Change of Occupancy in the International Building Code

by Sean O'Hara on March 17, 2009

In the 2006 International Building Code you are required to apply for a Change of Occupancy whenever a building (or portion of a building) moves from one occupancy category to another. In other words, even if you are not making changes to a building but you are changing the use of a space you may need to apply for a change of occupancy.

For this process, the building needs to meet the requirements for the new occupancy.  Where they are more restrictive than the existing requirements it may mean upgrades.

The building official is allowed to approve the change of occupancy without changes to the building where the new occupancy is less hazardous than the existing use.

This is actually fairly common where spaces are moving between offices, retail and restaurant/bar (assembly) uses in a strip center. It is advisable to consider designing these commercial building types where they can take the most hazardous occupancy.

It is also a big consideration in looking at space for your business if the previous use was lower hazard.

If you think this might apply please contact me for clarification.


{ 39 comments… read them below or add one }

Sean O'Hara December 11, 2011 at 9:37 pm

Hi Ron, what code are you referring to? There are a number of pieces that go into separations between structures. Thanks, Sean

Ron Foreback December 6, 2011 at 5:29 pm

WE have two sets of modular construction Trailers (temporary) and it is unclear as to the spacing beteen the two sets of structures. They are single story and will be set in place for 3 years. I read it as saying the spacing will be 10′ for temproary facilities, but others are telling me it is not so clear. Can yougive me your interpretation?

Sean O'Hara November 29, 2011 at 9:36 pm

Darrel, I’d really need more information to give you good advice. An I-1 can go to 10,500 sf without area modifications, so you may be able to get to the 16,000 sf. The framing choice isn’t an issue in that, you just need to shift the appropriate fire ratings from light gage metal to wood.

Steve Demarest October 4, 2011 at 7:46 am

My struggles with the city continue. They are issuing an updated certificate of occupancy, to include A-2, but it is going to circumscribe the physical location within the building. I have seen temporary CO, but I have never seen one defining the area within the building. Any further thoughts

Darrel Starkey October 3, 2011 at 8:32 pm

I’m wanting to change a 16,000 s.f. Alzheimer facility from Type IIB to Type VA, fully sprinkled. Basically moving from metal trusses and metal studs to all wood frame. Is this generally allowed? Thirty occupants max. on one ground level floor. Thanks.

Sean O'Hara August 6, 2011 at 11:58 pm

Steve, I guess the big question is what was the most recent use. If it was something other than A-2, then it is likely a change of occupancy. At the same time, the change of occupancy may not require that much work.

steve demarest August 5, 2011 at 11:30 am

thanks in advance for considering this question. We have an existing mixed use commercial building. One of the approved occupancies/uses is a beer garden with inside seating. Another approved use is a dentist office and a day spa. We applied for and received a demolition permit to remove the tenant improvements. That left us with an empty space. Now, we are applying for a permit to reconfigure the space for the inside seating for the beer garden. We believe it is a Level 2 Alteration under the IBEC. The City believes it is a change of occupancy. Is there any guidance on this?

judi wright July 30, 2011 at 11:03 am

My husband and I purchased a commercial building in2002. We opened a nightclub and were issued an A-3 299 occupancy certificate. In 2005 we installed a commercial fire alarm system in the building. Building main level is also barely under 12,000 sq. ft. In 2007 we leased building out still with same use.There lease expired in oct.2010 We reopened the business 4 month later in Mar. 2011. The City is telling us that we are required to install a sprinkler system in building because of closure time between business. Or we could accept an occupant load of 99 and now become an A-2. Is there a time requirement in use of building? The Kansas state fire Marshall office believes it to be 1 year. Can local impose there own? And under what conditions.

Mark July 23, 2011 at 11:36 am

Hello, I’m trying to find lease space for a non-profit musical education center. They teach one-on-one lessons to individual students. Ideally, a typical office building set up with small, 10′x10′ offices would be ideal since it will be single student/teacher lesson spaces, so we are looking in several high rise buildings, all Type IA construction, fully sprinklered, so we can go on any floor. There is a requirement that we have a few classrooms that would accomodate numerous students, so I’m sure we will need to classify those as “E” or maybe “A”. Most of the buildings we are looking at are classfied as “B” occupancy. If I were to take a partial floor from one of these buildings, can we simply request changing occupancy for PART of the leased space into E, and leave the rest as “B”? Because if we change it all to “E”, the egress requirements are much too strict for anything we’ve looked at so far, and the pure numbers I’m calculating are crazy, somthing like 5 occupants in a 10×10 room – something we would never have, or 400 total in an 8,000 square foot space, when we never hasve more than maybe 50-60 at a time. In fact, we are going to call each room an office since it will be assigned to a specific instructor. We use IBC 2006.

