Which ceiling type is not considered obstructed construction?

Which ceiling type is not considered obstructed construction?

• A. Flat slag, pan-type reinforced concrete
• B. Wood panel ceiling
• C. Suspended acoustic ceiling
• D. Plain drywall ceiling

Answer: (A)

The main idea here is how ceiling construction affects sprinkler spray distribution. Obstructed construction means the ceiling has features that block or divert the water pattern, such as voids, plenum spaces, or gridwork that can trap air or alter flow. A solid flat slag, pan-type reinforced concrete ceiling is a continuous, monolithic surface with no overhead plenum or obstructive features. Because it presents an uninterrupted barrier, it does not interfere with the sprinkler spray path, so it isn’t considered obstructed construction. In contrast, a wood panel ceiling introduces joints and irregularities that can disrupt uniform spray, a suspended acoustic ceiling creates a ceiling plenum and grid that can alter or trap water, and a plain drywall ceiling—though common—can be part of a ceiling assembly with potential voids or features that act as obstructions in certain designs.

The main idea here is how ceiling construction affects sprinkler spray distribution. Obstructed construction means the ceiling has features that block or divert the water pattern, such as voids, plenum spaces, or gridwork that can trap air or alter flow.

A solid flat slag, pan-type reinforced concrete ceiling is a continuous, monolithic surface with no overhead plenum or obstructive features. Because it presents an uninterrupted barrier, it does not interfere with the sprinkler spray path, so it isn’t considered obstructed construction.

In contrast, a wood panel ceiling introduces joints and irregularities that can disrupt uniform spray, a suspended acoustic ceiling creates a ceiling plenum and grid that can alter or trap water, and a plain drywall ceiling—though common—can be part of a ceiling assembly with potential voids or features that act as obstructions in certain designs.