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<![CDATA[ MeyerFire - Forum]]>Wed, 20 May 2026 13:13:15 -0500Weebly<![CDATA[Calcs Required to Replace K3.9 with K4.2?]]>Wed, 20 May 2026 10:00:00 GMThttps://www.meyerfire.com/daily/calcs-required-to-replace-k39-with-k42I have a campus housing situation with a few thousand reliable 3.9k heads that are no longer made, on 16x16 spacing, requiring 17 gpm and 19 psi per the cut sheet.

We are looking to replace these with 4.2k sprinklers, same 16x16 spacing, is 16 gpm and 14.5 psi per the cut sheet.

Question is, I know the 4.2K falls just over the allowed 5% deviation, but these 4.2k sprinklers are more "efficient", so would they require running new hydraulic calcs to verify, or would it be safe to swap out as is?

Thank you in advance.

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe]]><![CDATA[High Static Pressure Without a Fire Pump?]]>Tue, 19 May 2026 10:00:00 GMThttps://www.meyerfire.com/daily/high-static-pressure-without-a-fire-pumpHas anyone encountered unusually high and consistent static pressures in sprinkler systems where there is no visible fire pump?

I recently came across two examples that raised questions:
- A riser in our major metro showing about 165 psi static pressure.
- A five-story hotel with roughly 125 psi static pressure on every level, consistently throughout the building.

In both cases, I searched extensively for a fire pump and could not find one. The buildings were on normal city water supplies, not private systems or campuses, and there was nothing obviously unusual about the sites.

It made me wonder whether there are situations where some type of booster pump is being used for sprinkler systems without being readily identified as a traditional NFPA 20 fire pump? Or perhaps there is another explanation entirely.

Has anyone else seen this? If so:
- What was the situation?
- Was there hidden pressure-boosting equipment involved?
- Are there municipalities or systems where this is more common?
- Or is there another explanation for maintaining these pressures throughout a building without a fire pump?

Interested to hear what others have encountered.

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]]><![CDATA[Allowed to Use Voice FA for Elementary PA?]]>Mon, 18 May 2026 10:00:00 GMThttps://www.meyerfire.com/daily/allowed-to-use-voice-fa-for-elementary-paWe've been called back for service work to a recent voice fire alarm system installation, where we found that the elementary school is using the voice fire alarm system as their public address system (announcements, etc).

Is there anything codewise that prohibits this?

On one hand, it should allow the system to possibly become more reliable since they'll report outages right away; I'm mostly just concerned with less trained staff using fire alarm equipment and having messages come from speakers labeled as "FIRE ALARM."

What are your thoughts on this?

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]]><![CDATA[Are “POTS in a Box” Systems Code-Compliant?]]>Fri, 15 May 2026 10:00:00 GMThttps://www.meyerfire.com/daily/are-pots-in-a-box-systems-code-compliantWith POTS lines going away very soon, I'm seeing many companies switch to a "POTS in a Box."

Do these meet the NFPA 72 code requirements?

I can't find much information about these devices. One thing I am finding is that they do not appear to be UL-listed.

At what point does NFPA 72 stop regulating the communication method?

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe]]><![CDATA[Is Water Storage Tank Far from Pump a Problem?]]>Thu, 14 May 2026 10:00:00 GMThttps://www.meyerfire.com/daily/is-water-storage-tank-far-from-pump-a-problemHi, have you encountered cases where the fire pump is more than 100 ft (30 m) away from the water storage tank (underground)?

I know this isn't ideal. What type of pump or setup do you suggest or recommend in this situation?

Thank you.

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe]]><![CDATA[Minimum Height of Pipe in Underground Garage?]]>Wed, 13 May 2026 10:00:00 GMThttps://www.meyerfire.com/daily/minimum-height-of-pipe-in-underground-garageIs there a minimum height requirement of pipes in an underground parking garage?

Is that different than an ordinary occupiable space?

My vehicle is 75.8 inches tall, for instance.

