Thoughts on Storz vs. Dual-Inlet Threaded FDC?

5/2/2023

From the perspective of a responder, any thoughts on using large diameter hose on a freestanding Storz FDC versus the old 2-1/2 inch standard two-inlet threaded fire department connection?

Thanks in advance.

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19 Comments

Anthony

5/2/2023 07:09:35 am

1/2 as many hoses to connect. The threads don't get mangled by the general public.

Kyle

5/2/2023 08:05:41 am

Some areas already do this. Raleigh, NC and areas nearby do. Biggest thing to consider, when thinking about it from that point of view, is what the response plan/procedures dictate for the responding fire departments. Often times a quick phone call to the AHJ can provide some insight to the "why" they may operate that way as well.

5/2/2023 08:06:56 am

The Storz is same size as our supply hose, no threads, better volume of water, single hose connection, 1/3 turn for securing.

Jesse

5/2/2023 08:11:59 am

I spent 20 years as a professional firefighter / officer before getting into the fire protection engineering world. The LDH to standpipe was a big push in the late 90s early 2000s, using the same logic we used in the 80s and 90s going from tin 3" supply lines to one 5"..

It didn't really pan out the way we thought it would. We all know we trade pressure for volume. With a combined hose allowance of 500-gpm, twin 2.5" or 3" lines are more than able to support that. And yeah, connecting one Storz connection as opposed to two 2.5" is easier, but time isn't necessarily critical and it is way easier to move 2.5" than 5"

Chad

5/2/2023 08:20:08 am

Nothing like tugging on 100'+ of 5" uphill, at night, around a corner.... yada...yada...yada

2- 3's is easier and faster 9/10 times.

chad

5/2/2023 08:14:10 am

2-1/2 threads are not usually damaged (in my experience, in a city) The whole thing yes but not just the threads. The storz caps are stolen for scrap and much more expensive than a disposable 2-1/2 one. and then get filled with trash faster because its such a big hole.

Most non highrise/tax payer/low rise buildings DA calc is less than 500GPM and a 3" line can feed that so even if one of the two are damaged, as long as the clapper seats you can work with it.

We require 2-1/2"s in the downtown and dense areas, more reliably capped and most systems do not require over 500GPM, even when including a single engine connected to the standpipes. We have found this more reliable, in our experience and its easier/quicker for the DVO to make the connection. We do have some larger buildings that do get storz based on the flow calcs.

In more rural areas I would understand if you only wanted Storz

Our large industrial have less of a theft of cap issue and I spec them there, and of course bigger flow requirements.

5/2/2023 08:35:04 am

Hi,

When selecting which FDC configuration, it is important to contact the local fire department. Each jurisdiction usually picks one type of FDC and that type is applied almost universally throughout the jurisdiction for consistency with the fire department.

Maneuvering 2.5" hoses is substantially easier. Also, having one type of hose for the FDC and the same type of hose for inside the building at the standpipe can make for easier response from the fire department.

Aaron Easter

5/2/2023 08:45:54 am

I don’t see a clear “better” choice. I see pros and cons to both depending on what your tactics are. Norman FD uses the 5” Storz mounted on a 30° elbow for all new13 systems.

We have LDH with Storz and a threaded adapter for supply connections to hydrants (had ZipHuts originally). We also pump directly to our sticks with it. Quick connections are nice but humping hose is a full crew job over 100ft and impossible to reposition without draining.

Some have mentioned the pressure loss of LDH but here we don’t see much over idle sent to an FDC.

Mike

5/2/2023 08:59:22 am

That is a good question. There are legit reasons why both systems are better.

5 inch storz
Pros
1) Single hose to connect.

Cons -
1) Usually max operating pressure of 200psi on LDH. If head pressure is an issue, then you can bump the psi of a 2.5 / 3 inch line above 200psi, taking into account the friction loss of the appliances through the riser room, you would not be over 200 psi on the standpipe or sprinkler system.
2) If it fails you lose all water while putting a new line in place.

