Evacuation Analysis on Passenger Ships: Simplified and Advanced Method
SOLAS has two limbs: ro-ro passenger ships constructed from 1 July 1999 with no passenger threshold, and other passenger ships constructed from 1 January 2020 carrying more than 36 passengers.
Operational Explanation
MSC.1/Circ.1533 ("Revised Guidelines on Evacuation Analysis for New and Existing Passenger Ships") are the guidance for conducting the evacuation analysis at the design stage. The obligation does not come from the circular: it comes from paragraph SOLAS II-2/13.3.2.7, which applies to ro-ro passenger ships constructed on or after 1 July 1999 and to other passenger ships constructed on or after 1 January 2020 carrying more than 36 passengers. Non-ro-ro passenger ships carrying 36 passengers or fewer stay outside it.
The guidelines offer two methods: a simplified method, based on formulas and standard assumptions about the flow of people, suitable for less complex ship configurations; and an advanced method, based on dynamic simulation of people's movement, necessary when the assumptions of the simplified method no longer hold (for example in the presence of complex architectural layouts, multi-deck atriums, non-linear evacuation routes).
Regulatory Reference
MSC.1/Circ.1533 (superseding the previous MSC.1/Circ.1238): guidance on how to carry out the analysis, with a choice between the simplified and the advanced method depending on the complexity of the configuration.
The obligation, however, does not arise from the circular, and the distinction is not a formality. MSC.1/Circ.1533 is an MSC circular: it recommends, it does not bind, and it says as much of itself when it presents itself as “a guide for the implementation of amendments to SOLAS regulation II-2/13.3.2.7”. The obligation is a Convention one, and it lies in resolution MSC.404(96) of 19 May 2016, in force since 1 January 2020, which did two things: it deleted the old paragraph II-2/13.7.4 and inserted the new paragraph II-2/13.3.2.7 — not II-2/13.2.7, as is often written: the numbering is nested under section 3.2 of Regulation 13.
§13.3.2.7.1 provides that “escape routes shall be evaluated by an evacuation analysis early in the design process” and sets its scope on two distinct limbs: “ro-ro passenger ships constructed on or after 1 July 1999” — with no passenger threshold at all — “and other passenger ships constructed on or after 1 January 2020 carrying more than 36 passengers”. Reducing the scope to the second limb alone, as the common summary does, wrongly excludes twenty-five years of ro-ro passenger ships. §13.3.2.7.2 states what the analysis is for: to identify and eliminate, as far as practicable, congestion, taking into account that crew may need to move in a direction opposite to that of the passengers, and to demonstrate that the escape arrangements remain sufficiently flexible when some routes, assembly or embarkation stations, or survival craft are unavailable as a result of a casualty.
Scope of Application
Two distinct limbs of SOLAS II-2/13.3.2.7: ro-ro passenger ships constructed on or after 1 July 1999, with no passenger threshold; other passenger ships constructed on or after 1 January 2020 carrying more than 36 passengers. Use the applicable SOLAS definition of constructed, not keel laying alone.
Procedure / How to Complete It
- Classify the ship as ro-ro passenger or other passenger ship.
- Determine constructed under the applicable SOLAS definition.
- Apply the 1999 limb to ro-ro ships without a threshold or the 2020 limb to other ships carrying more than 36 passengers.
- Select simplified or advanced method for the configuration and applicable guidance.
Practical Example
Example: the designer of a cruise ship with a multi-deck central atrium and non-linear evacuation routes uses the advanced dynamic simulation method, since the simplified assumptions about the flow of people would not be representative of such a complex architectural configuration.
What Typically Goes Wrong
Common Mistakes Mistake Library
| Mistake | Consequence | How to avoid it |
|---|---|---|
| Using the simplified method for complex ship configurations in which its underlying assumptions no longer hold | Evacuation analysis not representative of actual behaviour in an emergency | Assess the complexity of the configuration before choosing the method, opting for the advanced method when necessary |
| Subsequent structural modifications to the ship that alter evacuation routes without reassessing the original analysis | Evacuation analysis no longer consistent with the ship's actual configuration | Reassess the evacuation analysis whenever a structural modification alters the routes or escape ways |
What the PSCO Checks
Operational Tips
- Do not underestimate the ship's architectural complexity when choosing the method: a multi-deck atrium is typically a signal that the advanced method is needed.
- Keep the documentation of the original evacuation analysis on board: it is a useful reference in case of future modifications or audits.
- Coordinate any refit that alters evacuation routes with a reassessment of the analysis, not just with the structural approval of the refit itself.
Preparation checklist
- Ship category identified
- Constructed definition applied
- Correct limb and threshold used
- Analysis matches approved configuration
FAQ
Related Topics
Last substantive revision of this page: 19 August 2026 · page fingerprint e5534f56eadd