Non-Intrusive Acoustic Valve Inspection (NAVI) system developed by Maintenance Measure Controle (France) in 1989. This offers non-intrusive inspection service via acoustic technology to identify condition of various valves type and applications while providing leak severity assessment as well as quantification of leak rate. 
 
Through valve leak represents a MAJOR SAFETY RISK which is the major source of fugitive emissions and major source of loss. Through valve leakage also possess hazards to the environment by flaring harmful substance to the atmosphere.