Glossary of Terminology

Lifejackets - a compex subject if you don't know what the terminology means!

Within this page we have tried to explain what various terms used mean in order to help you make an informed decision as to which type of lifejacket you should purchase.

UK lifejacket terminology explained!

Lets start with the dictionary definition:

Life jacket n.

A life preserver in the form of a sleeveless jacket or vest.


Lifejacket terms A - Z

24g - twenty four gram co2 cylinder, commonly used on kids automatic gas life jackets.

33g - thirty three gram co2 cylinder, commonly used on adult 150N gas lifejackets.

38g - thirty eight gram co2 cylinder, less common, found on 150-175N gas life jackets.

60g - sixty gram co2 cylinder, found on 275N gas life jackets.

ABS - Lifejacket buckles and clips are commonly made from ABS which is a very tough form of plastic.

Air only - term used to describe a life jacket that only becomes buoyant upon filling with gas.

Automatic, Auto - term used to describe a life jacket that only becomes bouyant upon activation, which is automatic upon entering water.

Auto cap - name given to an automatic firing capsule.

Bladder - the part of a gas life jacket that inflates during firing and provides the bouyancy.

Bobbin - generic term used for dissolving pellets or capsules that activate firing pins in automatic life jackets.

Buoyancy - The purpose of any lifejacket is to make the wearer float, how much floatation each life jacket has - buoyancy - is measured in Newtons, or N.

Buoyancy aid - name given to any buoyant vest or jacket that does not have the righting action of a lifejacket - with the head up, but does provide buoyancy, for example a dinghy sailing vest.

Cap - short for firing capsule.

CE, CE Mark. - stands for 'Conformite Europeenne' in short a product bearing the mark is manufactured to conform with the relevant European directives for that product.

Chamber - another term used to decribe a life jackets bladder.

Crutch Strap - fitted to life jackets to prevent the jacket riding up on the wearer.

Co2 - Carbon dioxide gas, commonly used for the inflation of gas lifejackets.

Cylinder - Co2 is stored in small metal cylinders attached to the firing mechanism of the life jacket. These are available in a range of sizes, depending of the volume of the lifejacket..

D Ring - is made from stainless steel, found on the front of lifejackets with harnesses and is the point where a lifeline is attached.

Doff, Doffing - name given to the action of removing a life jacket.

Don, Donning - name given to the action of putting on a lifejacket.

EN393 - European CE standard covers 50N buoyancy aids, providing a minimum of 5kg of buoyancy.

EN395 - European CE standard covers 100N lifejackets, providing a minimum of 10kg of buoyancy.

EN396 - European CE standard covers 150N lifejackets, providing a minimum of 15kg of buoyancy.

EN399 - European CE standardcovers 275N lifejackets, providing a minimum of 27.5kg of buoyancy.

EN 1095 - European CE standard covers lifelines.

False inflation - can occur when an automatic lifejacket inflates after becoming extremely wet due to heavy rain or spray, also see 'hammar'.

Firing pin - when the gas lifejacket is inflated the firing pin pierces the gas canister and allows the gas to fill the bladder.

Gas canister, gas cylinder - small metal cylinders containing co2 gas, attached to the firing mechanism of the life jacket.

Halkey-Roberts, HR - US manufacturer of lifejacket inflation devices.

Hammar - Swedish manufacturer of lifejacket inflations devices, uses a hydrostatic valve that virtually eliminates any chance of false inflations.

Harness - term used to describe a lifejacket that enables the wearer to attach a lifeline.

ISO - the new standard that lifejackets are manufactured to in Europe.

Lanyard - The string that is pulled to activate a gas lifejacket.

Lock pin - Lock pins hold the manual firing lever in the correct position and pop off when the jackets toggle is pulled to inflate.

Loose cylinder - most common reason for a gas lifejacket failing to inflate, regular checks of the co2 cylinders tight fit are essential.

Lifeline - connects the wearer of a lifejacket with a harness to the boat, recommended for singlehanded, night and offshore boating.

