RESOLUTION MSC.245(83) (adopted on 12 October 2007) RECOMMENDATION ON A STANDARD METHOD FOR EVALUATING CROSS-FLOODING ARRANGEMENTS

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2 EVALUAING CROSS-FLOODING ARRANGEMENS E MARIIME SAFEY COMMIEE, RECALLING Article 8(b) o the Convention on the International Maritime Organization concerning the unctions o the Committee, RECALLING ALSO resolution A.66(VIII) entitled Recommendation on a standard method or establishing compliance with the requirements or cross-looding arrangements in passenger ships, adopted by the Assembly at its eighth session, NOING that the above Recommendation does not include provisions or cross-looding arrangements other than pipes (i.e., cross-looding times through ducts) or a provision to ensure adequate air ventilation or eicient cross-looding (i.e., to account or the restrictive eect o air counter pressure during cross-looding), NOING ALSO the revised SOLAS chapter II-1 subdivision and damage stability requirements or passenger and cargo ships, adopted by resolution MSC.16(8), 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-1 to ensure uniorm treatment o cross-looding and equalization arrangements, AVING CONSIDERED the recommendations made by the Sub-Committee on Stability and Load Lines and on Fishing Vessels Saety at its itieth session, 1. ADOPS the Recommendation on a standard method or evaluating cross-looding arrangements, the text o which is set out in the Annex to the present resolution;. INVIES Governments to apply the annexed Recommendation to cross-looding calculations and to bring the Recommendation to the attention o all parties concerned.

3 Page ANNEX EVALUAING CROSS-FLOODING ARRANGEMENS able o contents Page 1 Deinitions... Formulae... 4 Air pipe venting criteria Alternatives... 5 Appendix 1 Example or treatment o heel angles and water heads at dierent stages o cross-looding... 6 Appendix Friction coeicients in cross-looding arrangement... 7 Appendix Example using igures or a passenger ship... 1

4 Page 1 Deinitions : Sum o riction coeicients in the considered cross-looding arrangement. S ( m ): Cross-section area o the cross-looding pipe or duct. I the cross-section area is not circular, then: S equiv π D 4 equiv where: D equiv A 4 p A actual cross-section area p actual cross-section perimeter () : Angle beore commencement o cross-looding. his assumes that the cross-looding device is ully looded but that no water has entered into the equalizing compartment on the opposite side o the damage (see appendix 1). () : eel angle at inal equilibrium ( ). () : Any angle o heel between the commencement o cross-looding and the inal equilibrium at a given time. W ( ) W ( ) m : Volume o water which is used to bring the ship rom commencement o cross-looding to inal equilibrium. m : Volume o water which is used to bring the ship rom any angle o heel to the inal equilibrium. ( m ): ( m ): ead o water beore commencement o cross-looding, with the same assumption as or. ead o water when any angle o heel is achieved. h ( ) m : Final head o water ater cross-looding ( h, when the level inside the equalizing compartment is equal to the ree level o the sea).

5 Page 4 Formulae.1 ime required rom commencement o cross-looding to the inal equilibrium : W S F 1 g 1 1. ime required to bring the ship rom any angle o heel to the inal equilibrium : 1 W S F g 1 1. ime required rom commencement o cross-looding until any angle o heel is achieved:.4 Dimensionless actor o reduction o speed through an equalization device, being a unction o bends, valves, etc., in the cross-looding system: F 1 where F is not to be taen as more than 1. Values or can be obtained rom appendix or other appropriate sources..5 Cross-looding through successive devices o dierent cross-section: I the same low crosses successive looding devices o cross-section S 1, S, S having corresponding riction coeicients 1,,, then the total coeicient reerred to S 1 is: Σ 1 + S 1 / S + S 1 / S.6 I dierent looding devices are not crossed by the same volume, each 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): Σ 1 + S 1 / S W / W 1 + S 1 / S W / W 1

6 Page 5.7 For cross-looding through devices in parallel that lead to the same space, equalisation time should be calculated assuming that: S F S 1 F 1 + S F + with F 1/ Σ or each device o cross-section S i Air pipe venting criteria.1 In arrangements where the total air pipe sectional area is 1% or more o the cross-looding sectional area, the restrictive eect o any air bac pressure may be neglected in the cross-looding calculations. he air pipe sectional area should be taen as the minimum or the net sectional area o any automatic closing devices, i that is less.. In arrangements where the total air pipe sectional area is less than 1% o the cross-looding sectional area, the restrictive eect o air bac pressure should be considered in the cross-looding calculations. he ollowing method may be used or this purpose: he coeicient used in the calculation o cross-looding time should tae into account the drop o head in the air pipe. his can be done using an equivalent coeicient e, which is calculated according to the ollowing ormula: e w + a (ρ a /ρ w ) (S w /S a )² where: 4 Alternatives w coeicient or the cross-looding arrangement (water) a 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 As an alternative to the provisions in sections and, and or arrangements other than those shown in appendix, direct calculation using computational luid dynamics (CFD), time-domain simulations or model testing may also be used.

