SCBA is highly specialised equipment! The wearers require high levels of training for safe use.
The SCBA is fitted with a full-face mask and a demand valve to provide a small positive pressure inside the mask. A 'Demand valve' is designed to provide air flow as demanded by the wearer and the BA can be cleaned and reused many times as recommended by the manufacturer and may be worn continuously for more than 1 hour, SCBA is suitable for use in oxygen deficient atmospheres, and in harsh and demanding environments. It is used for short term work such as work in tanks, trenches and sewers. Precautions and safety procedures are required for safe use. These come with training, experience and knowledge of the harsh environment. This BA is OK for medium work rate (work involving sustained hand and arm movements, or like brisk walking). It is also OK for a heavy work rate (heavy manual work requiring a lot of exertion and energy).