NFPA 13R system

[Sifu]

2018 IBC. I have a proposed R2, 3 stories, VB. Proposing a 13R. The floor plate is 21,864sf². The allowable area per t506.2 is 7,000sf² when a 13R is used. The DP is claiming they can use the 13R system allowable area because 903.3.1.2 says a 13R system can be installed. They do take a frontage increase, but it is not relevant to the issue I see. Do I completely misunderstand t506.2 & 903.3.1.2?

 

[RLGA]

They are reading the table incorrectly. "S13R" values are identical to "NS" values. "SM" values are limited to buildings sprinklered per NFPA 13, as stated in the footnotes. Other permitted occupancies within the building are limited to the "NS" values when "S13R" is not shown.

 

[Sifu]

They are reading the table incorrectly. "S13R" values are identical to "NS" values. "SM" values are limited to buildings sprinklered per NFPA 13, as stated in the footnotes. Other permitted occupancies within the building are limited to the "NS" values when "S13R" is not shown.

Their code analysis is the most comprehensive I have seen, and the most wrong in many areas (mostly a lot of copy and past.....maybe AI generated?) Their little blurb on this makes me wonder if they think they get to ignore t506.2 because of 903.3.1.2. When I see a licensed professional architect that has such a difference in understanding from me I wonder if it is me or them. However, the more time I spend on this one it is becoming more clear.

I think 13R is off the table, but I do have other questions about the use of the 13R:

1) They have an A2 on the 3rd floor, it is small but since it must be classified as an A2 even though it could be an accessory occupancy wouldn't that preclude the 13R as well?
2) Outside of the A2, is a balcony, no roof but with a 3' overhang from the roof above. When does an overhang become a roof?
3) If they could use a 13R, would sprinkler coverage not be required because it is not a balcony of a dwelling/sleeping unit?

 

[RLGA]

1) They have an A2 on the 3rd floor, it is small but since it must be classified as an A2 even though it could be an accessory occupancy wouldn't that preclude the 13R as well?
2) Outside of the A2, is a balcony, no roof but with a 3' overhang from the roof above. When does an overhang become a roof?
3) If they could use a 13R, would sprinkler coverage not be required because it is not a balcony of a dwelling/sleeping unit?

1) No. If the Group A-2 occupancy is ancillary to the Group R occupancy, it can be sprinklered using NFPA 13R. For example, a Group R-1 hotel can have a restaurant within the building and be sprinklered using NFPA 13R, provided the building is within the height and area limitations for an NFPA 13R system. This has been supported by NFPA interpretation and commentary.
2) I would be hard-pressed to defend a 3-foot overhang as a roof over occupiable space. If it extended out to cover the entire balcony or a significant portion of the balcony (depending on the size of the balcony), then I would consider it a roof and not a projection per Section 705.2.
3) Section 6.6.5 of NFPA 13R does not require sprinklers unless the balcony serves a dwelling unit. However, Section 6.6.8 of NFPA 13R states, "sprinkler location and position that are not directly discussed in NFPA 13R shall be in accordance with NFPA 13." Section 8.15.1.2.18 in NFPA 13 addresses "Exterior Soffits, Eaves, Overhangs, and Decorative Frame Elements." Sprinklers can be omitted from these areas, except they cannot exceed 4 feet. So, even NFPA 13 would not require sprinklers for a 3-foot eave/overhang.

 

[Sifu]

1) No. If the Group A-2 occupancy is ancillary to the Group R occupancy, it can be sprinklered using NFPA 13R. For example, a Group R-1 hotel can have a restaurant within the building and be sprinklered using NFPA 13R, provided the building is within the height and area limitations for an NFPA 13R system. This has been supported by NFPA interpretation and commentary.

I have read several editions of NFPA 13R, and several opinions about this, but don't see any consistent or definitive answers for this issue. IBC 903.2.1.2 indicates if the A occupancy is not on the level of exit discharge, the 13R system can't be used. Can you point me to the interpretation and/or commentary? All I see in the annex is that if an accessory occupancy s properly separated from the residential occupancy, using 13R for the residential and 13 for the non-residential is appropriate. The condition I have is an accessory occupancy not separated from the residential occupancy. The accessory A is less than 10% of the floor in which it is located, so it could be an accessory mixed use and nonseparated, but if they separate it then the 13 would be required in that space only?

 

[RLGA]

I have read several editions of NFPA 13R, and several opinions about this, but don't see any consistent or definitive answers for this issue. IBC 903.2.1.2 indicates if the A occupancy is not on the level of exit discharge, the 13R system can't be used. Can you point me to the interpretation and/or commentary? All I see in the annex is that if an accessory occupancy s properly separated from the residential occupancy, using 13R for the residential and 13 for the non-residential is appropriate. The condition I have is an accessory occupancy not separated from the residential occupancy. The accessory A is less than 10% of the floor in which it is located, so it could be an accessory mixed use and nonseparated, but if they separate it then the 13 would be required in that space only?

