I have an existing office building and we are renovating one floor. The building has an existing sprinkler system.

In the middle of the office floor, there is an outdoor patio (I believe all non-combustible) and it is open to the air above. It is 6' x 6' and surrounded by glass on all 4 sides.

There are currently no sprinklers protecting this courtyard and we are being told that there needs to be.

I am not sure which part of NFPA 13 I would even look at since Section 8.15 only discusses exterior projections and the like. Nothing about an open-air courtyard.

I would appreciate any help. There is room to install dry sidewalls above the glass even though the sprinklers would be watering the outside.

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Are there any restrictions (by code) for using a return bend on an ESFR pendent sprinkler?

We have structure in both directions, with 21-inch deep beams which requires the pipe be installed underneath the beams.

Thanks in advance!

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Do metal or steel pallets have any adverse effects on a storage system's (either racked or high-piled) sprinkler  demand or density?

I know plastic pallets can increase the commodity classification of class I-class IV commodities, but I don't think metal does. I have a storage facility that can't use wood pallets but also can't protect the level of plastic commodities required without a costly fire pump.

Thanks in advance.

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We have an external fire protection network in a marine port that has been served by 2 main electrical-driven fire pumps.

The proposed solution on this project is to utilize two main end-suction-type fire pumps using the seawater as a water supply source. 

The seawater is near the seashore at a lower elevation than the fire pump base.

To overcome the low pressure of the Net Positive Suction Head, a vacuum priming pump is installed on the suction line to get enough pressure to prime the fire pumps.

Considering this whole assembly is not listed nor approved, and there is no space for a water storage tank, what feedback might you have about the non-listed solution?

We can't provide an extended platform here with a vertical shaft turbine pump, so I'm at a loss for solutions. Thanks in advance.

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I would like to differentiate between the density requirements for low piled and miscellaneous storage using NFPA 13-2019 Edition.

I have reviewed the the definition and literature in the code. That is all completely understandable.

Does miscellaneous storage meet or excteed the requirements for low-piled storage?

Based on the commodity, total storage area, total storage percentage, pile size dimensions, and storage spacing requirements - does all this factored in mean that the design density for the non-storage areas (like manufacturing or assembly) can be used under the miscellaneous storage area, instead of the densities provided in NFPA 13 Table 4.3.1.7.1?

For Table 4.3.1.7.1 - there is no mention of low piled storage in the title of the table - is this the table that would be used for the determining the densities for any low-piled storage areas? Is there not a separate table for low-piled storage?

I am likely overthinking things but some clarification or opinions would be appreciated.

Thanks in advance for the help.

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Working on a project with an underground water storage tank, where the water level is under the pump suction inlet. The pump type is a vertical turbine pump.

Is the a maximum vertical length of suction pipe for this type arrangement?

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Is there a calculation method for sizing of air vents at the top of a sprinkler system riser?

NFPA 13 says 1/2-inch (15 mm), for a manual valve, but is there a way to calculate what this should be for a large system?

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Hello everyone -

I have a problem with two identical fire pumps rated at 145 psi at 2,500 gpm.

When testing for 0% flow and 100% flow the pump gives the correct pressure, but, when testing 150% flow the pressure drops dramatically, it has to show 125 psi and the result is 92 psi.

The pumps has a 10-inch flange suction an as NFPA allows it was installed a 10-inch pipe directly to the pipe, no suction reducer, having 16-ft (5 m) long of distance for one pump and 19'-6" (6 m) for another one, the second one with two 45-degree elbows installed more than 10 times the diameter from pump suction.

The tank is 23-ft (7 m), full of water. The test outlet is installed on the other side of the tank, so the flow does not fall over the suction inlets. The antivortex inlet has a plate of 7.5 inches above the floor.

The pump discharge is 10 inch.

The flow meter is 8-inch diameter with 8 diameters before and more than 5 diameters after.

Any idea why the pressure at 150% is so low?

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I have a project which includes two 6-level buildings (a parking garage and a residential structure).

