# Multiple occupancy classification of tenant space



## leothebuilder (Feb 20, 2017)

I have a difference of opinion with a colleague.
We have a tenancy of approximately 2500 s.f. of which half is mercantile (phone store) and the remainder is office space and break room plus a 140 s.f. secure store room.
I believe we should have a mixed occupancy classification of M-Mercantile and B-Business and calculate the occupancy load according to M and B. Ancillary occupancies are limited to 10% in area and when larger should be individually classified.

He believes that the main occupancy is M-Mercantile and thus the remainder of the area is ancillary and the occupant load should be 1 per 60 for the public area and the remainder at 1:300 for stock and shipping (2016 codes apply)

The additional question is that per code the maximum distance to a single exit is 75 feet for M-Mercantile which he believes should be the limit while I believe that from the B-Occupancy parts the distance can be 100 feet to a single exit (sprinklered)


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## RLGA (Feb 20, 2017)

You say the "2016 codes apply" -- What 2016 codes? The latest IBC edition is the 2015 edition, so you must be referring to codes adopted by a jurisdiction, which could be any IBC code edition. In my response below I'm assuming the 2015 IBC.

The building is a mixed occupancy building with Group M, Group B, and Group S-1. However, since this is a tenant space within a larger building, you have to look at the impact of the new tenant space on the occupancy classification of the existing building. The 10% limitation applies to the aggregate area of all accessory occupancies within a story and not just within the tenant space; therefore, you have to understand what is happening within the rest of the building.

In regard to allowable area, the Group M will probably be the most restrictive, so you could consider the tenant space a Group M nonseparated occupancy, but you'll need to see how allowable area is determined on the original building documents. Things to consider: construction type, the installation of a sprinkler system throughout the building, the presence of fire walls (if any), and the presence of existing fire barriers for occupancy separation (if any).

As for occupant load, the occupant load factors are based on the function, which does not necessarily align with a particular occupancy group (i.e., you could have an assembly use in a non-Group A occupancy, such as a conference room in an office building). The actual retail area will use the 60 s.f./occupant factor, the office areas will use the 100 s.f./occupant factor, and the storage room will use the 300 s.f./occupant factor. All are based on the gross floor area. So, using the floor areas you provided, the occupant load of the tenant space will be about 22 to 24.

Travel distance for Groups M and S-1 is 200 ft. (250 ft. if sprinklered), and for Group B it is also 200 ft., but 300 ft. if sprinklered. If only one exit is provided, then the common path of egress travel distance is limited to 75 ft.; however, Groups B and S can have a CPET distance of 100 ft. with the installation of a sprinkler system through the building.


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## cda (Feb 20, 2017)

leothebuilder said:


> I have a difference of opinion with a colleague.
> We have a tenancy of approximately 2500 s.f. of which half is mercantile (phone store) and the remainder is office space and break room plus a 140 s.f. secure store room.
> I believe we should have a mixed occupancy classification of M-Mercantile and B-Business and calculate the occupancy load according to M and B. Ancillary occupancies are limited to 10% in area and when larger should be individually classified.
> 
> ...




so what is the length and width of the entire  space???


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## leothebuilder (Feb 20, 2017)

RLGA said:


> You say the "2016 codes apply" -- What 2016 codes? The latest IBC edition is the 2015 edition, so you must be referring to codes adopted by a jurisdiction, which could be any IBC code edition. In my response below I'm assuming the 2015 IBC.
> 
> The building is a mixed occupancy building with Group M, Group B, and Group S-1. However, since this is a tenant space within a larger building, you have to look at the impact of the new tenant space on the occupancy classification of the existing building. The 10% limitation applies to the aggregate area of all accessory occupancies within a story and not just within the tenant space; therefore, you have to understand what is happening within the rest of the building.
> 
> ...





cda said:


> so what is the length and width of the entire  space???



I forgot to mention that this is 2016 California Building Code.
The total building area is 4,750 s.f. but I am not sure what the adjacent space will be as this is an existing building to be re-demised. My assumption would be that the vacant space is likely to be a B or an M occupancy.
Given the total building area of 4,740 s.f and that it is sprinklered I don't believe maximum areas will be a problem.
From your response I can now assume that we should consider these B and M occupancies and the small store room should remain an accessory use as it is less than 10% of the building area. 
It also reinforces my assumption that I can assign different exit distances based on each occupancy. 
I would use the non-separated occupancies per 508.3 although separating M from B does not appear to much of a problem.
Thanks for your concise response.


