Abstract: A suspended ceiling system for a clean room employing short cross runners connected to longer main runners. The connections serve to coax the cross runners against the main runners to keep the system intact and air tight. The grid of cross and main runners creates rectangular areas between them into which ledges extend from both runners. For a dry seal, a sealing gasket adheres to the ledges' upper surface. Ceiling components such as lights, filters, and tiles sit upon the gasket to provide the seal. For a wet seal, a trough sits upon the ledge and circumscribes each rectangular area. The trough contains a liquid material into which a knife edge depending from the ceiling fixtures sits. A continuous threaded slot runs along the center of the members' bottoms. This allows the attachment of accessories such as removable walls. The runners have a generally U-shaped cross section that gives it sufficient strength to bear the live weight of a person.

Abstract: A suspended ceiling system having tiles and fixtures with interspersed hooks resting on runners. The hooks from adjacent ceiling components rest on the top of the same runners, but not upon each other. Each tile, consequently, may undergo removal without interfering or disturbing any of its neighbors. The tiles may have kerfing and backcutting with a metal bracket, or spline, inserted in the kerfing. The hooks extend from the metal bracket upwards and over the top of the suspended runners. Generally, the location of the hooks and spaces form mirror images of each other through a plane passing through the middle of the tile. When used on the opposite side for a neighboring tile, the hooks from either tile land in the space between the hooks on the other tile. Although resting on top of the same runner, they do not lie on top of each other, permitting the removal of one tile without disturbing any others.