Life Support SDBA MK5


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Special Duty Oxygen Breathing Apparatus

Date: 9 May 2007


Database oxygen rebreathers by: J.W. Bech


Life Support Engineering Ltd





Land of origin

United Kingdom

Designed 1970-71

Special Note: 



User group



Part no:

Mouthpiece: 100043.00

FFM: 100043.01

Working principle

CMF + bypass manual


Gas type

Pure oxygen


Cylinder volume

Two aluminium cylinders on

Divers back volume ?

Max. cylinder pressure

200 bar


Material of cylinder



Counterlung inspire volume



Counterlung exhale volume



Dive time duration

Up to 3 hours


Dimensions HxWxD in mm


Depth cylinders 90 mm

Magnetic signature

Non magnetic


Weight ready to use unpacked scrubber

7,5 kg


Weight ready to use in charged

10 kg



6 meter


Scrubber material

Sofnolime / protosorb









On the chest, bottles on the back


Mouthpiece shut off valve



Full Face mask attached (FFM)




Yes for bottles twin alu.


Extra info:

Twin breathing tubes


Extra info:


Additional information:


Email address owner





If you have any information to add this sheet please mail it to References to source and names will always be added!  


Info found: send by Anthony Appleyard, thanks Anthony








SDBA Mk.5 – Special duty oxygen breathing apparatus.

This successful equipment has been in use with many of the world’s navies and army marine corps since 1971. The SDBA Mk. 5 is a balanced apparatus i.e. the breathing bag and carbon dioxide absorbent canister mounted on the front of the diver are neatly compensated by the two slim aluminium alloy cylinders on his back. The apparatus has a constant flow of oxygen which may be bench set to a range of 0,8 – 3.0 l/min. Alternatively a selector switch may be incorporated so that the diver can choose flows to suit his work regime. A manual bypass ideally located beside the absorbent canister enables the diver to quickly adjust his buoyancy. Twin breathing tubes with non-return valves and an atmospheric valve (for venting) ensure low inhaled carbon dioxide.
The whole unit may be quickly released by slipping shoulder and waist buckles.
The breathing bag is construted from a tough nylon-butyl-nylon material with extremely high tear resistance.
The bag incorporates a relief valve which is automatic but can be manually over-ridden.
Servicing of the LSE SDBA Mk. 5 is extremely simple and training in its use has shown few problems in practise. The set is ideal for use in free swimming, canoe patrol and submarine exit. All components are non magnetic and are easily cleaned after operation.



The photograph shows a diver using the ONBA special duty oxygen/nitrogen breathing apparatus which is based on the SDBA above, but which permits the diver to  descend to 42 metres.

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