What typically indicates there are 3 to 4 apartments per floor in an OLT?

The indication that there are typically 3 to 4 apartments per floor in an Old Law Tenement (OLT) is primarily tied to the architectural design commonly associated with these buildings. The presence of a front fire-escape is a characteristic feature of many OLTs that facilitates access to multiple floors. Generally, buildings designed with this type of layout often accommodate several apartments per floor to maximize living space. The design of the fire-escape usually reflects this density, as it allows for egress from multiple apartments.

In contrast, the absence of a front fire-escape or the installation of a standard fire alarm system does not inherently provide evidence of the number of apartments per floor in such buildings. Additionally, buildings lacking windows might imply different structural or regulatory limitations rather than directly relating to the apartment count per floor. Therefore, the presence of a front fire-escape serves as a clear and practical indicator of the typical design and occupancy of apartments in Old Law Tenements.