I was called to design a replacement domestic-water booster-pump system for a 30-story sprinklered office building. A field survey revealed that the domestic-water system also was connected to a 2½-in. standpipe system and an external fire-department connection.
The standpipe system extended the full height of the building and was used as a source of utility-hose connections. The building also had two functional 6-in. standpipe systems fed by fire pumps. They also were served by a separate external fire-department connection. The 6-in. standpipe systems are Class 1 standpipes with a 2½-in. hose-valve station on each floor in two independent staircases, which met relevant codes. The 2½-in. standpipe system could remain in place, but the fire-department connection had to be removed because the minimum code-required standpipe size is 4 in.
On the building's outside wall were duplex fire-hose connections for the smaller standpipe system and triplex fire-hose connections for the larger standpipe systems. The 6-in. standpipe-system fire-department connection was labeled “Auto Spkr Standpipe,” while the 2½-in. standpipe-system fire-department connection was labeled “Standpipe.” Looking at the outside nameplates, one would have no idea which system was served by the fire-hose connections.
The first problem was the improper nomenclature on the fire-department connections. The second issue was the wrongly sized and practically non-functional, code-prohibited standpipe system. The third issue was a domestic-water system cross-connected to a non-code-compliant standpipe system, which could be confused and used incorrectly by firefighters. Only after this condition was corrected could we proceed with the original pump replacements.
The hazardous extra fire-department connection was removed first. The undersized standpipe system was removed where feasible and abandoned in places where the demolition activity would be too disruptive. It was lucky that the building never had experienced a fire event because firefighters likely would have attached the water-supply hose to the wrong set of fire-hose connections. A blank cover plate was installed on the outside wall in place of the removed duplex fire-department connection.
Edward Liwerant, PE
Robert E. Lamb Inc.
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