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe]]><![CDATA[Route Diesel Fire Pump Flow Back Into Suction?]]>Tue, 12 May 2026 10:00:00 GMThttps://www.meyerfire.com/daily/route-diesel-fire-pump-flow-back-into-suctionI have a DoW project with specifications that require the diesel fire pump flow meter to discharge both into the pump suction and through the test header.

I don't have experience with this setup; in all my previous projects, the diesel fire pump discharged back to the water tank as well as to the test header.

I understand that NFPA 20 allows this arrangement (see attached figure from the 2025 edition), but I'm curious how it works in practice for two main reasons:

1. If we close the tank valve during testing, the pump's suction pipe will receive considerable pressure. Will this repeated pressure adjustment after each test impact the longevity of the soft packing, particularly regarding increased water leakage?

2. How does a diesel fire pump cool its motor if the heat exchanger water isn't returned to the tank with fresh cool water coming in?

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]]><![CDATA[Sprinkler Entire Attic With One Fuel-Fired Unit?]]>Mon, 11 May 2026 10:00:00 GMThttps://www.meyerfire.com/daily/sprinkler-entire-attic-with-one-fuel-fired-unitDo you have to protect the whole attic that has smoke partitions with fire sprinklers if only one area has gas-fueled equipment in it?

Can you just protect the one area that has the fuel-fired equipment in it?

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]]><![CDATA[UFC 3-601-02/NFPA 2001 Clean Agent Inspection?]]>Fri, 08 May 2026 10:00:00 GMThttps://www.meyerfire.com/daily/ufc-3-601-02nfpa-2001-clean-agent-inspectionClean agent system inspections for Department of Defense (DoD) buildings require UFC 3-601-02.

Should NFPA 2001 inspection requirements also be included?

Looks as if the UFC 3-601-02 guidelines are more stringent than NFPA 2001, correct?

Trying to sort this out, thanks in advance.

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe]]><![CDATA[Drop-Down Sprinkler for Coffered Ceiling?]]>Thu, 07 May 2026 10:00:00 GMThttps://www.meyerfire.com/daily/drop-down-sprinkler-for-chauffeured-ceilingWe have a coffered ceiling with a 3" drop as per design, and we'd like to have the fire sprinkler drop down 3" automatically when activated.

Is there a product or technique that can be used for this?

It's a high-end commercial space. Thanks in advance.

Moderator's Note: Updated "Chauffeured" to "Coffered."

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe]]><![CDATA[Water Supply Options for Rural Area with Pond?]]>Wed, 06 May 2026 10:00:00 GMThttps://www.meyerfire.com/daily/water-supply-options-for-rural-area-with-pondI am working on a new building in a rural area that will require sprinkler protection. There is no access to a public water supply, only a 30-100 gpm well on site.

Options for fire suppression water include pumping from a large farm pond 150 feet away or installing a 15,000-gallon water storage tank with a pump.

Any thoughts on which option is more feasible and cost-effective, or any alternatives we're not considering?

This is in a freezing climate. Thank you in advance!

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe]]><![CDATA[Cheers to Our Top April 2026 Voices!]]>Tue, 05 May 2026 14:48:09 GMThttps://www.meyerfire.com/daily/cheers-to-our-top-april-2026-voicesHuge appreciation to the folks leading the charge this past month. Thank you to our top April 2026 Contributors!

]]><![CDATA[Alternatives Tank Ideas for Seismic Area Highrise?]]>Tue, 05 May 2026 10:00:00 GMThttps://www.meyerfire.com/daily/alternatives-tank-ideas-for-seismic-area-highriseI've got a high-rise project in a seismic zone higher than category C. We are required by IBC to have a secondary water supply other than the city supply (IBC 403.3.3). The structural team is pushing to not put the tank on the roof, and our site is extremely limited, so there is discussion about trying to bury the tank.

What pump/tank configurations are available for this situation?

I am aware of either a concrete or fiberglass tank with a vertical turbine pump, but can you tie in the city supply to a vertical turbine submerged in a tank?

Is there a way to appease this rule other than a secondary fire tank that I'm not thinking of?

Thank you in advance for any help.

