Can someone explain part of a sprinkler system?

Can someone explain part of a sprinkler system? I see them all over, vaguely understand some parts.

I know you had asked about the FDC from the previous post, so I’ll answer that for now. Sprinkler systems are complicated, so I could write a novel describing the whole thing. But if there are specific parts you want to know about, just ask and I’ll be happy to explain.

The FDC or “fire department connection” is an inlet or series of inlets that have a hose connection on the outside, usually threaded or a Storz connection. They serve as a way for the fire department to connect to the sprinkler or standpipe system to boost the water pressure. If they are fighting a larger fire, the water pressure could drop as more sprinklers open or as more standpipe valves are used. So by connecting to the FDC, they can pump in more water and raise the psi to where it needs to be to adequately continue operations.

The FDC typically runs from the outside wall to the riser, riser manifold, or directly to Standpipe if it is present and close enough to the FDC piping. A check valve is installed on the FDC piping to allow water to flow INTO the system, but not from the system out to the FDC. A ball drip is also installed between the check valve and the outside wall. Its purpose is to drain water from the FDC when operations are done. From the connection to the ball drip, piping is installed angling down so gravity can bring the water to the drain.

Which part? To try to explain a sprinkler system overall is a pretty daunting task! Basically, you’re putting the wet stuff on the red stuff! There are four basic types of water based suppression systems - wet, dry, pre-action, and deluge systems. Commercial systems are also designed differently than residential systems. Firefly did a great job explaining the Fire Department Connection part of a system - but if you have any other questions feel free to post them up here. I also have a printout of a Powerpoint presentation that explains the different types and parts parts of sprinkler systems - I can make you a copy if you would like.

Nice explaination so far.

Which part of a system did have a question on?
Paul

If you have fire hose mounted thru a building, are they hooked to the riser?

I assume you must be thinking of Standpipe, and yes, often times the sprinkler system and Standpipe are often fed from the same riser. A very common practice is to have a wet valve that supplies a Standpipe riser, or several. In multi-story buildings for example, you would have a Standpipe riser in each egress stairway with a hose valve at each landing. In addition to the hose valve, you would also have your zone control here for the sprinkler system. The zone control is essentially an OS+Y or Butterfly valve, a flow switch, water gauge, and drain assembly. Each floor’s sprinkler system could then be its own zone and could be shut down and isolated for maintenance.

Standpipe and sprinkler can also be arranged together like this in large, single story buildings, too, but the multi-level scenario is a much better example to visualize.

Well this a factory, and they do wood work so i was wondering.

On building that there riser has a huge AC pump, what happens without power?

The fire pump should be tied into the fire alarm system so they know if the pump isn’t working or the power is out. Regardless, if power goes out, city water isn’t working (water main break, whatever), a fire pumper truck will hook up to the FDC (fire department connection) and pump water into the system.

That’s the entire point of the FDC, it’s a fire hose connection looking thing on the outside of buildings so fire trucks can bring water into the system or add to the pressure, etc. Sometimes it’s as easy as running a hose from a a fire hydrant on the street to the FDC. This is the backup plan if the normal building water supply isn’t working.

My middle school does not have one, whats that mean?

Fire hoses located throughout buildings are becoming rare. There is a maintenance issue with hoses - a brand spanking new hose is good for 5 years, after that it has to be hydrostatically tested every 3 years. Most building owners do not want to pay for that testing every 3 years so they elect to get the blessing of the local fire marshal to get them removed. Firefighters will not use a hose of an unknown condition, and any more, insurance companies and building owners do not want the occupants playing hero in a building and use a fire hose. I’ve seen some new buildings constructed with legitimate stages (schools with an auditorium is a good example) that have fire hoses installed on each side of the stage, but usually at that 5 year mark, they are getting removed.

For the most part, fire hoses are directly connected to the building sprinkler system. Standpipe systems can be either/or - they can be connected to the sprinkler system (backed up by a fire pump or FDC) or a “system” by themselves where there is no pressure on the system and the fire department must connect and charge the FDC to get water to the outlets. You will usually see that type in a outside parking garage and some older unsprinklered highrise buildings.

There are basically three types of standpipe systems:
Class I - 2 1/2" hose connections (no hoses) for fire department use
Class II - 1 1/2" hose stations for initial extinguishing by “trained personnel”
Class III - Combination of Class I and Class II - usually a 2 1/2" hose connection with a reducer installed with an 1 1/2" hose

Very rare, but I have come across fire hoses fed directly off the domestic water supply with no FDC - these are usually older buildings (seems to always be unsprinklered apartment buildings) where the hose cabinets are located in the corridors stacked floor to floor. Pressure on these systems is usually always questionable but back in the day they were acceptable. If there is a Class I or Class III system in the stairtower, these systems are usually abandoned.

If your school has a sprinkler system, it has an FDC.

FDC or fire pump? Probably has an FDC but may be hidden behind a bush or back in the loading dock or by the main boiler room area. The FDC could also be by itself out front of the building, you’ll just see a pipe sticking out of the ground with the siamese connection on top. These are sometimes hard to see, heck, I’ve even missed them because they tend to blend into the flowerbed with all the bushes and trees that got planted around them! If you don’t have a fire pump, not necessarily a bad thing, just didn’t need it.

There’s usually a bell above the FDC, sometimes controlled by the fire alarm system (through water flow switches), sometimes directly from the sprinkler system somehow. Firefly or someone else can elaborate on how that tie in works exactly.

There are water motor gongs (WMG’s) and electric bells. The electric bells are becoming more common these days and those are tied to the flow switches. The WMG’s operate with no electricity. When a sprinkler opens and water flows, it flows through a small pipe that goes through the back of the gong. The water turns a wheel, and the wheel is connected to a hammer that rings the gong. I actually have a few of these and a siamese FDC sitting in my back yard.

If the building has an electric fire pump and looses utility power there are two ways to back up the electric pump:

First would be a generator with an approved transfer switch. A fire pump will have a controller box - large red box that says “Fire Pump Controller” - can’t miss them, located for the most part right next to the fire pump itself. If there is a transfer switch installed, usually will look like two fire pump controllers side by side. Plus it will say “transfer switch” right on the front.

Second way to back up the electric pump is with a diesel pump. May seem redundant but that’s the purpose! The electric pump will kick on first, the diesel will kick on if the electric does not or if demand is really high and there is a significant pressure loss in the system. You will mostly see this setup in manufacturing plants or other large campus type systems. There is a local chemical plant that actually has two diesel pumps - one is the primary and the other the backup. And there’s a major food manufacturer in the area that has three pumps - an electric pump by the main guard gate as the primary, a diesel pump out back for the backup, and an old gasoline fire pump to back up the diesel!

Where my dad works they have those. I think it a company called Reliable Alarm

Many jurisdictions also require the FDC to be clearly marked with a reflective sign - some go as far as requiring the sign to be seen from the street and directional in case the FDC is on the side of the building or out back.

Rasco=Reliable Automatic Sprinkler Co.

Still in business today, its one of the major manufacturers of sprinkler equipment. I’m sure the bell you saw was red with a white center, sort of reminiscent of a target.

Nope.
More like this:

Just it has the shield all around,

It’s a 1950s system

Oh, so its an even older model.

I can’t seem to post the pics right now, but I have one from the '60s that resembles that one, but it is slightly different.