7 Page 6 APPENDIX 1 EXAMPLE FOR REAMEN OF EEL ANGLES AND WAER EADS A DIFFEREN SAGES OF CROSS-FLOODING Figure 1

8 Page 7 APPENDIX FRICION COEFFICIENS IN CROSS-FLOODING ARRANGEMEN FIGURE 1 FIG!;RE I :' I ' I ' I ll l io 1,'. 1,', I 9 Ci RCULAR BEN D RADiUS BEND Rm FIGURE 4 igure ~, r cmo'"'e""'ceo,',n"'' ,~,~ CO~O~u~'"'O'~M~'"'~'~'C'~'~N~'~ 1 PIPE INLE GUR 8 FIGURE 9 \,.' V ~.-+-- " I ".5 h. valye o lct!lluy ;nc:,uses wllh dc<:,e:ue in Froud. numbt:. pulic'jluly bdo"' 'peed. o mi.tc. :-4N.nEURN VALVE he co c!i ~i.nl above i. ~ mean yaj yc and docl in ~Cl vary 1 R.ynold'J ny,nlm:, (i.e. ~ ar;':, wilh V (: conll1nl D.nd ~. ) u... U n wjlh,cluivc,,,.,&-'1,,c.1. PIPE FRICION LOSS ES igure I I C V, ~4 _!_ It.) I-- -'AE VAl.VE '. c - " FICURE 11 " O. ~ aur F L Y VALVE. - /. DISC VA LVE

9 Page 8 Figure 1 Cross-looding through a series o structural ducts with 1 manhole i i i.748 Li +.1 i < L < Li Li 1.1 Li i 1 L i L > 4 Note: is the riction coeicient related to each space between two adjacent girders. is evaluated with eective cross-section area thereore in calculations use the real cross-section area A and not S equiv. he pressure loss or entrance in the irst manhole is already computed in the calculation, and 1 has to be added to tae into account the outlet losses. L i (in metres)

10 Page 9 Figure 14 Cross-looding through a series o structural ducts with manholes i i i.445 Li +.67 i < L < 1.44 Li.59 Li Li.56 i 1 L i L > 4 Note: is the riction coeicient related to each space between two adjacent girders. is evaluated with eective cross-section area thereore in calculations use the real cross-section area A and not S equiv. he pressure loss or entrance in the irst manhole is already computed in the calculation, and 1 has to be added to tae into account the outlet losses.

11 Page 1 APPENDIX EXAMPLE USING FIGURES FOR A PASSENGER SIP Dimension o the considered cross-looding pipe: Diameter Length Cross-section area Wall thicness D. 9 m l 1. m S.1 m t mm -values or the considered cross-looding system: Inlet.45.l Pipe riction 1.8 D radius bends ( α 45 ).6 Non-return valve.5 Outlet Suicient air venting is assumed to be in place. From this ollows: F 1 F ime required rom commencement o cross looding o to the inal equilibrium condition : 1 W S F g 1 1 ead o water beore commencement o cross-looding: 5. m Volume o water which is used to bring the ship rom commencement o cross-looding to the inal equilibrium condition: W 65m

12 Page 11 Final head o water ater cross-looding: h 1. 5m 65m.1m.54 71s 1. min 1.5m 1 5. m m 5.m 1.5m s 1 5.m ime required to bring the vessel rom the maximum allowable angle o heel or inal stage o looding to the inal equilibrium condition : 1 W S * F g 1 1 Maximum allowable angle o heel or inal stage o looding 7 ead o water when the maximum allowable angle o heel or inal stage o looding is achieved Volume o water which is used to bring the vessel rom the maximum allowable angle o heel or inal stage o looding to the inal equilibrium condition. 7m W 16m 16m.1m.54 54s 5.9 min 1.5m 1.7 m m.7m 1.5m s 1.7m ime required rom commencement o cross-looding o until the maximum allowable angle o heel or inal stage o looding is achieved: 1. min 5.9 min 6.1 min

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