2@ 2.5 inch
Pros -
1) Higher operating pressure. You can push the pressure above 200 psi to maximize the pressure inside the building.
2) Rredundancy, if one line fails, interior teams still have water while line is replaced with a new line.
3) usually faster to get 1 line flowing but then you would be at partial volume.

Cons -
1) slower to get max capacity flowing into the building

I am sure I am missing something. Once you are started one way it is hard to change because old buildings are not going to change. So... consistency is good. :)

Casey Milhorn

5/2/2023 09:00:23 am

As others have said, definitely pros and cons. We are in an area where it's a mixed bag. That concerns me because if we were to have a mass fire event (think of a terrorist attack by way of arson on multiple buildings) and other local departments had to respond, they may not have the proper hook ups on the trucks. I'm in favor of choosing one or the other for an entire state or area.

John

5/2/2023 09:33:18 am

Hello,
We typically go with 21/2 FDCs for 13Rs and our 5in Stortz for other commercial structures.

A couple of other things we considered:

What would the system support need be should, for example a fire pump failed.

We also look at what the FDC footing is capable of supporting in retrofit situations.

David Kendrick

5/2/2023 10:06:09 am

Can anyone explain the UL listing for the Storz connections?

From my understanding on National Hose Thread connections where there is a threaded plug at the connection. The the plug is unscrewed. There is the possibility to discover and relieve pressure slowly if there is a Fire Department Connection check valve leaking by. If sensible caps are in place the bypass leak will already show.

Storz connections being a twist lock do not have the same properties. Pressure relief is immediate.

Checking manufacturers that list a Storz connection with a UL listing qualify that certification with purchasing both the connection and the cap.

Maybe the cap has a weep hole.

Chad

5/2/2023 10:26:43 am

I've seen some Storz caps that have a small hole drilled in the center, assumed for that reason, we do not ask for it and its not factory. If there is a ball drip (installed properly) on the FDC line, that should not happen with a slowly leaking check valve. Of course I don't want to take a 5" cap off with 100psi behind it either, if I could even get it to budge.

Alex

5/2/2023 12:30:59 pm

I personally look at FDC location and accessibility. If the FDC is close to a capable location for an apparatus to park, then Storz. If you are up a hill, behind a few fences, or a ways away, 2 2-1/2" outlets would be preferred.

Make sure your storz connection matches the hose/fittings on the trucks! When my company still carried 4", we had a 5" storz installed.

Thanks

Pete H

5/2/2023 03:01:23 pm

From a responder perspective? Storz rules. The threads don't get mangled, single hose is easier to tap into and use.

But it requires a fire department that is set up to use it. Same as a threaded FDC (hence the difference in thread types on FDC. Out here we have NST threads and NY Corps threads). So having a 4" hose for a 5" Storz connection is useless.

Consult your local Fire Department and match the local threads or hoses that they have. If they're outfitted for Storz, go for it.

Richard Harrod

5/3/2023 01:25:09 pm

Here are my two cents....
As a career firefighter with 20 on the job, I see both sides and all the comments above are valid. With that said, if the 4" or 5" supply line fails, which will happen, you have to shut down and replace the section that failed. If your hooking in 2 lines instead of 1, then that aspect of shutting down completely is null and void. You can secure the section that fails while continuing to flow into the system. My choice will always be the pair just for redundancy purposes. At 2 or 3 in the morning, when youre rubbing the sleep from your eyes, I say no to "Murphy".
Make sense?

5/3/2023 02:02:04 pm

I heard that NFPA is going to start limiting the flow thru a storz to 500 gpm for a 4" and 750 gpm for a 5". So I guess we'll see FDC's that area siamese storz?

Robert

5/3/2023 10:04:14 pm

In all jurisdictions of which I have been an inspector it has been a requirement for storz fittings on all FDC’s.

Steven W Dube link

5/24/2023 02:04:00 pm

Hudson Fire has always used 4" Stortz, with a 30 degree down adapter

Thoughts on Storz vs. Dual-Inlet Threaded FDC?

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