What constitutes a "drop" on a fire alarm Class A circuit?

NFPA 72 12.3.8.1 (2016 Edition): 
"The outgoing and return circuit conductors shall be permitted in the same cable assembly, enclosure, or raceway only under the following conditions:
(1) For a distance not to exceed 10 feet where the outgoing and return conductors enter or exit the initiating device, notification appliance, or control unit enclosures.
(2) Single drops installed in the raceway to individual devices or appliances.
(3) In a single room not exceeding 1000 sq ft in area, a drop installed in the raceway to multiple devices or appliances that does not include any emergency control function devices."

For this project in question an appliance is located approximately 12 feet away from a device. The circuit runs from the device, out 12 feet horizontally, down a wall a few feet, then back up and back to the first device. 

In my opinion, the outgoing and return circuit exceeds 10 feet so it would not qualify as Class A wiring. However, the contractor is calling this a "single drop" to an individual appliance, so he feels it qualifies as exception (2) above.

Is this considered a single drop if it's only serving an individual appliance?

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Per NFPA 13D 2019 Edition Section 8.2.1.3, "Concealed Sprinklers shall be permitted to be installed in beams not greater than 4 in. (100mm) in depth."

Semi-recessed heads can be permitted to be installed in beams up to 14in.

Why do concealed sprinklers installed in beamed applications have a 4 inch limitation? 

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Have a 4-story townhouse, sprinklered in accordance with 13R.

Is a sprinkler at the top of an elevator shaft an acceptable trade off for a 1-hour rating of the shaft (in lieu of a 2-hour rating)?

NFPA 13R, 2013 Section 6.6.6 says sprinklers are not required in non-combustible elevator shafts in accordance with ANSI 17.1. The state is says they will not certify the elevator/does not require a certificate in a residential elevator, so there is no confirmation that the elevator code is upheld.

If the sprinkler is an acceptable trade off (or if the sprinkler is elected to be installed in excess of the code requirements) is then a shunt trip and flow switch/heat detector required to shut off power in the event of a sprinkler activation?

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What is the best way to cut in to an existing underground line that may have a thrust block at the end?

We are doing a project that has scope to retrofit an 8" backflow into an existing approximately 200' of 8" underground. There is an existing detector check valve in the line which will be removed. Because of the age of the building and underground (about 30 years old) it is assumed the piping has a thrust block at the end. But with cutting into the line and adding a couple 90 degree elbows to get the backflow above ground there is fear that the line may slip back to the water main because the thrust block at the end of the 200' run is no longer holding the entire line in place.

We are planning to add a thrust block to the new 90s, but the issue is that there is only a shut off valve that is in the straight line of the 200' of pipe. If we shut that valve, there will still be pressure on the front side of the valve and when we cut into the pipe, the pipe may slip.

Any suggestions on securing the pipe on the supply side of the new backflow or limiting the pressure prior to the concrete being poured on the elbows for the backflow?

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Have a kitchen exhaust "ecological unit" which filters oil, grease, dust particles, and smoke odor from a kitchen hood exhaust system.

Are there requirements for how to be protect the unit? 

I'm not sure whether sprinklers would be required within the unit as I'm unfamiliar with these. Any guidance or tips from those who've worked with these before would be appreciated.

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I am looking at a sprinkler relocation-job were food is to be packaged. They are installing a drop ceiling above the packaging equipment.

I am having a hard time finding a concealed sprinkler head to spec out that has a metal temperature element and a rubber dust cover that is suitable for an ordinary hazard space. The VK538 jumped to mind but they do not offer a rubber gasket for the plate. I just found the TY5521 that says it comes with a rubber dust seal.

Do FDA-grade facilities require dust cover gaskets?

Does adding a dust cover ring to a escutcheon de-list the product?

Thanks in advance.

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Our common CRAC Units (Cooling, Refrigeration and A/C) for data centers only cool the air directly from the data center and back into the data center.

Do these need to be shutdown with the use of a total-flooding clean agent system? 

If the CRAC unit is only exchanging air within the same space then I'm not sure what harm it would do if it's running during or after clean agent discharge. I'm curious if I'm off the mark here, thanks!

