I'm designing a system with sprinklers at the ceiling of a large open space. There is a vestibule within this space that has a lower ceiling that requires 3 sprinklers. The client does not want pipe drops or hangers above the vestibule to be visible from the rest of the open space.

The proposed solution is to run a branchline down the wall and horizontal tight to the ceiling. Is there a good way to support this that meets the requirements of NFPA 13 chapter 9? The vestibule has CMU walls and metal stud ceiling.

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A building owner has bought a large old warehouse and in about 6-8 months will convert it into educational spaces. They've asked if over the winter they could drain down the large wet sprinkler system as they aren't planning on heating the space or occupying the building during that time. 

I recommended against it since they'd be without protection during that entire time and a fire could result in a total loss of the building. 

I also suggested they speak with their property insurer, couldn't store anything in the building, and would need to talk with the fire department as it would be a system impairment.

Aside from that, what other barriers would they come across? What would you have recommended?

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This project is a residential occupancy (dormitory) with a sprinkler system designed under NFPA 13. The contractor is using residential-style sprinklers within each unit, but standard-spray sprinklers in the corridor.

The corridor has these standard spray sprinklers just off the main which runs down the corridor. The contractor has provided calculations for the four most demanding adjacent residential style sprinklers, which is fine. He's also provided a calculation for the corridor using five sprinklers.

NFPA 13-2016 11.2.3.4.2 states:
11.2.3.4.2 Where an area is to be protected by a single line of sprinklers, the design area shall include all sprinklers on the line up to a maximum of seven. 

Since the corridor's sprinklers are not residential, how many sprinklers should be calculated in the corridor?

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This is giving me heartburn. A clothing manufacturing company wants to store group IV commodities.

16.1.3 Movable Racks. Rack storage in movable racks shall be protected in the same manner as multiple-row racks.

16.2.1.2 Protection Criteria for Rack Storage of Class I Through Class IV Commodities Stored Up to 12 ft in Height.
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16.2.1.2.1 The protection criteria for storage up to and including 12 ft shall be the same as miscellaneous storage from Chapter 13.

The definition of Compact Storage Module does not specify passive protection to qualify as such.

My question is: “Is it correct to treat this rack configuration as moveable racks?”

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Have a flow test in a semi-rural area that has static pressures of over 130 psi but a residual pressure of 60 psi at just 500 gpm.

A flow test from nearly a decade ago shows worse results - with a static of around 120 and a residual of 20 psi at just 600 gpm.

My initial concern with the older flow test was a partially-closed valve or obstruction in the line. 

With the newer test the residual pressure seems more reasonable, but other than something being wrong with the system is there a reason that would justify a residual pressure less than half the static at only 500 gpm of flow? Perhaps a system fed with small pumps and no tower? What are your thoughts?

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NFPA 72 states that audibility from a fire alarm system is required to be provided throughout a building. Most jurisdictions are less concerned with attaining audibility in small, non-normally-occupied rooms such as janitor closets, small electrical rooms, or small mechanical rooms. However, several military reviews have pointed to exactly these rooms and asked how audibility is going to be achieved. 

I typically provide speakers just outside of these groups of rooms such that there should be an achieved audible level, but how could I prove that during the design phase?

Is there any calculation for audible loss through a door or software that could model this loss?

I feel like there's a good handful of variables that play into whether audibility is achieved in these small rooms that may be difficult to predict.

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Is there a complete list of points I need to monitor with fire alarm for a diesel driven fire pump?

I can't seem to find a comprehensive/definitive list in NFPA 20 or 72, but I would imagine at least one or more of the following would need to be monitored by code: fire pump running, primary sensor failure, low fuel level, main disconnect in "off" position, main disconnect in "manual" position, low pump room temperature, flowmeter left on, loss of AC power supply, loss of battery (load side of DC overcurrent), over-speed, and engine trouble (low oil, over temp, other?).