View attachment 13203

I asked this question of NFPA many years ago (nine to be exact) here is the response I received from a fire protection engineer at NFPA:

NFPA 13R is permitted to be used for sprinkler systems in buildings of residential occupancy up to four stories in height. It is still permitted for use in buildings with incidental occupancies, provided the primary occupancy or use is residential. An example would be a hotel with a restaurant and gift shop. NFPA 13R can still be used throughout the building, as indicated in Annex Section A.1.1 provided the building is four stories or less in height and predominantly residential. The use of residential sprinklers outside of the residential portions may be limited per NFPA 13R, although an NFPA 13R system is still permitted throughout the entire building, even the spaces incidental to the residential occupancy.

See Section 6.2.2 for locations where residential sprinklers can be used outside the dwelling unit. If residential sprinklers are not permitted in a portion of the building (a non-residential incidental occupancy), the sprinklers must still quick response although the system as a whole is still considered designed in accordance with NFPA 13R.

The above response is based on the 2013 edition of NFPA 13R. After reviewing the language of Section 1.1 in the 2013 and 2022 editions I have found that they are identical; however, the explanatory information in Annex A has changed over the years. Since the scoping language has not changed, I cannot see how the information in the Annex in the 2013 edition would not still apply.

Section 6.2.2 has changed between the two editions, but I would argue that the changes are not significant--the 2022 edition seems to be a bit more prescriptive regarding where residential sprinklers may be used.

 

[Tim Mailloux]

I asked this question of NFPA many years ago (nine to be exact) here is the response I received from a fire protection engineer at NFPA:


The above response is based on the 2013 edition of NFPA 13R. After reviewing the language of Section 1.1 in the 2013 and 2022 editions I have found that they are identical; however, the explanatory information in Annex A has changed over the years. Since the scoping language has not changed, I cannot see how the information in the Annex in the 2013 edition would not still apply.

Section 6.2.2 has changed between the two editions, but I would argue that the changes are not significant--the 2022 edition seems to be a bit more prescriptive regarding where residential sprinklers may be used.

does this conflict with the IBC and IFC? Table 504.3, 504.4 & 506.2 clearly identify allowable heights, number of stories and area for non sprinklered buildings, sprinklered single story buildings, sprinklered multi-story buildings and buildings with an residential 13R system. The 13R system isnt listed as an allowable option for any of the A occupancioes.

 

[Tim Mailloux]

section 508.1.2 states that Accessory occupancies shall be individually classified in accordance with Section 302.1. The requirements of this code shall apply
to each portion of the building based on the occupancy classification of that space.

section 903.2.1.1 states that where provisions of this code require and automatic sprinkler system, it shall be a full NFPA 13 system unless stated otherwide in 903.3.1.1.1 and 903.3.1.1.2. Neither of those sections get you out of providing a full NFPA 13 system in the A occupancy.

903.3.1.2 allows for NFPA 13R systems in Group R occupances.

 

[RLGA]

does this conflict with the IBC and IFC? Table 504.3, 504.4 & 506.2 clearly identify allowable heights, number of stories and area for non sprinklered buildings, sprinklered single story buildings, sprinklered multi-story buildings and buildings with an residential 13R system. The 13R system isnt listed as an allowable option for any of the A occupancioes.

For occupancy groups without "S13R" values, they must use the "NS" values, since the "S1" and "SM" values require NFPA 13 per Section 903.3.1.1 as stated in the footnotes of each of those tables. Buildings will still be restricted in height and area as any other building, except that Group R buildings can be four stories (except for Type VB). However, if a Group A occupancy was within a predominantly Group R building and the occupancies were nonseparated, then the Group A occupancy would be the most restrictive, thus limiting the height to two or three stories (except for Type VB).

Using the "NS" values for ancillary occupancies in an NFPA 13R sprinklered building seems much better to me than using the "NS" values for a building without a sprinkler system.

 

[RLGA]

section 508.1.2 states that Accessory occupancies shall be individually classified in accordance with Section 302.1. The requirements of this code shall apply
to each portion of the building based on the occupancy classification of that space.

section 903.2.1.1 states that where provisions of this code require and automatic sprinkler system, it shall be a full NFPA 13 system unless stated otherwide in 903.3.1.1.1 and 903.3.1.1.2. Neither of those sections get you out of providing a full NFPA 13 system in the A occupancy.

903.3.1.2 allows for NFPA 13R systems in Group R occupances.

Section 903.3.1.2 states "Automatic sprinkler systems in Group R occupancies shall be permitted to be installed throughout in accordance with NFPA 13R..."

It does not state throughout the Group R occupancy only, which is probably why the NFPA response stated that the building had to be predominantly Group R.

 

[Tim Mailloux]

Section 903.3.1.2 states "Automatic sprinkler systems in Group R occupancies shall be permitted to be installed throughout in accordance with NFPA 13R..."

It does not state throughout the Group R occupancy only, which is probably why the NFPA response stated that the building had to be predominantly Group R.

how do you get around 508.1.2?

 

[Tim Mailloux]

deleted, answered my own question