| 
  
    | Non-flammable gases | Colour | Tape Ref |  
    | Oxygen |  | GY-BU-GY |  
    | Inert gas |  | GY-BN-GY |  
    | Nitrogen |  | GY-GN-GY |  
    | Refrigerant |  | GY-MN-GY |  
    | Compressed air LP (Low Pressure)
 |  | GY-OG-GY |  
    | Compressed air HP (High Pressure)
 |  | GY-RD-GY |  
    | Control air / Regulating air |  | GY-VT-GY |  
    | Breathing air * |  | GY-WH-GY |  
    | Breathing gas * |  | GY-YEO-GY |  * This marking is used in sub-marines for distribution systems of breathing air from cylinders.
 |  | 
  
    | Air in ventilation systems | Colour | Tape Ref |  
    | Discharge air |  | WH-BK-WH |  
    | Mechanical supply air, cold |  | WH-BU-WH |  
    | Natural exhaust air |  | WH-BN-WH |  
    | Atmospheric air |  | WH-GN-WH |  
    | Mechanical exhaust air |  | WH-GY-WH |  
    | Decontaminated supply air |  | WH-MN-WH |  
    | Mechanical recirculated air |  | WH-OG-WH |  
    | Mechanical supply air, warm |  | WH-SR-WH |  
    | Smoke clearance |  | WH-RD-WH |  
    | Conditioned supply air |  | WH-VT-WH |  
    | Natural supply air |  | WH-YEO-WH |  |