Sean O'Hara July 12, 2011 at 10:28 pm

Hi Eddie,

Right off, I’m not licensed in Washington State, so this is just general interpretation of the IBC. Being under 750 sf, you are correct, it is a B occupancy. With a total building at 5,000 sf and no residential occupancies, you should be able to call it all “non-separated” and assuming the spaces exit to the outside and there are no corridors, it is unlikely that sprinklers would be required. My suggestion for dealing with the building department is to get it drawn with a code review and you should get straight answers.

Good luck, Sean

Eddie Bedell July 3, 2011 at 1:01 am

I am from Spokane, WA and I recently leased a 500 sq ft space that was previously classified as retail sales/service, as the previous business sold soap. I am converting the building into a small tavern serving only microbrews and wine. It is part of older and larger building, around 5000 sq. ft total, filled with a hair salon, a wig shop, and a couple of music instrument stores. Will it be necessary for me to complete a change of use, since my use is still within the retail sales/service use? My space has 1 bathroom, and after all furniture and equipment is moved in, my customer space will be about 350 sq feet. Also, will it be necessary to install a sprinkler system? It seems that I am an A-2 occupancy, but thebuilding department said that becasue my occupancy will be below 50, I will be a B occupancy. Each time I go to city hall to discuss, I get different answers. The work that will need to be done on the inside is minmal, and includes installing a floor drain and, converting the bathroom to ADA standards, and removing 2 partial non-load bearing walls.


Sean O'Hara January 25, 2011 at 10:27 pm

Hi Rick, it looks like Sheridan is on the 2003 International Building Code. Table 503 holds most of the answer. The big question is whether or not the building is built from combustible or non-combustible. If it is V-B (combustible) or even V-A with the area increases, it can’t be 30,000 sf. In that case it will need to be divided into smaller buildings or sprinkled.

If it is non-combustible construction (Type II) then it is possible if it meets the criteria for area increases to get it to 30,000 sf or greater. They’ll need access to a large amount of the perimeter.

The move from storage to manufacturing is a move to a higher hazard and would trigger a review of the building code. If they don’t want to build fire separations then they’ll need to have the entire building meet the requirements for F-1 to go to a non-separated setup.

They’ll also need to show accessibility to the primary function and the structural requirements meet the manufacturing criteria.

If you have any other questions feel free to give me a call. Direct is 303.322.4964.

Rick Young January 25, 2011 at 3:26 pm


I have a business that purchased an old building that was constructed in the 1970′s. In the mid 2000′s the building was added onto, but never brought into compliance with teh Code. The total square footage is in excess of 30,000 sq’. NONE of the building is sprinkler protected. In the past it was all used for warehouse only. stock moved in and then moved out. The new owner wasnts to use part of it for warehouse and another part for fabrication F-1 – would this be a change in occupancy that could push the new occupant into sprinkler protection or separations in the buildings to reduce the fire areas?

Rick Young

Sean O'Hara April 19, 2010 at 1:50 am

First, for our non-Pennsylvania readers, the UCC (Uniform Construction Code) is the Pennsylvania State Building Code which is basically the 2009 I-Code.

This sounds like a change of occupancy, so even if you had a certificate of occupancy (CO), you would need to get a new one. Sales of prepackaged food sounds like a mercantile occupancy. This will require plumbing and sewer, there isn’t any way around that unless you’re connected to another building that covers it.

If you decide to install the plumbing fixtures, I can help you with the required number of fixtures. Good luck

Jarrett April 17, 2010 at 7:54 pm


I found your website while researching the UCC and hopefully you can answer my question. I live in Pennsylvania and I am interested in purchasing a building that was built in the late 1800′s and used for a general store/post office until the late 1990′s. The current owner uses the building for storage, but
there was never any certificate of occupancy for the building when he purchased it, but it was zoned for commercial use. The building has no water or sewage, and there is no handicapped entrance just a set of 5 steps. Would a building with no plumbing/sewer pass an inspection for occupancy? I would like to open the store and sell “prepackaged” food. The food inspector said I could, but to do so a occupancy permit was required. Any suggestions/comments would help.


Sean O'Hara April 2, 2010 at 11:15 am

Allan, that’s a great question.

First, I’ll admit I’m not familiar with the specifics of the California code, but I think I can help explain.

