We are completing the build of a 95,000 sqft, 2-story facility. The sprinkler installers are using two manufacturers of fittings and couplings.

Our construction specifications require the fittings, couplings, and gaskets to be from the same manufacturer.

They have installed fittings (elbows, tees, etc) from one manufacturer with couplings from another, and vice versa, in multiple areas. I am concerned that any issue later on with that condition could be problematic with liability. 

I understand there are specifications and tolerances the manufacturers must meet - but is this an issue?

I am the AHJ as well as the owner (this is a state building). Thanks in advance.

​​​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

Hello lovely forum. Recently there was a question on taking the FDC off the fire pump bypass as long as it was downstream of any control valves on the pump bypass.

[Moderator Note: link to that question is here: https://www.meyerfire.com/daily/allowed-to-tap-fdc-into-fire-pump-bypass]

Building off that question, I have seen freestanding fire department connections being feed into an exterior hotbox that has the backflow preventer. This setup is before the feeds enter the building, and before going to a fire pump inside the building (and control valves before the pump).

Is this a violation of code, for having control valves on the FDC line before the valve header?

Thanks for your time.

​​​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

I have a combustible attic framed with standard wood truss framing. There are dormers that are framed on top of the roof sheathing, that have small 2-ft x 2-ft openings in the sheathing to access the dormer and provide ventilation for the dormers. Both the attic and the dormers are fully protected by the dry system.

My hydraulic calculation area is 2,535 sqft, which is increased for slope and for it being dry.

A dormer falls within my remote area.

My understanding is that the dormer is considered a combustible concealed space per NFPA 13-2019. The small opening of 2-ft x 2-ft is allowed under NFPA 13 Section 3.3.195. Therefore, the dormer space should not be included in the hydraulic calculations, under NFPA 13-2019 Section 23.4.4.6.5.

I am being instructed by an engineer that this area is not qualifying as a concealed space and the additional sprinklers in the dormer need to be included in the hydraulic calculations. Adding the additional 8 sprinkler for the dormer to the already-calculated 34 sprinklers in the attic is causing the possibility of now needing a fire pump.

Am I wrong here?

Do the dormers need to be included in the remote area for this hydraulic calculation?

​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

NFPA 101 has commentary that states that kitchen hood suppression systems are not required to activate public mode alarm for fire alarm systems.

Our Authority Having Jurisdiction stated that since the kitchen hood systems are provided in lieu of required sprinkler systems, then they are required to activate public mode alarm.

What is the generally accepted practice for kitchen hood suppression monitoring?

​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

Is an access panel or access door required for sprinklers that are installed in a concealed space?

​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

I have a mixed-occupancy, 100-year old 1-story house within a metro area. There is existing office space up in the front of the building, and a one-bedroom apartment in the back.

We are adding a camelback addition to the building. The existing office space will remain as is and we will have two 3-bedroom apartments in the back. The camelback will be set back 20-feet from the front of the house. The height of the building will be 30-feet. 

Can I use 13R or 13D in the residential units? 

Do I need any sprinkler in the commercial office space upfront?

​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

We want to extend a heartfelt way-to-go to all those who took the P.E. Exam this week. Preparing and taking the exam itself is no small feat, regardless of the outcome. 

With the end of PE Prep season comes our final 2021 Prep Series Leaderboard. These top players consistently topped the charts throughout our week to week competitions, and we're happy to announce the top ten finalists:

Congratulations to our top winners from the 2021 PE Prep Series. Each of the top ten finalists will receive a plaque commemorating their hard work this summer.

​To see our full standings for the 2021 season, visit our PE Prep Series page here: PE Prep Series.

For Fire Pump rooms located in a basement, that is accessed through a common corridor, is it acceptable to have other rooms (like plantrooms, storage, etc) off the same corridor coming from the staircase to the Fire Pump Room door?

We would provide the required fire resistance rating for the stair, the corridor, and the fire pump room. I'm assuming no storage would be allowed within the corridor itself.

​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

Already made alternative arrangements for the immediate install, but it can't hurt to ask for the future if this ever comes up again:

Is there any listed upright K8.0 extended coverage sprinkler that is listed for light hazard and combustible construction?

Couldn't find any with Reliable, Tyco, or Viking; but if an alternate manufacturer makes one, it'd be nice to remember for the future.

​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

We have a residential project where we are looking to use a residential sidewall sprinklers. The project is under NFPA 13 - 2016 Edition

On a wall where we have a sprinkler, there is a a projecting 3-inch x 24-inch wide x full-height obstruction bump-out of the wall. 

How far away from this would the sprinkler need to be? 

Or, do I need to add a sprinkler on the other side of the obstruction?

I'm wondering if these could be considered "shadow areas" because the shadow area would be under 3 sqft (NFPA 13-2016 8.10.7.1.4, and A.8.1.1(3)).

Thanks in advance.

​​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

I purchased a house with fire sprinkler system that is 30 years old. The previous owner had the sprinkler disconnected about 10 years ago when a furnace repairman stepped on one of the sprinkler pipes. The damage was repaired but the water line to the sprinkler system was not reconnected (not sure why).

I was wondering if it would be okay to have it reconnected now?

It is a 30-year old system and has been inactive for 10 years.

Do the pipes become brittle are there other concerns in reconnecting?

Thanks for you help.

