Two FDCs When Building Permiter(s) Over 900ft?

2/6/2025

In NFPA 14, Sections 7.12.2.2(2) (2019) or 10.7.2.2(2) (2024) state that a "minimum of two FDCs shall be provided for each zone for the following: (1)* High-rise buildings (2) Buildings or multiple attached buildings exceeding 900 ft (274.3 m) perimeter distance."

Neither edition defines "perimeter".

Is it measured where the building meets grade?

Should it account for all exterior walls?

Two building which share similar "A" length and "B" width dimensions can produce vastly different "perimeters" depending how they're measured. (See image below.)

Thanks in advance.

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14 Comments

Pete H

2/6/2025 06:34:45 am

In my opinion: If it's undefined, typically account for the more stringent requirement.

So yeah, all exterior walls.

Anthony

2/6/2025 12:31:21 pm

I agree with Pete as well. I wouldn't start measuring small architectural features but gross building features if over 900' then add an FDC.

Aaron Easter

2/6/2025 08:09:49 am

I agree with Pete. Also, I believe the purpose is related to both building size AND ease of access.

Glenn Berger

2/6/2025 08:21:35 am

The complete and organization of the requirement was significantly changed between the two versions.

I am guessing that your issue is with the arbitrary 900 feet perimeter distance requirement.

There is a write-up in Appendix A for both referenced statements. I do like how the Appendix does state that "redundant FDCs could be needed," instead of shall be provided.

Back to your question on how to measure the perimeter distance - The "U" shaped building has more perimeter distance and most likely has more exits and therefore requires more standpipes and then the redundant FDC would be required..

Dan Wilder

2/6/2025 08:26:22 am

When not defined, common definition within Webster's is the next resource (Section 3.1) and see the bottom.

Intent - Where else is it defined in that standard (hopefully) but this one is vague...NFPA 1 assigns "Net Floor Area" as "...the inside perimeter of the outside walls..." which leads me to think to follow the total exterior wall length or the longer of the two options.

Even this is a little confusing because 1 & 2 differ enough to apply to both of your options.
perimeter
noun
pe·rim·e·ter pə-ˈri-mə-tər
Synonyms of perimeter
1a: the boundary of a closed plane figure
b: the length of a perimeter
2: a line or strip bounding or protecting an area
3: outer limits —often used in plural
4: the part of a basketball court outside the three-point line

J.H.

2/6/2025 08:38:14 am

This requirement is driven by fire department access requirements, which is described in the Fire Code to be measured as follows:

NFPA 1:18.2.3.2.2 ...[A]ny portion of the facility or any portion of an exterior wall of the first story of the building...as measured by an approved route around the exterior of the building or facility."(2021 Ed.)

NFPA 14:7.12.2.2* Two fire department connections shall be provided for each zone, located either on opposite corners of the buildings where fire department apparatus access is provided or,
where not possible, physically separated to the greatest extent
possible for the following:
(1) High-rise buildings
(2) Buildings or multiple attached buildings exceeding 900 ft.
(274.3 m) perimeter distance

NFPA 14:A.7.12.2.2 For larger buildings, redundant fire department connections could be needed. Connections can be compromised by parked vehicles, damaged hose threads, debris in the intake piping, and other conditions such as falling debris from a fire above.
When a large campus-style facility is served by private fire
service mains that feed the standpipe systems, and the campus
covers a large area, additional fire department connections
could be provided at strategic locations to enhance the fire
department’s ability to pump to the system.

If you truly need a definition for the word "perimeter", then check which Code-adopted dictionary needs to be referenced.
NFPA 1:2.3.23 (2021 Ed.) references the "Merriam-Webster Collegiate Dictionary, 11th Edition."

Chad

2/6/2025 09:47:51 am

Check with the FD.... they may not want more than one. We very occasionally will have two if its more than a full city block or massive building but they are not always necessary.

Jack G

2/6/2025 11:22:41 am

Meyer Fire has an fdc cheat sheet that is applicable here and gives the code references and paragraphs.
In it they indicate building or multiple buildings were the perimeter exceeds 900 feet. The code references are from NFPA 14, so one would assume “ standpipe box “ would need to be checked.
From the diagram above the space between the two looks like an alley and not a street . In fact streets or parking lots or hydrants are not shown.
Hydrants would need to be within 100 feet per the city of Philadelphia ( to fdc) IBC standards references section 912 only indicate accessibility.
Of course the fdc s should be on a street. If ann fdc s are on rear or opposite ends signage with 6 inch letters apply.
For the example above I would install 2 each and on the signage I would identify the building/ and systems as they are in close proximity.
If a street— the paving is probably rated for the large heavy fire trucks.
If a parking lot the fire department access must be rated for the truck access also.

Todd E Wyatt

2/6/2025 12:14:22 pm

The scoping Code (e.g. IBC-2021) includes other FDC requirements (Section 912) but none regarding how to determine the number of FDCs.

IBC-2021
Chapter 9 Fire Protection and Life Safety Systems
Section 912 FIRE DEPARTMENT CONNECTIONS
912.1 Installation
912.2 Location
912.2.1 Visible Location
912.2.2 Existing Buildings
912.3 Fire Hose Threads
912.4 Access
912.4.1 Locking Fire Department Connection Caps
912.4.2 Clear Space Around Connections
912.4.3 Physical Protection
912.5 Signs
912.6 Backflow Protection

Sergei Gluhushkin

2/12/2025 11:22:21 am

How should the multiple Siamese be connected to the header?
If at some point they are connected together and then only one main connected to the header, then if piping in one is damaged, both will be unusable. So both need to be connected all the way back to the header.

Jon Bernal

2/12/2025 03:17:08 pm

Since the FDC feeds the fire pump, does that mean now this new FDC 900+ feet away needs to be pipped all the back to the pump?

Sergei G

2/14/2025 08:13:59 pm

NFPA 20 does not allow Siamese connections on the Suction side of the pumps

Andrew Almazan

2/28/2025 08:09:41 am

The FDC does not feed the fire pump. NFPA 13: 16.12.5.9 Fire department connections shall not be connected on the suction side of fire pumps.

Andrew

2/16/2025 03:58:08 am

Another weird clash between 13 and 14, one that neglects urban versus suburban applications, and that moves towards a design spec.

Remote FDCs have a very specific purpose for high rises. Makes little sense for low rise structures (and in some cases could be downright ridiculous). I'm familiar with many large footprint 3-4 story projects with standpipes (education)...never seen this rule applied.

Buildings that, shouldn't even have standpipes in a day when no FD is ever going connect to an outlet at a third floor open stair when they have hundreds of feet of preconnect, but I digress.

Two FDCs When Building Permiter(s) Over 900ft?

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