Exhaust-Only Ventilation Exhaust-only ventilation is the reverse of supply-only ventilation; stale air leaves the building from a known location (through exhaust fans ducted to the outdoors) and outdoor air enters the building from an unknown location.
In the 1960s, the Soviet Union began to prepare the Warsaw Pact for its internal function of keeping the NSWP member states within the alliance. The Soviet Union took a series of steps to transform the Warsaw Pact into its intra-alliance intervention force.
Total number of emigrants before Velvet revolution reached 300,000. The Warsaw Pact invasion of Czechoslovakia, officially known as Operation Danube, was a joint invasion of Czechoslovakia by four Warsaw Pact nations â the Soviet Union, Bulgaria, Hungary and Poland â on the night of 20â21 August 1968.