NFPA 13r 2013 Edition design areas outside the dwelling units when using quick response sprinklers

[SprinklerDesigner2]

Maybe I have been wrong for a number of years but the error, if I am in error, was on the good side.

Ceilings do not exceed 10'-0" in height.

I have a motel with a laundry room of 1,000 sq ft protected by a total of twelve quick response sprinklers. This is obviously OH1 and requires a density of .15 gpm over 900 sq ft.

What I have always done is design the system to provide a density of .15 gpm over area to 900 sq ft which would require nearly all the sprinklers to operate.

7.2* Design Criteria — Outside Dwelling Unit
A.7.2 It is only the intent of NFPA 13R to reference the sprinkler discharge (flow and pressure), number of design sprinklers, and position of sprinklers (distance from walls, ceilings, and other sprinklers) requirements of NFPA 13. Other rules from NFPA 13 such as sprinklering of combustible concealed spaces, hose stream demand, and water supply duration are not intended to be referenced by Section 7.2. It is also the intent of Section 7.2 to apply to those systems or portions of systems that are outside the dwelling unit but have been determined to be considered residential or incidental to residential and within the scope of this standard. (Also see A.1.1.)

I have always done it this way but have I always been wrong, even using quick response sprinklers in an OH area does NFPA #13r limit the number of flowing heads to four?

7.2.2.1 For compartments 500 ft2 (46 m2) or less that meet all of the following conditions and are protected with quick-response sprinklers, the design area shall be permitted to be limited to the number of sprinklers in the compartment but shall not exc eed four sprinklers: The four-sprinkler design in this case applies to both residential and quick-response sprinklers. This requirement was added in the 2010 edition of NFPA 13R. Prior to the 2010 edition, residential sprinklers would have used a four-sprinkler design (or less if fewer than four sprinklers were in the corridor), but quick-response sprinklers would have had a minimum of five sprinklers in the design unless the room design method was being used.

The way I read it, the way I have always read it, is if the compartment is <500 sq ft then the four head design would be used regardless of the occupancy hazard but in compartments 500 sq ft or more I would have to use the area of application from NFPA 13.

I have a Hampton Inn and the dining room is 1,500 sq ft... if I used quick response sprinklers my area of calculation would have to be 900 sq ft but if I used residential sprinklers in the dining area I would use discharge four sprinklers per the head listing.

The more I read it the more confused I become.

 

[TravisMack]

This is from 2013 edition:
6.2.2.1 - A ll sprinklers used outside of the dwelling units shall be in accordance with 6.2.2.
6.2.2.2 Sprinklers outside the dwelling units shall be quick-response, except as allowed by 6.2.2.3 and 6.2.2.4.
6.2.2.3 Residential sprinklers shall be permitted to be used in garages that are accessible only from and directly connected to a single dwelling unit.
6.2.2.4 Residential sprinklers shall be permitted to be used in ordinary hazard areas that meet the following conditions:
(1) The area is compartmented into 500 ft2 (46 m2) or less by 30-minute fire-rated construction.
(2) The sprinklers are spaced at 130 ft2 (12 m2) per sprinkler.
(3) Openings have a lintel at least 8 in. (203 mm) in depth.
(4) The total area of openings, excluding any overhead garage doors that open to the exterior, does not exceed 50 ft2 (4.6 m2) for each compartment.
(5) Discharge densities are in accordance with NFPA 13 for ordinary hazard.

So your premise of using residential sprinklers in your 1500 sq ft dining room doesn't hold since it is outside the dwelling unit and doesn't meet the criteria for using residential sprinklers.

Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, LLC

http://www.mfpdesign.com

 

[SprinklerDesigner2]

I've always used standard quick response sprinklers in areas outside the dwelling units that are Ordinary Hazard and to be on the safe side I've calculated all the sprinklers in the space up to 900 sq ft as the ceilings in these areas are seldom higher than 10'.

I had someone tell me that I could calculate the laundry room using standard quick response sprinklers with a maximum of four heads open. I have a problem buying into this because it is contrary to what I always thought. I always thought that in those areas of Ordinary Hazard Hazard exceeding 500 sq ft you standard quick response sprinklers had to be used and the density and number of heads opened was governed by NFPA #13. If a Laundry room had 1,800 sq ft the density was .15 while the area of calculation would be 900 sq ft when using quick response sprinklers where the ceiling did not exceed 10 ft in height.

