The installation contractor and I have had an argument about how sprinklers should be spaced and calculated in a 13R system.

I have argued that per NFPA 13R Section 7.1.1.3.1, we should calculate 3 sprinklers in the greatest hydraulic demand area. This area is furthest from the riser and the calculation permits 16x16-ft spacing for the area that has the most sprinklers.

Section 7.1.1.3.1:
For each of the following situations, the number of sprinklers in the design area shall be all of the sprinklers within a compartment, up to a maximum of four sprinklers, that require the greatest hydraulic demand:

The contractor wants to remove a sprinkler in a single room and move a sprinkler 10 feet off of the exterior wall, but in NFPA 13R makes no mention of a single sprinkler proof calculation that could justify such a move.

There is no mention of a single sprinkler calculation in NFPA 13R permitting a spacing of 20x20, and so all sprinklers on the project can be only 16x16 if the greatest hydraulic demand is permitting it.

In NFPA 13D, it makes no mention of a single sprinkler calculation either, but does refer to single sprinkler operations in A.10.1. I did not feel comfortable designing a sprinkler system that was not up to code standards and need an outside opinion on this matter. Thanks in advance.

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In the 2015 International Building Code, Section 101.2:

The provisions of this code shall apply to the construction, alteration... of every building or structure in any appurtenances connected or attached to such buildings or structures.

Exception: Detached one- and two-family dwellings and multiple single-family dwellings (townhouses) not more than three stories above grade plane in height with a separate means of egress, and their accessory structures not more than three stories above grade plane in height, shall comply with the International Residential Code.

The debate: Why in the world are we going to allow them to label this design as residential?

The townhouse exception is seemingly being used pretty loosely around the building department.

In our college community, these structures meet the requirements of a townhouse, but with obvious intent to be student housing.

After looking at code....I cant say I blame these designers. I see no way to combat their argument. They meet all the code requirements to avoid the extra costs of a 13R system and only have to add an additional layer of gyp to comply!?

If I am missing something, please let me know! Maybe I just need to accept them as townhouse?

It sure doesn't "feel" right. 

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We are a sprinkler contractor running into a new situation for an apartment building. The apartment is designed under NFPA 13R.

We have an inspector requesting that we firestop a draft stop from the corridor into an apartment.

Can you point us in the right direction whether this is required?

I'm dealing with a situation now where we are completely renovating an old mixed-occupancy property and the plans were drawn and approved with a 2-inch incoming service for both the residential domestic water and the fire suppression system.

Now that the fire sprinkler contractor is ready to install, and the fire chief reviewed plans for the 2-inch pipe, the fire chief says he won't approve it unless we install a minimum of 4-inch incoming pipe from the main.

The architect says the city already approved the pipe size. Fire Marshal says no.

Anyone have code/insight to support either way?

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I am designing a fire sprinkler system for a 5-story residential apartment building.

The building is Type V wood truss construction with 16" open web wood trusses.

The floor/ceiling assembly is a one-hour fire-resistance-rated construction (UL listed). Sheetrock is attached directly to the bottom of the joists with wood subfloor on top. The ceiling is inaccessible (concealed).

The question of sprinkler above the ceiling has come up. I don't see a need for them. There is 6" sound batting above the ceiling.

The Fire Marshal does not allow NFPA 13R design. It an NFPA 13 design.

Is this space required to be protected?

Any input would be helpful, thanks in advance.

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I have a project with four separate apartment buildings with 4-units in each building.

All buildings identified as R-3 Occupancy, Type V-B Construction, single story. There are demising walls between each unit that are 1-hour fire-resistance-rated including a 1-hour draft stop between each unit.

The Architect has noted on the approved plans, "Fire Sprinklers Per NFPA-13D".

My question #1: would NFPA-13D be allowed in these 4-unit buildings?

These are not townhome style zero lot line buildings built independent to one another. I think the project should be designed according to NFPA-13R.

Question #2: One building has a unit designated as a "Laundry room and folding room". I think this single unit should be designed according to NFPA-13 under Ordinary Hazard Group-1, correct?

Thanks in advance for your feedback!

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Assuming that it's been approved by a structural engineer, is there any code or standard restrictions that would prevent running CPVC branch pipe through a built-up floor beam?

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I cannot find a residential sprinkler that will allow for sloped ceilings greater than an 8/12 pitch.

How can we approach this and still provide proper protection in a residential property?

Most log cabins have ceilings with a pitch up to 12/12. Thanks in advance.

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I have a Type V-A Group R-2 apartment building whose code summary indicates as having four stories atop two levels of basement, all of the same construction and occupancy, and requiring a 13R system type.

I’m no expert in the building code, but it's my understanding that in order to have a building taller than four stories and still use 13R, a 3-hour horizontal assembly would be required having Type I construction below such assembly and up to four stories above; this building looks to be Type V throughout six levels with no horizontal assembly.

The large building is vertically separated into four individual buildings by 2-hour fire walls but I see no horizontal separation.

Is there a way this proposed 13R sprinkler system can be code compliant (IBC 2015)?

Thanks in advance.

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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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Can you run sprinkler pipe underground after the riser has entered the building?

