Clarify "Vaccum sealing arrangement in valves".
It means the valve shall seal when pipe pressure becomes lower than valve external pressure (usually athmospheric pressure).
In such case, differential pressure is reversed. You shall insure your gate valve sealing arrangement works in reverse way too. It is not the case for lip seals or chevron type seals.
Particular care shall be also considered with O'rings in high pressure designs.
For standard Gate valve, I don't see any problem as far as packing is design for.
Gate and globe valves are not generally vacuum tight or may leak after some time in service.  In order to prevent air in-leakage, a water supply is piped to the atmospheric-pressure side of the valve to provide a water seal.  (Most installations are in a vertical run of pipe.)  A level control may be used to automatically replenish any water leakage through the valve into the vacuum space.
In addition, a "lantern ring" may be used to prevent air leakage through the stem packing.  The "lantern ring" also requires a water supply.

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