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There is a confusing discrepancy between NFPA 13's ban on hanging 1.25" and greater pipe to bare metal deck versus the availability of UL listed anchors with a test load of 850 lb (that is the number for the 3/8" Sammy XP 20).

I don't understand how something that has passed such rigorous testing could be forbidden by the code. Does anybody have any background knowledge on this subject?

On top of this, I don't understand the configuration required for this application by NFPA 13. It says anchorage needs to be provided by "punching the vertical portion of the metal deck and using through bolts." (2016 Ed. 9.2.1.4.1) I don't know how to visualize this arrangement and there are no details or photos in the handbook.

Does anyone know what this is supposed to look like?

I've tried reaching out to NFPA's technical resources and have not gotten a response.

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Would an auto lift fall under the same rules as an elevator? I cannot find any specific code regarding this situation.

The main (ground-floor) level drives straight into the upper position for a car lift. The car lift can take the cars down into a basement parking level.

I was going to install a dry ordinary hazards horizontal sidewall sprinkler at the top and bottom as a standard elevator. I am waiting for the architectural details at this time. I appreciate any input you may have.

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Are others experiencing AHJ's requiring that sprinklers placed in ceiling tiles directly adjacent to HVAC ceiling tile diffusers either be moved to at least 2'-6" away or replaced with intermediate-temperature rated sprinklers?

I am primarily referring to the vane style horizontal discharge diffusers you see in almost every office building, typically with an ordinary-temperature rated sprinkler in the center of an adjacent tile, only 1 ft. away.

Referencing NFPA 13, 2019 Edition, A.8.3.2.5: A diffuser in ceiling sheathing labeled by the manufacturer as "horizontal discharge" has directional vanes to move air further along the ceiling, and sprinklers located within the 2 ft. 6 in. (750 mm) radius should have an intermediate-temperature rating.

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How do you engrave your hydraulic calculation signs, general information signs, etc.?

We use a hand held Dremel engraver which, while functional, is not a fun experience. I have seen some contractors who have perfectly imprinted engravings on their plates and I wondered if they used a machine, sent it to a company, or some other solution? Our engravings tend to look sloppy.

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We are working on a hospital project where the underground service pipe to the pump room was buried at 4 feet (1.2 m). Are we required to provide a concrete sleeve or any special concrete provisions to protect the HDPE pipe? 

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We have a dormitory project where, on the first floor, and entry lobby at the front entrance connects directly into a main corridor that runs the length of the dormitory. On either end of the corridor are exterior exits. There are also exit enclosures from the two upper levels that discharge to the exterior on both ends of the building. This project is under NFPA 101-2018 and is fully-sprinklered.

NFPA 101-2018 7.1.3.1 and 28.3.6 state the following:

7.1.3 Separation of Means of Egress.
7.1.3.1 Exit Access Corridors. Corridors used as exit access and serving an area having an occupant load exceeding 30 shall be separated from other parts of the building by walls having not less than a 1-hour fire resistance rating in accordance with Section 8.3, unless otherwise permitted by one of the following:
(1) This requirement shall not apply to existing buildings, provided that the occupancy classification does not change.
(2) This requirement shall not apply where otherwise provided in Chapters 11 through 43.

Because this is a new dormitory, Chapter 28 also applies:
28.3.6 Corridors.
28.3.6.1 Walls.
28.3.6.1.1 Exit access corridor walls shall comply with 28.3.6.1.2 or 28.3.6.1.3.
28.3.6.1.2 In buildings not complying with 28.3.6.1.3, exit access corridor walls shall consist of fire barriers in accordance
with Section 8.3 that have not less than a 1-hour fire resistance rating.
28.3.6.1.3 In buildings protected throughout by an approved, supervised automatic sprinkler system in accordance with
28.3.5, corridor walls shall have a minimum 1∕2-hour fire resistance rating.

Our question is - is the lobby, by code, considered part of the corridor (and therefore need to be rated)?

Two ways of looking at this - one is that the code is strictly only discussing requirements for the corridor and not a lobby. The other way of looking at it is that the lobby is acting as the corridor when it serves as part of the exit access for the building. 

