Probabilistic Damage Stability Rules for cargo ships and SPS (Part B – SOLAS 2009) Paris, March...
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Transcript of Probabilistic Damage Stability Rules for cargo ships and SPS (Part B – SOLAS 2009) Paris, March...
Probabilistic Damage Stability Rules for cargo shipsand SPS (Part B – SOLAS 2009)
Paris, March 2011
Marine Technical DepartmentStability Section (DT5)
2SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
Probabilistic concept
Stability criteria to be satisfied
Parameters to be considered
Concepts for simplified analysis
Openings, controls & escape routes
Bottom damage
Minimum required GM
SOLAS 92 and SOLAS 2009
CONTENTS
3SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
APPLICATION
SOLAS PART B – 1
MSC.281(85) : Explanatory notes to SOLAS CH II-1
Dry cargo ships with type B freeboard
L > 80 m, if constructed on or after 1 January 2009
L is the length as defined in the ICLL in force
For SPS : MSC.266(84) : application depending on
flag requirements.
4SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
PROBABILISTIC CONCEPT
What is the basis of the probabilistic concept?
The probabilistic concept is based on the probability of survival after collision (damaged ship condition)
This probability of survival is expressed by the attained index A
The attained index A is obtained from the summation of the partial indices As, Ap, Al
For which values of attained index A do we consider a ship as surviving?
The requirement for the survivability of the ship is set by the required index R
Therefore, the attained index A is to be compared with the required index R
5SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
STABILITY CRITERIA TO BE SATISFIED
Four criteria need to satisfied for cargo ships/SPS
1. As ≥ 0.5R/0.9R, and
2. Ap ≥ 0.5R/0.9R, and
3. Al ≥ 0.5R/0.9R, and
4. A ≥ R
Partial attained index
As : corresponds to the deepest subdivision draught ds
Ap :corresponds to the partial subdivision draught dp
Al : corresponds to the lightest subdivision draught dl
6SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
REQUIRED INDEX R FOR CARGO SHIPS
Where:
Ro = R as calculated for Ls > 100 m
mLmif
R
RLR
mLifL
R
s
o
os
ss
10080,
11001
11
100,152
1281
7SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
REQUIRED INDEX R FOR PASSENGER SHIPS/SPS
225,155.2
000,51
NLR
s
N= N1+ 2 N2 with
N1, number of persons for whom lifeboats are provided and
N2, number of persons the ship is permitted to carry in excess of N1
N can be reduced to a minimum of N1+N2 subject to the agreement of the flag
8SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
Each partial attained index is a summation of the contribution from all damage cases taken into consideration, using the following formula:
Where:
i : damaged zone or group of compartments under consideration
c : the considered loading condition
lps A2.0A4.0A4.0A
ATTAINED INDEX A
ti
1iiiiic ]sv)[r(pA
9SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
Example:
p(j=3) : represents the probability that only zone number 3 will be flooded taking into account the transverse subdivision (factors r1, r2, r3)
FACTORS OF PROBABILITY
10SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
FACTORS OF PROBABILITY
Example 1: Calculation of damage cases
Vertical limit: v1
Penetration: r1
Case Nr Damaged spaces
Transverse extent (r)
Vertical extent (v) s-factor
1 3 r1 v1 s3
2 3+2 r1 v1 s32
3 3+2+1 r1 v1 s321
Select the case whichgives the smallest value for s: MIN {s3;s32;s321}
11SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
FACTORS OF PROBABILITY
Example 2: Calculation of damage cases
Vertical limit: v2 = 1Penetration: r1
Case Nr Damaged spaces
Transverse extent (r)
Vertical extent (v) s-factor
4 3+4 r1 1 - v1 s34
5 3+4+2 r1 1 - v1 s342
6 3+4+2+1 r1 1 - v1 s3421
Select the case whichgives the smallest value for s: MIN{s34;s342;s3421}
12SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
FACTORS OF PROBABILITY
Example 3: Calculation of damage cases
Vertical limit: v1
Penetration: r2
Case Nr Damaged spaces
Transverse extent (r)
Vertical extent (v) s-factor
4 3+6 1 - r1 v1 s36
5 3+6+2+5 1 - r1 v1 s3625
6a 3+6+2+5+1 1 - r1 v1 s36251
6b 3+6+2+5+1+8 1 - r1 v1 s362518
Select the case whichgives the smallest value for s: MIN{s36;s3625;s36251/s362518}
Case 6a or 6b depending onB/2 exceeding the CL or not
13SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
PARAMETERS TO BE CONSIDERED
Watertight bulkheads and decks
Weathertight bulkheads and decks
Doors (watertight, weathertight of sufficient tightness and strength to restrict the flow
Air pipes
Ventilators
Piping systems
Horizontal evacuation routes
Vertical escape hatches
Controls: operation of watertight doors, equalisation arrangements, valves on piping or ventilation ducts, etc.)
