ISO 12402:2006 personal flotation devices

Courtesy: ISO 12402:2006 personal flotation devices

Life jackets or life vests are mandatory on airplanes flying over water bodies, in which case they consist of a pair of air cells (bladders) that can be inflated by triggering the release of carbon dioxide gas from a canister—one for each cell. Or the cells can be inflated “orally” that is by blowing into a flexible tube with a one-way valve to seal the air in the cell. Life jackets must also be supplied on commercial seafaring vessels, be accessible to all crew and passengers, and be donned in an emergency.

Flotation devices are also found in near water-edges and at swimming pools. They may take the form of a simple vest, a jacket, a full-body suit (one piece coverall), or their variations suited for particular purposes. They are most commonly made of a tough synthetic fiber material encapsulating a source of buoyancy, such as foam or a chamber of air, and are often brightly colored yellow or orange to maximize visibility for rescuers. Some devices consist of a combination of both buoyancy foam and an air chamber. Retroreflective “SOLAS” tape is often sewn to the fabric used to construct life jackets and PFDs to facilitate a person being spotted in darkness when a search light is shone towards the wearer. In the US, federal regulations require all persons under the age of 13 to wear a life jacket (PFD) when in a watercraft under 12 meters long. State regulations may raise or lower this number and must be followed when in that state’s jurisdiction.

The simplest and least buoyant type of PFD comes in the form of nylon-lined foam vests, used predominantly in water sports such as kayaking, canoeing and dinghy sailing.

Buoyancy aids are designed to allow freedom of movement while providing a user with the necessary buoyancy. They are also designed for minimal maintenance and as they are only constructed from foam and can be mass-produced inexpensively, making them one of the most common forms of PFDs.

Some buoyancy aids also come designed especially for children and youth. These vests may include one or two understraps to be worn between the legs of the wearer and also a headrest flap. The understraps are designed to keep the vest from riding up when worn in the water and restrict the wearer from slipping out of the life vest. These straps are adjustable and are included on many different life vests designed to be worn by everyone from infants to adults. The headrest flap is designed to help support the head and keep it out of the water. A grab handle is attached to the headrest to be used if needed to rescue or lift someone out of the water.

Buoyancy aids are rated by the amount of buoyancy they provide in Newtons – the minimum rating to be considered suitable as an adult life-jacket for offshore use is 150 newtons (34 lbf).