The provisions in the IBC only apply to the IBC. What you are asking about is the Change of Occupancy in the International Energy Conservation Code. (IECC). This is what the IECC says about change of occupancy:

“Buildings undergoing a change in occupancy that would result in an increase in demand for either fossil fuel or electrical energy shall comply with this code.”

So if you have a case, its all about energy use, my inclination is that a spa may take more energy. However if you are installing new lighting or other items that save you energy you might have an argument that it is a net savings.

Let me know if that covers it, thanks for the question, Sean

Allan April 2, 2010 at 6:57 am

This is a fascinating thread ! (& a terrific website)

UNIT Tenant Improvement (1,100sf) : Going from an “M” to a “B” ( from grocery /mini-market to a therapy/spa – max 8 occupants)

Construction is internal partition walls & lighting & shower – plus convert toilet rm. to ADA.

First comments were simple, but Supervisor took over & decided that since it’s Change of Occupancy, everything needed compliance with CA 2007 (IBC 2006).
I provided Energy LIGHTING code compliance docs, but they want Energy CONDITIONING compliance (there’s no change in the (e)furnace or WH ! )
Changing old furnace & WH (& therefore meeting 2007 Energy Code) would nearly double the project cost.

It seems to me that Change in Occ. only triggers compliance with new code for items that require changes just for that new use, but not everything ?

Then there’s also the equal (or less?) hazard matter – but when I mentioned it, he didn’t really understand (he thought that only applied to fire matters) & I didn’t understand enough to argue it intelligently – but if it is less hazardous, do I have a case ?

Sean O'Hara March 30, 2010 at 1:24 am


It sounds like you’ve spent some time looking at this. To answer your question, I think direct access would be interpreted as the door needs to open to the outside, not into an intervening space. Otherwise they would say that you need to be provided with two means of egress.

That being said, the section states that any classrooms serving children less than 2-1/2 must have direct access to the outside, the classrooms that serve older children do not require this. You should note that any classrooms with more than 10 occupants need two means of egress from each classroom.

I-4 does require sprinklering, though it can be a 13R or 13D system which will be a little less expensive.

Please let me know if you need further assistance, we do have an office in Texas. Sean

Bill March 29, 2010 at 9:59 pm

We are trying to open a daycare facility and would like to take 2 year olds, but the sprinkler system for the I-4 is getting in the way of this project. An exception is if each classroom has direct access to the outside and then you can be rated E. If a room has direct access to a 4 season porch leading to the outside, would that be considered direct access to the outside?

Sean O'Hara March 23, 2010 at 5:18 pm

Alice, the change of occupancy is often a trigger for the building department to require other upgrades in the building. If you were adding a disparate use, like residential, its almost a guarantee. With a similar use that might be negotiable. What I can’t tell you is whether or not there are deficiencies that have to be remedied.

alice March 19, 2010 at 10:02 am

thank you so much!

Yes, the space is quite small. 1350 sq ft.

If you don’t mind…one more question. Is it true that if you change use, you must upgrade the entire building to current building standards?

Sean O'Hara March 18, 2010 at 3:51 pm

Hi, Alice, hope I can help some.

The difference between B and F-1 is about the use of the space. It sounds like you are fabricating a product (woodworking) at the location so it should be F-1. The concern is that your space is full of items that will readily burn; wood and of course varnish and paint thinner. While we don’t think of it as hazardous, it is more hazardous that a business.

However, the interesting thing is that it really shouldn’t matter much to you. A business occupancy does not have to be fire separated from a F-1. They have the same requirements for number of exits too. There is a minor difference where F-1 in a building with a sprinkler system must have an exit in 250 feet vs 300 feet for a B. But that sounds like a much larger space.

If you have a spray room in either occupancy it must be rated 1-hour no matter your occupancy.

You said the space is fairly small so you shouldn’t be pushing the allowable area requirements unless the entire building is very large and you are making it a mixed occupancy.

I hope that helps alleviate your concerns. Good luck , I checked out the website and the jewelry boxes you make are very nice. Sean

alice March 18, 2010 at 2:00 pm

I have just purchased what used to be a restaurant and I want to have my small artisan woodworking business in its place. It is just me, no employees. The building official is considering whether I will be classified as B or F-1. Is there any discretion about this since i am such a small operation?

Also, since this fellow is a little slow in responding, can you tell me where I can find out what upgrades would be needed to make the building F-1 compliant.

Glad I found your site.


Sean O'Hara March 1, 2010 at 1:37 pm

Steve, first let me point out that this is a different type of occupancy than the “occupancy” discussed earlier in the discussion. The rest of the discussion is about occupancy that feeds into exiting and separations and fixture counts. Another confusing bit of the IBC.

