We have a 6-story condo building. It's an NFPA 13 system on the first floor, and NFPA 13D with PVC piping above.

Over the years this building has had leaking sprinklers. The last two leaks were within a week of each other, one in the second floor laundry room and one in the large lobby sitting area.

The leaks have been found by residents; no waterflow alarms. The sprinkler company who put it in is still doing yearly testing and maintenance. The fire units for these two events found the pressures in the stairwells at 150 psi. The jockey pump turns on at 120 and off at 133.

The sprinkler company says the sprinklers in the PVC piping are leaking at the fitting behind the sprinkler and not the sprinkler itself.

The connection between the sprinkler and the fitting was either cross threaded or over torqued.

Last week I found the gauge on the 6th floor reading 110 psi and the 1st floor at 130 psi.

Can pressures of 150 psi plus at extended periods of time cause the leaking?

The pipe is rated to 175 psi. The building was built in 1989.

And for my own knowledge-the pressure in systems of this type are this high for what reason?

We are told the pressures are typical. Thanks in advance.

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UL designs discuss loading-bearing and non-load bearing walls.

I haven't seem many where they discuss when, say, electrical, fire pump, fire alarm panels or other equipment are mounted on the walls.

At what point do you have to consider the objects on the wall and consider the wall as load-bearing?

It may just be a structural question, but my structural contacts have said not to worry but I wanted to hear others opinions. Thank you in advance!

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Is there an FM Global requirement for a minimum safety factor in a hydraulic calculation?

We have a project that is following FM requirements, and the calculation "safety cushion" is coming in at 2 PSI.

We have looked through the FM Data Sheets, but cannot find anything to give a minimum criteria.

Thanks in advance.

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Is there an egress requirement for a garage structure that only houses the car stacker, with 10 bays and 3 levels?

What would a code path be for or against such a requirement?

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I have a non-combustible shell building with 18-inch steel beams under corrugated metal deck.

Some of the beams are spaced in excess of 7'-6" apart, but not exceeding 9'-6" and creating an area exceeding 300 sq. ft.

To loosely summarize definitions, per NFPA 13, 2019 edition Section A.3.3.41.1 for Obstructed Construction, Beam and Girder Construction, the steel beams are to be spaced between 3 ft. up to 7½ ft.

Panel Construction requires that all cross-sectional areas be filled including the interface at the roof, (which this is not the case on my project), and not exceed the 300 sq. ft. area.

My question is this, since this building does not meet either criteria and is not combustible construction, (no wood is being utilized in the structure), there are no concrete tees being utilized and there are no bar joists present, would this then be considered as Unobstructed?

My thoughts are no, and that this is still Obstructed Construction, however I can't find a proper definition within the Obstructed Construction definition.

I am wanting to know if I can utilize the 1" to 6" below Obstructed Construction allowance however I am held up by the definition of the construction type and am unsure if I need to space within the bays or if I can space below the 18-inch steel beams.

Any thoughts or input on this would be greatly appreciated.

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Does a double wall diesel tank require a reservoir?

​Thanks in advance.

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Does NFPA 13 2022 Section 10.2.6.1.1.3 about "Vertical Change in Ceiling Elevation Greater Than 36 in." apply to all types of sprinklers?

I have a contractor who argues that the paragraph does not apply to ESFR sprinklers.

The design has a change in elevation of 14-feet and the last sprinkler on the high-bay side is 8'-4" feet horizontally from the vertical plane. 

Thanks for helping settle the disagreement here. 

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I have sprinklers at an exterior overhang over 100 feet above the floor (ground) it protects. There will not be anything stored directly beneath the overhang.

There is occupiable space above the overhang. It's noncombustible construction; a mid-rise office tower.

Questions have been brought up about heat collection, and the effectiveness of sprinkler spray: if there was a fire on the ground level, will enough heat be collected at the overhang 100-ft up in order to operate an intermediate temperature sprinkler that is 286 degrees F?

