Means of Escape and Emergency Escape Routes
Every Category A machinery space requires two independent means of escape, but the exact meaning of 'lower part of the space' remains subject to differing interpretations among Administrations: an issue the IMO SDC sub-committee closed in January 2026, and not in the way expected.
Operational Explanation
Means of escape must ensure that personnel on board can safely and quickly reach the embarkation deck for lifeboats and liferafts in an emergency. For Category A machinery spaces, SOLAS requires two independent means of escape, arranged according to one of two alternative provisions (SOLAS II-2/13.4.2.1 for cargo ships, 13.4.1.1 for passenger ships where the space is below the bulkhead deck): under the first, one of the two ladders must be located within a protected enclosure extending from the lower part of the space to a safe position outside; the second does not feature the enclosure: for cargo ships (13.4.2.1.2) it calls for one steel ladder leading to a door in the upper part of the space and, in the lower part of the space and well separated from that ladder, a steel door capable of being operated from each side and giving access to a safe escape route; for passenger ships we were unable to open the text of 13.4.1.1.2, and what is verified is that there too the second provision does not prescribe the enclosure. For passenger ship machinery spaces above the bulkhead deck, 13.4.1.2 applies, which provides for no protected enclosure.
Inclined ladders forming part of the means of escape in the engine room, but not located within a protected enclosure, must not have an inclination exceeding 60° nor a clear width less than 600 mm. Neither figure is in the text of the regulation. They are in circular MSC.1/Circ.1511 (5 June 2015, and in its Rev.1 of 26 June 2024), which states them with “should”, and in Unified Interpretations IACS UI SC 277 for cargo ships and SC 276 for passenger ships, which state them with “shall”. The difference is not formal: the IMO circular invites Governments to apply the interpretation, the UIs bind the classification societies. And the UIs carry a threshold the circular does not have: “This Unified Interpretation is to be uniformly implemented by IACS Societies on ships contracted for construction on or after 1 February 2016”, with Rev.1 applying to ships contracted from 1 July 2025. The test is the contract date, not the keel-laying or delivery date. There is one exception to the two limits, and it is narrow: “Such requirement need not be applied to ladders/stairways not forming part of an escape route, only provided for access to equipment or components, or similar areas”. The Maritime Safety Committee had noted differing interpretations among Administrations of the meaning of “lower part” of the space in Regulations II-2/13.4.1 and 13.4.2, and the question was referred to sub-committee SDC 12 (19-23 January 2026). The outcome is that nothing changes. The Sub-Committee concluded that no changes to the SOLAS regulations are necessary, noting that the arrangements in use have over four decades of safe use with no documented safety concerns, and recommended that MSC 111 revoke circular MSC.1/Circ.1689. MSC 111 (May 2026) noted that no safety issue had been demonstrated and closed the item, but the circular was not revoked: amendments to it were approved instead, and it still invites PSC authorities to take a pragmatic approach. Anyone designing in expectation of a new rule was waiting for something that is not coming; so was anyone expecting the interim circular to disappear.
Regulatory Reference
SOLAS Chapter II-2, Regulation 13 (Means of escape), in particular Regulations 13.4.1.1 (passenger ships, spaces below the bulkhead deck) and 13.4.2.1 (cargo ships) for Category A machinery spaces: two independent means of escape required, arranged according to one of two alternative provisions; the protected enclosure is prescribed only by the first of them (13.4.1.1.1 and 13.4.2.1.1). The differing interpretations of the term “lower part of the space” were examined by SDC 12 (January 2026), which concluded in favour of keeping the existing text and recommended revoking MSC.1/Circ.1689. MSC 111 (May 2026) closed the item without amending SOLAS, but amended the circular rather than revoking it.
Scope of Application
Every ship subject to SOLAS Chapter II-2, with particular attention to Category A machinery spaces where the risk of rapid fire spread makes the availability of two independent, functional means of escape critical.
