Figure 6. Blocks (light lead-lined).
(3) Where pipe chases or other obstructions occur, unpierced lead sheet will be installed to form a continuous
overlap with the lead lining in adjoining structures. Overlapping lead on adjoining structures will form a tight overlap.
(4) Voids around frames, pipes, and conduit chases must be filled with concrete and will be finished flush with
face of the structure. Pipes and conduit chases are to be installed so that they are not directly opposite each other within
the same partition.
Lead bricks . Lead bricks can be used in constructing walls, partitions, and floors. Standard full-size brick for 2
inches of radiation protection is 6 by 2 by 3 inches, for 4 inches of protection it is 8 by 4 by 2 inches, and for 6 inches of
protection it is 8 by 6 by 2 inches. Bricks come in fitted or regular-shaped bricks. When using fitted bricks, all significant
joining faces are curved either convex or concave. Due to the curves, there is no straight-line-of-break in a barrier built of
these bricks. When using regular bricks, to ensure continuity of shielding, two or more layers of bricks are required.
g. Floor lead. When sheet lead is used for floor protection on concrete floors, the floors must be thoroughly clean
and smooth, and any defects likely to damage the lead must be corrected. When necessary, a smooth screed coat is
applied over rough concrete slabs. Before the lead is installed, the concrete is surface coated with asphaltum paint. After
the sheet lead is installed, it must be protected from damage until the cement fill or other floor finish is installed. Where
cement fill is specified, the top surface of the sheet lead must be protected with a coat of asphaltum paint.