Hello, Gregory, I'm surprised that the backup system is wet pipe rather than dry pipe pre-action? May I ask why? Thanks! Richard At 06:28 PM 2/18/2004 -0500, you wrote: >Hannah - For the Library of Congress' main new collections storage >facility at the National Audio-Visual Conservation Center in Culpeper, >Virginia, we are utilizing a layered dual-system fire protection >approach, with an FM200 gas-based system as the initial primary >suppression agent back up by a wet-pipe sprinkler system.