The building we're working on is an apartment building that is being sprinklered to NFPA 13R (2016 Edition). The apartment is 4-story and has open air breezeways. There are dry sidewalls protecting the breezeways.

The owner wants to run pipe under the slab in the open air breezeways instead of providing a heated path for sprinkler pipe across the breezeway. I have strongly recommended against this, but have gotten pushback from the owner and contractor regarding this pipe arrangement.

Is this underground arrangement allowed?

I believe there are some cases where this is acceptable but not many. Thanks in advance!

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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?

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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.

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I'm reviewing a apartment building that meets the requirements for an NFPA 13R system.

My questions: A pump is going to be required for this project and they are proposing to use a booster pump on the incoming waterline at the property line to reach the required pressure for domestic and fire demands.

Is a combined domestic/fire pump like this allowed?

It would be a private pump.

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In NFPA 13R, sprinklers may be omitted from bathrooms and closets provided they meet the area and size requirements, and are constructed with limited or non-combustible materials (gypsum/drywall).

Should sprinklers be installed in bathrooms and closets on the top floor regardless of area/size and construction to prevent a fire on the top floor from getting into the ceiling space and spreading?

I have seen other designers do this but I can't find any formal requirements for this approach.

Has anyone else ever done this? Would it matter if the ceiling and roof assembly were fire rated?

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We have a two story apartment building, and we are installing an NFPA 13R wet pipe sprinkler system.

Is an outside hose demand required to be included within the calculations?

There are no inside hose stations.

If outside hose demand is required, is the demand the same as light hazard? 100 gpm?

We couldn't find a reference to this in NFPA 13R.

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13, 13R, 13D: Calculations and High Ceilings

I was reading through NFPA 13 (2016 ed.) and caught Section 8.10.2.2:
Residential Sprinklers shall not be permitted to be used on ceilings with slopes greater than 8 or 12 or ceiling heights greater than 24 feet unless specifically listed for this purpose.

This got me curious about how it affects NFPA 13R and 13D, checking into those I didn't see any restrictions where residential sprinklers stop being allowed at the ceiling height, however the maximum 24-ft ceiling was noted in NFPA 13D (2019) 10.2.1 and NFPA 13R (2019) 7.1.1.3.1 in regards to design sprinklers.

So am I correct in assuming that if you have a residence with a 24'-1" foot ceiling in the family room (say there's a loft second floor), that you now have to calculate and design the space per NFPA 13 rather than 13R or 13D (as that ceiling height is outside of the scope of 13R and 13D)?

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When are standard response sprinkler heads a better choice than quick or fast response heads (5mm vs. 3mm bulb)?

Are there applications where it would be preferable to have a slower response time?

As far as I know, quick and standard response heads cost the same, come with the same k-factors, and the same temperature ratings.

Why would the slower one be chosen? When would you choose a Tyco TY-B instead of a TY-FRB?

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Does code allow the drilling of load-bearing beam in multi-family residential buildings, for the purpose of running sprinkler pipe through it?

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We are getting a plumbing department reviewer's comment that the combined sprinkler/domestic water service cannot exceed a flow of 5 feet per second.

Their justification is that flow above 5 ft/s will negatively impact the "coating" on the inner surface of the copper pipe.

I've never heard of such a concern, and 5 ft/s is far slower than the hydraulic calculations can support. This is for small diameter services on an NFPA 13R project that is 3 stories in height.

The difference in tap fees between a 2-inch combined service (with an automatic domestic shutoff in this case) and a 3-inch ductile iron is at least ten thousand to the owner.

Is there some truth or justification to limit fire sprinkler flow to 5 ft/s on copper pipe?

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Are sprinklers within NFPA 13R required to be quick-response, or can they be standard response residential sprinklers?

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I have inherited a totally fun project, a R-2 III-B multifamily residential building at 27,300 sqft per story, three stories total. I'm on the architect side. 

Our mechanical engineer did a 61G (Florida fire suppression analysis) and designed the central lobby to be under NFPA 13 and the rest of the building NFPA 13R. I immediately thought where are the area separation firewalls, because we are over our allowable area for a III-B. The building is in construction, trusses have been set.

I was told that you can do an area increase in the hydraulic calculations, one with the NFPA 13 portion of the building and one with NFPA 13R add them together and get your increase. I'm calling BS because I cannot find this in the code anywhere, but supposedly this is coming from a FP consultant.

Any clues on the location of this allowance in code?

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I'm designing the fire suppression system for a 6-story wood frame residential building. There will be 6-ft wide balconies made of non- and limited-combustible materials. Normally that would mean sprinklers under the balconies could be omitted, but it occurred to me that people will likely have BBQs and the accompanying propane tank on their balconies.

Would this count as "combustible storage" and thus require sprinklers (dry sidewall heads), or can they still be omitted?

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If a building has an NFPA 13R system and the building is now being converted to a commercial building and does not require a sprinkler system for new construction, can you remove the system?

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I have a project with 90 apartments, and each unit has a recessed telecom (fiber-optic) panel in a closet that would normally not require a sprinkler. The project is under NFPA 13R.

The Authority Having Jurisdiction is requesting sprinklers in these closets, feeling that these are now combustible after the telecom panel is installed. Is anyone else running into this?

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