But let's take a look at the dining area of a Hampton Inn. I am picking on Hampton Inn because I am sure we've all stayed in one.

I think we can all agree the dining area is light hazard.

The way I interpret the standard is if we use quick response sprinklers the dining area needs an area of calculation would be 900 sq ft assuming the ceiling did not exceed 10 ft in height.

Section 7.2 contains the design criteria for sprinklers protecting areas outside the dwelling unit, such as lobbies, corridors, halls, and foyers that are not contained within dwelling units; basements and storage areas; inside stairwells; and equipment, furnace, trash, laundry, and linen rooms. The user is given several options as follows for determining the discharge criteria for sprinklers protecting areas outside of the dwelling units:

1. Residential or quick-response sprinklers are allowed to be used in corridors. In either case, the design area is the four most demanding adjacent sprinklers (7.2.1.1).
2. Residential sprinklers are permitted to be used in certain spaces that have fire loads similar to the fire loads in residential occupancies. In this case, the design area will be the same as it was for residential sprinklers within the dwelling unit (7.2.3) — all of the sprinklers in a compartment up to the most demanding adjacent four sprinklers. See the commentary on 7.1.1.3 for more information.

Why can't we use residential sprinklers in the dining area? Am I wrong in thinking the fire load would be similar to that in a dwelling unit? I've been to plenty of these and if anything I would think the fire load would be less than the dwelling unit. In the dining area we don't have any bedding and there really is very little in the way of combustibles in the space.

If we use residential sprinklers in the dining area our area of application would be four sprinklers.

The standard clearly states I can use residential sprinklers in areas having fire loads similar to the residential units so I would have to think residential sprinklers in a workout room with a treadmill would be acceptable as well.

 

[TravisMack]

If you can call your dining area a lounge, then 13R states you can use residential sprinklers. I typically only use in corridors leading to dwelling units. I guess I keep that carryover from 13. Everything else is QR.


Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, LLC

http://www.mfpdesign.com

 

[SprinklerDesigner2]

Travis, for those areas using QR the design is per NFPA #13 per the occupancy with a minimum of 900 sq ft assuming the area exceeds 900 sq ft and the ceiling does not exceed 10'-0", right?

For upper floors everything gets residential with the exception of OH areas which is usually limited to janitorial closets. In these areas I have always used QR even in compartments < 500 sq ft. No biggie really.

I had a professional engineer tell me that I could use QR heads in the dining area and the area of calculation would be limited to a maximum of four sprinklers. I disagreed with him but I need to find out for sure. If he is right then I have been practicing over kill for years but I really think I am right.

Am I? An 800 sq ft laundry room must have QR heads and the area of calculation would be the entire room? That is how I interpret it and always have.

 

[stookeyfpe]

I would really enjoy engaging in this discussion. But without an occupancy classification, construction type, building height and area, as well as the building code in effect at the time a building construction was issued, I am absolutely confused.

 

[SprinklerDesigner2]

Off the life safety sheet:

A four story motel with wet manual standpipes and a sprinkler system designed per NFPA 13r.

It's a pet peeve of mine so allow me to make something real clear. The decision as to what the building requires, whether it is a 13 or 13r, is not mine to make but must be left up to the architect of record because it must be his call. I can give a "guess" as to what it might be but it's just that, it's only a guess. Not even an educated guess and I believe it I made the decision as to what standard applied I would be practicing architecture without a license and breaking the law.

I do have a signed letter from the architect of record for this project instructing me to design the sprinkler system per NFPA #13r so I am good with that.

Watched a sprinkler designer make the wrong call on a three story project that wasn't caught until the building was complete with carpet laid. I don't get paid enough to take that responsibility and if it isn't clear on the drawings I want a signed letter telling me what standard to go by and I will take it from there. Sorry for the rant.

 

[MatthewJWillis]

Really enjoying this thread...

I agree with Tmack.
I tend to go with the more stringent as well.
I do feel however, that the Fire Load is a "loaded" description.

R/
Matt

 

[SprinklerDesigner2]

To me it is clear that a 13R system requires a maximum of four heads be calculated in a compartment.

Generally speaking when not using residential heads outside the dwelling unit we will have a calculated area of 1,500 sq ft adjusted for ceiling height which would put most areas at 900 sq ft.

