What materials are included in the term "grillage" for bedding in piping systems?

The term "grillage" refers to the materials used for bedding in piping systems. The correct answer includes sand, pea gravel, or gravel rock size #57 and smaller. This specification is significant because the size of the aggregate material plays a crucial role in providing the necessary support and stability for the pipes as well as facilitating proper drainage.

Using smaller aggregate sizes ensures that the bedding can conform more easily to the shape of the piping and can disperse load evenly. Smaller particles also reduce the risk of voids that can lead to settling or shifting over time, which is vital for maintaining the integrity of the piping system.

Considering the other options, they either include inappropriate sizes that do not conform to the required specifications for effective bedding, or they describe materials that would not provide the necessary support and stability for piping systems. Therefore, option B correctly encompasses the suitable materials for "grillage," thus ensuring adherence to proper plumbing practices as outlined in the Kentucky Plumbing Code.