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe]]><![CDATA[How to Comply with Liquid Oxygen MAQ for Lab?]]>Mon, 04 May 2026 10:00:00 GMThttps://www.meyerfire.com/daily/how-to-comply-with-liquid-oxygen-maq-for-labI have an existing higher education laboratory suite (as defined by IFC) on the 8th floor that is used only for research (no instruction). The owner wants to store, and use in a closed system, liquid oxygen and liquid nitrogen.

The MAQ for liquid oxygen is what I'm concerned about.

Cryogenic oxidizing MAQ: 45 gallons (2021 IFC Table 5003.1.1(1)) > can be doubled because sprinklered building > must be reduced by 50% because it is a laboratory suite on a floor between (7-10 2021 IFC Table 3804.1.1). So we're at an MAQ of 45 gallons.

The issue is that IFC 3803.2.1 states that the maximum container size for all hazardous materials must be 5.3 gallons.

The most common dewars/cylinders for this application start at 42-43 gallons minimum, and that is what the owner has requested. It doesn't seem like there is a way around this requirement, though. The 2021 IFC is the adopted code by the jurisdiction.

Do you see a path for compliance in this situation?

Any advice would be greatly appreciated.

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe]]><![CDATA[Space Sprinkler to Front or Back of Cabinets?]]>Fri, 01 May 2026 10:00:00 GMThttps://www.meyerfire.com/daily/space-sprinkler-to-front-or-back-of-cabinetsThere is a great debate in my office whether or not we are required to protect to the back of lower/upper cabinets.

NFPA 13 9.2.9.3 (2022) states that we need to cover the area below the cabinets to the back wall. Seems pretty straightforward to me, but someone in my office states that we only sprinkler floor space, without providing any code reference.

Do we protect to the wall, or the face of the cabinet where only floor area is exposed?

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe]]><![CDATA[Take 10-Question Leader Insights Survey]]>Thu, 30 Apr 2026 12:57:50 GMThttps://www.meyerfire.com/daily/take-10-question-leader-insights-surveyWe're conducting a short, 10-question survey to gather tips, concerns & trends for a 2026 Leader Insights course on MeyerFire University and a talk on Industry Shifts Due to Technology at the NFPA Conference in June.

If you'd like to participate, it's only 10 questions and takes about two minutes:

TAKE 10-QUESTION LEADER TREND SURVEY

At the end we have a question on what topics you'd like to see us cover in the future as part of MeyerFire University.

Thanks in advance!

]]><![CDATA[Where is Hose Allowance for Combined System?]]>Thu, 30 Apr 2026 10:00:00 GMThttps://www.meyerfire.com/daily/where-is-hose-allowance-for-combined-systemWhen hose allowance is added to the sprinkler demand on a Class III Standpipe/Sprinkler wet riser, where on the system are the inside and outside flow and pressure allowances input when calculating the system?

NFPA 13 Chapter 19 states that the allowances are not required when calculating a combined system, which appears to contradict NFPA 14 requirements to include them.

In my case, the sprinkler demand is for OH2 (ceiling higher than 40 ft), resulting in a sprinkler demand plus hose allowance that is greater than the standpipe demand.

If I don’t include hose allowance in the sprinkler calculation as per Chapter 19, this combined system is not equivalent and robust as two independent systems. Any thoughts?

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe]]><![CDATA[Are Sprinklers Required In or Below Overhang?]]>Wed, 29 Apr 2026 10:00:00 GMThttps://www.meyerfire.com/daily/are-sprinklers-required-in-or-below-overhangIs sprinkler protection required for the overhang shown in the simplified detail below?

If sprinkler protection IS NOT required, which allowable sprinkler omission does this comply with in NFPA 13 (2022)?

If sprinkler protection IS required, what component(s) are triggering this requirement?

Thank you!

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]]><![CDATA[Can CPVC Be Used for Highrise Sprinkler System?]]>Tue, 28 Apr 2026 10:00:00 GMThttps://www.meyerfire.com/daily/can-cpvc-be-used-for-highrise-sprinkler-systemWe have a high-rise building (residential from 5-24 floors).

