Elevator Mechanic Practice Exam

Which door is heavier on bi-parting freight doors?

1. The lower door because of the tucking sill

2. The upper door due to the frame structure

3. The lower door because of added safety features

4. The upper door due to balancing weights

The correct answer is: The lower door because of the tucking sill

In bi-parting freight doors, the design involves a combination of factors that influence the weight distribution between the upper and lower doors. The lower door is often heavier because of its construction, which may include a tucking sill that contributes additional weight. This tucking sill is a critical component that not only enhances the door's stability and sealing capacity but also adds to its overall mass. Generally, freight doors are built to endure more stress and weight compared to regular commercial doors, which explains why the lower door's design can lead to it being heavier. The way these doors are engineered supports their functionality in high-use environments, ensuring they can withstand the demands placed upon them in terms of load-bearing and durability.