12. Interments in special or private vaults may be made in the following manner only:
(1) By depositing the coffin in a grave and covering it with three feet of earth; or
(2) By enclosing the coffin in masonry at least twelve inches thick if in stone, and at least eighteen inches thick if in brick, both brick and stone being well covered with cement; or
(3) By surrounding the coffin on all sides with a layer of cement four inches thick. For that purpose a casing must be built, so that the inside measurements of the case will be eight inches greater in length, width and height than the coffin to be enclosed therein, the walls of the case to be of burnt brick, cemented, and to be four inches thick. The bottom of the cases in the lower range shall be made of cemented brick or concrete. The lower cases shall serve as the bottom for the upper cases. The coffin shall be deposited in the case so built on four stone blocks four inches high, so as to have a free space of four inches on all faces, and such space shall be filled in with cement up to the height of the walls in brick.