Light - lifejacket lights fit inside the jacket are manually activated and have long life batteries.

Manual - common term for gas lifejackets that require the wearer to pull the lanyard to activate, not recommended for general boating use, preferred by pilots and aircrew.

Manual cap - some inflator mechanisms are interchangeable between automatic and manual only activation by changing the auto cap for a manual cap.

Manual inflation - lifejackets that are not necessarily bouyant until the wearer activates or inflates orally.

Manufacture date - all lifejackets and inflation parts carry a manufacturing date, gas life jackets particularly as components have a limited life.

MCA - Maritime and Coastguard Agency UK. This Agency is responsible throughout the UK for implementing the Government’s maritime safety policy. That includes co-ordinating search and rescue at sea through Her Majesty’s Coastguard, and checking that ships meet UK and international safety rules.

MED - Marine Equipment Directive applied to lifejackets for use on Solas class commerical vessels.

Newton, N - Measure of buoyancy 10 newtons = 1 kilo of buoyancy.

Oral Infation Tube - all gas lifejackets, manual and auto, have a tube in the chest area to top up air by mouth into inflated bladder.

Orange foam - generic term given to lifejackets that use closed cell foam for buoyancy and have bright orange fabric outer shell.

Pill - another term used to describe the salt pellet or bobbin, that fires automatic gas lifejackets..

Reflective tape - found on lifejackets to aid visibility for finding a person in the water in darkness.

Release valve - Gas lifejackets have a release valve usually found inside the top of the oral inflation tube.

Re-arming kit - a rearming kit contains the necessary parts to rearm a lifejacket that has been inflated, it contains a lock pin, a co2 cylinder and depending upon model a salt pellet capsule or hydrostatic valve.

Salt Pellet - common term for disolving pellet that activates firing pin in automatic lifejackets.

Serial Number - Lifejackets carry a serial number that identify the maker, batch and manufacturing date.

Service - all life jackets require regular maintenance and some require a service by an approved station at pre determined dates, usually bi-anually.

Shelf life - Many safety products have shelf lives, in particular regards to lifejackets, salt pellets, valves and co2 cylinders have a fixed life.

Ships Wheel - symbol used on lifejackets that comply with MED directive for commercial use.

SOLAS -stands for 'Safety Of Lives At Sea' and is an International Convention that is generally applied to commercial vessels on international and domestic voyages only.

SOLAS V - Most of the SOLAS convention only applies to large commercial ships, but parts of Chapter V apply to small, privately owned pleasure craft, this does not cover lifejackets. Read more at www.mcga.gov.uk/

Stainless steel - metal used for buckles and d rings on better quality lifejackets.

Stitching - Lifejacket webbing is stitched together and should be checked for wear as part of routine maintenance.

Stole - another name for a life jacket bladder.

Toggles - better quality lifejackets have toggles for attaching the lifejacket to a sailing coat, the loops are found on most sailing jackets on the chest and neck.

United Moulders, UML - UK manufacturer of lifejacket inflations devices.

Velcro - Used as a fastener on lifejackets usually found around protective covers on gas lifejackets that split on inflation, and on belts on speciality vests.

Waistbelt model - name given to a life jacket that does not have a harness, these life jackets are generally lighter as they dont have metal fittings, ideal for fishing and light use.

Webbing - Lifejacket straps, belts and harnesses are made from tough webbing, similar to car seatbelts.

Whistle - a signal whistle can be found on lifejackets, part of the ce requirement, but not necessary on dinghy or ski vests.

Zip - a self bursting zip can be employed on a lifejacket instead of velcro closure, this makes a lifejacket tamper proof.


Glossary for lifejackets

This lifejacket glossary is provided as a guide and does not form part of any contract.

It is soley intended for use by private individuals and customers of The Marine Warehouse Ltd. No part of this glossary may be reproduced in any form without our written permission.

Copyright The Marine Warehouse Ltd 2001-2015.