What will happen if there are high winds (common for this area)?

And if the sprinklers do discharge, will the water spray droplets evaporate before reaching a proximity of effectiveness?

Will a "cooling effect" even happen?

The AHJ will allow the sprinklers to be omitted. I'm not seeing anything specific to very high ceilings in NFPA 13 (2016).

My question to you all: Where can I find the science to backup their decision?

Do you know of any resources where this scenario has been studied, evaluated, or fire-modeled? (FM or non-FM?)

Obtaining a PE review is not a desirable option. (I am aware that FM datasheets address this scenario as requiring sprinklers.) Thanks in advance.

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I'm currently looking at a water treatment plant.

Electrical design wanted to coordinate using the same horn/strobes to notify for a chlorine gas leak, as it would avoid being redundant and putting up their own horn/strobes to go off during a leak.

This would require hooking up a non-fire related notification appliance to the fire alarm panel.

What are thoughts on this?

Thanks in advance.

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I'm working on an existing system in a seven-story building. There is an existing pump and piping which snakes its way through the building.

There is a pressure gauge at the inlet and outlet of the pump, but none afterward until 200' away from the pump room. The pipe branches off with a zone valve assembly with pressure gauge serving that floor area, and then upwards through the remaining floors with no gauge.

Zone valve assemblies with gauges are located on the floors above.

Now for my question - when performing hydraulic calculations, where would you indicate the "bottom of riser"?

Thanks in advance.

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Hi everyone - thanks for answering my previous questions and for checking out today's as well.

I have three projects all connected to the same central fire pump assembly. It's a huge network of pipe running for miles. 

The client is having a problem with the fluctuating pressure (up and down) on the network for some reason that affects the fire pump's suction pressure. It's in series, and connected to each project.

The client refuses to add a break tank and cut the fluctuation. 

In your experience, is there any alternative solution available? 

Would a pressure relief valve help? What would happen when the pressure is less than design?

Thanks in advance!

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In regards to installing pressure reducing stations for separating areas of the building into different pressure zones, NFPA 14 calls out that the FDC needs to be installed downstream of the pressure reducing valves.

Is a separate FDC required for each pressure zone?

If you provide just one FDC, and the fire department supplies the system for an upper floor of a high-rise, you will exceed the maximum working pressure of the lower systems. I'm not sure how that's possible to avoid.

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What concerns should I have about hanging from old wood?

Like very old wood, almost petrified?

I'm doing an NFPA 13R job for an old historic building that has been moved. I don't know how old, but it uses full dimension wood. The 2x's look like they measure 2-inches thick.

I'm wondering what hanging to this old dry wood is going to be like?

Do they need to predrill? Are screws better?

Any ideas appreciated!

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What are the physical or regulatory concerns of leaving an older dry pipe valve as wet for an extended amount of time?

This would be during the non-freezing months.

I can think of the alarm trim - water gong changed to electric, clapper gasket integrity, and the inevitable leaks in the overhead system.

Curious on other perspectives, thank you!

​

I am working on a project with a new client who develops multi-level Self Storage Facilities.

The typical units are 10'x20' with 8-ft bent metal purlin dividing walls. The walls do not extend to the ceiling deck which is 11'-6" above finished floor.

All sorts of household items are being stored, which can include exposed expanded foam mattresses that are greater than 5-ft in height when on their side. The tenants are limited in storage height to 8-ft because of 14 gauge metal wire netting above the units.

On previous projects the client has been permitted to classify the hazard as OH2 (possibly because of the definition in NFPA 13, 5.3.2. 2016 edition, which includes contents with high-heat release rates up to 8-ft).

The question is whether or not it should be Extra Hazard Group 1 or Extra Hazard Group 2?

I am leaning towards EH1.

The occupancy is a storage facility so I believe we fall into Chapter 12 for our design requirements. Because we have exposed expanded plastics stored greater than 5-ft we cannot be considered Low-Piled (Chapter 13). Therefore we fall into Chapter 15.

