In the United States the cell size in the suspension grids is typically either 2 ft × 2 ft or 2 ft × 4 ft and the ceiling tiles are the same size. In Europe the cell size in the suspension grids is 600×600 mm, while the ceiling tiles are slightly smaller at 595mm x 595mm or 595mm x 1195mm.
In older buildings the space above the dropped ceiling was often used as a plenum space for ventilation systems, requiring only enclosed ducts that deliver fresh air into the room below, with return air entering the ceiling space through open grilles across the ceiling. This practice is now used less frequently in new construction.
Many manufacturers of modern dropped ceilings include sustainability as an objective. Sustainable features may include: Energy efficiency, including daylight efficacy and thermal insulating qualities. This uses the ceiling plane to reflect daylight as well as electrical illumination to maximize lumen efficacy, which also improves the comfort and usability of interior spaces. A common measure of the light reflectance of a ceiling material is ASTM E 1477 for Light Reflectance (LR-1). A level of about 75% is considered good, although higher levels are possible. Reduced resources needed for construction of the tiles. Recyclable/reused/renewable materials.
When installing a stretch ceiling, semi-concealed plastic/aluminum track, the preferred choice for most architects and designers, is cut to size and fixed to the perimeter of the ceiling area. The membrane is stretched and the harpoon or catch edge is clipped into the track. Stretching is aided by heating up the membrane or sheet prior to fitting.