An FDC Required with Dedicated Fire Water Tank?

3/15/2022

We have a project that has a dedicated fire water supply storage tank. Is an FDC required on this setup?

Thanks in advance.

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13 Comments

Alex

3/15/2022 07:34:11 am

Hi,

The purpose of an FDC is to allow the fire department to provide supplemental pressure upon arrival. FDCs should be installed on all buildings except [NFPA 13 (2013) 8.17.2.2] :

(1) Buildings located in remote areas that are inaccessible for fire department support
(2) large-capacity deluge systems exceeding the pumping capacity
(3) single-story buildings not exceeding 2000 SQFT in area

Installing an FDC, in my opinion, is a no brainer. If the fire inside is overwhelming the sprinkler system, adding more pressure to increase flow from the outside is the safest option for firefighters.

Thanks,
Alex

Justin P Milne link

3/15/2022 08:20:16 am

The answer to your question depends on the application.

Are you providing wildfire engineering? Then the fire water storage tank is your fire flow for your fire truck. Depending on how remote the site is, you might have an FDC at the building to pump into and augment the pressure of the fire pump.

Are you providing standpipe engineering? Standpipes require fire department connections as the exterior and interior connections are needed for fire department use.

Are you providing standpipe engineering? Standpipes require fire department connections as the exterior and interior connections are needed for fire department use.

Are you providing deluge system engineering? Deluge systems require fire department connections because these fixed-fire suppression systems are intended to replace the need for a fire department in a very high-hazard environment.

Are you doing high-rise engineering? Then the fire water storage tank supplies your fire pump, but you'll still require fire department connections exterior to the building to augment the fire water supply.

Are you doing industrial engineering? Then the fire water storage tank is probably remote from the building complex, and you are going to need a HUGE amount of fire department connections so that you can get the GPM required per code.

To sum up, you need an FDC basically everywhere, unless there's no way to get the water supply to a location if you have remote buildings with no access to underground utilities.

Barry Carr

3/15/2022 10:17:27 am

I agree with Justin. It depends upon the application. In my view the AHJ certainly has the right to recommend an FDC be placed at the location, and be able to interject the reason for this request. I'm a firm believer in the Fire Service working within the intent of the Fire Code and preventing fires. (Sometimes a request and a good explanation for asking what you're asking people to do goes a long ways verses forcing them.)

Jon

3/15/2022 08:17:34 am

Alex pulled the code language but think about it this way as well. Theres only a finite amount of water in that storage tank so how would the suppression system be supplemented once that stored water runs low? Even in (most) remote locations where there isn't municipal water close to building, the fire department will use tankers/tenders and pumper relays to bring water to the site. The FDC is the avenue to bring that water to the system.

Jesse

3/15/2022 08:46:13 am

Wearing the fire protection engineering hat - yes, and Alex provided the code language.

Dusting off the retired fire chief officer helmet - also yes. Whereas the tank supplies the AS system the FDC allows the FD to supplement it. The tank may be there because there is no city source, or because the city source is too far. The FD will secure a water supply either by laying large diameter hose to a hydrant a distance away, drafting from a static source if available, or bringing it on their responding engines and tender apparatus, and if necessary running water shuttles to establish a continued water supply for long durations.

Pete H

3/15/2022 09:18:01 am

Yes.

Even if there's no hydrant to connect to, Fire Departments still might have their own pumper truck which is “[a] fire apparatus with a permanently mounted fire pump of at least 750 gpm (3000 L/min) capacity, water tank, and hose body whose primary purpose is to combat structural and associated fires.” to supplement fire suppression and control of the sprinkler system.

Justin Phillip Milne link

3/15/2022 09:21:29 am

Excellent adder here, Mr. H.

Matt C

3/15/2022 10:35:33 am

If you would require an FDC anyway, then yes you can't just omit the FDC. Even if the tank wasn't required, water would be shuttled in (via tanker/shuttle run from some other source, be it pressurized, or static) and dumped into porta-tanks set up by the FD on either end of the run.

In addition, if this is a static source (no fire pump) ensure that a drafting port is provided, and protection from mechanical damage is installed (bollards, for example).
Note that this connection can vary jurisdictionally. Where I'm located we require a 6" NH because that's what our hard suction hoses on the trucks are and allow a direct connection. In older areas, I've seen a standard fire hydrant which can be super confusing for responding personnel (the assumption being that hydrants are always pressurized). This also usually requires an adapter of some sort to be fitted onto the length of hard suction hose that connects to the hydrant (4" Storz to 6" NH, in our area) which can kill time during an emergency response.

I strongly recommend consulting with the AHJ on what connections/thread types are best suited for them.

Glenn Berger

3/15/2022 11:21:35 am

There is no exception for not providing a FDC for a building fire suppression system per NFPA standards for a dedicated water supply.

Matt Cornell

3/15/2022 11:33:56 am

What I like to see in our area is a large diameter draft point on the tank and the FDC in line right after the fire pump. This allows a short suction line thru the fire apparatus and a short discharge to the FDC. This allows for the fire department to support the pressure provided by the fire pump or by pass the fire pump all together if it fails.

Manny Rios

3/15/2022 12:26:36 pm

In our jurisdiction we have two remote sites that are provided with storage tanks to supply the fire protection systems, the AHJ (State Fire Marshal) using the code language required fire department connections at both sites.

Mahendra Sheth link

3/16/2022 11:56:04 am

Yes, the Fire Department Connection should be provided.

Some local Fire Departments have trucks with water tank that can be used to pump into FDC.

However, in order to provide good design,
1. The capacity of the tank must include required hose allowance.
2. There should be a wall hydrant mounted on the pump house wall with an inside control valve (to prevent freezing).
3. The wall hydrant should be supplied from the pump suction piping (not flowing thru the pump).

Thus, when the fire truck arrives to the site, they have a wall hydrant and the FDC available to pump in more water in the sprinkler system without stealing any system flow from the tank.

Greg C

3/16/2022 12:37:40 pm

In accordance with NFPA 22 it could be an approved method of filling the tank.

It may also be a local FD standard or approved method. Many areas have fire flow requirements in land use standards.

An FDC Required with Dedicated Fire Water Tank?

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