What is an Elevator Pit?
Considering standard pit requirements and undertaking a series of prerequisites before the implementation of elevator installation and commissioning projects prevents the need for repeating stages and incurs additional time and cost. One of the crucial aspects to consider is the elevator pit.
Difference Between Shaft and Elevator Pit
Before delving into the definition of an elevator pit, it’s essential to understand the elevator shaft or pit. Simply put, the shaft or pit is a vertical tunnel from the lowest point (i.e., the building’s foundation) to the topmost floor, which includes the machine room.
In other words, the elevator pit is a space where the elevator car and all its components move. Typically, the walls of the elevator pit are plastered with cement and have no gaps or cracks. Additionally, walls with plaster covering must be painted.
According to the definition set by the National Building Regulations of Iran, in Chapter Fifteen, the distance from the lowest landing to the end of the shaft is referred to as “pit.” This space is created to provide a suitable area for technicians to work and install certain elevator equipment and components such as buffers and safeties.
Important points such as the proper reinforcement of the pit, determining the dimensions of the elevator shaft, and the design and execution of the pit should be carefully considered in your projects.
Apart from the rail bases, buffers, and drainage facilities, this area must be smooth and level. It should also be resistant to water penetration. If the pit is deeper than 2.5 meters, and the building design permits, it needs an access door for entry and exit. Alternatively, if no door is present, a ladder can be used as an alternative.
Additionally, the pit floor should have a mushroom stop, an illumination switch, and a waterproof outlet. The condition for the mushroom stop is that it must be accessible not only from the pit floor but also from the first-floor door.
The pit also needs to have a telephone. The standard specifies that if there is a risk of people working inside the pit and there are no provisions for their rescue through the car or the pit, signaling devices must be installed in areas where this danger is present.
The car must be placed on a compressed buffer, where the discussion about air gap and compression comes into play. If the buffer is made of polyurethane, it should be compressed to 90% of its height, and if it is hydraulic, it should be compressed to the value indicated on the compacted plate.
When the car is placed on fully compressed safeties, the counterweight guide shoe should have an additional rail length of 0.1m + 0.035v2 to allow for guided movement and provide balanced weight to at least the specified minimum value of 0.1m + 0.035v2.
A set of conditions must be established in the pit together.
The first condition is that there must be a minimum adequate space in the pit to accommodate an imaginary cube with dimensions of 0.5m × 0.6m × 1.0m on one of its sides.
The second part states that the distance from the lowest part of the car to the pit floor must be at least 0.5m. In high-capacity cars, it is possible to have a large yoke, but in low-capacity cars, the lowest tray is considered.
If both conditions are met, this distance can be reduced by up to 10cm. The first condition for this reduction is that the distance from the tray under the car doors or vertical sliding doors to the opposing wall should be less than 15cm. The second condition is that the guide shoes and safety brakes should not have a distance of more than 15cm from the car rails.
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