 

[TravisMack]

Scott: All of this is based on the premise that 13R is the correct standard for the project.

Art: In your 1500 sq ft dining area, I can see no way that you get to 4 sprinklers only (without 20' spacing of ex cov sprinklers). NFPA 13R is pretty clear about what you reference and when. For outside the dwelling unit, you are doing QR - with some very specific limits to use residential outside the dwelling units.

As far as calcs, in your 1500 sq ft dining area, permitted all allowances for QR reduction apply, then you are doing 900 sq ft. Note, this is density, spacing and hose allowance only. You are not required to protect concealed combustible spaces outside the dwelling units.

Now, for a wrinkle. In the 800 sq ft laundry area, you can calc the entire area. BUT, you must also check the requirements in Chap 23 that you don't have to add a "phantom flow" to get a minimum discharge for the area.

Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, LLC

http://www.mfpdesign.com

 

[TravisMack]

It's a pet peeve of mine so allow me to make something real clear. The decision as to what the building requires, whether it is a 13 or 13r, is not mine to make but must be left up to the architect of record because it must be his call. I can give a "guess" as to what it might be but it's just that, it's only a guess. Not even an educated guess and I believe it I made the decision as to what standard applied I would be practicing architecture without a license and breaking the law.

While I get where you are coming from, I have to somewhat disagree on this. We can't do something we know is wrong because the architect or other professional of record has been in error of their part. If the architect and engineer instructed you to prepare documents protecting a storage facility at light hazard criteria, I believe you would balk and hold your feet firm.

In my opinion, this is no different on the application of 13 or 13R. The IBC is quite clear. If they are using the sprinkler increase, then a 13 system is required. Now, there are other allowances they can get. In this project, it lists 12k per floor is the tabular value. It then says gross building area is 51,xxx sq ft. So, something doesn't jive for 4 stories. Either they have used the frontage increase to get the building size, or they have selected the wrong standard. Your snip doesn't provide enough information to clarify.

In these cases, when the code study by the architect is not clear, I send an RFI asking for clarification and spell out where the building code says area increase allowed for systems per 903.3.1.1. That is clearly 13. Area increase not permitted for 903.3.1.2 (13R). Just because an architect is wrong, I can't just hide my understanding.

Again, in my opinion, this is no different than when the design team has a building that is 12' floor to deck, 2' deep structure, a 10'-6" ceiling and 2' deep duct. There was just an error and it needs to be addressed.

Don't worry, this is one of my pet peeves, too.

Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, LLC

http://www.mfpdesign.com

 

[SprinklerDesigner2]

Travis, I spotted the 51,738 sq ft which is exactly why I sent an RFI to the architect. I guess the footprint of the building itself is exactly 12,000 sq ft per floor if you do not count the porte cochere which I don't think is attached to the building.

For what it is worth the building permit for the building has been issued by the state fire marshals office and now references a 13r system but didn't when I bid the project.

 

[TravisMack]

I guess this has always been such an issue for me because it is very costly if it is done wrong. Even if the architect calls it 13R, building dept approves it, etc... I've seen jobs, like you said above, at inspection where some one catches it and you are ripping out a ton of stuff. Complete disaster.

Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, LLC

http://www.mfpdesign.com

 

[SprinklerDesigner2]

Which is exactly why I always ask the question... I don't (I will not) be the one to make the mistake because I am not the licensed architect or engineer of record.

Ran into a job three years ago where this actually happened. Specifications/sealed drawings called for a 13r system and having my doubts I asked which is all I can do. Long story short it was a 13 system but a reasonably easy fix except for installing the 600' of new 6" underground.... crossing a highway.... yeah, it got ugly but it wasn't me because I asked.

 

[TravisMack]

Ha ha. Some are worse. All of a sudden, you need to protect the attic and those are often dry systems. It gets real ugly.

Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, LLC

http://www.mfpdesign.com

 

[ButlerNFPA]

Firstly ... If you're inside Canada or the US no unlicensed sprinkler contractor is allowed to even drain a fire system let alone modify said system. It wasnt always this way, living in Canada plumbers etc up until aprox 5 or 6 years ago were able to install sprinkler systems.

Your comments about residential throughout a building including the dining area was correct. Residential heads will not be used outside an individual living unit, be it old age home, condos, hotel etc .. hallways and any publi areas will be sprinkled with commercial style sprinkler heads