Permeability of spaces
14SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
PARAMETERS TO BE CONSIDERED
Other figures for permeability may be used if substantiated by calculation
Spaces Permeability
at draught ds
Permeability
at draught dp
Permeability
at draught dl
Appropriated to stores 0.60 0.60 0.60
Occupied by accommodation 0.95 0.95 0.95
Occupied by machinery 0.85 0.85 0.85
Void spaces 0.95 0.95 0.95
Intended for liquids 0 or 0.95 * 0 or 0.95 * 0 or 0.95 *
Dry cargo spaces 0.70 0.80 0.95
Container spaces 0.70 0.80 0.95
Ro-ro spaces 0.90 0.90 0.95
Cargo liquids 0.70 0.80 0.95
* whichever results in the more severe
15SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
Specific requirements for SPS
16SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
CONCEPTS FOR SIMPLIFYING THE ANALYSIS
V-lines concept
Important factors for the calculation of the s-value:
θe : Equilibrium heel angle
θv : Angle where GZ < 0 or submersion of unprotected openings (downflooding point: openings cannot be closed weathertight)
17SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
CONCEPTS FOR SIMPLIFYING THE ANALYSIS
V-lines concept
The envelope curve of worst waterlines after damage for all the damage cases giving positive contribution to the attained index A
Type of V-lines
“Watertight V-lines” derived from equilibrium heel angle (final or intermediate stages of flooding)
“Weathertight V-lines” derived from positive range (of GZ-curve)
Input for the calculation of the V-lines
Bulkheads limiting the boundary of damage under consideration
Decks limiting the boundary of damage under consideration
18SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
CONCEPTS FOR SIMPLIFYING THE ANALYSIS
V-lines concept
V-lines from positive range
V-lines from equilibrium
Construction
Scantling calculation (sufficient strength to resist flooding loads)
Machinery
Position of ventilators, air pipes
Electricity
Control of watertight doors, valves, etc.
Safety
Horizontal evacuation routes
Vertical escape hatch
Escape routes, etc.
Stability
Verification of progressive flooding
No immersion of openings
Watertight openings
Weathertight
openings
19SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
CONCEPTS FOR SIMPLIFYING THE ANALYSIS
Safe Area concept
Area far away from side shell (damage)
Probability (r-factor) to have damage to area close to CL is very small
Piping system as much as possible positioned close to the CL
Maximum penetration is the boundary of the safe area (r2) instead of CL
Way to simplify the investigation of progressive flooding
Negligible impact on attained index A: r3 = 1 – r2 is very small
20SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
CONCEPTS FOR SIMPLIFYING THE ANALYSIS
No Safe Area
Investigation on progressive flooding for each damage case giving positive contribution to the attained index A
Fitting of valves to prevent progressive flooding
Maximum penetration is CL (or B/2)
21SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
CONCEPTS FOR SIMPLIFYING THE ANALYSIS
Shadow of Tank concept
Damage case:
Damage in zone 1
Consequences:
Damage in space 1
Damage of pipe
Progressive flooding of space 3
1 2
3
CL CL
22SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
CONCEPTS FOR SIMPLIFYING THE ANALYSIS
Shadow of Tank concept
Damage case:
Damage in zone 1
Consequences:
Damage in space 1
(No damage of pipe)
(No progressive flooding of space 3)
1 2
3
CL CL
23SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
CONCEPTS FOR SIMPLIFYING THE ANALYSIS
Shadow of Tank concept
Damage case:
Damage in zone 2, up to r
Consequences:
Damage in space 2
Damage of pipe
Progressive flooding of space 3
1
2
3
r
CL CL
24SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
CONCEPTS FOR SIMPLIFYING THE ANALYSIS
Shadow of Tank concept
1
2
3
r1
CL CL
r1 r2
Damage case:
Damage in zone 2
Consequences:
up to r1: damage in space 2 (no damage of pipe, no progressive flooding of space 3)
up to r2: damage in space 2, space 3 and pipe
25SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
OPENINGS, CONTROLS AND ESCAPE ROUTES
s = 0 (means: ship is not surviving), if position of
Air pipes, ventilators and openings closed by means of weathertight doors or hatch covers through which progressive flooding may take place
Horizontal evacuation route
is below the waterline at final equilibrium
