Dynamic Terminology meanings?

[Mech]

2018 IEBC

IEBC definition Change of Occupancy: A change in the use of a building or a portion of a building that results in any of the following:
1. A change of occupancy classification.
2. A change from one group to another group within an occupancy classification.
3. Any change in use within a group for which there is a change in application of the requirements of this code.
<Commentary>
Changing the occupancy classification in an existing structure may change the level of inherent hazards addressed by the code. For example, a change from a Mercantile occupancy to a Business occupancy renders all Group B provisions applicable to all portions of the structure where the occupancy was changed. In addition, change of occupancy by way of change of use can change the level of inherent hazards (for example, a Group A-2 restaurant change to a Group A-2 nightclub). The classification may be the same, but the risk level has changed. Change of occupancy, whether change of occupancy classification or simply use, is specifically addressed in Chapter 10 of the code.


Is "occupancy classification" in the above definition equivalent to the IBC Overall Use Groups, such as A, B, F, H, S, etc? Is it the Use Group subsets A-1 through A-5, F-1 & F-2, H-1 through H-5, etc.? Or is it all-inclusive A, A-1 through A-5, B, E, F, F-1, F-2, H, H-1 through H-5, M, R-1 through R-4, etc.?

What does "group" from item 2 mean? Is it the subsets, such as A-1 through A-5, F1 & F2, etc? Is it the space utilization such as bank, post office, and professional services (attorneys, dentists, physicians, etc.) in a B Use group? Is it a change of ownership, such as PNC bank moving out and Wells Fargo bank moving in?

In the commentary portion, I am thinking Mercantile "occupancy" would be the space utilization such as Drug Store, Market, Sales, etc. and Business "occupancy" would be space utilizations such as bank, post office, professional services, etc. Then the commentary refers to change of "use" in the third line as switching the space utilization from restaurant and nightclub. It appears this the same as "group" from item 2 in the IEBC change of occupancy definition above.


Section 1011 Change of Occupancy Classification
1011.1 General. The provisions of this section shall apply to buildings or portions thereof undergoing a change of occupancy classification. This includes a change of occupancy classification within a group as well as a change of occupancy classification from one group to a different group or where there is a change of occupancy within a space where there is a different fire protection system threshold requirement in Chapter 9 of the International Building Code. Such building shall also comply with Sections 1002 through 1010 of this code. The application of requirements for the change of occupancy shall be a set forth in Sections 1011.1.1 through 1011.1.4. A change of occupancy, as defined in Section 202, without a corresponding change of occupancy classification shall comply with Section 1001.2.

Is it just me, or does this part of the IEBC alter the meaning of "occupancy classification"? In Section 1011.1, "occupancy classification" appears to mean the space utilization (bank, professional services, post office) while it appears to mean Use Group in the definition Change of Occupancy above. Likewise in Section 1011.1, "group" appears to mean the IBC Use Group while "group" in might be something different in the Change of Occupancy definition above.


<Section 1011.1 Commentary>
Buildings that undergo a change of occupancy classification must meet the requirements of Section 1011. This would include a Group A-2 occupancy changing to a Group A-3 occupancy as well as a Group B occupancy that changes to a Group M occupancy classification group.
Here, it appears "occupancy" means the same as "occupancy classification group" instead of the space utilization.

Do these words have a set meaning or do they change based on the context of the section?

Thanks a million!!!

 

[Sifu]

IMHO:

I have struggled with the verbiage of these sections and commentaries since I first started using the IEBC. I just counted the comments I have placed in the first page of IEBC ch. 10; 6 notes placed by me just trying to understand and justify my interpretations (plus some additional comments in the commentary). It seems that the code AND commentary randomly use "group" in different ways, and sprinkle in other terms for good measure.

I understand the IBC (and by extension the IEBC mish-mash) to mean that A,B,M,S,F,H,R,E,I,U are classifications, some of which have groups, and some don't. So the A classification has 5 groups within the classification, S has 2, F has 2, H has 5, etc. B is a classification, not a group (it has no groups). This seems simple, yet when the codes uses the terms in different ways it creates questions.

Using the quoted commentary from your post as an example:
<Section 1011.1 Commentary>
Buildings that undergo a change of occupancy classification must meet the requirements of Section 1011. This would include a Group A-2 occupancy [A-2 is not a classification, it is a group within classification A], changing to a Group A-3 occupancy as well as a Group B occupancy that changes to a Group M occupancy classification group [Group B & M are occupancy classifications, not groups and there are no groups within a B or M occupancy classification. Note within in the last sentence of this commentary section, they use two different terms: "Group B occupancy" and "Group M occupancy classification group". To me, the last sentence should read this way: "...as well as a B occupancy classification that changes to an M occupancy classification". Group shouldn't even be mentioned.

I think both the code and the commentaries were written from a base-line of this understanding, but they indiscriminately use terms that they understand completely in their own heads, but that when parsed outside of their heads create issues. Both appear to be an attempt to be succinct, which I appreciate, but it may be better to use the exact same terms, consistently. In the end, I understand what an A2 is and a B, so I just overlook the word salad. But, I have had several questions posed to me by DP's and contractors about this, so maybe it deserves some attention.

 

[Joe.B]

Just to offer a different perspective, I think that you could look at it a different way. You're saying that a "B" occupancy isn't a group because there's only one item on the list, but I would argue that it's still a group because there are so many things out there that are classified as "B" occupancy. When you look at it that way then it's pretty easy to call it a "B occupancy group".

 

[Plumb-bob]

A-1 through to F-3 are all occupancy classifications, and the code is largely organized this way. The construction articles in 3.2 refer to classifications, not groups.

 

[Sifu]

A-1 through to F-3 are all occupancy classifications, and the code is largely organized this way. The construction articles in 3.2 refer to classifications, not groups.

View attachment 10969

This is a clear representation based on your codes, something like this might help with ours.

 

[Paul Sweet]

I think the commentary is out of date. Restaurants were moved from A-3 to A-2 several editions ago because most restaurants served alcohol and many had occasional entertainment.

If a restaurant originally permitted as A-3 is changed to a nightclub, then it might become a change of occupancy because it moved from A-3 to A-2 and has a different threshold for requiring sprinklers.

Is Table 3.1.2.1 from the Canadian code? In the IBC A-3 includes art galleries, courtrooms, libraries, and several other occupancies that aren't arenas.