The garage is reinforced concrete and cold. The residential portion right next to it (8 inches away) is mostly wood construction and warm. The project has a seismic design category of B - so no earthquake bracing throughout. Because the garage is cold, I have the dry control valve on a combination standpipe in a warm closet in the residential portion. The 3" feed then travels across the 8" gap to the garage. This happens at all 6 levels.

My question is, do I need a seismic separation assembly on one side or the other at each of the levels where the dry feed travels across the gap?

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In Section 19.4.1.3(3) of NFPA 13-2019 Edition, discusses that rooms or compartments 800 sqft or less (small rooms) should be calculated based on delivering 0.10 gpm/sqft over the room or the compartment by using the area of the room divided by the number of sprinklers in the room.

I believe I've overcalculated remote areas in the past.

My project now is an apartment building designed according to NFPA 13. Using residential type sprinklers with non-sprinklered combustible concealed spaces. According to Section 19.4.1.2 I need to calculate a minimum of eight sprinklers.

In the past I've calculated the eight sprinklers using the actual spacing based on the S x L rules with a 0.10 gpm/sqft density.

One room example - room dimension of 24 x 12 is 288 sqft. Two sprinklers spaced in a compartment 8'-0" off one wall and 6'-0" from adjacent wall. Using the S x L rule: 16' x 12' = 192 sqft x 0.10 gpm/sqft = 19.2 gpm each.

Or, according to Section 19.4.1.3 (3), would I divide the room size 288 sqft by 2 sprinklers, which is 144 sqft per sprinkler, regardless of the actual sprinkler distance from the walls? This second scenario would result in a 14.4 gpm required flow.

Or, was the code option (3) assuming the sprinklers are evenly centered within the compartment.

Thanks in advance for your input and clarification.

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Happy New Year everyone!

We are upgrading protection for one of our Crude Oil Storage Facilities for a major oil and gas clients in the Middle East region. We have 4,000 gpm diesel driven pumps for fire water use. There are 8-inch pressure relief valves provided, per Section 4.20 of NFPA 20-2019.

Section 4.20.4.1 (Type) reads as "pressure relief valves shall be either a listed spring-loaded or a pilot-operated diaphragm type."

My interpretation of this section is that the listing is required in either of these cases, whether it's spring loaded or pilot operated.

However, it's being challenged by those who are reading word-to-word meaning and saying that the listing requirement is only applicable for spring-loaded, and not for pilot operated relief valves as the sentence is separated by "or" along with the latter "a". If the letter "a" is not there, then I'm convinced with my interpretation that the listing is applicable for both cases.

Also, I checked the handbook but it does not provided any further detail.

Has anyone had any insight/experience as to whether the listed requirement applies to pilot-operated relief valves?

I appreciate any further detail or discussions on the above with reference to code interpretations. Thanks!

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We have a project light hazard occupancy, that is a highrise building, and has glass all along the perimeter of the building. 

Is the maximum sprinkler spacing measured off the knee wall, or the glass?

There is a knee wall that rises up from the floor 2'-6" and is 12-inches in depth. 

Do we measure the 7'-6" off this knee wall for floor coverage, or do we measure off the glass for the maximum distance?

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For a fire department connection that is remote (freestanding) from the building, what is the minimum distance between the building and the remote fire department connection?

I've seen some authors recommend a distance equal to the building height, but others recommend half the building height.

Is there a code or standard reference that indicates this?

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I have a four-story hotel project to design that has bathrooms in the guest suites. These bathrooms measure out to 55.4 sqft per the architectural drawings of the bathrooms. 

I am getting pushback from individuals as I don't feel this complies with NFPA 13-2016 Section 8.15.8.1.1's exception, and therefore it would require sprinklers.

I interpret the 55 sqft threshold as 55.00 sqft, or am I interpreting this incorrectly and should allow sprinklers to be omitted as long as the square footage does not break into the 56-sqft threshold?

The exception also states 5.1 square meters, which converts to 54.89 sqft, which to me, reinforces my 55.00 sqft threshold.

What are your thoughts and feedback?

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What is the proper approach to classify a storage container that could be filled with any handful of miscellaneous materials?

We have a project and can't seem to get a straight answer from anyone, including the local plan reviewer. 

