The lightweight frame for SKR-1 manholes is an essential structural element of the upper part of the cable well, serving as support for the lightweight cover, mounted on surfaces designated for pedestrian and vehicular traffic. It is made of steel and filled with reinforced concrete. It is typically installed on the body of the manhole, often by embedding it in concrete mortar.
The A15 load class indicates that the frame is designed to withstand a static load of up to 1.5 tons. In practice, such a frame is usually installed in green areas or pedestrian walkways.