What you are asking about is the occupancy category as it relates to structural design. Occupancy category I is structures that represent a low hazard to human life in the event of failure. It includes:

Agricultural facilities (buildings) which are defined as “a structure designed and constructed to house farm implements, hay, grain, poultry, livestock and other horticultural products. This structure shall not be a place of human in habitation or a place of employment where agricultural products are processes, treated or packaged, nor shall it be a place used by the public.” Also certain temporary facilities and minor storage facilities.

Based on that equipment storage, livestock and feed or produce sounds fine. Horse riding areas do not appear to meet the definition. If they include spectator seating or more than 300 occupants, you’re in Type III and anything else is Type II.

Hope that helps, Sean

Steve March 1, 2010 at 12:22 pm


I’m hoping you can clear up the description of the occupancy category “Type I” from IBC2006 table1604.5. My company provides building components for many types of buildings, but it is this category that seems to raise the most questions. Many of the barns we supply are for farms, but I don’t know if that automatically qualifies them as Type I. If we assume each building has a specific use, can we use an occupancy category “Type I” for farm buildings such as:
Equipment storage
Horse riding arenas
Feed or produce storage


Sean O'Hara February 6, 2010 at 6:27 pm


First, I’m going to assume that we’re talking the IBC. I don’t have the code book in front of me today so this is off the top of my head and based on our experience.

If the baking is primarily going to be sold on site then you’re going to be mercantile not manufacturing. The F-1 is really for bakeries that are large scale operations selling through multiple locations.

As far as the difference between A-3 and M, if the area that is dedicated to eating is under 750 sf or 50 occupants then you can look at the exceptions under assembly. Under 750 sf (or 50 occupants) you can stick with the primary occupancy.

A building official that I know at Denver would say “call it a market specializing in baked goods”.

Of course in all cases, now that you have this idea, call the building official and explain what you want to do before you get too committed. While A-3 is about consumption of food and F is about processing as mass production this is still an interpretation of the intent of the code.

Lorie February 6, 2010 at 8:49 am


I am trying to upfit an old building in NC from a previous mercantile occupancy to a retail bakery. It will be used for catering weddings and walk in bakery goods. No sit down eating. What occupancy would this be considered?

This is an old 1905 building which would be hard to create a fire sepparation between the mercantile business next door and an abandoned upper floor that served as a boarding house in the 1930′s. Can it still be considered mercantile?

I am trying to figure out what use it would be because bakeries are listed as F-1 bit this is in a small downtown urban space not for real manufacturing and i do not want to get into calling is a A-2 assembly.

Sean O'Hara December 23, 2009 at 12:03 pm


First a quick caveat, I’m not sure which municipality you are in or what code they use. I’m going to assume 2006 IBC, but that could vary. In the end you’ll likely want to check with them.

A Kumon center is most likely an E occupancy. A church is A-3 unless the space is designed for less than 50 people or is less than 750 sf, then it can be a B occupancy. In any case, it is a change of occupancy.

The big question is going to be exiting. The building department will want to know if you have sufficient exiting because your new use is more intensive. For that we need to know the square footage of the space. In the old configuration you could divide the size of the space by 20, for your use by 7. Then if that number is over 49 you’ll need to have two exits. The exits need to be separated from each other. There are a few other items to check but the number of exits and distance between them is the most critical.

A, E and B occupancies don’t have to be separated from each other within the building.

The other issue that you may run into is parking and the locations zoning. You’ll want to make sure that you have enough parking for a church use.

If you have further questions or need someone to contact the building department, please let us know and someone from our Texas office can get in contact with you.


Rene December 23, 2009 at 7:01 am


We are a small church with about 40 to 43 people max including children. We wanted to rent one of the rooms of a Kumon Learning center here in Texas. The Kumon has occupancy as a Learning Center and with sprinklers, etc. Are we allowed to use the place without applying for a new occupancy? We intend to use the place temporarili until we find a permanent plae on Sunday basis.

Appreciate if somebody could give us explanation.

Sean O'Hara December 10, 2009 at 4:03 pm


I’m going to have to make some assumptions starting with your municipality using the IBC. A cabinet showroom is an M occupancy and a hair salon is a B occupancy. So, yes it is a change of occupancy. But the change from M to B isn’t a big deal, in fact your occupant load will likely go down. If is is a single tenant building (you occupy the whole building) then a 1,500 sf building shouldn’t be a problem for fire ratings. The only question might be zoning and a change of use and that’s mostly a question about adequate parking.

