EasilyConfused
Bronze Member
1st post. Need help getting my head wrapped around some basics. Sorry so LOOOOONG.
In studying the code, it appears to me that an individual space can be designated as (Say S-2 or A-3) for the space itself, BUT if it's part of a mixed use occupancy could fall under the umbrella of "B" for purposes of establishing the primary occupancy. I'm having a hard time getting my head wrapped around the reasons for Occupancy global use vs Occupancy individual room use.
Current building under consideration:
Single story, & the building is about half "B" with the other half "A-3" (can't be "B" because of size) and another smaller portion that is S-2 (can't be "B" because of size).
I'm currently thinking that even though the building will be classified as a mixed use occupancy, The primary occupancy will/should be designated as "B" because, in my mind, that will be the primary use as the "A-3" area will only be used for that purpose on a relatively limited basis. The S-2 area is storage for chairs, tables and such so, again subordinate to the B occupancy.
Am I correct so far?
So, even though the primary occupancy would be established as B, to figure out occupant loads, I need to do individual calculations for the three areas and total these up to arrive at the total occupancy.
Is this correct?
If so, then this is relatively easy for me to understand, and I can use this info (based on sizes of these individual occupancies to establish whether fire separation is required, number of exits req’d, etc based on decisions I make as to separated or non-separated mixed use occupancy, accessory use, incidental use etc.
Here’s where I get confused:
Handling of the large assembly and storage spaces is “easy” to understand because, for all practical purposes, they are individual spaces when compared to the Business designated component of the building where “gross” calculations are used that would include corridors, toilets etc. in the mix. Meaning to do occupant load for B, I include and add up ALL the B space, including accessory use spaces, corridors, toilets etc….. even if those toilets etc are used by occupants in the A3 & S2 occupancy areas.
Now let’s say I have a A 303.1.2_2 “small assembly space” (maybe a smaller conference room) that is under 750SF in addition to the large assembly space (say the large A-3 training room above). Well the smaller space doesn’t have to be designated as “A”, and therefor now becomes a part of the “B” occupancy…..
Therefor that same space would now fall under the umbrella of “B” for figuring out the total occupant load of the building (where the three larger occupancy calculations are added together)….. I think.
So, in the process, now I’ve figured out the total occupant load (combined B, A-3, and S-2), but still have to do individual room area calculations based on occupancy type, in order to determine means of egress requirements. Again, I think. If so, procedure takes me to table 1004.1.2, which lists a lot of individual room use functions that would generally fall under a broader category when determining building occupancy types. So, question is, even though the “small assembly space” falls under the B umbrella for the building occupant loads, does it have to get redesignated as an individual space that is now assembly and calculated individually by table 1004.1.2 or does it remain a B space and is calculated as such by table 1004.1.2?
Similar question surrounding, say, a small coat closet in the “B” area. Does it stay business or does it become “S” for purposes of calculations related to means of egress requirements?
For me to understand this better, I’m wondering about/ thinking that there are 2 separate issues here and they both need to be treated individually, so in my mind, yes, a space could be designated B for determining total occupant load, but would revert back to say, assembly further into the process of code analysis.
Meaning, I establish Primary Building Occupancy, and Mixed Use Occupancy to come up with project criteria for Size of building and separation required and I use individual room occupancies (designated as their real function) to establish egress requirements for a particular portion of the building.
So, say in the business portion of the project I have 2 corrridors where half of the offices (and any accessory spaces) ONLY use one corridor and the other half of the offices (and any accessory spaces) use the other corridor. The way I would go about breaking the whole business space up would be to globally assign business to only the areas accessing one corridor or the other (which would include toilets, the corridor itself, offices etc, and do gross calcualtions for the business specific components of that area of the building, but I would need to separate out any area that is assembly (even though under 750 sf or less than 50 occupants) from the B part but add the occupant load back in with the combined B area to establish total occupant load for that particular corridor.
If this is correct then I think I’m starting to understand this a little. Hopefully this is the case.
Probably a separate question but related….
If I’m understanding all of the above correctly then one other aspect that has me confused is how to handle that same corridor for all those offices and all those assembly spaces if the corridor has 2 exits. Do you assign half of the total occupant load for that area of the building to each of the doors, or can this kind of be finagled in certain proportions to possible advantage. In the end are you basically just presenting what occupants from what rooms you anticipate that would likely use a particular exit and assign that number to the exit? Assuming that however the occupants are rationed out per door, in the end, total occupant load for the building area the corridor serves would need to total whatever the doors etc can handle.
