INTERIM GUIDELINES FOR A SIMPLIFIED EVACUATION ANALYSIS OF HIGH-SPEED PASSENGER CRAFT
1 General
1.1 In addition to the relevant requirements for means of escape, escape routes in high-speed passenger craft are required to be evaluated by an evacuation analysis early in the design process, under the International Code of Safety for High-Speed Craft, 2000 (2000 HSC Code), section 4.8.2.
1.2 The purpose of the Interim Guidelines is to provide guidance on how to execute a simplified (hydraulic) evacuation analysis and use its results to plan the evacuation demonstration required in section 4.8.5 of the 2000 HSC Code.
2 Definitions
2.1 Ideal deployment time (t M) is the time needed for the preparation and launching of the marine evacuation system (MES) and the first survival craft in calm water.
2.2 Ideal travel time (tI) is the time needed for the slowest group of people to reach the embarkation point in calm water. Unless otherwise stated in the evacuation procedure, the number of people of the slowest group should be assumed equal to the capacity of the largest survival craft onboard. For the purpose of these Interim Guidelines, tI is assumed to run concurrently with tM.
2.3 Ideal embarkation time (t E) is the time needed for all passengers and crew to board the survival craft in calm water.
2.4 Structural fire protection time (SFP) is the protection time for areas of major fire risk as defined in section 4.8.1 of the 2000 HSC Code.
2.5 Slowest group of people is the group of evacuating persons for which the highest travel time is obtained from calculations according to paragraph 3.6.3.3.
3 Method of evaluation
The steps in the evacuation analysis are:
3.1 Description of the system
.1 Identification of assembly stations.
.2 Identification of embarkation stations, MES and survival craft.
.3 Description of the evacuation procedure including the role of the crew.
.4 Identification of groups and their escape route.
3.2 Assumptions
This method for estimating evacuation time is basic in nature and, therefore, common evacuation analysis assumptions should be made as follows:
.1 passengers and crew should carry out the evacuation in a sequence of groups according to the evacuation procedure;
.2 passengers and crew will evacuate via the primary escape route;
.3 walking speed depends on the type of escape facility, assuming that the flow is only
in the direction of the escape route, and that there is no overtaking;
.4 passengers disabilities or medical conditions that will severely hamper their ability to keep up with the flow are neglected (see paragraph 3.2.8.1 below);
.5 passenger load is assumed to be 100% (full load);
.6 full availability of escape arrangements is considered;
.7 people can move unhindered;
.8 the allowable evacuation time as per section 4.8.1 of the 2000 HSC Code is given by SFP - 7(min), where:
3
.8.1 division by 3 accounts for the safety factor, which includes passengers ages and disabilities, restricted visibility due to smoke, effects of waves and craft motions on deployment, travel and embarkation time and of violations to the evacuation procedure;
.8.2 subtraction of 7 min accounts for initial detection and extinguishing action
(section 4.8.1 of the 2000 HSC Code); and
.8.3 for category B craft, the passenger awareness time, the time needed for passengers to reach assembly stations and the time needed for manning emergency stations is included in the 7 min time (see section 4.8 of the 2000 HSC Code);
.9 as the evacuation procedure is designed to carry out evacuation under controlled conditions (section 4.8.1 of the 2000 HSC Code), no counter flow takes place; and
.10 when using table 3.6 it is assumed that at the beginning of the evacuation, passengers are located at a distance not greater than two decks from the embarkation station.
3.3 Scenarios to be considered
3.3.1 For the purpose of calculating the evacuation time in category A craft, passengers should be assumed to be distributed in a normal voyage configuration (section 4.8.4.1 of the 2000 HSC Code).
3.3.2 For the purpose of calculating the evacuation time in category B craft, passengers and the crew should be assumed to be distributed among assembly stations and be ready for embarkation
(section 4.8.4.2 of the 2000 HSC Code).
3.4 Performance standards
3.4.1 The following two performance standards should be complied with for calculating the overall evacuation time:
tM +tE < SFP-7 (3.4.1.1)
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tI +tE < SFP-7 (3.4.1.2)
3
3.4.2 Both performance standards are derived from section 4.8.1 of the 2000 HSC Code.
3.5 Calculation of t E and t M
3.5.1 The values tE and tM should be calculated separately based on:
.1 the results of full scale trials on similar craft and evacuation systems; or
.2 data provided by the manufacturers; however, in this case, the method of calculation should be documented.
