To top of page What is a rebreather and which types are there?
A rebreather is a system in which the air you exhale is processed (carbon dioxide is filtered out and oxygen is added), so that you can inhale it again. In regular diving equipment, all exhaled air vanishes into the environment and cannot be used again. There are two types of rebreathers: fully closed circuit (FCC) and semi-closed circuit (SCC). Fully closed A fully closed rebreather will keep the partial oxygen pressure at the same level during the whole dive, regardless of depth. This will give you a lot more bottom time. To achieve this constant pressure, the system mixes air (or trimix) with 100% oxygen. If, for example, the partial oxygen pressure is set to 1.3 bar, the mixture you inhale will be nearly 100% oxygen at 5 meters; at 40 meters, it is nearly 27% oxygen. A fully closed system will also allow you to use the gases more efficiently: you only use what you need. Fully closed systems are to be used if you don’t want to produce any air bubbles, if you want to make deeper dive