If you were able to get through all (or even some of this) thanks for looking! Hopefully I’m not way out in never never land.
In studying the code, it appears to me that an individual space can be designated as (Say S-2 or A-3) for the space itself, BUT if it's part of a mixed use occupancy could fall under the umbrella of "B" for purposes of establishing the primary occupancy. I'm having a hard time getting my head wrapped around the reasons for Occupancy global use vs Occupancy individual room use.
Current building under consideration:
Single story, & the building is about half "B" with the other half "A-3" (can't be "B" because of size) and another smaller portion that is S-2 (can't be "B" because of size).
I'm currently thinking that even though the building will be classified as a mixed use occupancy, The primary occupancy will/should be designated as "B" because, in my mind, that will be the primary use as the "A-3" area will only be used for that purpose on a relatively limited basis. The S-2 area is storage for chairs, tables and such so, again subordinate to the B occupancy.
Am I correct so far?
So, even though the primary occupancy would be established as B, to figure out occupant loads, I need to do individual calculations for the three areas and total these up to arrive at the total occupancy.
Is this correct?
If so, then this is relatively easy for me to understand, and I can use this info (based on sizes of these individual occupancies to establish whether fire separation is required, number of exits req’d, etc based on decisions I make as to separated or non-separated mixed use occupancy, accessory use, incidental use etc.
Here’s where I get confused:
Handling of the large assembly and storage spaces is “easy” to understand because, for all practical purposes, they are individual spaces when compared to the Business designated component of the building where “gross” calculations are used that would include corridors, toilets etc. in the mix. Meaning to do occupant load for B, I include and add up ALL the B space, including accessory use spaces, corridors, toilets etc….. even if those toilets etc are used by occupants in the A3 & S2 occupancy areas.
Now let’s say I have a A 303.1.2_2 “small assembly space” (maybe a smaller conference room) that is under 750SF in addition to the large assembly space (say the large A-3 training room above). Well the smaller space doesn’t have to be designated as “A”, and therefor now becomes a part of the “B” occupancy…..
Therefor that same space would now fall under the umbrella of “B” for figuring out the total occupant load of the building (where the three larger occupancy calculations are added together)….. I think.
So, in the process, now I’ve figured out the total occupant load (combined B, A-3, and S-2), but still have to do individual room area calculations based on occupancy type, in order to determine means of egress requirements. Again, I think. If so, procedure takes me to table 1004.1.2, which lists a lot of individual room use functions that would generally fall under a broader category when determining building occupancy types. So, question is, even though the “small assembly space” falls under the B umbrella for the building occupant loads, does it have to get redesignated as an individual space that is now assembly and calculated individually by table 1004.1.2 or does it remain a B space and is calculated as such by table 1004.1.2?
Similar question surrounding, say, a small coat closet in the “B” area. Does it stay business or does it become “S” for purposes of calculations related to means of egress requirements?
For me to understand this better, I’m wondering about/ thinking that there are 2 separate issues here and they both need to be treated individually, so in my mind, yes, a space could be designated B for determining total occupant load, but would revert back to say, assembly further into the process of code analysis.
Meaning, I establish Primary Building Occupancy, and Mixed Use Occupancy to come up with project criteria for Size of building and separation required and I use individual room occupancies (designated as their real function) to establish egress requirements for a particular portion of the building.
So, say in the business portion of the project I have 2 corrridors where half of the offices (and any accessory spaces) ONLY use one corridor and the other half of the offices (and any accessory spaces) use the other corridor. The way I would go about breaking the whole business space up would be to globally assign business to only the areas accessing one corridor or the other (which would include toilets, the corridor itself, offices etc, and do gross calcualtions for the business specific components of that area of the building, but I would need to separate out any area that is assembly (even though under 750 sf or less than 50 occupants) from the B part but add the occupant load back in with the combined B area to establish total occupant load for that particular corridor.
If this is correct then I think I’m starting to understand this a little. Hopefully this is the case.
Probably a separate question but related….
If I’m understanding all of the above correctly then one other aspect that has me confused is how to handle that same corridor for all those offices and all those assembly spaces if the corridor has 2 exits. Do you assign half of the total occupant load for that area of the building to each of the doors, or can this kind of be finagled in certain proportions to possible advantage. In the end are you basically just presenting what occupants from what rooms you anticipate that would likely use a particular exit and assign that number to the exit? Assuming that however the occupants are rationed out per door, in the end, total occupant load for the building area the corridor serves would need to total whatever the doors etc can handle.
If you were able to get through all (or even some of this) thanks for looking! Hopefully I’m not way out in never never land.
