When using wood sleepers for laying wood flooring on masonry, what is the maximum area in square feet for open space under the flooring that requires fireblocking?

The maximum area of open space under wood flooring that necessitates fireblocking is indeed 100 square feet. This requirement is established to prevent the spread of fire through concealed spaces. When there are voids or unoccupied areas beneath the flooring, fire can travel rapidly if those spaces are not blocked. Fireblocking involves using materials that impede fire's ability to pass from one area to another, effectively creating barriers within these open spaces.

In the context of building codes—specifically those related to fire safety and structural integrity—the stipulation for 100 square feet ensures that any cavity large enough to potentially influence fire dynamics is adequately protected. Fireblocking needs to be implemented in such a way that it creates a continuous barrier, especially in large or open areas, to minimize the risk of fire propagation and improve overall safety.

Understanding this requirement highlights the importance of proper installation practices in construction and the role of fire safety measures in building design, ensuring that any concealed spaces are managed appropriately to aid in fire prevention.