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NFPA 13D vs 13R

NFPA 13D vs 13R

NFPA 13D vs 13R

I am involved in the AS design for a townhouse project consisting of 24 units which will have independent AS piping for each unit.  Each unit will have 2 stories and there will be 12 units side-by-side and another 12 on top of the others (i.e. there will be 4 stories with one unit on floors 1 & 2 and another on floors 3 & 4).

In reviewing the scope of both 13D and 13R, I can make a case for using either one of these standards.  I have 2 questions:

1. Which of these standards would be applicable to this project?

2. Are there are any major differences between these standards? (Those that I am aware of would not have a major impact on the final cost of the project, with the possible exception of the need for a FD connection.)


RE: NFPA 13D vs 13R

have seen both used

with 13 r there is a question of running pipe through the fire wall, and if one unit burns, does that put your entire system out of service.

than on 13d side do you monitor the systems, do you some how  check to see if they are on, do you check to see if they are maintained.

if you have decided to do a riser for each unit sounds like 13d  

RE: NFPA 13D vs 13R

Be sure to check the building code and make sure the architect did not take any allowances for area increases for sprinklers.  If that is done, you would be looking at a 13 system.

If the units are separate "buildings" you may be able to get by with a 13D system.  Are you going to bring in a separate riser for each unit, or are you wanting to have 1 riser for all of the units combined.

The major differences in the standards are the 2 head vs 4 head calculation requirement.  Additionally, I don't believe you need to have listed valves for the 13D, whereas you do for 13R.

Good luck with the project!!!

Travis Mack
MFP Design, LLC

RE: NFPA 13D vs 13R


NFPA 13D in my community. If the dwellings are constructed under the International Residential Code, NFPA 13D is applicable. If they are constructed using the International Building Code, then NFPA 13R is applicable.

I also concur with Travis's advice. If the architect using the sprinklers to increase the building's area, then a NFPA 13 sprinkler system is required.

Finally, if the townhomes have outdoor decks, the IFC requires sprinkler protection at the deck area.

RE: NFPA 13D vs 13R

This project is in Montreal so the applicable code is the National Building Code (Canada), as modified by the Quebec Construction Code.  I am pretty sure that I can use the definitions provided in those documents to justify using 13D, possibly with some elements taken from 13R.  

I was originally looking for an answer within 13D or 13R but I should have known better as these are standards, not codes.

Thank you all for your replies.   

RE: NFPA 13D vs 13R

As Travis mentions, you don't have to use listed valves and devices. The  bigger cost though is having to install, along with the tampered valve and flow switch required by 13R, fire alarm equipment which I believe then has to be monitored according to NBC. Regarding "code" vs "standard", if NBC requires a building have a sprinkler system installed for example to NFPA 13R 1995 addition, this then does become code.


RE: NFPA 13D vs 13R

Also there is the matter of the 200 psi hydrostatic test required by 13R


RE: NFPA 13D vs 13R

Thank you Dave (lightecho) for your comments.  I just wanted to clarify my comment about "code" vs "standard".

I initially was looking for the NFPA standards to specify whether to use 13D or 13R for this project.  However, they leave that question to the building codes, so I was looking in the wrong place.  Based on the response from stookeyfpe, I see that the answer varies from one jurisdiction to the next.

RE: NFPA 13D vs 13R

To all,

I was just re-reading some of the old posts and this one caught my eye.
I thought that NFPA qualified the unit separation had to be vertical. If there are two units stacked then the horizontal fire separation wouldn't be acceptable and 13R would be the applicable standard.
I am going to try and look this up but wanted to get any feed back before I forgot.


RE: NFPA 13D vs 13R

Based on the information provided in the OP it appears that you will be designing a 13R due to the compartment specifications found in 13R and 13D and your 2 story arrangement for each dwelling unit.......but that's just my opinion if it were in our area of the US.  

Also I agree that the design standard should be found in your country's building code.

"Fire suppression is a failure in prevention"

RE: NFPA 13D vs 13R

Travis said "Be sure to check the building code and make sure the architect did not take any allowances for area increases for sprinklers."

To many sprinkler system layout technicans have a nasty habit of second guessing architectural specifications where you have a three story motel where specifications call for a full 13 system.