3.5.2 Safety factors on tE and tM are accounted for by dividing by 3 in performance standards formulae (3.4.1.1) and (3.4.1.2).
3.6 Calculation of t I
3.6.1 Parameters to be considered:
.1 clear width, Wc , is:
.1 measured off the handrail(s) for corridors and stairways;
.2 the actual passage width of a door in its fully open position;
.3 the space between the fixed seats for aisles in public spaces; and
.4 the space between the most intruding portions of the seats (when unoccupied) in a row of seats in public spaces;
.2 speed of persons, S (m/s) is the speed of evacuees along the escape route (table 3.6
provides the values of S which should be used for the analysis);
.3 specific flow of persons, Fs (p/(m/s)), is the number of evacuating persons past a
point in the escape route per unit time per unit of clear width Wc (table 3.6 provides
the values of Fs which should be used for the analysis)
Table 3.6*
Type of Facility | Speed of persons S (m/s) | Specific Flow Fs (p/(m/s)) |
Stairs (down) | 0.55 | 1.1 |
Stairs (up) | 0.44 | 0.88 |
Corridors, doorways | 0.67 | 1.3 |
.4 calculated flow of persons, Fc (p/s), is the predicted number of persons passing a
particular point in an escape route per unit time. It is obtained from:
Fc = Fs · Wc (3.6.1.4)
.5 flow time, tF (s), is the total time needed for a group of N persons to move past a point in the egress system. It is calculated as:
tF = N / Fc (3.6.1.5)
.6 walking time, tw (s), is the total time needed for a person to cover the distance between the assembly station and the embarkation station.
3.6.2 Transitions
Transitions are those points in the egress system where the type of a route changes (e.g. from a corridor to a stairway) where routes merge or branch out.
3.6.3 Procedure for calculation of tI is as follows:
.1 Groups of people:
Forthepurposesofevacuation,thetotalnumberofpersonsonboardisbrokendown intooneormore groupsofpeople. Itshouldbeassumedthatallpersonsinagroup carryouttheevacuationatthesametime,alongthesamerouteandtowardsthesame embarkationstation. Thenumberofpersonsineachgroup,thenumberofgroupsand theembarkationstationassignedtoeachgroupshouldbeinaccordancewiththe evacuation procedure.
.2 Schematic representation:
Theescaperoutesfromassemblystationstoembarkationstationsarerepresentedasa hydraulicnetwork,wherethepipesarethecorridorsandstairways,thevalvesarethe doors and restrictions in general.
.3 For each foreseen group of people:
.1 The walking time, tw, is calculated by using the speed of persons specified in table 3.6 and the distance between the pertinent assembly and embarkation stations.
.2 The flow time, tF, of each portion of the escape route is calculated using the specific flow Fs from table 3.6 and the appropriate clear width of that portion
of escape route. The total flow time is the largest value obtained.
.3 The travel time is obtained as the sum of the walking time and the total flow time.
3.6.4 Ideal travel time tI
Calculations as per paragraph 3.6.3.3 should be repeated for each foreseen group of people. The highest resulting travel time is then taken as the ideal travel time for use in performance standard in paragraph 3.4.
4 Corrective actions
If the performance standards under paragraph 3.4 are not fulfilled, corrective actions should be considered at the design stage by either modifying one or more components in the evacuation system
(e.g., escape routes, life-saving appliances, passengers load, etc.) or by modifying the evacuation procedure.
5 Documentation
The documentation of the analysis should report the following items:
.1 the basic assumptions for the analysis;
.2 a schematic representation of the layout of the craft;
.3 position and role of the crew during the evacuation, according to the evacuation procedure;
.4 the method for the analysis, if different from these Interim Guidelines;
.5 details of the calculation; and
.6 the resulting overall evacuation time.
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* Dataderivedfromland-basedstairs,corridorsanddoorsincivilbuildings,andareextractedfromthepublication
“SFPEFireProtectionEngineeringHandbook,2nd editionNFPA1995”.