​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

A firestop question from someone who doesn't venture much into that space - if we are using a firestop sealant around through-wall pipe and duct penetrations, and there is exposed structure in the room where everything is being painted black, can the sealant also be painted black?

The concern would be possibly compromising the sealant itself, or making future inspections more difficult.

​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

I ran into a wet pipe fire sprinkler system that has a small pressure pump installed on the riser.

The control valve and the alarm valve are dated 1957.

Since this pump was installed and accepted, can it be removed or taken out if it's not working?

I understand the pump was used to keep the alarm valve from opening during water pressure fluctuations to keep the false alarms from happening.

​​​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

How should I properly be sizing a vertical branch line that feeds only a five-story trash chute?

Would a hydraulic calculation be a line calculation, so I would calculate as many as five sprinklers?

I typically feed sprinklers from the adjacent floor level, so I've never ran a separate calculation just for a trash chute. My gut says a 1-inch threaded line isn't enough for a trash chute, but I'm not 100% positive how a hydraulic calculation should be done here.

​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

Do you specify single phase or 3-phase power for dry system air compressors?

If 3-phase, what horsepower?

I've always gone with single phase but I had a sprinkler contractor tell me recently that they prefer 3-phase compressors because they fill the system better and last longer. I was curious what others would recommend as better practice.

​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

So the issue of "forward-flow testing" of the backflow preventers has come up a lot as of late, at least here in Massachusetts. More and more design drawings are calling for "provisions" to forward-flow test the backflow preventer. I've seen multiple ways of doing this and I'm curious as to which method is best.

One method I see is adding a bypass around the FDC check with a normally-closed butterfly valve in it. This allows you to open the butterfly valve when you want to test the backflow preventer and flush through the FDC piping.

The other method I see is to extend the manifold and install a couple hose valves to use in testing.

My personal opinion is that if you have the ability to run the hoses outside, use the second method. The reason for this is that if each zone has a control valve, you can shut off the sprinkler system while flushing and not introduce any of the debris in the underground into your system. By doing it the other way with the bypass, you have to mess with the FDC, and if the FDC is fed from anywhere on the system other than the end of the manifold, you can introduce debris into your system.

Is this a better approach?

​​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

Is there any reason in code (NFPA 13 or 20) that you cannot tie a Fire Department Connection (FDC) line to a pump bypass line as long as the FDC line is downstream of all control valves on the pump bypass?

​​​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

We're doing a full remodel on an existing, vacant, 3-story building.

During the remodel, there won't be any heat in the building. There is an existing fire sprinkler system that would freeze during the winter.

How should we proceed during the remodel? 

Are we required to keep the sprinkler system active? Is the owner required to provide heat? What would you recommend from experience?

​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

We have a project that has Class III liquids in Non-metallic IBC (Intermediate Bulk Containers).

NFPA 30 Tables 16.5.2.9 and 16.5.2.10 list storage requirements for Class III liquids in Nonmetallic IBCs. Stacked IBCs are limited to two-high (~8 feet), and in racks, only single and double row racks are allowed.

Under Section 12.8, these containers may be protected as "high storage of Class IV commodities" through NFPA 13, provided that the volume is limited to 13,750 gal (Class IIIB).

Does this mean that under NFPA 13, IBCs can be stacked up to 40-feet with 45-feet ceilings as per Table 23.3.1, or in multiple-row racks up to 40-feet high with 45-feet ceilings as per Table 23.5.1?

Or similar configurations as per Chapter 22 (CMSA)?

Provided the volume limit is not exceeded, of course.

​​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

In my area many designers use the main test/drain or one of the FDC inlets to conduct forward flow for the double check backflow assembly. They use the velocity pressure pitot equation to demonstrate that they will achieve the system demand flow. During the acceptance testing, I verify that the system demand is achieved by measuring with a pitot gauge and calculating the flow.

I generally use a coefficient of 1 when a hose monster or the main drain piping is flowed from, because they are long runs of smooth continuous pipe.

Is this appropriate or should I be using some other coefficient?

​​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

You all make this forum excellent - and I couldn't be more thankful. Like many of you I very much enjoy learning new perspectives each day, and hope the forum is a positive contributor to your industry experience.- Joe
Here's our top ten Contributors for September 2021:

Looking at installing a cable tray that runs the length of the room in an Ordinary Hazard Occupancy.

The cable tray is about 2-feet wide and the sprinklers are standard uprights. The cable tray is less than 18-inches below the sprinkler.

However, the cable tray may be centered directly below some sprinklers, but off to the side for other sprinklers.

What obstruction criteria from NFPA 13 (2016 Edition) would apply?

Three Times Rule (Section 8.6.5.2.1.3)?

If Three Time Rule applies, is that measured vertically, horizontally, diagonally, or all?

Thanks in advance.

​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

I'm designing a sprinkler system that uses 1-1/2" diameter pipes working their way through a roof structure.

Once I got the branches run, it occurred to me that they could be sufficient to provide water to the system on their own. I looped the ends together, ran hydraulic calculations, and that theory checked out.

The issue is - how am I to seismic brace this pipe?

I have the pipe "restrained" as branch lines, but there is no main that they tie into. Even if I had a main, these branch pipes take so many turns that functionally it would act isolated from the bracing on the main.

How best should I approach this situation?

​​​​​​​​​​​​​​​​​​​​​​Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe