Operational Guide · Registers & Logbooks

# Immersion Suits and Thermal Protection

Less than 2 minutes: the maximum time within which an immersion suit must be able to be donned without assistance, including clothing and lifejacket.

immersion suit thermal protection SOLAS III/22 LSA Code

## Operational Explanation

Immersion suits and thermal protective aids protect against hypothermia for people in the water or on a survival craft awaiting rescue. The LSA Code sets precise technical requirements: the suit must be able to be donned without assistance in less than 2 minutes, including clothing and lifejacket if intended to be worn in combination; it must cover the entire body except the face, with hands covered unless integral gloves are fitted; it must not continue to burn or melt after being enveloped in fire for 2 seconds; and it must guarantee no undue entry of water after a jump from at least 4.5 metres.

Passenger ships must have, for every lifeboat, at least 3 compliant immersion suits, plus a thermal protective aid for every person not provided with an immersion suit; these requirements do not apply to persons on totally or partially enclosed lifeboats, or on ships operating exclusively on routes in warm climates where the Administration considers them superfluous.

## Regulatory Reference

SOLAS Chapter III, Regulation 22 and LSA Code Sections 2.3 (immersion suits) and 2.5 (thermal protective aids): technical requirements on donning time (<2 minutes), fire resistance, body coverage and watertight integrity; minimum quantities per passenger ship based on the number of lifeboats.

## Scope of Application

Every ship subject to SOLAS Chapter III, with specific and more stringent quantity requirements for passenger ships compared with cargo ships.

## Procedure / How to Complete It

1. Verify that the number of immersion suits/thermal protective aids on board matches the requirements for the number of lifeboats and the crew/passengers embarked.
2. Periodically inspect the condition of the suits (material integrity, zips, watertight seal) per the LSA maintenance programme.
3. Include timed practical donning of the immersion suit in periodic drills, verifying compliance with the 2-minute limit.
4. Verify correct storage of the suits in a readily accessible location near the embarkation stations.
5. Train the crew on the operational difference between immersion suits and thermal protective aids, and when each is actually required based on lifeboat type.

## Practical Example

Example: during the monthly abandon ship drill, three crew members on a rotating basis time their donning of the immersion suit, verifying that the complete donning time, including lifejacket, stays under the 2 minutes required by the LSA Code.

## Real Cases

Survival in cold water depends critically on the speed of donning thermal protection equipment: delays of even a few minutes in donning, often due to poor practical familiarity rather than an equipment defect, have a direct impact on survival in abandon ship scenarios in adverse weather conditions.

## Common Mistakes Mistake Library

Mistake | Consequence | How to avoid it
--- | --- | ---
Quantity of immersion suits/thermal protective aids on board not verified against the number of lifeboats and the crew actually embarked | Insufficient coverage in a real abandon ship situation | Periodically verify the required quantity against the ship's actual crew/passenger configuration
Immersion suit donning rarely practised or never timed during drills | Crew unaware of real donning times under emergency conditions | Include timed practical donning in periodic drills, not just simulation of the route
Suits stored in locations not immediately accessible from the embarkation stations | Delay in retrieving equipment during a real emergency | Verify that suits are stored in a readily accessible location, consistent with their emergency function

## PSC Observations

PSCOs verify the quantity of immersion suits/thermal protective aids on board against the applicable requirements, their maintenance condition, and may request a practical demonstration of donning during the inspection.

## Operational Tips

- Always time donning during drills: the 2-minute limit is a real technical requirement, not a generic guideline.
- Verify the required equipment quantity whenever the crew or passenger configuration on board changes.
- Don't confuse immersion suits and thermal protective aids: they have distinct technical requirements and use cases under the LSA Code.

## Checklist

- Quantity of immersion suits/thermal protective aids verified against applicable requirements
- Maintenance condition of the suits periodically inspected
- Timed practical donning included in periodic drills
- Suits stored in a location readily accessible from the embarkation stations
- Crew trained on the operational difference between immersion suits and thermal protective aids

## FAQ

Within what time must an immersion suit be able to be donned?
In less than 2 minutes, without assistance, including any clothing and lifejacket if intended to be worn in combination, per the LSA Code.
Does every lifeboat always require immersion suits?
No: the requirement does not apply to persons accommodated on totally or partially enclosed lifeboats, nor to ships operating exclusively on routes in warm climates where the Administration considers them superfluous.
What is the difference between an immersion suit and a thermal protective aid?
The immersion suit is a watertight garment covering the entire body with specific technical requirements (donning time, fire resistance, watertight seal); the thermal protective aid is a simpler thermal protection device, provided as an alternative for those not equipped with an immersion suit.
🎬 Additional photos, videos and interactive diagrams for this topic will be available in a future version of the platform.

## Related Topics

Musters and Abandon Ship Drill Life-Saving Appliances: Liferafts, EPIRB and SART

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