These are basically 8-foot tall steel shipping containers that are pod-type portable storage units, where people can load their belongings into them and these pods get collected inside this warehouse until the original owners need them.

The existing warehouse building has a CMDA system, designed at 0.38 gpm over 2,000 sqft. 

Has anyone here had experience going about classifying these shielded hazards with non-defined storage inside?

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How do I go about designing protection below a dome?

We have a church project, and the dome is 30'-0" in diameter and is about 15'-0" high. It's basically a hemisphere. 

Looking for tips/guidance/creativity on getting this one started. Thanks.

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I have a customer that has a paint storage facility. All the liquids are Class III-B and stored at a maximum height of 6-ft with a minimum 8-ft aisle.

Does anyone have helpful information/guidance information for designing spill containment and coordinating ventilation requirements for a space like this?

I know containment is touched on in NFPA 30 - but I'm looking for some more in-depth guidance to get started. Thanks in advance.

Around here we're all about promoting the industry by bringing together a community of experts and sharing best practices. It's too important of an industry not to promote.

With that goal in mind, we have a happy announcement today.

Here are our 2021 Top Ten Contributors to the Forum!

These experts have regularly shared quality expertise through the year and have helped countless people, like myself, learn a little more each day. Some days I learn a lot. 

This Forum wouldn't be what it has become today without all of the contributors - especially these professionals who we would like to thank and celebrate today:

We'll be shipping a Top Contributor Plaque to each of the Top Ten Contributors as a small thank you for contributing to the conversations that do nothing but help our industry grow and improve. Thank again for a fantastic year around here!

Is it possible (maybe someone has encountered this already) to trigger a false alarm on a VESDA system or photoelectric smoke detector from refrigerant discharge mixture that contains both refrigerant and oil?

I'm concerned about the combination possibly affecting the fire alarm system.

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We have submitted plans for a new shoe store in an existing mall. The entire space is about 4,400 sqft and the stock room is 840 sqft with full-height walls.

The plans reviewer is requiring us to revise and resubmit using the calculation method in NFPA 13, 2016 Edition, citing Section A.23.4.4.2.

We are coming up short and the main (distribution pipe) is limited to 6".

Does this requirement seem reasonable?

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I have a distillery with H-3 occupancy. They will have one (1) stainless steel 100 gallon tank (never full) of 65% alcohol for distilling whiskey.

They plan to have maximum 6-ft storage of approximately 25-gallons maximum of finished product in bottles on shelves.

Also planned is approximately thirty (30) 30-gallon wood barrels stacked (2) high in adjacent areas

I am seeing a lot of exceptions in IBC and IFC for the wooden barrels with the H-3 Occupancy.

Can you provide any insight to this allowance for wood barrels and how I might determine the proper sprinkler density and maximum volume (if any with the H-3)?

​Thanks in advance.

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One of the consultants on my project provided a review comment requiring us to submit a calculation for stress in the hanger support.

We follow NFPA 13 here, and I've never provided something like this.

What exactly are they asking here, and is there guidance on how would I go about calculating the stress in the hanger components?

​Thanks in advance.

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Can a commercial pool be used as the required secondary water supply to a high-rise sprinkler system?

The 2019 IBC/CBC Section 403.3.3 requires an automatic secondary water supply in certain seismic design categories. This is typically met by installing a dedicated tank that meets the minimum demand for 30 minutes.

I have a developer asking if they can run a feed line to their 100k +/- gallon commercial pool so it can serve this purpose.

Outside of the engineering challenges and value engineering their team must address, I'm wondering if this arrangement is even allowed. I cannot find anything in IBC/CBC, NFPA 24, NFPA 13, etc. that wouldn't allow this. Any help is appreciated.

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What is maximum distance above a ceiling before concealed-space sprinklers have to be installed?

I can't find the code reference, but seems like there was a 3-foot maximum if it was non-combustible with insulation on the pipe?

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I'm an AHJ seeking training material on deluge sprinkler systems - particularly for acceptance testing.

Does anyone have a source for manufacturer-specified (or other) testing procedures that you could share?

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