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## cda (Feb 20, 2017)

So what is the length and width of the space ??

70 by 65??

Longer skinnier ????


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## leothebuilder (Feb 20, 2017)

cda said:


> So what is the length and width of the space ??
> 
> 70 by 65??
> 
> Longer skinnier ????




It's an odd shape. Imagine a building that is half a circle. The tenant space is approximately a quarter circle. The width is approx. 55 feet by approx. 70 feet deep with a single exit.


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## leothebuilder (Feb 21, 2017)

cda said:


> So what is the length and width of the space ??
> 
> 70 by 65??
> 
> Longer skinnier ????


I forgot to mention, the B-occupancy needs to exit through the M-occupancy to reach the single exit door.


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## mark handler (Feb 21, 2017)

What is the Common Path of Egress Travel?


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## leothebuilder (Feb 21, 2017)

mark handler said:


> What is the Common Path of Egress Travel?


There is only one exit, so I don't think common path applies.
The max travel distance from the M-occupancy is 51 feet which is well within the 75 feet max allowable
The max travel distance for the B-occupancy is 98 feet, close to the 100 feet max allowable, but the travel
from the B-occupancy passes through the M-occupancy to the single exit.


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## RLGA (Feb 21, 2017)

Common path of egress travel distance does apply, since there is only one exit. In this case travel distance and CPET are the same with the CPET requirements being the most restrictive.


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## cda (Feb 21, 2017)

leothebuilder said:


> There is only one exit, so I don't think common path applies.
> The max travel distance from the M-occupancy is 51 feet which is well within the 75 feet max allowable
> The max travel distance for the B-occupancy is 98 feet, close to the 100 feet max allowable, but the travel
> from the B-occupancy passes through the M-occupancy to the single exit.





So what is the problem or question??


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## leothebuilder (Feb 21, 2017)

cda said:


> So what is the problem or question??


The questions are in the first posting which have been answered by RLGA, thanks


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## wunaswerve (Feb 8, 2022)

This is an old thread but it never hurts to add information to an important topic. 

Section 1004.4 - Where a building contains two or more occupancies, the means of egress requirements are considered for each portion of the building individually and based on the occupancy.  If two occupancies utilize the same means of egress, the more stringent requirements for the egress components are to be used for all occupancies served. 

So, yeah, for occupant load: business (100-150 depending on the code) for back of house and mercantile (30-60 depending on the code) for front of house. sales The storage could be at 300. That is spot on to create the occupant load count.

For exit travel distance, I would agree that CPET distances would be used for a single exit tenant space.  In the scenario described, since there is only one exit and the most stringent occupancy is Mercantile, I would interpret that the maximum CPET would be 75' sprinklered or not. 

In an alternate scenario where the BOH had its own exit, I would think that 100' could be applied as long as the building were sprinklered.


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## fatboy (Feb 9, 2022)

Welcome wunaswerve!


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## Genduct (Feb 9, 2022)

leothebuilder said:


> I have a difference of opinion with a colleague.
> We have a tenancy of approximately 2500 s.f. of which half is mercantile (phone store) and the remainder is office space and break room plus a 140 s.f. secure store room.
> I believe we should have a mixed occupancy classification of M-Mercantile and B-Business and calculate the occupancy load according to M and B. Ancillary occupancies are limited to 10% in area and when larger should be individually classified.
> 
> ...



Interesting Situation
If the 2 spaces are in fact separated with a Rated Wall/ Assembly, why not just review as 2 seperate spaces that stand on their own?

Actually for such a small space, subject to future tenants, I like the idea of using the most restrictive to guide the design,  This will simplify future tenant changes where the least restrictive space get re-leased and making for a complicated future review for a new tenant


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## Paul Sweet (Feb 11, 2022)

Why not use 1 per 60 for the entire space?  You would still be under 50 occupants, and would make future tenant changes (other than a restaurant) simple.  Or is he trying to get away with a single toilet?


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