FRESH AIR SUPPLY EQUIPMENT
Unpowered Fresh Air Hose System or Powered Fresh Air Hose System (Powered by Mini-Turbine)
Selection of Systems
The Full Face Mask Fresh Air System can be used either as unpowered (Negative pressure ), where the air is drawn through the system by the lungs of the user, or as a Powered system where air is supplied by connecting a Martindale Mini turbine to the end of the air supply hose.
The choice of which system to use is left to the user. Normally if the system is likely to be used for any significant period of time (i.e. over an hour) then the powered option is preferable in terms of comfort to the user.
The unpowered system should be used if there is no power available for the turbine or if the atmosphere where the turbine is to be sited does not permit the use of electrical equipment (for example a potentially explosive atmosphere).
Both systems conform to the higher specification of EN 138, namely Fresh air BA EN 138 class2.