Always", during initial leak test make sure, that all pumps / compressors are isolated with vents / drains open to atmosphere to prevent accidental pressurization and as such possible seal damage. Pumps and compressors are only to be leak tested when seal systems are cleaned and properly commissioned by Vendor / Suppliers representatives and /or Rotating Equipment specialists.
During the "Construction Phase"; all seals and all rotating equipment must be carefully isolated, must never be pressurized and should always be kept in a protective clean environment with conservation oil in the seals.