The Water Flow Laboratory has specialized test rigs for the precise calibration of flowmeters, testing of valves, pipe fittings and other flow products. The whole system is designed to handle a maximum flowrate of 5000m3/h. Pipeline size upto 900mm. The gravimetric static weighing method as per ISO 4185 is adopted here for the measurement of flow rate.The two weighing tanks are of capacities 2T & 20T. Diverter systems are used to collect water in the weighing tank, for an accurately measured period of time. The mass measurement is by load cells. The relative density together with measurements of water temperature at the moment of each diversion enables the mass readings after correction for air buoyancy, to be converted into volume. These volumes are divided by the respective diversion times to obtain accurate measurement of flow rate.