Lifejacket buoyancy: 50N, 100N, 150N or 275N?
Lifejacket buoyancy: 50N, 100N, 150N or 275N?
The number on a lifejacket is its buoyancy in newtons under EN ISO 12402. It is not a quality rating and a higher number is not automatically better. It describes the conditions the jacket is designed for, and the clothing the wearer is expected to have on.
The short answer
| Level | Designed for | Turns an unconscious wearer face-up? |
|---|---|---|
| 50N | Buoyancy aid. Competent swimmers, sheltered water, help close by | No |
| 100N | Sheltered and inshore water, light clothing | Not reliably in all conditions |
| 150N | General offshore use, normal and foul-weather clothing | Yes, in most conditions |
| 275N | Offshore and extreme conditions, heavy protective clothing, or when carrying tools | Yes, including with heavy clothing |
Why 150N is the usual answer
150N is the level most recreational and professional users end up with, because it is the lowest level that reliably turns an unconscious person face-up while they are wearing ordinary clothing. Below that, the jacket keeps you afloat but does not guarantee your airway stays clear, which is the part that matters if you are knocked out going overboard.
When you need 275N
275N exists for a specific problem: heavy clothing and equipment trap air and add weight, and both work against a lifejacket. If the wearer has foul-weather gear, a survival suit, tool belts or heavy boots, a 150N jacket may not turn them. Commercial crews, offshore workers and anyone working on deck in winter gear should be on 275N.
Automatic or manual inflation?
An automatic lifejacket inflates on contact with water without any action from the wearer. That is exactly what you want if the wearer may be unconscious or disoriented. A manual jacket only inflates when the wearer pulls the toggle, which makes it the wrong choice for anyone who might go in the water unexpectedly. If in doubt, choose automatic.
What the level does not tell you
- Fit. A correctly rated jacket that is too loose will ride up over the wearer’s head. Check the weight and chest range for each model.
- Servicing. Inflatable jackets contain a gas cylinder and an inflator that need periodic inspection. A jacket with a spent cylinder provides no buoyancy at all.
- Visibility. Buoyancy keeps you afloat; it does not get you found. A lifejacket light and a whistle do.
Do you need SOLAS approval?
If the vessel is commercial, the answer is usually yes, and the buoyancy level alone is not enough: the jacket has to carry the right approval mark. See our guide on SOLAS approval.
Our range
We stock 100N, 150N and 275N models, in manual and automatic versions, including a 150N jacket in SOLAS specification. If you are choosing for a crew rather than yourself, contact us at info@maritiem-winkel.nl and tell us how they will be dressed on deck, because that determines the level more than anything else.