Two 3-way splitters with Storz
A Siamese connection or splitter in fire protection engineering is a pipe fitting that allows two or more fire hoses to be connected to a single standpipe riser at the same general location.
It is so-called due to the visual allegory to Siamese twins.
Ramsey, Charles; Hoke, John Ray, Jr. (ed) (2000). Architectural Graphics Standards (10th Edition). John Wiley & Sons, Inc. ISBN 0-471-34816-3.