How do self inflating life jackets work

One of the 6 types of life-jackets is an inflatable PFD (personal floatation device). This is the only life-jacket of the 6 types that offers small, lightweight storage and then inflation upon use. They are most commonly associated with airlines as they are easily stored under seats.

In this article, I’ll be discussing all about inflatable life-jackets including the following:

  • What is an inflatable life-jacket?
  • The pros
  • The cons
  • How their mechanics work
  • How to manually and automatically activate your inflatable life-jacket
  • Whether or not they can be re-used
  • How long they last
  • If they are a safe choice, considering the other types of life-jackets

What is an inflatable life-jacket?

The inflatable life vest is a lightweight and easily portable buoyancy vest allowing businesses and individuals to have nearby access to life-saving equipment.

As the only type of PFD that can be activated and inflated, it offers very unique capabilities, as well as special maintenance and care requirements.

If you’re considering the inflatable life-jacket, make sure you are familiar with how they work, how they fit and how they should feel when submerged in the water. As well as this, they come in multiple sizes for adults and children, so I urge you to be equipped respectively.

Let’s go into the safety details: the self-inflating life-jackets have a PFD rating of 22 to 33 (which is quite high!). This means that they have approximately 22 to 33 pounds of counterweight added to your body’s buoyancy.

For more information about the different PFD ratings and how buoyancy works, look at my other article; “What is the Best Way to Check the Buoyancy of your PFD?”.


  • As they are less bulky than traditional life-jackets, they can be more comfortable to the wearer.
  • They are easier to apply because they are smaller than foam-filled life-jackets.
  • They have a tube whereby the wearer can blow and increase their PFD rating.


  • They can be punctured to release their air and render them useless.
  • If they do not have automatic features, they will not inflate for an unconscious wearer.
  • Their sensitive components need to be regularly maintained and evaluated before use.

How do you inflate a life-jacket?

Inflatable life-jackets have a CO2 (carbon dioxide) cartridge sewn inside the jacket itself. This CO2 needs to be released into the jacket in order for the jacket to be considered inflated.

The CO2 can be activated either manually or automatically, with both scenarios pushing a pin or bobbin into the CO2 canister to release the gas.

The canister must be checked securely before the wearer uses the jacket. And, the wearer must make sure that the life-jacket is worn on top of clothes in case they are waterproof or restricts the life-jacket’s ability to inflate.

The self-inflating life-jacket will have extra bells and whistles attached – quite literally – in order to aid in the floatation device’s continued use and to allow coast guards to find you in a rescue. These extras include:

  • A whistle to alert nearby individuals.
  • Reflective strips, so you can be seen in the dark.
  • A blow-tube so you can continue to add air through oral inflation and increase your buoyancy.
  • A string that can be pulled to manually inflate your life-jacket.
  • A crotch strap to prevent the PFD from going over the wearer’s head.

How does an automatic inflatable life-jacket work?

To go into further detail about the automatic self-inflating life-jackets, they do not need to have a string as they do not need to be manually activated.

The automatic life vest can be activated through different means depending on the manufacturer, so do your research to understand which activation method may best suit your needs.

Some self-inflating life-jackets are activated through water pressure in a method called ‘hydrostatic release’. When the gauge on a life-jacket reaches over 10cm of water pressure, the CO2 canister will be automatically activated and the life-jacket will be inflated within seconds.

Other self-inflating life-jackets work by a chemical reaction of a ‘pill’. When these pills are introduced to water, they dissolve and allow the CO2 cartridge to release. these are often considered more reliable than hydrostatic release self-inflating life-jackets.

Are self-inflating life-jackets re-useable?

In short: yes. I am here to let you know that you are able to purchase extra CO2 cartridges for self-inflating life-jackets and continue their beneficial use to your safety. However, this can only be done as long as you take care and properly maintain your life-jacket.

You can re-arm your personal floatation device by putting a new CO2 cylinder inside the jacket as well as a new automatic firing mechanism. As the firing mechanism has a use-by date, these can easily be replaced when in for servicing.

For safety reasons, your life-jacket will always come with manufacturer’s instructions on how to re-arm your life-jacket. So I strongly suggest familiarising yourself with those as they can differ depending on the model.

How long to self-inflating life-jackets last?

Self-inflating life-jackets have a life span of ten years when they have been correctly maintained.

These life vests need servicing every six months to ensure they are still fit for purpose.

For a routine maintenance check or to re-arm your life-jacket, you will first need to manually inflate through the oral inflation tube. Once inflated, leave the life vest over night to check pressure. Or, submerge in water to see air bubbles. This will allow you to check for holes or perforations.

Then, you will need to wipe down your self-inflating life-jacket with water to clean it. While you are cleaning, check to make sure the reflective tape isn’t peeling, the stitching is still secure, and all zips and straps remain strong.

Next you will need to check for corrosion and expiration dates on your gas cylinder and firing mechanism. Simply replace where needed following the instructions provided with your life vest model.

And, now you know all about how self-inflating life-jackets work. They are a safe option for water sports users, but the safest life-jacket on the market is the Type 1 Off-Shore Life-Jacket. This life vest doesn’t need to be inflated, can withstand open seas and choppy waters, turns the wearer up-right and has the highest PFD rating.

Check out my other articles to find out more!

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