Fan filter mounting frame

In a suspended ceiling system wherein a rectangular equipment unit is mounted in a rectangular equipment opening in a suspension grid system positioned at an elevated position in a room, the suspension grid system comprising a number of rails and cross rails that define a plurality of generally rectangular cells having open interiors, at least one open interior comprising an equipment opening, the rails and cross rails surrounding the equipment opening having generally vertical stems suspended from a ceiling and generally horizontal support flanges extending outwardly from the stems toward an interior of the equipment opening, the equipment opening being sufficiently large that the rectangular equipment unit fits through the equipment opening while horizontally oriented, the improvement wherein:

• one corner of the equipment unit is positioned over adjacent flanges of an intersecting rail and cross rail at one corner of the equipment opening, such that the equipment unit rests directly on the respective adjacent flanges of the rail and cross rail adjacent said one corner of the equipment opening when oriented for support by the grid system;
• a diagonally opposite corner of the equipment unit is spaced laterally away from supporting engagement with adjacent grid support flanges at a second corner of the equipment opening opposite to said one corner of the equipment opening, such that without further support said opposite corner of the equipment unit would fall through the equipment opening, wherein the equipment unit includes downwardly facing recesses at the sides adjacent the opposite corner;
• a removable frame insert being positioned over each of the two perpendicular support flanges adjacent said second corner of the equipment opening, the inserts upwardly extending projections at inner sides thereof that fit in supporting engagement with the recesses in the equipment units and having outwardly extending portions that rest on the horizontal flanges on the rails, the frame inserts being formed and attached in the system such that the frame inserts cause the equipment unit to be supported by the support flanges adjacent said second corner, whereby the equipment unit may be installed in the equipment opening by passing the equipment unit upwardly through the equipment opening, moving the equipment unit laterally so that one corner thereof is positioned over the flanges at one corner of the equipment opening, inserting one or more frame inserts into supporting engagement between the support flanges and the equipment unit adjacent the second corner of the equipment opening, and lowering the equipment unit for supporting engagement with the support flanges on the sides adjacent said one corner and with the frame inserts at the sides adjacent said second corner.