Please let me know if you need more information or someone to help with the design.


Mark Holste December 10, 2009 at 3:20 pm


I recently purchased a 1,500 sq ft, single-story 1930′s retail building to put a hair salon in. The building was a hair salon about 10 yrs ago then purchased and converted to a retail custom cabinet showroom. I am replacing all electrical, HVAC and plumbing, but how can I determine if this requires a change of occupancy group and/or division.



Sean O'Hara November 16, 2009 at 4:57 pm


Because you are increasing the number of occupants I’m not surprised that they asked for a floor plan and code review. Increasing the occupant load has effects on exiting, plumbing, mechanical, fire and a handful of other items. Basically occupancy is all about the number of occupants so I’d say you’re into their processes if you want to make these changes.

Let me know how else I can help, Sean

Bernie Poranski November 16, 2009 at 1:28 pm

I left a message back in April. The Building Inspector never got back to me and now 7 months later, I am back asking some questions. We run a day program for the developmentally disabled. We are a tenant in the building. We have about 6,000 to 6,500 square feet of space. When last we communicated, I categorized us as an A-3. Less than 12,000sf, less than 300 occupants and is on the main level. We are currently rated Maximum Occupancy Load as 30 persons. We are expanding our program and want to increase the Occupancy to 60. The Building Inspector wants us to apply for a zoning permit (Hopatcong, NJ) and then he will inspect all the systems, plumbing, electrical, structrual and fire. He will also require us to have a licensed architectural floor plan, (we don’t have because we were grandfathered in). We have added space twice over the years in 1,500sf and now total the 6,500sf. The program is not changing, just the amount of clents we are servicing. Is the whole Cert of Occupancy procedure necessary to change only the number of people?

Thanks, Bernie

Sean O'Hara September 14, 2009 at 9:23 am

Tony, you’re correct in stating that the IBC uses occupancy and use in the same sentence. There isn’t any easy code section that I can cite to answer your question. I do have some possibilities. First, the certificate of occupancy is issued in the name of the owner of the building, so depending on the rules, a new owner could need a new CO (though I haven’t seen this). Another possibility is that if the new tenant wanted to make changes to the building, they would have to bring it up to code, possibly the F-1 is no longer allowed as the building is currently constructed. Any new permits would trigger a code review. Finally some hazardous materials might concern a code official and make them look at it as a hazardous occupancy, not sure if that is true for your space.

Now I should also point out that there may be options other than sprinkling to meet the code requirements. Just depends on your situation if they make sense.

Tony September 14, 2009 at 8:50 am

A problem I recently encountered was related to a question of the definition of a change in use. In this situation a prospective buyer of a building wanted to move his manufacturing (logic boards, electronic contols for machinery including wood working and snow pushing equipment, tennis ball throwers, etc…. F-1) business into a large building which previously was a manufacturer of wood workking machinery (F-1). The code official required the existing non-sprinklered building to be sprinklered and the business was not able to purchase the building with the cost to upgrade because of a change in use designation. The IBC seems to define change in use by a change in occupancy class or division categories. It does not appear to define a change based upon change in ownership, or variations in the character between the same occupancy categories. Any thoughts?

Sean O'Hara April 29, 2009 at 1:03 pm

The exception is: “A facility where occupants are capable of responding to an emergency situation without physical assistance from the staff shall be classified as Group A-3.” I would say that makes it A-3.

Bernie April 29, 2009 at 12:28 pm

Thanks for your quick reply. If an adult is in a wheel chair and can respond to an emergency situation without physical assistance, only verbal prompting, is this considered A-3?

Sean O'Hara April 29, 2009 at 12:05 pm


The occupancy class would be the first thing to determine. If the adults in your care are capable of responding to an emergency situation without physical assistance then you are a group A-3. If they are not physically capable, it is an I-4 occupancy.

If is is an I-4, it needs to be fully sprinkled, and type 13R and 13D are not allowed. If it is A-3, then it needs to be sprinkled if it is over 12,000 sf, has more than 300 occupants (not you) or is not on the main level.

There are some other implications to knowing your correct occupant load. Feel free to email or call me directly as I’ll need to ask you a few questions.

Bernie April 29, 2009 at 11:35 am

I am renting space for Developmentally Disabled Adult Day Program. We service about 29 clients, all of which are not present at the same time. With Staff, the maximum total is 44. However, history records show 25-30 max on any give day. What would be our intended occupancy use and what are the ramifications in fire systems (sprinklers) with our intended use?

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