Headroom, also called overhead, is the vertical distance from the level of the top landing floor to the underside of the elevator shaft ceiling (machine beam or shaft top slab). Minimum headroom dimensions are specified in EN 81-20 and depend on the rated speed of the elevator, the type of drive system, and the equipment installed in the overhead. Sufficient headroom is essential for safe maintenance access above the elevator car and must accommodate the car top clearance and refuge space.