-looding pipe or duct. I the cross-section area is not circular, then: where: D equiv = 4. A p A = actual cross-section area p = actual cross-section perimeter : Angle beore commencement o cross-looding. The cross-looding device may be assumed to be ull or empty dependent on its arrangement and internal volume (see igure (b) in appendix ). : Heel angle at inal equilibrium ( ). : Any angle o heel between the commencement o cross-looding and the inal equilibrium at a given time. : Volume o water which is used to bring the ship rom commencement o cross-looding to inal equilibrium. : Volume o water which is used to bring the ship rom any angle o heel to the inal equilibrium. : Head o water beore commencement o cross-looding, with the same assumption as or. : Head o water when any angle o heel is achieved. : Final head o water ater cross-looding (, when the level inside the equalizing compartment is equal to the ree level o the sea). g (m/s 2 ): The acceleration due to gravity (9.8 m/s 2 ). 2 Formulae 2. Time required rom commencement o cross-looding to the inal equilibrium : T 2W S F 2gH 0 h H 0 I:\MSC\92\26-Add-.doc

4 MSC 92/26/Add. Annex 8, page Time required to bring the ship rom any angle o heel to the inal equilibrium : T 2W S F 2gH h H 2.3 Time required rom commencement o cross-looding until any angle o heel is achieved: 2.4 Dimensionless actor o reduction o speed through an equalization device, being a unction o bends, valves, etc. in the cross-looding system: F ( k i ) Values or k can be obtained rom appendix 2 or other appropriate sources such as computational luid dynamics (CFD) or model testing. I other appropriate sources are used, then the + actor in the ormulae may not be appropriate. CFD can also be used to evaluate the discharge coeicient or the whole cross-looding duct. 2.5 Cross-looding through successive devices o dierent cross-section: I the same low crosses successive looding devices o cross-section S, S 2, S 3 having corresponding riction coeicients k, k 2, k 3, then the total k coeicient reerred to S is: 2.6 I dierent looding devices are not crossed by the same volume, each k coeicient should be multiplied by the square o the ratio o the volume crossing the device and the volume crossing the reerence section (which will be used or the time calculation): 2.7 For cross-looding through devices in parallel that lead to the same space, equalization time should be calculated assuming that: With F ( or each device o cross-section S i ) k i I:\MSC\92\26-Add-.doc

5 MSC 92/26/Add. Annex 8, page 5 3 Air pipe venting criteria 3. In arrangements where the total air pipe sectional area is 0 per cent or more o the cross-looding sectional area, the restrictive eect o any air back pressure may be neglected in the cross-looding calculations. The air pipe sectional area should be taken as the minimum or the net sectional area o any automatic closing devices, i that is less. 3.2 In arrangements where the total air pipe sectional area is less than 0 per cent o the cross-looding sectional area, the restrictive eect o air back pressure should be considered in the cross-looding calculations. The ollowing method may be used or this purpose: The k coeicient used in the calculation o cross-looding time should take into account the drop o head in the air pipe. This can be done using an equivalent coeicient k e, which is calculated according to the ollowing ormula: where: k w = k coeicient or the cross-looding arrangement (water) k a = k coeicient or the air pipe ρ a = air density ρ w = water density S w = cross-section area o the cross-looding device (water) S a = cross-section o air pipe 4 Alternatives As an alternative to the provisions in sections 2 and 3, and or arrangements other than those shown in appendix 2, direct calculation using computational luid dynamics (CFD), time-domain simulations or model testing may also be used. * * * I:\MSC\92\26-Add-.doc

6 MSC 92/26/Add. Annex 8, page 6 Appendix EXAMPLES FOR TREATMENT OF HEEL ANGLES AND WATER HEADS AT DIFFERENT STAGES OF CROSS-FLOODING Upper Deck Intact waterline Main Deck Location o damage cross-looding pipe Equalizing Compartment Flooded Compartments Figure (a) Section showing cross-looding pipe and compartments I:\MSC\92\26-Add-.doc

