Australasian Mining Review
Issue link: http://ebook.aprs.com.au/i/37922
56 Self contained Breathing apparatus use The concept of using self contained breathing apparatus (SCBA) in the mining industry is not exactly new. Since the early 1870s breathing apparatus was designed and manufactured to rely on a single small compressed air cylinder and a simple demand valve that only lasted around 15 minutes. This fi rst generation of SCBA included a bulky steel cylinder and purportedly weighed in at 30 – 40kgs. Duration times of SCBA Duration times of SCBA have since dramatically increased. For example a 9 litre 300 bar cylinder lasts approximately 67 minutes. Two cylinders can be used in a back plate configuration to provide extended use times, for example an approximate 102 minutes of duration can be provided by two 6.8 litre 300 bar cylinders. Developments in ‘Fast Fill” systems have certainly enhanced extended breathing apparatus use and are quite a common technology on mine sites. More user friendly Technology has moved forward to provide more ergonomic breathing apparatus sets. Steel cylinders are being replaced by carbon fibre cylinders. Carbon fibre cylinders are lightweight both empty and full, and are very durable. Lighter cylinders greatly reduce wearer fatigue and for those regularly using SCBA this is a long term benefit. SCBA sets are being designed with comfort and simplicity in mind with some now available with soft flexible back plates. SCBA has moved away from negative pressure masks to positive pressure masks. This offers the wearer higher protection and is also enforced by current standards. Breathing apparatus continue to be designed with the user in mind with warning whistles and gauges being a requirement. Mines around Australia use single or twin cylinder SCBA, which are kept below ground in the gate roads of longwall or pillar and stall workings. All SCBA used in mines require specific approvals. Advantages of using SCBA There are many advantages in using Self Contained Breathing Apparatus: • Positive pressure system provides higher level of protection • Less breathing resistance • Many system can be refilled while being worn • SCBA can be used over and over, so that training can take place in the actual unit at no additional cost • Personnel have their eyes protected from smoke • Air supply is known and easily identified with gauges and whistles • Devices can be approved for different applications from mining to fire fighting • SCBA has 10-15 year service life • SCBA is the highest respiratory protection available • In some instances breathing apparatus is the old option, for example in IDLH environments All respiratory protection has limitations. SCBA has a maximum duration of around 1½ hours (twin cylinders). The cylinder duration can also vary depending on the breathing rate of the wearer. Situations have to be assessed before using breathing apparatus as it is no good attempting a casualty rescue if the travel time is 45 minutes each way. Breathing apparatus also requires regular maintenance and should be inspected before use. When determining if a Self Contained Breathing Apparatus is required consult the current standards, AS/NZS 1715 and AS/NZS 1716. For a great deal of industrial workers, SCBA is ideal for numerous work applications. [Breathing Apparatus] _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _