What is a disadvantage of a wet standpipe with a Siamese connection?

A wet standpipe with a Siamese connection is designed to provide immediate water supply for fire suppression situations. One of the disadvantages associated with this system is indeed the potential for water contamination from unknown sources. This can occur because the Siamese connection allows for external connections to be made to the standpipe system, which introduces the risk that untested or contaminated water supplies might enter the standpipe. This poses a significant risk to the quality of water that may be used in firefighting, as any contaminants present could be harmful not only to the firefighters but also to the public if the system were to malfunction.

In addition to contamination risks, the other potential disadvantages, such as higher installation costs or increased maintenance requirements, may exist, but they do not directly tie to the immediate operational concerns that arise from allowing external water connection points. Similarly, while limited water flow can be problematic in certain contexts, wet standpipe systems are generally designed to provide adequate flow for firefighting purposes, so this concern is less significant compared to contamination risks.