How Do Auto Inflatable Life Jackets Work?

How Do Auto Inflatable Life Jackets Work?

When it comes to doing anything on the water, you will need to ensure that you are safe, first and foremost. Even the most experienced swimmers have a deep-rooted respect for water, as it can hold the power over life and death, and that goes doubly so for those who are inexperienced around water.

A common mistake that people make is the assumption that a portable flotation device or a life jacket is only necessary if you don’t know how to swim. You can be the greatest swimmer in the world, but a life jacket is a necessity because everyone has their limits, and you may not be able to keep yourself above water in an emergency.

A man with an auto inflatable life jacket.

There are many possibilities when you are on the water, and you will always want to be prepared, but there are many different kinds of life jackets, and some require preparation. For example, inflatable life jackets will need to have air in them before an emergency happens, which can take crucial moments.

This leads us to the self inflating life vest, which is designed to do exactly what you think, there are many different ways that these vests can inflate, and we'll be looking at them closely. Join us for a guide in which we will detail how an auto inflatable life vest works.

What Are Auto Inflatable Life Jackets?

An automatic inflatable life vest is a type of personal flotation device that contains automatic elements which are designed to fill your vest with a gas as quickly as possible. There are several reasons why auto inflatable life jackets are so popular, and we’ll go over a few of the crucial ones.

You may be wondering why you wouldn’t just use a regular inflatable life jacket and there are a few reasons for that. Most of the time, you will find that a life vest that is already inflated is bulky to the point of discomfort, which can discourage their use, especially on a boat or somewhere seemingly safe.

The automatic inflatable life vest is an excellent idea as it doesn’t get in your way when you are safe, but it will be inflated when you are in the water through a variety of methods. There are a few different options when it comes to inflating the life vest, and we’ll look at them all shortly.

How Automatic Inflatable Life Vest Works

A self inflatable life vest actually doesn’t use air to keep you above water, using carbon dioxide instead. This gas has the benefit of improved buoyancy over some of the other options on the market, including materials that have a low enough density to float on their own.

You may be wondering how the carbon dioxide is deployed, however, and that depends on the kind of auto inflatable life vest you are using. Some models will inflate automatically while others will feature a cord that you can use to inflate the vest.

Man in an auto-inflatable life jacket.

These vests work by containing the carbon dioxide in small canisters under pressure to ensure that the vest isn't too bulky. When you find yourself in an emergency situation, the vest will be deployed, and the canisters will no longer be blocked off to the rest of the vest. Once this happens, the gas rushes into the vest itself out of the canisters.

Auto Inflation Mechanism Types

There are mainly two different kinds of auto inflation mechanism, and they depend on how much you are willing to spend on the vest itself. The more expensive option is to purchase a life jacket that inflates automatically while the more affordable vests will feature a cord that you can pull on.

Manual (Cord Pull)

In automatic life vests where you must pull a cord, everything is done manually, and it is recommended that you pull it before or while you are entering the water. When you tug on the cord, they are attached to reinforced stoppers that hold the gas canisters closed, and the gas rushes out.

Since the carbon dioxide in the canisters is under pressure, it doesn't need to be pumped out, as it will follow Bernoulli's Principle and move from a high-pressure area to low pressure area. These life vests will often be more affordable than other auto inflatable life vests because of their manual operation.

Keep in mind that these vests can often be unsafe when compared to truly automatic options, especially in violent scenarios like shipwrecks. For example, if you are knocked unconscious when you are jumping off of the boat, you won’t be able to inflate your life vest by pulling the cord.


This is the pricier variant of these life vests, and it inflates automatically when it comes into contact with the water, requiring no input from the user. These life vests are an excellent choice for situations in which you may be injured or otherwise incapacitated, and you wouldn't be able to pull a cord.

There are a few different ways that automatic models can function, but there are two that are more common than others. The first kind of automatic life vest will feature a dissolving tablet that is holding the gas bottles closed; when submerged in water, it will rapidly disintegrate and inflate.

On the other hand, you have automatic life jackets that inflate using a pressure gauge. When a life vest is submerged in water, the surrounding pressure increases, and the vest senses this. Once the pressure reaches a certain point, the vest will automatically unblock the gas supply and send it into the main compartment.

Inflation mechanism on a life jacket.

CO2 Cylinders Require Maintenance

Of course, there is a single disadvantage to these life vests, and it is that you must maintain the CO2 canisters or they may not function. Every time you use your life vest, you will want to check the cylinders on the interior as they will often feature a pressure gauge that lets you know their status.


As you can see, auto inflating PFDs are a serious matter, and we hope that we have been able to teach you everything you wanted to learn about them. Feel free to leave a comment in the section down below.

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