Normally a 1/2-hour rating wouldn't make all that much of a difference, but there's storefront in the lobby space between an adjacent office and the lobby which would have a cost impact to the project.

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I'm laying out heads on a project that has large ceiling clouds that do not meet the requirements for sprinkler omission. I do have heads in the lower ceilings. The clouds are within 18" of the deflector for the upper ceiling.

How do I space the sprinklers above the clouds since the spray pattern is disrupted? Many of the clouds are wider than my allowed max distance between heads. Anyone have any thoughts on this?

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Split case pump - flow meter installation question:

As indicated in NFPA 20, the distance from the flowmeter to either isolation valve should be as recommended by the meter manufacturer.

​Based on your own experience, do fittings (elbows or bends) need to be included in this distance calculation?

For example - should the distance recommendation length of 10-diameters be calculated from the last fitting or is the fitting ignored and only calculated from the isolation valve? Thank you.

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Does anybody have a reliable and accurate formula to figure out the flow through the 3" gang drain for a high rise standpipe with PRVs?

This to size the floor drain properly and to pass along to the plumber.

Also, when draining a system, you only drain one system per floor at a time when needed. The annual testing of PRVs, would be the worst case scenario in my opinion...250 gpm out of each. The 500 gpm at the roof should be handled by the Rain storm drains, right? Thank you kindly.

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This project has a canopy. It canopy is not attached to the building. The building is required to have a sprinkler system installed in accordance with IBC 903.3.1.1 (an NFPA 13 system) in order to increase the allowable building area. 

The canopy is providing weather protection for transit passengers. It's Type II-B, non-combustible, and made of steel, concrete, and metal panels. The canopy is also very large, and on its own exceeds the allowable area for a non-sprinklered Group A-3 occupancy.

Do the provisions of NFPA 13-2016 Section 8.15.7.2 (copied below) allow for an omission of sprinklers from an exterior canopy as described here?

8.15.7.2* Sprinklers shall be permitted to be omitted where the exterior canopies, roofs, porte-cocheres, balconies, decks, and similar projections are constructed with materials that are noncombustible, limited-combustible, or fire retardant–treated wood as defined in NFPA 703, or where the projections are constructed utilizing a noncombustible frame, limited combustibles, or fire retardant–treated wood with an inherently flame-resistant fabric overlay as demonstrated by Test Method 2 in accordance with NFPA 701.

A.8.15.7.2 Vehicles that are temporarily parked are not considered storage. Areas located at drive-in bank windows or
porte-cocheres at hotels and motels normally do not require sprinklers where there is no occupancy above, where the area is entirely constructed of noncombustible or limited combustible materials or fire retardant–treated lumber, and
where the area is not the only means of egress. However, areas under exterior ceilings where the building is sprinklered
should be protected due to the occupancy above.

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Have a project that is a large ESFR warehouse with many storage bays and many zoned systems. About every 150 to 200 feet is a 1-1/2 inch hose valve that is tied to the overhead system with 1-inch pipe drops.

What is the purpose for these? Where is the code basis?

We may be modifying some of these areas with new work and I want to be sure we're upkeeping code, but I'm not familiar with the purpose of these hose valves. Thanks in advance.

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One of the frustrating non real-world things in consulting is that on the contracting side, 99.9% of the time we start at flange inside the building. Red-line the contract if needed, or work out an informal deal with the underground contractor. 

On the consulting/engineering side we have this whole underground spec section, just for five-feet out, including tracing wire and tape, testing offsite soils, soils disposal, shoring, compaction, size of rock, etc.  I understand the civil engineers will only take it to five feet. 

I’ve asked my people why we can't just match reality and just start inside the building? I am told if we did there is this 5-ft. gap that has to be claimed by someone (despite what is done in reality).

Have you addressed this in your experience in any way? I am wondering how others deal with it. On the contracting side we all just made it happen.  On the consulting/paperwork side, it’s hard to make the paperwork match reality.  Do you even seen thrust block calcs submitted from anyone since it is part of the imaginary five-feet out?

Sorry, ranting a bit, it came to mind again today because I have constructability comments from the architect that recognized that in this particular case, the AHJ permit covers from the flange, their solution is to have my spec cover the entire fire line. I’m not comfortable with that.   

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