Wet? Dry? Combination? Huh…?!?

Standpipes are those mysterious plumbing contraptions found in a number of different sorts of structures.  For lack of a better explanation, it’s a fire hydrant system built into the building – usually used by firefighters – to avoid needing to drag hoses up multiple flights of stairs.

That said, there’s no “one” type of standpipe.  In fact, National Fire Protection Association (NFPA) 14 gives us six or so flavors. 

For ease, I’ve re-grouped them, but the definition citation is the NFPA 14 (2016 Edition) reference:

  • WET Varieties
    • Wet Standpipes (a) have water in the pipes at all times. (3.3.17.7), but more to the point:
      • Automatic Wet Standpipes have (a) water in the pipes at all times; (b) it is attached to a water supply capable of supplying the system demand at all times; (c) it requires no action other than opening a valve to provide water to a hose connection. (3.3.17.2).  (This MAY or MAY NOT be connected to a fire pump to ensure the required water pressure is available at all times.)
      • Manual Wet Standpipes have (a) water in the pipes at all times, but (b) relies on the fire department to supply the water and pressure needed for fire fighting. (3.3.17.5) (This may be ‘fed’ to remain wet by a small hose or pipe to ensure the pipe itself remains full, but nothing else; there is NO pump present.)
      • Combination Systems supplies both standpipe hose connections and automatic (like ceiling) sprinkler systems. (3.3.17.3). This is really a subset of the two above – and why I didn’t count it as a seventh variety, as a Combination could be Manual – a small apartment complex – or Automatic, as in a high-rise hotel.
  • DRY Varieties
    • Automatic Dry Standpipes (a) are permanently connected to a water supply, but (b) are kept under air pressure (air or other gas, like nitrogen). When a hose valve or other valve is opened, the air pressure is released, starting the flow of water. (3.3.17.1)
    • Manual Dry Standpipes (a) has no permanent water supply present, and (b) relies exclusively on the fire department connection (FDC) to provide both water supply and pressure. (3.3.17.4)  In its simpliest form, this is an empty pipe with a FDC at street level, and climbs up or through a building, with fire department hose connection throughout the structure.
    • Semiautomatic Dry Standpipes (a) is permanently connected to a water supply, but (b) is activated by a secondary trigger or remote control before water is delivered. (3.3.17.6)  You would more likely find these in industrial, aircraft or military settings.


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