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NFPA 13 (2016 Edition) Section 9.2.1.4.1 states:

9.2.1.4.1 Branch line hangers attached to metal deck shall be permitted only for the support of pipe 1 inch of smaller in size, by drilling or punching the vertical portion of the metal deck and using through bolts.

The Sammy X-Press has listed hangers that call out attachment directly to metal deck for pipe up through 4" in some cases. 

From a code perspective, does the section above not apply, or would this be a code approved alternative? Just looking for the code logic that would allow use of listed special materials where the section above wouldn't trump this method.

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I came across a specification requirement I've never seen before.

The specifications called for "sprinkler systems that require a fire pump to meet sprinkler requirements, all sprinkler pipe sizes shall be based on the Pipe Schedule method. This is to provide maximum sprinkler operation when the fire pump is not available, and minimizes the size of the fire pump. This also provides the possibility that with future water infrastructure improvements, the fire pump would no longer be required."

A few questions about this - first, if the Pipe Schedule method could be used, wouldn't a fire pump not be necessary in the first place?

Second, has anyone ran into something like this before and designed their system that way? For large facilities the only cost savings that comes back with having a fire pump is better pipe sizing. If that goes away, I could see the fire pump being a major cost burden above and beyond what it already is to the owner.

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I have been asked to design a sprinkler system for a 4 story building as per NFPA 13R.  The building has existing standpipes consisting of three 2 1/2” risers.  I am hoping to use the existing standpipe risers to also feed the sprinkler system.  

In this scenario would it make sense to include a hose allowance even though NFPA 13R does not require it?   Also, since NFPA 13R doesn’t require zoning by floor, would it be plausible to have one single “Standpipe & Sprinkler Water Flow Alarm” at the water entry?  

I appreciate and respect your input.  

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Thank you to all forum contributors for September. We're continually seeing an uptick in interest and expertise, and I appreciate your willingness to encourage growth in our industry with your contributions! Here's the top commenters for September:

Being told I need two fire dampers to serve a single fire wall. The fire wall is made of a "double wall", essentially two masonry walls next to each other with a very small (less than 2-inch) air gap in-between. The engineer on the project is stating that this "double wall" requires a fire damper in each.

I've never come across this as a requirement before. Do I need two fire dampers?

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I have an inspector who wants me to prove that calculating run or through tees is appropriate for 13 Residential systems.

I showed them that run tees are in 13D, he thinks they should be calc'd in 13? How do I prove something is not in a code?

Any help would be appreciated.

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Our firm specializes in corporate interiors, buildings retrofits, modernizations, etc. A common problem that we encounter is how to provide sprinkler protection during construction.

As an example, suppose a tenant leases a single floor in a multi-story, fully sprinklered, office building. The design of the new office space requires the existing systems to be gutted and refitted. Ideally, the existing sprinkler system would be demolished to permit new ductwork, plumbing, conduit, etc. to be installed in coordination with the new sprinkler system that is designed to meet the proposed architectural layout and ceiling design. However, most municipalities would not permit the existing system to be demolished unless a fire watch was provided during system impairment. For a project with a construction schedule duration of 12-16 weeks, this could be extremely cost prohibitive.

Currently, the IBC Section 3312 states that the space can only be occupied once the sprinkler system is tested and accepted for service. No guidance is given for protection during actual construction activity (even though the name of Chapter 33 is Safeguards During Construction)

I have spoken with some AHJ’s about the topic. Some offer a solution of providing smoke/heat detection in lieu of the sprinklers during construction while others simply state to “follow the code”.

I see NFPA has a similar code to the IBC (NFPA-241) but it also lacks guidance for sprinkler protection during construction.

In NYC, a solution referred to as a Temp-Loop has been implemented for years. The Temp-Loop consists of a 2-1/2” pipe installed at 7’-6” AFF with heads spaced 12’-0” OC along the pipe, installed close to the ceiling slab. The Temp Loop piping is installed along a single path of egress connecting all egress stairs and elevator openings. The basic concept is to provide a protected path of egress and notify the FDNY should a fire occur. But by the time a sprinkler head is fused, a lot of damage would have already been done.

