What is the minimum clearance required around sprinkler heads to ensure proper functioning?

The correct answer is 18 inches. This distance is essential to ensure that the sprinkler heads can function effectively without obstruction. The clearance around sprinkler heads is critical because any items positioned too close can hinder the spray pattern and coverage area, which negatively impacts the system's ability to contain or extinguish a fire.

By maintaining an 18-inch clearance, it ensures that the sprinklers have the necessary space to distribute water adequately across the intended area. This measurement is grounded in fire safety standards and codes, which aim to optimize fire suppression capabilities and protect occupants as well as property.

Other distances may not provide sufficient coverage or could increase the risk of obstructions preventing the sprinklers from functioning as intended, which is why the specific requirement of 18 inches is essential for effective fire safety management.