Let me first set the stage for this hypothetical examination. For this I will be using the 2006 International Building Code and 2006 International Fire Code. We will be examining whether a structure is required to have a sprinkler system or not based on the fire area. To make it simple, we will not be considering other factors such as corridors, multiple floors or occupancy load, albeit it must be recognized that these items and more can change the requirement for sprinkler systems.
The structure is new construction, typical strip mall style. The total structure square footage is 30,000 sq. ft.; it is occupied by three tenants of group "M" occupancy, each tenant space is separated into 10,000 sq. ft. areas.
The code:
903.2.6 Group M.
An automatic sprinkler system shall be provided throughout buildings containing a Group M occupancy where one of the following conditions exists:
1. Where a Group M fire area exceeds 12,000 square feet (1115 m2);
2. Where a Group M fire area is located more than three stories above grade plane; or
3. Where the combined area of all Group M fire areas on all floors, including any mezzanines, exceeds 24,000 square feet (2230 m2).
Looking at the overall structure at 30,000 sq. ft., it should require a sprinkler system as it exceeds 12,000 sq. ft.
However, enter the following code:
901.7 Fire areas.
Where buildings, or portions thereof, are divided into fire areas so as not to exceed the limits established for requiring a fire protection system in accordance with this chapter, such fire areas shall be separated by fire barriers having a fire-resistance rating of not less than that determined in accordance with Section 706.3.9.
TABLE 706.3.9
FIRE-RESISTANCE RATING REQUIREMENTS FOR
FIRE BARRIER ASSEMBLIES BETWEEN FIRE AREAS
OCCUPANCY GROUP FIRE-RESISTANCE RATING (hours)
H-1, H-2 4
F-1, H-3, S-1 3
A, B, E, F-2, H-4, H-5,
I, M, R, S-2 2
U 1
So based on 901.7 and table 706.3.9, all three tenants can be separated with a fire barrier of no less than 2 hour rating, which creates three independent fire areas of 10,000 sq. ft. each. Thereby bringing us below the 12,000 sq. ft. mark.
However, now enter the caveat; "3. Where the combined area of all Group M fire areas on all floors, including any mezzanines, exceeds 24,000 square feet (2230 m2)."
Correct me if I am wrong here, but even though these tenants are separated by a 2 hour rated fire barrier, the sum of their floor area can be added together, if it exceeds 24,000 sq. ft. the sprinkler requirement is now met?
Now, let's add the following code:
705.1 General.
Each portion of a building separated by one or more fire walls that comply with the provisions of this section shall be considered a separate building. The extent and location of such fire walls shall provide a complete separation. Where a fire wall also separates occupancies that are required to be separated by a fire barrier wall, the most restrictive requirements of each separation shall apply.
TABLE 705.4
FIRE WALL FIRE-RESISTANCE RATINGS
GROUP FIRE-RESISTANCE RATING (hours)
A, B, E, H-4, I, R-1, R-2, U 3 a
F-1, H-3b, H-5, M, S-1 3
H-1, H-2 4 b
F-2, S-2, R-3, R-4 2
So it would seem that according to this, if one of the tenants install a fire wall rated at least 3 hours resistance, that particular tenant would be considered a separate building and therefore it' square footage would no longer be added into the total of the other two tenants?
Instead of 3 fire areas of 10,000 sq. ft. each we now have one fire area at 10,000 sq.ft. that is separated with a 3 hour fire wall from two other 10,000 sq. ft. tenants, each of those separated by a 2 hour fire barrier for a total sum of 20,000 sq. ft.. In this last hypothetical, a sprinkler system would not be required.
Is my understanding of fire areas and sprinkler system requirements for a group M occupancy flawed or correct based on this information? Just trying to learn here, go easy on me. Any help is very much appreciated.
The structure is new construction, typical strip mall style. The total structure square footage is 30,000 sq. ft.; it is occupied by three tenants of group "M" occupancy, each tenant space is separated into 10,000 sq. ft. areas.
The code:
903.2.6 Group M.
An automatic sprinkler system shall be provided throughout buildings containing a Group M occupancy where one of the following conditions exists:
1. Where a Group M fire area exceeds 12,000 square feet (1115 m2);
2. Where a Group M fire area is located more than three stories above grade plane; or
3. Where the combined area of all Group M fire areas on all floors, including any mezzanines, exceeds 24,000 square feet (2230 m2).
Looking at the overall structure at 30,000 sq. ft., it should require a sprinkler system as it exceeds 12,000 sq. ft.
However, enter the following code:
901.7 Fire areas.
Where buildings, or portions thereof, are divided into fire areas so as not to exceed the limits established for requiring a fire protection system in accordance with this chapter, such fire areas shall be separated by fire barriers having a fire-resistance rating of not less than that determined in accordance with Section 706.3.9.
TABLE 706.3.9
FIRE-RESISTANCE RATING REQUIREMENTS FOR
FIRE BARRIER ASSEMBLIES BETWEEN FIRE AREAS
OCCUPANCY GROUP FIRE-RESISTANCE RATING (hours)
H-1, H-2 4
F-1, H-3, S-1 3
A, B, E, F-2, H-4, H-5,
I, M, R, S-2 2
U 1
So based on 901.7 and table 706.3.9, all three tenants can be separated with a fire barrier of no less than 2 hour rating, which creates three independent fire areas of 10,000 sq. ft. each. Thereby bringing us below the 12,000 sq. ft. mark.
However, now enter the caveat; "3. Where the combined area of all Group M fire areas on all floors, including any mezzanines, exceeds 24,000 square feet (2230 m2)."
Correct me if I am wrong here, but even though these tenants are separated by a 2 hour rated fire barrier, the sum of their floor area can be added together, if it exceeds 24,000 sq. ft. the sprinkler requirement is now met?
Now, let's add the following code:
705.1 General.
Each portion of a building separated by one or more fire walls that comply with the provisions of this section shall be considered a separate building. The extent and location of such fire walls shall provide a complete separation. Where a fire wall also separates occupancies that are required to be separated by a fire barrier wall, the most restrictive requirements of each separation shall apply.
TABLE 705.4
FIRE WALL FIRE-RESISTANCE RATINGS
GROUP FIRE-RESISTANCE RATING (hours)
A, B, E, H-4, I, R-1, R-2, U 3 a
F-1, H-3b, H-5, M, S-1 3
H-1, H-2 4 b
F-2, S-2, R-3, R-4 2
So it would seem that according to this, if one of the tenants install a fire wall rated at least 3 hours resistance, that particular tenant would be considered a separate building and therefore it' square footage would no longer be added into the total of the other two tenants?
Instead of 3 fire areas of 10,000 sq. ft. each we now have one fire area at 10,000 sq.ft. that is separated with a 3 hour fire wall from two other 10,000 sq. ft. tenants, each of those separated by a 2 hour fire barrier for a total sum of 20,000 sq. ft.. In this last hypothetical, a sprinkler system would not be required.
Is my understanding of fire areas and sprinkler system requirements for a group M occupancy flawed or correct based on this information? Just trying to learn here, go easy on me. Any help is very much appreciated.
