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2006 IBC 3410 evaluation on non-separated mixed occupancy

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From the link that **steveray** provided [ from the `09 IBC - Commentary ]:

`09 IBC - Commentary, TABLE 3412.6.16 - MIXED OCCUPANCY VALUESa:

[TABLE=class: MsoNormalTable]

[TR]

[TD]OCCUPANCY[/TD]

[TD=colspan: 3]CATEGORIES[/TD]

[/TR]

[TR]

[TD]a[/TD]

[TD]b[/TD]

[TD]c[/TD]

[/TR]

[TR]

[TD=width: 167] A-1, A-2, R[/TD]

[TD=width: 60]-10[/TD]

[TD=width: 60]0[/TD]

[TD=width: 60]10[/TD]

[/TR]

[TR]

[TD=width: 167] A-3, A-4, B, E, F, M, S[/TD]

[TD=width: 60]-5[/TD]

[TD=width: 60]0[/TD]

[TD=width: 60]5[/TD]

[/TR]

[/TABLE]

[TABLE=class: MsoTableGrid]

[TR]

[TD]a. For fire-resistance ratings between categories, the value shall be obtained by linear interpolation.

[/TD]

[/TR]

[/TABLE]



[TD=bgcolor: #E9E9E9] This table addresses the relative risk of a building in or close to compliance with the provisions for separated mixed occupancies.............When mixed occupancies are not separated from each other, the risk from hazards is greater in high-density occupancies, such as Groups A-1 and A-2........This risk is also greater in residential occupancies, because occupants may be sleeping and not fully alert. For this reason, inadequate separation is given greater negative values. ........In buildings with lower occupant loads, and where the occupants are alert, the risks are relatively lower. [/TD]


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Last edited by a moderator:
This still doesn't answer the question of the F occupancy area not requiring sprinklers. If I look at the F occupancy area (3500sf) as part of the total "fire area" of 7000sf that also contains an A-2 occupancy area, then I believe the F requires sprinklers. They are stating the F occupancy evaluation is on a 7000sf F "fire area" and doesn't require sprinklers.
 
So they are interpreting Section 3410.6 where it states "In applying this section to a building with mixed occupancies, where the separation between the mixed occupancies does not qualify for any category indicated in Section 3410.6.16, the score for each occupancy shall be determined and the lower score determined for each section of the evaluation process shall apply to the entire building." to mean that they first look at the entire building ("fire area") as an A-2 occupancy. Then they look at the entire building ("fire area") as an F-1 occupancy. Then they determined the F-1 occupancy doesn't require sprinklers because the building ("fire area") is less than 12000sf.

I interpret that when evaluating "each occupancy" per 3410.6.16, that you look at the actual occupancy area (not the entire building area or "fire area"). So I look at the A-2 "occupancy area" of 3500 sf and determine that because it is within a "fire area" over 5000sf, it requires sprinklers. Then I look at the F-1 "occupancy area" of 3500sf and determine that it too is within a "fire area" over 5000sf that contains an A-2 and therefore the F-1 "occupancy area" requires sprinklers as well.
 
cballinger said:
This still doesn't answer the question of the F occupancy area not requiring sprinklers. If I look at the F occupancy area (3500sf) as part of the total "fire area" of 7000sf that also contains an A-2 occupancy area, then I believe the F requires sprinklers. They are stating the F occupancy evaluation is on a 7000sf F "fire area" and doesn't require sprinklers.
Click to expand...
Are the possibly saying base code would not require sprinklers in a 7000 sq ft F???

903.2.4 Group F-1. An automatic sprinkler system shall be provided throughout all buildings containing a Group F-1 occupancy where one of the following conditions exists:

1. A Group F-1 fire area exceeds 12,000 square feet (1115 m2).

2. A Group F-1 fire area is located more than three stories above grade plane.

3. The combined area of all Group F-1 fire areas on all floors, including any mezzanines, exceeds 24,000 square feet (2230 m2).
 
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Which code section(s) are you citing \ interpreting to require the

sprinkling of the F designated area ?

cda,

That is what I was thinking also !

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I'm saying, the sprinkler requirement isn't based upon the "fire area" being an F-1 "fire area". The F-1 "occupancy area" is not separated from the A-2 "occupancy area". The sprinkler requirement for the F "occupancy area" is due to the fact that it is part of a "fire area" containing an A-2 occupancy. Big difference between an "occupancy area" and a "fire area"....
 
I cited them on section 3410.6.17, with the explanation that the F-1 "occupancy" requires sprinklers because it is not separated from the A-2 "occupancy", referencing Section 508.3.2.1 and Section 903.2.1.
 
They have interpreted that when evaluating non-separated mixed occupancies, you would evaluate the entire building as A-2, then the entire building as F, and then choose the value for each and use most restrictive in the overall scoring.
Click to expand...
not correct

I am saying, you can't evaluate the entire building as a single occupancy and not take into consideration other occupancies in the building when there is no separation
Click to expand...
Not correct

3410.6.....In applying this section to a building with mixed occupancies, where the separation between the mixed occupancies does not qualify for any category indicated in Section 3410.6.16, the score for each occupancy shall be determined and the lower score determined for each section of the evaluation process shall apply to the entire building



They should be evaluating the entire building as an A-2 through out the entire evaluation process

Where the separation between the mixed occupancies qualifies for any category indicated in Section 3410.6.16, the score for each occupancy shall apply to each portion of the building based on the occupancy of the space.



