I have an obstruction question regarding what I feel is a gray area of NFPA 13. I'm looking at obstructions greater than 18 inches below sprinklers.

NFPA 13 states that any obstruction over 4 ft wide requires sprinkler protection under the obstruction. What if you have multiple parallel obstructions that are less than 4 ft wide with gaps in between?

For example, multiple 36-inch diameter parallel pipes with 6 inches of space between each pipe.

I feel that even if these obstructions do not require sprinkler protection below per code, they would still significantly alter the listed spray pattern of the sprinkler. I have seen some info regarding a 50% rule, but I can only find that in code as it relates to ceiling fans.

I am curious what other opinions are. Thanks!

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Working on a fire house that is fully-sprinklered, non-separated construction type V-B, wood construction, R-2, S-1 & S-2 classifications, with R-2 being the most restrictive. We have 83 total occupants. IBC 2015.

We have a full- sprinklered attic with a nitrogen generator. We have gas-fired mechanical equipment in the attic.

My question is that the contractor is suggesting to VE the attic sprinkler by installing fire treated roof sheathing. IBC 903.2.8.3.2 "Attics not used for living purposes, storage or fuel-fired equipment." tells me that we are required to have them. Am I incorrect?

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Within stairwells, how are standpipes addressed in regards to cane detection with ABA/ADA rules? Are there any special cane-detection requirements (anything special to allow a visually-impaired person to detect a vertical standpipe)?

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Does anyone have any literature on the installation of face sprinklers (the sprinkler along the first row of a rack on the "face" of the rack)?

I have an AHJ who is saying that the height of the pipes serving the face sprinklers must not meet the definition of "hindrance" or "obstruction" in the building code. 

The face sprinklers in my situation are placed on first row of a rack system with the face sprinklers of the upright type. (2015 NFPA-30 16.5.1.10 (6)).  The sprinkler line is located parallel with the face of the rack. The bottom of the pipe is 4"-6" below the bottom of the rack. 

I have checked for the definition of what he mentioned and I can't find anything in the building codes. Building code is 2015 IBC/IFC.  Also checked the NFPA-13 handbooks but the installation requirements are concerned with sprinkler deflector versus the piping itself.  Thanks in advance!

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Do underground gate valves for fire main water supplies have to be monitored and supervised?

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Where exactly does a hydraulic calculation need to end? 

When we run a hydrant flow test, there's a static/residual hydrant and a flow hydrant. I regularly run my hydraulic calculations from the building, through the service main, to a street main, and then up the tee'd branch that serves a hydrant so that my source point is exactly at the elevation of the static/residual hydrant. I do this so that I make sure to account for the proper elevation of the water supply.

Most other hydraulic calculations I see will end wherever the building's service main intersects with the street's supply. Is this correct? Wouldn't that place the source at an elevation lower than what the hydrant indicated is available?

Wondering what the proper way is that I should be precisely calculating systems. Thanks in advance.

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What should I do about a sprinkler contractor who insists that rooms of dedicated Ordinary Hazard occupancy (storage, janitors, mechanical etc.) within an otherwise Light Hazard occupancy building can be protected as Light Hazard?

NFPA 13 clearly provides direction for adjacent and multiple hazard classifications. I think Chapter 5 and 11 (and common sense) are clear on this. Classroom Labs are even another matter that NFPA has addressed. Do you all run into this "it's all light hazard" belief as well?

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When sprinklers (recessed, pendant, or concealed) are installed in a ceiling, do the distances to heating ducts and steam piping listed in Table 8.3.2.5(a) of NFPA 13-13 still apply when those elements are above a ceiling?

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I have a question that a architect brought up to me.  He is saying that on a highrise (11 stories) it is a fire code requirement to have floor control valves on both stairwells. I cannot find anything that states this in any of the NFPA books. The square foot of each floor is small and is NOT separated into zones.

Does an 11-story high-rise require floor control valves on both stairwells?

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Will you please clarify why a Building Area Increase is NOT permitted for an NFPA 13R design?

We are working on a project and the architect has stated that the calculations following IBC T506.2 allow for an area increase up to 135,000 sf. We are working in IBC 2015. The Owner would like confirmation that the 4 story R-2 Type V-A building can be protected under NFPA 13R when it is over 12,000 sf.

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I could use some help with sprinkler obstructions.

Generally, I’m looking at piping and ductwork, that is installed within 18” below the plane of the standard upright sprinkler deflector. Light or ordinary occupancies.

I called NFPA 13 and got an interpretation that these would be considered a sprinkler obstruction, and I would need sprinklers on either side, regardless of the size of the duct/pipe (no rule here about only being over 4’). This was per Section 10.2.7.2 in the 2019 edition.

I didn’t think to ask, but could I still apply the three times rule of 10.2.7.2.1.3, even though these aren’t structural members? As long as I was three times, or 24-inches away, it wouldn’t be an obstruction, right?

I’ve seen these close configurations all over the place in many different peoples’ designs, so I’m wondering if I’m missing some allowance.

Most recently, I observed a 14” wide (horizontally) x 6” deep duct (vertically), with a sprinkler installed directly above with the deflector 5” above the top of the duct. The next sprinkler head is approximately 12 feet away. Also observed in the same room, was a 5” diameter pipe about 8” diagonally down from a deflector, measured at a 45-degree angle. If I’m understanding NFPA 13 correctly, these would both be considered obstructed. I have a question into NFPA 13, but would appreciate others’ opinions as well.

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NFPA 20, 4.12.6 "Ventilation. Provision shall be made for ventilation of a pump room or pump house."

