What is a standpipe? Classes, types and testing

What is a standpipe? It is a system of pipes that carries water through a building to hose connections on each floor, so firefighters can connect a hose on the floor where they need water. The connections are usually in the exit stairwells. This is what a standpipe does, the classes and types you may have, and the testing that comes with it.

What a standpipe is for

In many buildings, a standpipe is there for the fire department. Firefighters bring their own hose, connect it to the standpipe on the floor they are working on, and the standpipe supplies the water.

Outside, on the wall of the building, there is a fire department connection. That is where a fire engine can pump water into the standpipe. Some standpipes depend on it for all of their water. Others are connected to the building's own water supply.

When is a standpipe required?

The building code decides. It generally calls for a standpipe where the top floor is more than 30 feet above the lowest level fire trucks can reach the building from, or where the lowest floor is more than 30 feet below the highest level they can reach it from. Newer editions of the code also call for one in buildings of four or more stories, and it is required in some other buildings as well, such as large venues where people gather.

If your building has a standpipe, it is part of the fire protection you keep inspected and tested under NFPA 25, the same standard that covers your sprinklers.

Standpipe classes

Standpipes come in three classes, named for who uses them:

• Class I has 2½-inch hose connections for the fire department. No hose is kept in the building; firefighters bring their own.
• Class II has 1½-inch hose stations with a hose kept on site, meant for building occupants or trained building staff to use on a small fire before the fire department arrives.
• Class III is both: 2½-inch connections for the fire department and 1½-inch hose stations.

In a building with sprinklers throughout, the code generally allows a Class I standpipe in place of Class III.

Wet and dry standpipes

A wet standpipe has water in its pipes all the time. A dry standpipe does not: its pipes hold air, or nothing at all, until water is let in or pumped in. Dry standpipes are used where the pipes could freeze, such as open parking garages.

Standpipes are also described by where their water comes from:

• Automatic: connected to a water supply that can deliver what the system is designed to flow, on its own.
• Manual: depends on the fire department pumping water in through the fire department connection. A manual wet standpipe keeps water in its pipes, but the fire department still supplies the flow.
• Semiautomatic dry: water is let into the pipes when a control at a hose connection is used.

If you are not sure which type your building has, we can confirm it on site.

How a standpipe is inspected and tested

Standpipes are covered by NFPA 25, alongside sprinklers. The biggest tests come every five years, and which ones apply depends on the type of standpipe:

• A flow test, where water is run from the outlet that is hardest for the water to reach, to confirm the system delivers the flow and pressure it was designed for.
• A pressure test of the pipe on dry and semiautomatic standpipes, which hold no water day to day.
• A check inside the pipe for anything blocking it and for corrosion, the same five-year internal sprinkler inspection your sprinkler systems get.

Between those, the hose connections, caps, cabinets and signs are checked on a shorter cycle. Every interval is on our fire protection inspection calendar.

What we find most often on standpipes

Much of what we write up on standpipes is one of these five-year tests coming due. Because they come only once every five years, they are easy to lose track of, so we give each one its own due date on your inspection calendar.

From a single stairwell to a campus of buildings, we inspect and test standpipes across New Jersey, Pennsylvania and Delaware, alongside your fire sprinkler inspection and testing. Tell us what you have and we'll set up the schedule for it.