Did the architect really mean 13 or did he mean 13R?  I've found sometimes they mean 13 and other times they don't know the difference between the two.  For most motels and hotels it doesn't really mean that much of a difference unless there's a combustible attic or open web wood joists between floors in which cases differences are huge.

This should not be the sprinkler technicians call (we are not qualified) but given the market we need to verify.  When specs call for a full 13 failure to verify could very well mean you don't get the job should unknowing competition submit a bid for a 13R system.  Might not be right but especially now money does talk.

So, if you are one of the architects I've called don't take it personally, I am not questioning your ability I just need to make sure everyone knows it's a full 13 system so there's an even playing field and I got an equal shot.

RE: NFPA 13D vs 13R


The phrase "trust, but verify" comes to mind smile

Hope you had a great weekend.

Travis Mack
MFP Design, LLC

RE: NFPA 13D vs 13R


I have a feeling there's lots of motels across the country that should have full 13 systems in lieu of the 13R systems they got.

Lots of layout technicians spouting "It's a 50,000 sq. ft. motel so I can use 13R to save money".

I've been reviewing the International Building Code Table 202 and in particular the height and building area for R1 use groups, and where I am having trouble is differenciating between Type III A and B for example.

Wish I had a greater understanding, will study more.

Note to registered design professionals: I know it is not my area, not my call and I am incompetent to make such a call but no reason I can't learn something for myself.  The more I know the better layout technician I will be.

RE: NFPA 13D vs 13R


The "A" designation in the construction types indicates that a load bearing element has a minimum fire-resistance rating of one-hour. If the construction type has the "B" designation, the load bearing elements have no rated fire resistance.

I prefer the legacy Uniform Building Code system that used the following terms:

N = no fire resistance
1 = 1 hour rated fire resistance
FR = 2 hour or greater rated fire resistance

If you want me to go into greater detail on Type I-V construction let me know and I'll start putting something together.

RE: NFPA 13D vs 13R


I would find it VERY INFORMATIVE if you could put something like that together.  

Thanks in advance!

Travis Mack
MFP Design, LLC

RE: NFPA 13D vs 13R


I'm still reading up.

Use group R1.

Safest thing would be to look on the architectural drawings to determine what type construction the building was but I've seen some drawings where it wasn't mentioned.  Where it isn't I would assume it was on the permit application but I am rarely privy to that sort of thing.

Assume a four story motel along the lines of a Hampton Inn which most of us have had some experience with.

Most I have seen are wood using wood T-joist or open web wood joists.

Wood stud walls covered with drywall.

With only the information I've given it's probably impossible to determine what Type it is but wouldn't it be safe to assume it would be a Type II, III or IV?

Assuming it is a Type II, III or IV would I not be safe in assuming a 13R would be appropriate as long as the footprint didn't exceed 16,000 sq ft if "B" or 24,000 sq ft if "A"? I haven't gotten into the frontages yet but I assume more frontage or separation between buildings would allow for a larger footprint.  

I am going to spend the weekend reading and then maybe I can ask a coherent question.

This is kind of fun to research though.


RE: NFPA 13D vs 13R

Here's a basic summary of the five IBC construction types:


I have a lot of information on this but I'm apprehensive to post it as part of my salary is based on seminars on these and similar subjects.

SD2: Sounds like your starting to get a handle on it. I'll offer one suggestion: Review sections 903.3.1.1 and 903.3.1.2, because once you understand them, you'll quickly see the limitations of a NFPA 13R versus NFPA 13 sprinkler system.

RE: NFPA 13D vs 13R


That was a huge help.  Thanks for the link!

Travis Mack
MFP Design, LLC

RE: NFPA 13D vs 13R

"SD2: Sounds like your starting to get a handle on it. I'll offer one suggestion: Review sections 903.3.1.1 and 903.3.1.2, because once you understand them, you'll quickly see the limitations of a NFPA 13R versus NFPA 13 sprinkler system."

Thank you much, exactly the sort of thing I was looking for.

I don't need to be spot on correct, that's for the guys that make the big bucks. but I at least want to be able to ask the right questions from those that do know.

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