DIESEL FIRE PUMPS - These rooms require a lot more air for combustion air and heat removal. This is usually done in generator and boiler rooms with separate fan-forced intake air and exhaust ducts to the outside. In the case of a fire pump, fireproofing these ducts through the building offer additional "protection" under NFPA 20, 4.12.1 in the event of a fire. Diesel data sheets show the amount of CFM required for the various engines. In addition, the extra distance for the exhaust pipe lengths to the outside needs to be considered. Some of the engine manufacturers have calculators on their websites for VENTILATION, COOLING LOOP and EXHAUST PIPING.

PUMP ROOM TEMPERATURE LIMITS - Most microprocessor controllers are limited to 120 deg. F. A small non-vented pump room, especially on a west wall, could easily exceed that with a motor running under load on a hot 100+ degree day.

My question? This site/facility does not have an emergency backup generator. Do we need a backup generator to power the exhaust fan and/or the unit heater?

In the event of power loss during winter… a room temp sensor would send supervisory alarm company for an owner response.

Also, please confirm the Jockey pump does not require backup power.

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I would appreciate some feedback on using quick response sprinklers in a dry system. I have found no reference in NFPA 13 indicating specifically if QR Uprights can or can not be used.  Therefore, I assume that they are acceptable providing it is a light or ordinary hazard classification. 

I have researched and found varying opinions.  I believe fire testing shows that the use of QR sprinklers in dry systems can help decrease fluid delivery time.  However, with more sprinklers operating before the water arrives to control the fire, some argue that there is increased system demand.  I agree with both scenarios, however, I don't believe the amount of sprinklers operating would exceed the design area of a properly calculated system. 

I would love to hear some different opinions on the subject.

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For straight pipe couplings, are thrust blocks required, or is it only at any change of direction in the piping? It seems as though restrained joints seem to be common now, but the question came up when using thrust blocks instead of the restrained joints.

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I occasionally am the one to choose which dry valve make and model we use for our installation projects. If you're a specifying engineer/designer or on the contractor side of things, what criteria do you consider when you choose when deciding which dry valve model to use?

Obviously the calculations have to accomodate the pressure loss, but that mostly impacts size. What other factors do you consider when making the decision?

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As an engineering consultant I've worked across a good scattering of the continental US. Occasionally I find jurisdictions who do not allow a "performance-specification" set of documents, but rather require that the fire sprinkler system be entirely laid out and hydraulically calculated with the building permit submittal.

Right now I'm aware of some areas in Florida and New York City as being two that have stood out as having this requirement.

In your experience is this common? What other jurisdictions do you know of require "full-design"?

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I would like to open up a topic to this amazing forum.

Preaction systems...types, cost, challenges, panel set-ups...I continue to see the vast lack of knowledge amongst the design and management community.

Which type is best? Which is more economical? Which is best for your company to install or to maintain? How does a double interlock system affect design/cost? Can a single interlock system be set up to operate the way you need and at a lower cost? Does the AHJ typically have any special requests?

Knowing these answers could only make everyone's lives easier. Thanks in advance!

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Fire hydrant flow test question - is the pitot the same as the residual pressure on a water flow test from a fire hydrant?

Is it possible to know the residual pressure and 'chart out' the flow of the fire hydrant, or is there a way to determine the flow with only the static and residual pressures?

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What is the maximum working pressure allowed for CPVC?

I understand many manufacturers have 175 psi listings, but I'm wondering if there's anything that's listed for higher pressures. Thanks in advance!

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If I have multiple compounding remote area adjustments, when does the minimum remote area size for high-temperature sprinklers get applied?

For example, if there is a dry system protecting storage starting at 2,500 sqft, which calculation is correct?:

(a) 2,500 sqft x 0.75 (high-temperature reduction) = 1,875 ... rounded up to 2,000 sqft for minimum area, then 2,000 x 1.3 (dry system area increase) = 2,600 sqft.

or

(b) 2,500 sqft x 0.75 (high-temperature reduction) = 1,875 ... 1,875 x 1.3 (dry system area increase) = 2,437 sqft, which is greater than the 2,000 sqft high-temperature minimum.

Thanks in advance!

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A three-story dormitory and we have residential-style pendent sprinklers in the corridors with residential sidewall and pendent sprinklers in most of the units. 

By code, are the pendent and sidewall sprinklers required to have the same k-factor?

Residential k-factors jump around a little and I wasn't sure if the requirement (or industry standard) to not mix k-factors would cover different sprinkler orientations too. Thanks in advance!

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Where exactly in the International Fire Code or International Building Code (or NFPA standards) does it state that a standpipe riser must be visible or unobstructed? 

Is there anything that prohibits me from sheetrocking the standpipe riser os installing it inside a wall? Of course the hose outlets will be exposed - but what about the riser?

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Can we run a 6-inch standpipe for a highrise building (24-story) fully on an external wall? The main would come out of the pump room and take branches for each floor from the riser. This new building has a major space shortage and it's not possible to run the pipe within a shaft inside the building. There is no issue of freezing as the temperature does not drop to the freezing point.

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Why does a townhouse which is 4-story require an NFPA 13R system?

The IRC is specifically geared toward one-and two-family dwellings up to 3 stories, but the IBC allows 13D systems in R-3, R-4 condition 1 and townhouses (903.3.1.3).

Is there another prevailing code reference that overrules this allowance?

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We have a non-conforming fraternity building that wants to build a new two-story covered entrance canopy that ties into the existing roof. It is a heavy timber construction and has no concealed spaces. The fire area is already too large, so our interpretation is this would trigger a sprinkler system in the whole building.

A more lenient interpretation might be to only sprinkler the new portion, and potentially add some rated separation between the existing non-sprinklered building and the new sprinklered entry canopy, but I am not aware and I can't find anything about separation between sprinklered and unsprinklered portions of a building. Would this arrangement be permissible by code?

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