Using NFPA13 Table 15.2.2.5(a) and the decision tree, selecting plastic commodities, Group A, Expanded, Exposed, Unstable, I believe the Density would be 0.30 gpm/sqft. This would be EH1.

I am using NFPA13, 2016 edition.

Can anyone speak to how they would classify the hazard (design area and density) for this type of storage facility?

​Should it be OH2, EH1 or EH2?

Thank you.

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We have a customer who is building a storage building that includes flammable liquids.

The liquids are Class I-B flammable (as classified under NFPA 30).

I understand that there are limits for the quantity that is allowed within one control area. The Maximum Allowable Quantity (MAQ) is 120 gallons, from NFPA 30 tables. The reading can be increased 100% when a sprinkler system is used. 

So the limit increases to 240 gallons with sprinkler protection.

The number can increase even more when stored in approved liquid storage cabinets or safety cans, which I assume the customer would prefer.

So the final MAQ becomes 240 gallons x 2 = 480 gallons.

The biggest storage room is 2,000 square feet and the customer wants to exceed the MAQ to be above 480 gallons in that storage room.

I have understood that exceeding the MAQ is permitted if the building is classified as an H-3 Occupancy (High Hazard). This occupancy applies more restrictive requirements. 

Is there any numerical value for a new MAQ limit in that case?

My current path is as follows:
Class I-B liquid storage in Storage occupancy > maximum MAQ exceeded > building re-classified as H-3 Occupancy > but where is the new MAQ?

Thanks in advance for your input. I usually design under SFS and CEA standards, and they don't have the same MAQ concept within those standards.

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Thanks to everyone for another great month on the forum, and a shout out to our top ten forum contributors for March 2023 below as well! Perhaps it's just my own anecdotal experience, but it sure seems like we have lots more involvement and through discussions here than we have ever had before. I very much enjoy the company.
​ - Joe

Does a fire pump on an NFPA 13D system require backup power?

It seems like it should, but 13D does not say that it has to and does not reference NFPA 20.

Thanks in advance.

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Would the rack storage of non-encapsulated, Group A, unexpanded plastic commodities, stored in solid plastic containers (totes), be considered cartoned or exposed?

NFPA-13 Section 3.9.1.1 defines cartoned as storage consisting of corrugated cardboard or paperboared containers fully enclosing the commodity.

NFPA-13 Section 3.9.1.13 defines Exposed Group A Plastic Commodites as those plastics not in packaging or coverings that absorb water.

This leads me to think that any rack storage of Group A unexpanded plastics within solid plastic containers should be considered exposed, as these are not cardboard or paperboard nor does plastic absorb water.

Thanks in advance!

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We have an NFPA 13 commercial project.

Do you allow a domestic water tap coming from an NFPA 13 fire sprinkler riser?

If it is allowed, what provisions should I be looking for when reviewing a layout with this arrangement?

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This feels like a silly question, but we have high-piled, non-combustible storage, with open-grate or solid level single/double row permanent racks with Extra Hazard Group 2 overhead system.

I'm trying to identify the actual code verbiage that says nothing is required from an code/NFPA standpoint.

The product is metallic car parts with no added materials, just exposed solid metal, no plastic gaskets or spacers, etc.

The 2015 IFC is the highest code in my jurisdiction, so starting with that, Chapter 32 is for High-Piled "Combustible" Storage and provides no avenue for code justification.

NFPA 13-2013 defines "Noncombustible Material & Automotive Components on Portable Racks" but also gives no criteria for non-combustible storage.

FM Global Data Sheet 8-1 actually lists noncombustible as a commodity classification, unlike NFPA 13, but does not provide a criteria stating no coverage.

Is this just the simple scenario where code or NFPA standards don't list a requirement or criteria because it just doesn't require anything?

Again I feel like it's a silly question given the commodity but I believe the only rules to follow would be obstruction rules and distance from deflector to storage.

Thoughts?

Thanks in advance.

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