Can CPVC listed piping be utilized in high‑rise fire sprinkler systems (residential portion), and are there restrictions related to maximum elevation and/or pressure limitations?

Thanks in advance.

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe]]><![CDATA[Omit Sprinklers At Entire Bottom Area of Stair?]]>Mon, 27 Apr 2026 10:00:00 GMThttps://www.meyerfire.com/daily/omit-sprinklers-at-entire-bottom-area-of-stairUnder NFPA 13, 2022: in noncombustible stair shafts, can sprinklers be omitted at the entire bottom area of the stairs?

For example, if the first floor is the bottom of the stairs, can sprinklers be omitted under the second floor at the area where you enter the stairwell?

Section 9.3.4.2.3.1 states, "Sprinklers shall be permitted to be omitted from the bottom of the stairwell when the space under the stairs at the bottom is blocked off so that no storage can occur."

Is this only referring to under the intermediate landing and not the entire first floor area of the stairs?

I know that at the beginning of this Section 9.3.4.2.1 states in part "under the first accessible landing above the bottom of the shaft."

So does the omission apply in this case?

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe]]><![CDATA[ESFRs Allowed on Single Interlock Preaction?]]>Fri, 24 Apr 2026 10:00:00 GMThttps://www.meyerfire.com/daily/esfrs-allowed-on-single-interlock-preactionWould ESFR K25.2 be permitted to be installed on a single interlock pre-action system?

I have a system conversion that is currently a gridded warehouse with K25.2 ESFR pendents that the client wants to convert to single interlock. The system will be converted to not be gridded anymore, but I am not seeing any clear information on whether the existing ESFR can remain.

If we were to remove the sprinklers, it would now dive into possible in-racks to protect the class IV storage. Warehouse is 35ft max height, bar joist.

Thanks in advance.

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe]]><![CDATA[Include Hydrants in Fire Pump Total Design Flow?]]>Thu, 23 Apr 2026 10:00:00 GMThttps://www.meyerfire.com/daily/include-hydrants-in-fire-pump-total-design-flowDoes the fire hydrant flow rate need to be included in the total design flow rate?

Assuming a building is only equipped with a standpipe system and a private hydrant system, both supplied by a private fire pump, does the design flow rate of the fire pump still need to account for the fire hydrant flow rate?

In addition, in accordance with NFPA 14‑2024 10.5.3.5.1, when the local fire department can meet the water supply capacity requirements, is the supply main for the standpipe system still required to be arranged in a loop?

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe]]><![CDATA[Standpipe Allowed to Run In-Between Stair?]]>Wed, 22 Apr 2026 10:00:00 GMThttps://www.meyerfire.com/daily/standpipe-allowed-to-run-in-between-stairIs this an allowed and feasible installation for FHV's that are required to be installed at intermediate landings, to avoid penetrations in a precast stair?

Is there a code basis against this, or any differing recommendations on routing here?

See image below.

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]]><![CDATA[Will Backflow Dump When Fire Pump Starts?]]>Tue, 21 Apr 2026 10:00:00 GMThttps://www.meyerfire.com/daily/will-backflow-dump-when-fire-pump-startsWe have a situation where we need to replace a 40-year-old fire pump where the original RPZ is located downstream of the pump. Our current code requires all BFP's upstream of the pump. We are worried that the RPZ will start dumping every time the pump is started.

Does anyone have experience with this that could lend a recommendation?

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]]><![CDATA[When Does An Area Serve a Dwelling Unit?]]>Mon, 20 Apr 2026 10:00:00 GMThttps://www.meyerfire.com/daily/when-does-an-area-serve-a-dwelling-unitNFPA 13R, Section 6.6.5.1 (2019 Edition) requires sprinklers to be installed to protect balconies, decks, etc, that serve dwelling units.

What constitutes the definition of "serving dwelling units?"

If we have a landing over a stair in an exterior corridor, would that landing over the stair "serve a dwelling unit?"

This is a situation that the inspector is now bringing up at the end of the project and is requiring protection, even though the plans were approved, stating that this area was not to be protected per sections 6.6.5 and 6.6.5.1.

Please see the attached picture and let me know your thoughts.

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