– the intergovernmental organization through which Member States act together
     on matters related to measurement science and measurement standards.
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Vibration isolation

Two concrete foundations – one for the watt balance (64 tonnes) and one for the gravimeter (10 tonnes) – have been cast in the watt balance laboratory. Each is isolated from the main floor of the building but remains in lateral contact with the earth to avoid low-frequency swinging motions (excited by surface Rayleigh waves). The horizontal and vertical rms velocities due to ground vibrations are respectively 1 µm s-1 and 0.76 µm s-1 (for frequencies between 0.003 Hz and 100 Hz).

BIPM watt balance: new laboratory showing concrete foundations for vibration isolation