Vertical escape hatch
Controls for the operation of watertight doors, equalisation devices, valves on piping or on ventilation ducts intended to maintain the integrity of watertight bulkheads above the bulkhead deck
Any part of piping or ventilation ducts not fitted with watertight means of closure, carried through a watertight boundary
is below the waterline in intermediate stages or at final equilibrium
26SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
OPENINGS, CONTROLS AND ESCAPE ROUTES
s not automatically 0 if position of
Air pipes, ventilators and openings closed by means of weathertight doors or hatch covers through which progressive flooding may take place
Horizontal evacuation route and vertical escape hatch
Controls for the operation of watertight doors, equalisation devices, valves on piping or on ventilation ducts intended to maintain the integrity of watertight bulkheads above the bulkhead deck
is above the V-lines
Any part of piping or ventilation ducts carried through a watertight boundary is fitted with valves able to prevent progressive flooding
27SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
SIMPLIFIED ANALYSIS – SUMMARY
V-lines concept
Safe Area concept
Shadow of Tank concept
Pipes and valves are adjacent to a bulkhead (longitudinal/transverse) or deck
Provision: the separation distance is of the same order as the stiffening structure
Total cross sectional area of pipe < 710 mm2 (where possible)
Otherwise:
Investigation on progressive flooding for each damage case
If pipes and valves are outside the order of the stiffening structure, introduction of a gap or additional zone and investigation of progressive flooding
28SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
LOCATION OF VALVES AT BULKHEADS
Example:
or
or
29SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
SURVIVABILITY FACTORS
}{ ,,ite,intermedia imomifinali ssorsMINs sintermediate and smom not applicable to cargo ships but to passenger ships/SPS
30SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
S intermediate and S mom
31SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
S intermediate and S mom
→ S intermediate to be calculated for passenger ships only if :
► progressive flooding / equalization before cross flooding
greater than > 60 s
►Non watertight bulkheads restricting the immediate flow of water such as A class fire bulkheads, incenerator room, refrigerated spaces.
32SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
S intermediate and S mom
33SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
S intermediate and S mom
34SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
S intermediate and S mom
35SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
S intermediate and S mom
36SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
BOTTOM DAMAGE
Double bottom height [m] Bottom damage
h ≥ MIN{B/20,2}hmin = 0.76 NO
37SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
MINIMUM REQUIRED GM
pr, v-factors s-factor
Geometry of watertight
arrangement
Loading condition
VCG
Trim
Operationaltrim range ≤
0.5% Ls
Operational trimrange ≥ 0.5% Ls
p: longitudinal direction
r: transverse direction
v: vertical direction
Light draught
(dl)VCGl Actual Actual
Partial draught
(dp)VCGp 0 0
≠0 with steps≤1% Ls
Deepest draught
(ds)VCGs 0 0
≠0 with steps≤1% Ls
If the attained index A = pr v s satisfies the stability criteria of SOLAS 2009, the minimum GM-curve is drawn based on the chosen VCGs
38SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
Minimum GM-curve = envelope GM-curve covering calculations for different trim values
MINIMUM REQUIRED GM
39SOLAS 2009– New Probabilistic Damage Stability Rules – Copyright Bureau Veritas, March 2011
2. SOLAS 92 and SOLAS 2009
► SOLAS 1992 (cargo ships)
Calculations for 2 draughts (deepest & partial)
No partial index requirements
Permeability for cargo holds is constant and equal to 0.70
Damage extent is up to CL
Calculations are performed at even keel (trim = 0)
► SOLAS 2009 (cargo and passenger ships)
Calculation for 3 draughts (deepest, light service & partial)
Partial indices Ai ≥ 0.5R
Permeability of cargo holds is function of draughts and cargo type
Damage extent is up to B/2
Calculations are performed for several trims if range of operational trims exceed +/- 0.5% Ls (subdivision length)
Thank you for your attention