When disaster strikes at sea — fire, grounding, or flooding — and you have no choice but to abandon ship into freezing water, one piece of equipment can mean the difference between life and death:
your immersion suit.
Yet, many officers in charge of safety inspections rarely give these suits more than a glance. They check the bag, maybe the light — and that’s it.
This neglect, though common, is dangerous. Because an immersion suit isn’t just a “formality item.”
It’s your final layer of protection when everything else fails.
What is an Immersion Suit?
As defined by SOLAS Chapter III, Regulation 3.7,
“An immersion suit is a protective suit designed to reduce body heat loss in cold water.”
In simple terms — it keeps you warm, afloat, and alive long enough to be rescued.
Imagine abandoning ship in the North Atlantic. The water is 0°C. Without protection, hypothermia sets in within 15 minutes. With a properly fitted immersion suit, you could survive for hours, even days.
SOLAS & LSA Code Requirements for Immersion Suits
SOLAS Chapter III and the LSA Code (Chapter 2, Section 2.3) set the design and performance standards for immersion suits.
Let’s summarize the key technical points before we explore them in-depth.
âś… Quick Summary (For Revision)
| Requirement | SOLAS Reference | Summary |
|---|---|---|
| Donning time | LSA Code 2.3.1.1 | Must be donned without assistance within 2 minutes, including lifejacket if required. |
| Fire resistance | LSA Code 2.3.1.1(b) | Must not burn or melt after being engulfed in fire for 2 seconds. |
| Coverage | LSA Code 2.3.1.1(c) | Must cover entire body except face. Gloves may be attached or separate. |
| Jump test | LSA Code 2.3.1.1(e) | Must withstand a 4.5m jump without water ingress. |
| Buoyancy | LSA Code 2.3.1.2 | Must lift unconscious wearer’s mouth 120mm above water, and turn face-up within 5 seconds. |
| Thermal protection | LSA Code 2.3.2 | Body temperature drop ≤2°C after 1h at 5°C (non-insulated) or 6h at 0–2°C (insulated). |
| Buddy line & lifting loop | LSA Code 2.3.1.5–2.3.1.6 | Must have buddy line and lifting means. |
| Light & whistle | LSA Code 2.3.1.4 | Mandatory for suits with built-in buoyancy (no lifejacket). |
Types of Immersion Suits
Immersion suits are divided into two major categories depending on buoyancy and insulation.
1. Immersion Suit with Built-in Buoyancy
Lifejacket not required.
Features:
- Inherent buoyancy built into the material
- Fitted with whistle and SOLAS-approved light
- Equipped with buddy line for attaching to another person
- Has lifting handle or loop for rescue hoist
- Must meet all lifejacket requirements of LSA Code 2.2
Used in cold climates or ships carrying open lifeboats.
2. Immersion Suit Requiring Lifejacket
Lifejacket must be worn over the immersion suit.
- Suit must be marked clearly as “To be worn with Lifejacket”
- The wearer must be able to don both without assistance
- Offers flexibility for ships trading in variable climates
Insulated vs Non-Insulated Suits
| Type | Temperature Test | Requirement |
|---|---|---|
| Non-Insulated | 1 hour in 5°C water | Core body temp must not drop >2°C (requires warm clothing underneath) |
| Insulated | 6 hours in 0–2°C water | Core body temp must not drop >2°C |
Carriage Requirements as per SOLAS
Different ship types carry different numbers of immersion suits.
Here’s the full summary for officers, cargo, and passenger ships.
| Ship Type | Minimum Requirement | SOLAS Reference |
|---|---|---|
| All ships | One suit for each crew member assigned to a rescue boat or marine evacuation party | Reg. 7.3 |
| Cargo ships | One suit per person onboard | Reg. 32.3.2 |
| Passenger ships | At least 3 suits per lifeboat, plus 1 TPA (Thermal Protective Aid) for each person not having an immersion suit | Reg. 22.4 |
| Warm climate exemption | Not required if Administration deems unnecessary (tropical operations) | MSC/Circ.1046 |
| Remotely located stations | At least 2 additional suits near each survival craft stowage (Bridge, ECR, Forecastle) | Reg. 31.1.4 |
Markings on Immersion Suits (as per SOLAS)
Each immersion suit must display clear, permanent markings that include:
- Manufacturer’s name
- Type and model identification
- Size range (height/weight)
- Donning instructions
- Serial or approval number
- Relevant accessories (gloves, hood, etc.)
- Approval authority (e.g., DNV, Lloyd’s Register)
These ensure traceability and compliance during PSC inspections.
Donning Time as per SOLAS
The suit must be capable of being donned without any assistance within 2 minutes,
including associated clothing and lifejacket if applicable.
That’s why seafarers are trained to practice donning during monthly drills. In panic, those 2 minutes can feel like seconds — practice saves time, and time saves life.
