What is the maximum allowable area of glazed openings in 1- and 1-1/2-hour fire rated doors?

The maximum allowable area of glazed openings in 1- and 1-1/2-hour fire-rated doors is indeed 100 square inches. This limit is established by fire safety codes and standards, which are designed to ensure that fire-rated doors maintain their integrity in a fire situation while allowing for some degree of visibility through glazed openings.

In the case of fire-rated doors, the glazing must comply with specific fire-resistance ratings and must be tested in accordance with recognized standards, such as the National Fire Protection Association (NFPA) guidelines. The restriction on the size of the glazed openings is crucial because larger openings could compromise the door's ability to contain fire and smoke, which could undermine safety measures in a building.

Regardless of other options provided, the focus on maintaining a maximum area of 100 square inches for glazed openings balances the need for light and visibility while ensuring that the fire rating of the door is not adversely affected. This is why the specified area is set at this threshold, making it the correct choice.