7 MSC 92/26/Add. Annex 8, page 7 Beore cross-looding h H Intact Waterline Final Equilibrium 0 H 0 Figure (b) Initial and Final stages o cross-looding Note: H 0 on the let side o igure (b) depicts the head o water i the cross-looding device was assumed ull whereas H 0 on the right side o igure (b) shows the head o water i the cross-looding device was assumed empty.. Any transient angle o heel between 0 and W = Volume o water to bring the ship rom to H Water inlow at Figure (c) Situation at any transient angle o heel, * * * I:\MSC\92\26-Add-.doc

8 MSC 92/26/Add. Annex 8, page 8 W = Volume o water to bring the ship rom to Final Equilibrium h Water inlow until inal equilibrium is achieved Figure (d) Situation at inal equilibrium * * * I:\MSC\92\26-Add-.doc

9 MSC 92/26/Add. Annex 8, page 9 Appendix 2 FRICTION COEFFICIENTS IN CROSS-FLOODING ARRANGEMENTS FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 8 FIGURE 9 FIGURE 0 FIGURE I:\MSC\92\26-Add-.doc

10 MSC 92/26/Add. Annex 8, page k L i (0 L i 2) k.903 (2 L ) 0 i where: k Li riction coeicient related to each space between two adjacent girders Length o the duct in meters Note: k is evaluated with eective cross-section area thereore in calculations use the real cross-section area A and not S equiv. The pressure loss or entrance in the irst manhole is already computed in the calculation. Figure 2 I:\MSC\92\26-Add-.doc

11 MSC 92/26/Add. Annex 8, page where: k.7968 L i (0 L i 2) k.684 (2 L ) i k Li riction coeicient related to each space between two adjacent girders Length o the duct in meters Note: k is evaluated with eective cross-section area thereore in calculations use the real cross-section area A and not S equiv. The pressure loss or entrance in the irst manhole is already computed in the calculation. * * * I:\MSC\92\26-Add-.doc

12 MSC 92/26/Add. Annex 8, page 2 Appendix 3 EXAMPLE USING FIGURES FOR A PASSENGER SHIP Dimension o the considered cross-looding pipe: Diameter Length Cross-section area Wall thickness D = 0.39 m l = 2.0 m S = 0.2 m2 t = 7.5 mm k-values or the considered cross-looding system: Inlet 0.45 Pipe riction ( 02 l D ).08 2 radius bends (α = 45 ) 0.36 Non-return valve 0.50 Suicient air venting is assumed to be in place. From this ollows: F F ( ) 3.39 k i Time required rom commencement o cross-looding to the inal equilibrium condition : T 2W. S F 2gH 0 h H 0 Head o water beore commencement o cross-looding: Volume o water which is used to bring the ship rom commencement o cross-looding to the inal equilibrium condition: I:\MSC\92\26-Add-.doc

13 MSC 92/26/Add. Annex 8, page 3 Final head o water ater cross-looding: h.5m T T m m s 2 9.8m s 2 5.3m.5m 5.3m Calculation o any transient situation o cross-looding: The purpose is to ind the situation ater 600s. Assumed transient situation: Cross-looded volume: 265 m 3 Volume o water which is used to bring the vessel rom the transient situation to the inal equilibrium : W = 365 m m 3 = 00 m 3 Corresponding head o water: H = 2.8 m Time required to bring the vessel rom any transient situation to the inal equilibrium condition: T 2W S F 2gH h H 200m3 T. 0.2m T = 240 s 2*9.8m / s2*2.8m m m Time between commencement o cross-looding and assumed transient situation: T = T T = 72 s 240 s = 48 s As T is less than 600 s, urther transient situations with larger cross-looded volume may be calculated in the same way. On the reverse, i T was o more than 600 s, urther transient situation with smaller cross-looded volume may be calculated. Situation ater 600 s may be ound by successive iterations. *** I:\MSC\92\26-Add-.doc