Monthly Inspection Requirements (SOLAS Reg. 20.7 + MSC/Circ.1047)
Every month, the designated officer must check each immersion suit for:
| Inspection Item | Requirement |
|---|---|
| Suit bag condition | Clean, dry, correct labeling |
| Exterior / interior | No cuts, mold, or moisture |
| Zipper | Opens and closes freely |
| Inflatable parts (if any) | Inflate quarterly, check for leaks |
| Reflective tape | Must be intact and visible |
| Whistle & light | Test function and check expiry date |
| Size label | Matches bag marking |
| Donning drill | Crew should practice wearing during inspection |
| Storage | Keep zipper open before stowing |
🧴 Lubricating jelly may be applied on zippers to prevent corrosion or sticking.
Annual and Pressure Test Requirements
| Test Type | Interval | Description |
|---|---|---|
| Pressure / Leak Test | Every 3 years | Check for air leakage or damage |
| Over 10 years old | Annually | Old suits lose flexibility and sealing ability |
| Operational testing | During drills | Practice donning & checking fit |
Testing ensures seals, seams, and zip closures remain watertight.
🗂️ Donning Instruction Posters
As per SOLAS Regulation 35:
“Instructions on donning of immersion suits shall be displayed in crew mess rooms, recreation rooms, and cabins, and included in the training manual.”
These posters should include step-by-step graphics with sequence:
- Open the bag
- Pull the suit over legs
- Insert arms
- Pull hood over head
- Zip up completely
- Put on gloves
- Wear lifejacket (if required)
🌍 Flag State Circular References
| Flag State | Circular / Notice | Notes |
|---|---|---|
| Australia | Marine Order 25 | Local requirement |
| Bahamas | BMA Marine Notice MN085 | Reaffirms SOLAS Reg. 32 |
| Cayman Islands | Shipping Notice MACI 003/2007 | Mandatory 3-year testing |
| Liberia | Marine Notice SAF-007 | Includes TPA guidelines |
| Singapore | Shipping Circular 31/2005 | Donning drill requirements |
| Malta | Technical Notice SLS.8 | Pressure test frequency |
| Panama | MMC No.144 | Warm climate exemptions |
| Marshall Islands | Marine Notice 2-011-5 | Testing standards |
People Also Ask (FAQ Section)
🔹 How do you know how many immersion suits are onboard?
Check the Record of Equipment for Cargo Safety (Form C) or Passenger Safety (Form P).
Cross-verify with Fire & Safety Plan markings onboard.
🔹 What’s the difference between an Immersion Suit and a TPA?
| Feature | Immersion Suit | Thermal Protective Aid (TPA) |
|---|---|---|
| Function | Thermal + flotation protection | Thermal protection only |
| Buoyancy | Built-in or with lifejacket | None |
| Face-up rotation | Yes | No |
| Duration | Hours or days | Limited (short term) |
| Material | Neoprene / waterproof fabric | Thin aluminized film |
🔹 What’s true about an immersion suit?
It reduces body cooling and increases survival time in cold water to hours or days.
🔹 How often should immersion suits be inspected?
- Monthly: Visual inspection + function check
- Every 3 years: Pressure / leak test
- After 10 years: Annual pressure test
How many immersion suits are required on a ship?
| Vessel Type | Requirement |
|---|---|
| Cargo ships | One per person onboard |
| Passenger ships | 3 per lifeboat + 1 TPA for others |
| Warm climate ships | Exemption possible |
| Bridge / ECR / Remote stations | 2 additional each |
In Short
An immersion suit:
- Must be donned in 2 minutes
- Keeps body temperature loss under 2°C
- Must have light, whistle, buddy line, and reflective tape
- Must be pressure-tested every 3 years
- Must be stored dry and easily accessible
Life Saving Appliances (LSA) under 3rd Officer:
* Lifeboats (enclosed, rescue boats) and launching arrangements​
* Liferafts and their hydrostatic release units​
* Lifebuoys (with lights, smoke signals, and lifelines)​
* Lifejackets (with lights and whistles) for all persons on board​
* Immersion suits and thermal protective aids​
* Emergency Position Indicating Radio Beacons (EPIRBs) and Search and Rescue Transponders (SARTs)​
* Rocket parachute flares, hand flares, and buoyant smoke signals​
* Line throwing appliances​
* Muster list and SOLAS/LSA/Fire safety training manuals and posters​
* Spare batteries, bulbs, and supporting inventory for LSA​
Fire Fighting Appliances (FFA) under 3rd Officer
* Fire extinguishers (of all types) throughout accommodation and deck areas​
* Fire hoses, hydrants, and nozzles​
* Fireman’s outfits (protective clothing, boots, helmets, gloves)​
* Self-contained breathing apparatus (SCBA) sets​
* Fire blankets and sand buckets​
* Fire alarms and detection systems​
* Fire main and emergency fire pumps​
* Fixed firefighting systems (CO2, foam, water mist, dry powder, etc.)​
* Emergency escape breathing devices (EEBD)​
* Portable and fixed communication equipment used in fire emergencies​
Additional Responsibilities
* Keeping LSA/FFA inspection and maintenance records up to date (PMS)​
* Training and familiarizing crew with the use of all equipment​
* Ensuring LSA/FFA manuals, posters, and muster lists are current and correctly displayed​
* Planning inventory needs and raising requisitions for expiring items/spares​
* Reporting deficiencies and planning for shore-based inspections or servicing as required​
