Open grid ceilings are an architectural feature that provide a visual sense of openness, but create potential obstructions for sprinkler discharge.
Controlling The Hazard
To avoid putting sprinklers beneath an open grid ceiling, the openings must be at least ¼ inch (6.35 mm) in the smallest dimension, the ceiling material thickness or depth cannot exceed the smallest dimension of the opening, and the sum of the area of all openings must be at least 70% of the area of the ceiling material.
If sprinklers are installed above the open grid ceiling, there must be adequate clearance beneath the sprinkler deflector to develop an unobstructed spray pattern.
The table below provides minimum clearances measured between the sprinkler deflector and the upper surface of an open grid ceiling.
For further information, please contact your RMC Engineer
