Self contained breathing apparatus (SCBA) onboard ships

Self Contained Breathing Apparatus (SCBA) is a device when worn provides breathable air which is compressed ,which helps the user from harmful outer air  was hazardous compartments. SCBA is used onboard ships for enclosed space entry, firefighting or any work in a hazardous atmosphere.
  •  SCBA cylinders contain 1240 litres of compressed air at a 200 bars pressure. In normal conditions the cylinder will give the compressed air for about 31 minutes for the crew and at working conditions this may reduce as the worker may breath heavier in those conditions. It will depend upon the severity of the work.                                                          
  • A reducing valve fitted, will reduce the 200 bars pressure to 4 bars and it is further reduced by the demand valve which is attached to the mask.    
  • When inhaling through the mask, the demand valve supplies the air to the user.                                                          
  • Exhalation is done through the exhalation valve fitted on the face mask.                                                        
  • The cylinder will give a continuous warning whistle when the air inside the cylinder is for less than 10 minutes (40-45 bar pressure). The warning whistle is sounded till the air inside the cylinder gets empty. This whistle will alert the user to get out of the compartment or workspace which is hazardous for him.                    
  • The facemask is made of soft moulded nature rubber and it is provided with five adjustable head straps and a nylon lanyard or neck strap. The facemask has a full vision visor and a foam filled or air cushion seal. For the correct positioning of the face mask, the head straps should be tightened in a sequence with upper pair first, middle pair second and lastly the lower pair. The straps should be over tightened. This may cause discomfort for the user. Facemask is provided with an exhalation port with a speech diaphragm and a nose guard.                 
  • The user should have a good clear field of vision through the visor.             
  • With the harness that carries the cylinder, a pressure gauge is clipped or attached . This gauge will monitor the pressure inside the cylinder and is positioned to be easily visible by the user.                                                   
  • For each set of breathing apparatus , spare cylinders should be provided onboard. A small air compressor is also provided onboard to refill the cylinder with compressed air.                
  • If the facemask is not proper or dislocated in a hazardous atmosphere, the user should hold his breath and position the mask correctly. It is really hazardous if air from a toxic atmosphere is inhaled.