Procedure / How to Complete It
- Verify that every Category A machinery space has two independent means of escape, as required by SOLAS II-2/13.4.
- Confirm which of the two alternative provisions is adopted (for passenger ships the alternative structure applies to spaces below the bulkhead deck): under the first (13.4.1.1.1 / 13.4.2.1.1), that one of the two means of escape is located within a protected enclosure, extending from the lower part of the space to a safe position outside; under the second (13.4.1.1.2 / 13.4.2.1.2), that the enclosure is not prescribed and, for cargo ships (13.4.2.1.2), that there are one steel ladder leading to a door in the upper part of the space and, in the lower part of the space and well separated from that ladder, a steel door capable of being operated from each side and giving access to a safe escape route; for 13.4.1.1.2 (passenger ships) we do not have the text.
- Verify that inclined ladders forming part of unprotected means of escape comply with the inclination (max 60°) and width (min 600 mm) limits, knowing where they come from: MSC.1/Circ.1511 recommends them, IACS UI SC 276 and SC 277 impose them on ships contracted for construction from 1 February 2016. On an earlier ship the class obligation does not exist, and compliance has to be argued on the text of the regulation.
- If an escape trunk cannot be extended to the lowest level of the space due to construction constraints, prepare a detailed technical statement justifying the configuration, formally accepted by the flag Administration.
- Keep the complete documentation of the means of escape (approved plans with calculations, installation certificates for fire doors/dampers, training and drill records) always available on board.
Practical Example
Example: at the design stage of a new unit, a construction constraint prevents the escape trunk from being extended to the lowest level of the engine room; the shipyard prepares a detailed technical statement justifying the alternative configuration adopted, submitted to and formally accepted by the flag Administration before the plan is approved.
What Typically Goes Wrong
Common Mistakes Mistake Library
| Mistake | Consequence | How to avoid it |
|---|---|---|
| Means of escape from Category A machinery spaces verified only for their formal existence, without verifying the actual independence of the two routes | Both means of escape potentially compromised by the same event (e.g. a fire blocking a single common route) | Verify the actual physical independence of the two means of escape, not just their formal presence on the plan |
| Inclined ladders in the means of escape not verified against the required inclination and width limits | Means of escape formally present but not compliant with dimensional safety requirements | Always verify the inclination (max 60°) and width (min 600 mm) of unprotected inclined ladders |
| Alternative escape trunk configuration adopted without a technical statement formally accepted by the flag Administration | Non-compliant configuration, potentially challenged during subsequent inspections | Always obtain formal acceptance from the flag Administration for any alternative escape trunk configuration |
What the PSCO Checks
Operational Tips
- Don't just verify the formal presence of two means of escape: verify that they are actually independent of each other.
- Do not wait for a new rule on the interpretation of “lower part of the space”: SDC 12 closed the question in January 2026 with no changes. Agree the interpretation with your flag Administration in writing.
- Always keep the complete technical documentation of the means of escape on board, including any agreements with the flag Administration on alternative configurations.
Preparation checklist
Educational checklist. This summary supports learning and preparation only. It does not replace the vessel’s approved procedures, manuals, statutory documents, company SMS, or applicable official requirements. Completing it demonstrates neither compliance nor readiness for an inspection: it shows that a list has been read, not that the ship is in order. Always verify the current documents carried on board.
- Two independent means of escape verified for every Category A machinery space
- Arrangement identified (13.4.1.1.1 / 13.4.2.1.1 or 13.4.1.1.2 / 13.4.2.1.2; for passenger ships, spaces below the bulkhead deck) and the requirements of that arrangement verified: protected enclosure down to the lower part of the space, or — cargo ships, 13.4.2.1.2 — steel door in the lower part capable of being operated from each side
- Unprotected inclined ladders compliant with inclination and width limits
- Technical statement for alternative configurations accepted by the flag Administration, if applicable
- Complete means-of-escape documentation available on board
FAQ
Related Topics
Last substantive revision of this page: 19 August 2026 · page fingerprint 406722097890