Have you encountered this situation previously?

I’m trying to get a consensus of what can be done in situations like above that would be mutually agreeable to the AHJ’s, landlords, leasing tenants, EOR’s, etc…

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Are calculated stair widths based on occupant loads based only on a single level that the stair is serving, or a cumulative (total) occupant load for all floors the stair serves? 

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Can I add a fire pump to my combination Manual wet standpipe and sprinkler system and still use a manual wet standpipe?

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I have a fire pump rated at 100 psi at 1000 GPM. The curve for the pump is starts at 125 psi and goes to 0 GPM. I know 140% is the 125 PSI. On my hydraulic calculations should I use the 140% pump curve or should I use the 100% Pump curve? Where in NFPA 13/20 can I find this guidance?

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Can anyone confirm that a "skillet" as mentioned in NFPA 13, 2013 Edition Section A.10.10.2.2.6 is the same thing as a spectacle blind flange?

10.10.2.2.6* Hydrostatic Testing Allowance. Where additional water is added to the system to maintain the test pressures required by 10.10.2.2.1, the amount of water shall be measured and shall not exceed the limits of Table 10.10.2.2.6, which are based upon the following equation...

A.10.10.2.2.6 The use of a blind flange or skillet is preferred for use when hydrostatically testing segments of new work. Metal-seated valves are susceptible to developing slight imperfections during transport, installation, and operation and thus can be likely to leak more than 1 fl oz/in. (1.2 mL/mm) of valve diameter per hour. For this reason, the blind flange should be used when hydrostatically testing.

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I understand per guidance in the annex of NFPA 13 (2016 edition, A.5.3.2(25)) stages are an example of an OH2 hazard, but would this apply in an auditorium/theater with a platform (no curtains)?

5.3.2.1 Ordinary hazard (Group 2) occupancies shall be defined as occupancies or portions of other occupancies where the quantity and combustibility of contents are moderate to high, stockpiles of contents with moderate rates of heat release do not exceed 12 ft (3.7 m), and stockpiles of contents with high rates of heat release do not exceed 8 ft (2.4 m).

A.5.3.2 Ordinary hazard (Group 2) occupancies include occupancies having uses and conditions similar to the following: (25) Stages

I'm not quite clear why a stage is considered an ordinary hazard instead of a light hazard.

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With all our submittals we are required to have a PE review and stamp before submitting to the AHJ.

Has anyone else wondered why it takes two business weeks to get review and approval?

I appreciate the statement that they are being reviewed for quality control yet when I've found errors with approved city drawings and they have no responsibility.

Any opinions? Anyone seeing "pay the fee" and getting immediate AHJ approval?

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I have a few different contractor clients who all operate a little differently. I'd be very interested in others' opinions, especially where it's not a consensus.

When you stocklist, do you pre-cut (1) drops, (2) hanger rods, and/or (3) sprigs?

I've heard different philosophies for different companies. If there's a consistent flat structure then I could see cutting hanger rods in the shop as a time saver, but what's your take? Obviously if the designer gets the measurement wrong or something changes in the field, then there could be far more labor in correcting the pre-cuts then there would be if they were measured and ordered from the field.

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I wonder if you could help me with this we tested a fire pump last week using mini hose monsters. The hose monsters were at an elevation 46’ higher than the pump outlet.

Are there any calcs that I need to do to get an accurate test?

In elevation this is a 20 psi loss plus 130’ of piping to reach the test header (one size larger than required) 8” for a 1000 gpm pump. Any help would be appreciated.

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I'm only a year into the industry, and I'm still pretty green but hungry to learn. 

If you could give one piece of advice to your former self who is one year into the industry, what would it be?

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Can anyone provide me some guidance on how to determine whether or not a chemical fume hood, and associated ductwork, requires sprinkler protection?

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