ATLAS RPCs gas system maintenance and improvement

The ATLAS RPC trigger detector consists of 3592 gas volume containing 14 m3 of gas mixture flowed in 2080 line. The gas circulates in closed-loop currently operated at flow rate of about 0.3 gas changes per hour. The LHC operation in the 2015 foresees a centre-of-mass energy of 13-14 TeV with a luminosity up to the project value of 1034 cm-2 s-1 which will be increased up a factor two in 2019. For this reason, the ATLAS background rate is expected to increase up to almost one order of magnitude with respect to the present conditions. This requires a new gas distribution to increase the flow in the more irradiated zone and the increment of the total flow up to the project value of 1 volume change per hour. A systematic search and repair of the gas leaks is in course and for this purpose sophisticated methods have been developed which allows to operate on sites normally considered unreachable. Finally the implementation of an extend network of gas flow sensors is under development for early and precise leaks detection.