3410.6.16 Mixed occupancies.

Where a building has two or more occupancies that are not in the same occupancy classification, the separation between the mixed occupancies shall be evaluated in accordance with this section. Where there is no separation between the mixed occupancies or the separation between mixed occupancies does not qualify for any of the categories indicated in Section 3410.6.16.1, the building shall be evaluated as indicated in Section 3410.6 and the value for mixed occupancies shall be zero.
 
When interpreting 3410.6, where it states "the score for each occupancy shall be determined" you are interpreting that to mean that they should evaluate the "entire building" (7000sf fire area) as an A-2 and the "entire building" (7000sf fire area) as an F.... my question is why? I interpret it to mean that you evaluate each "occupancy", as in, the 3500sf area of that "occupancy". Where does it say I should evaluate the "entire building" as the occupancy. It doesn't. It says I should evaluate the occupancy, then the lower score for each section shall apply to the entire building.
 
In other words, you evaluate each "occupancy area", then take the lower score of each section and enter into Table 3410.7 for the overall building scores.
 
cballinger said:
In other words, you evaluate each "occupancy area", then take the lower score of each section and enter into Table 3410.7 for the overall building scores.
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not a chap 34 person, but you all may be saying the same thing just different terms.

hope this is stated correctly::

from an outsider on regular non seperated use, the stricter of the occupancies applies to the entire building. So basicly you have the same thing in what you are looking at. The A occupancy requirements apply to the entire building, which kicks in the fire sprinkler requirement for th entire building. The F is just along for the ride.
 
There is a big difference between an "occupancy area" and a "fire area". The fire area is dependent upon fire rated separations. The occupancy area is just the area in a space designated for a particular use.

But that's my point exactly, the F occupancy is required to be sprinklered because it is not separated from the A-2.
 
cballinger said:
There is a big difference between an "occupancy area" and a "fire area". The fire area is dependent upon fire rated separations. The occupancy area is just the area in a space designated for a particular use.But that's my point exactly, the F occupancy is required to be sprinklered because it is not separated from the A-2.
Click to expand...
Ok and? like I said I think you all are saying the same thing, just in a different way
 
"""""""They, on the other hand, have interpreted that when doing the evaluation, you should look at the entire building as an A-2 and then the entire building as an F to determine sprinkler requirements. So, they are saying, if you look at the entire building as an F occupancy, then it wouldn’t require sprinklers and used category c for a value of 0. They then used the A-2 value of -4 as most restrictive for the section."""""""""

so the answer to them is they are wrong.

just have them look at the regular non seperated use and I would say it has the same language.

Once again not a chap 34 person
 
The people I'm in disagreement with are saying, for the 3410 evaluation process, the F occupancy isn't required to be sprinklered because of how they are interpreting Section 3410.6, which determines how the occupancies are evaluated. You can't evaluate the whole building as an F and the whole building as an A-2 because there are two non-separated occupancies in the building. You can evaluate each occupancy area, with consideration that it is not separated from the other occupancy area.
 
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If you desire, you could call the ICC Technical Staff and speak with them

for their interpretation.

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From the 2009 commentary......The evaluation of sprinklers in an existing building is based on whether an automatic sprinkler system is both required and installed. The criteria used to determine when an automatic sprinkler system is required are tied to the same requirements for new construction in Section 903. The thresholds listed in Sections 903.2 through 903.2.12 must be used to evaluate whether those characteristics and occupancies are present and whether a sprinkler system is needed.

Haven't they already lost points for not having the proper seperation in a previous section of analysis?

Section from 2009...

TABLE 3412.6.16 MIXED OCCUPANCY VALUESa

OCCUPANCY CATEGORIES

a b c

A-1, A-2, R -10 0 10

A-3, A-4, B, E, F, M, S -5 0 5
 
These 19 safety parameters are focused on critical factors related to the minimum degree of life safety and property protection needed in an existing building.

When mixed occupancies in an existing building are not separated by fire-resistance-rated assemblies or fire walls meeting the most restrictive fire rating of the different occupancies, the entire evaluation must be based on the occupancy with the most restrictive requirements.
 
After reading and re-reading the commentary on 3410.6.17 and 3410.6.17.1 Categories I am in agreement with you analyses

Category "A" is the correct one for both occupancies because as you have pointed out the fire area exceeds the requirements of 903 for an A-2 use and a fire sprinkler system is required throughout the entire fire area

No sprinklers through out the entire building puts both occupancies in a category "A" for evaluation
 
steveray said:
From the 2009 commentary......The evaluation of sprinklers in an existing building is based on whether an automatic sprinkler system is both required and installed. The criteria used to determine when an automatic sprinkler system is required are tied to the same requirements for new construction in Section 903. The thresholds listed in Sections 903.2 through 903.2.12 must be used to evaluate whether those characteristics and occupancies are present and whether a sprinkler system is needed.Haven't they already lost points for not having the proper seperation in a previous section of analysis?

Section from 2009...

TABLE 3412.6.16 MIXED OCCUPANCY VALUESa

OCCUPANCY CATEGORIES

a b c

A-1, A-2, R -10 0 10

A-3, A-4, B, E, F, M, S -5 0 5
Click to expand...
No, they did not lose points in this section because, "where there is no separation between mixed occupancies or the separation between mixed occupancies does not qualify for any of the categories indicated in Section 3410.6.16.1, the building shall be evaluated as indicated in Section 3410.6 and the value for mixed occupancies shall be zero."
 
north star said:
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If you desire, you could call the ICC Technical Staff and speak with them

for their interpretation.

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Click to expand...
I had thought about requesting a Technical Opinion from ICC, but I figure I'll be lucky if I get any better answer from "staff" than I would get here unless I get lucky and someone responds that was familiar with the development of Chapter 34. I'm probably going to request one though anyway. I'll post here if I find out any new relative info.
 
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