What is the maximum floor area per unit of A for ordinary hazard occupancy?

The maximum floor area for ordinary hazard occupancy is indeed 1500 ft² per unit of A. This limitation is based on the classification of fire hazards in buildings, established by fire safety codes and regulations, such as those in the National Fire Protection Association (NFPA) standards.

Ordinary hazard occupancies are classified as those that present a moderate level of fire risk. The specified area limit helps to ensure that the fire extinguishers provided are adequate in number and capacity to cover the potential fire risk within that space. When the area exceeds 1500 ft², additional fire protection measures may be required, such as more fire extinguishers, enhanced alarm systems, or additional suppression systems, to ensure safety. This regulation is important to mitigate the risk of fire incidents in such environments and protect life and property.

In contrast, larger floor areas, such as those mentioned in the other choices, would indicate a greater risk which necessitates stricter fire safety measures and is not permissible under the ordinary hazard classification.