Suppression Systems completes double interlock pre-action sprinkler system for Goldman Sachs top floor suite at Rainer Square Seattle. The system protects IDF and Server equipment rooms. The difference between a wet system and the pre-action system is that in the pre-action system, the pipes are filled with compressed air and the sprinkler heads are all closed, and water is held back from the piping by a pre-action valve. This way the system is considered a dry system until activated when it becomes a wet system. Pre-action systems are used anywhere accidental discharge of water could be detrimental.