Siamese Connections - Subject to the provisions of subparagraph (b) all 100 millimeters dry standpipes shall be equipped with a two-way Siamese fire department connection. All 125 millimeters dry standpipes shall be equipped with a three-way Siamese fire department connection, and 150 millimeters dry standpipes shall be equipped with four-way Siamese fire department connections. All Siamese inlet connections shall be located on a street-front of the building and not less than 300 millimeters nor more than 1.20 meters above the grade and shall be equipped with a clapper-checks and substantial plugs. All Siamese inlet connections shall be recessed in the wall or otherwise substantially protected.