Occupancy Classifications
Part One
By Kerwin Lee, AIA, CASp
One of the basic fundamental in the building code is occupancy classifications. Occupancy classifications or use within a building helps to establish the hazard level, fire and life safety, based on the use or uses. A factory could be more hazardous than an office use. Chapter 3 provides the definition and classification of uses within a building and laying the ground work for how the building needs to be constructed to protect the occupants and the building.
We will assume that everyone understand the basic occupancy classification in the code. If not, read through Chapter 3 to understand the basic for each type of classification; A/assembly, B/business, E/education, F/factory, H/hazardous, I/institutional, L/laboratory (California only), M/mercantile, R/residential, S/storage and U/utility. Every building will have a primary occupancy classification. Very few buildings will have only one use classification. Most buildings will have multiple occupancies under one roof. These are mixed use buildings. A B/office use will sometimes have an assembly space, like a conference room or even a cafeteria, which could be an A/assembly uses. In addition there may be S/storage space, F/factory or a mechanical room that can be classified as an F/factory use. Sometime a room or space can have multiple uses. A school gymnasium is an exercise classroom; it also can be used as an assembly space or even a cafeteria/dining space. So how does one classify this use? It is then up to the user or designer to classify the space based on the most risk or hazardous as viewed by the code. This would be fire hazard and risk to the type and number of occupants. It would be appropriate to classify this gym as an assembly use for determining exiting and other life safety requirements.
When a building has a number of uses in it, the code could require fire barrier separation between different types of uses or occupancy classifications. This takes us to Chapter 5 and Section 508 for Mixed Use and Occupancy requirements. Once you have established or labeled each space/room, the code wants to determine if any separation is required between uses. Table 508.4 lays the ground rules for occupancy separation between certain types of uses. For example, the Table requires a 1-hour fire separation between A or E to a B occupancy in a building with an automatic sprinkler system (S at the heading of the column). This code approach is for “separated occupancies”, under Section 508.4.
If having physical separations a hindrance to the design or functional use of the space, there are options to eliminate the physical separation.
• Classification as an Accessory occupancy under Section 508.2. These are ancillary uses to the main occupancy, usually less than 10% of the building area on a given floor. There are limitations under the height and area provisions of the code in using this approach.
• Another method is to use the “Non-separated occupancy” provisions of the code, under Section 508.3. What this section says is if the building is designed to the most restrictive occupancy classification for height and area, then occupancy separations are not required. If the building is a B and F occupancies and the design complies as a F use for the entire building, no separations are required between the B and F uses.
• One other code section to look at is Section 509 for “Incidental Uses”. Here the code allows certain type of small uses where separation may be reduced or eliminated based on Table 509.
There are many exception and specific rule associated with occupancy separations. For these you will have to read the code and find what may be applicable to your project.
Part Two
By Erick Mikiten, AIA
When you’re working out occupancies on existing buildings, keep in mind that any change in occupancy is considered an Alteration (Section 202 Definitions). That means that even if your client is just doing cosmetic work that wouldn’t normally be an Alteration (such as normal maintenance, reroofing, painting, or mechanical and electrical system changes), the change in occupancy alone classifies it as an Alteration.
This is important because for Alterations, 11B-202.4 provisions apply. This states that “When alterations or additions are made to existing buildings or facilities, an accessible path of travel to the specific area of alteration or addition shall be provided.” The Division of the State Architect (DSA) has an Advisory that says that “When a building or facility undergoes a change of occupancy, the entire building or facility (or portion thereof) is considered the area of alteration. The entire building or facility (or portion thereof) must be upgraded to comply with current accessibility requirements for new construction.”
The priorities of the Path of Travel upgrades are primary entrance, toilet and bathing facilities, drinking fountains, public telephones, and signs. See Section 11B-202.4 for more information, including many listed exceptions.
More and more cities require drawings documenting the existing non-conforming conditions, in addition to the new proposed work. This gives them a reference document for future remodels, and allows the plan checker to have all the information needed for negotiating with you which pieces should be upgraded, which might include elements that were in compliance when built, but that don’t meet the current code.
So the bottom line is that if a client comes to you just wanting help with a change of occupancy, do your research, talk to the building official about what accessibility upgrades they might reasonably require before your client just gets a Zoning approval for a change of occupancy and starts moving in.
By Kerwin Lee, AIA, CASp
One of the basic fundamental in the building code is occupancy classifications. Occupancy classifications or use within a building helps to establish the hazard level, fire and life safety, based on the use or uses. A factory could be more hazardous than an office use. Chapter 3 provides the definition and classification of uses within a building and laying the ground work for how the building needs to be constructed to protect the occupants and the building.
We will assume that everyone understand the basic occupancy classification in the code. If not, read through Chapter 3 to understand the basic for each type of classification; A/assembly, B/business, E/education, F/factory, H/hazardous, I/institutional, L/laboratory (California only), M/mercantile, R/residential, S/storage and U/utility. Every building will have a primary occupancy classification. Very few buildings will have only one use classification. Most buildings will have multiple occupancies under one roof. These are mixed use buildings. A B/office use will sometimes have an assembly space, like a conference room or even a cafeteria, which could be an A/assembly uses. In addition there may be S/storage space, F/factory or a mechanical room that can be classified as an F/factory use. Sometime a room or space can have multiple uses. A school gymnasium is an exercise classroom; it also can be used as an assembly space or even a cafeteria/dining space. So how does one classify this use? It is then up to the user or designer to classify the space based on the most risk or hazardous as viewed by the code. This would be fire hazard and risk to the type and number of occupants. It would be appropriate to classify this gym as an assembly use for determining exiting and other life safety requirements.
When a building has a number of uses in it, the code could require fire barrier separation between different types of uses or occupancy classifications. This takes us to Chapter 5 and Section 508 for Mixed Use and Occupancy requirements. Once you have established or labeled each space/room, the code wants to determine if any separation is required between uses. Table 508.4 lays the ground rules for occupancy separation between certain types of uses. For example, the Table requires a 1-hour fire separation between A or E to a B occupancy in a building with an automatic sprinkler system (S at the heading of the column). This code approach is for “separated occupancies”, under Section 508.4.
If having physical separations a hindrance to the design or functional use of the space, there are options to eliminate the physical separation.
• Classification as an Accessory occupancy under Section 508.2. These are ancillary uses to the main occupancy, usually less than 10% of the building area on a given floor. There are limitations under the height and area provisions of the code in using this approach.
• Another method is to use the “Non-separated occupancy” provisions of the code, under Section 508.3. What this section says is if the building is designed to the most restrictive occupancy classification for height and area, then occupancy separations are not required. If the building is a B and F occupancies and the design complies as a F use for the entire building, no separations are required between the B and F uses.
• One other code section to look at is Section 509 for “Incidental Uses”. Here the code allows certain type of small uses where separation may be reduced or eliminated based on Table 509.
There are many exception and specific rule associated with occupancy separations. For these you will have to read the code and find what may be applicable to your project.
Part Two
By Erick Mikiten, AIA
When you’re working out occupancies on existing buildings, keep in mind that any change in occupancy is considered an Alteration (Section 202 Definitions). That means that even if your client is just doing cosmetic work that wouldn’t normally be an Alteration (such as normal maintenance, reroofing, painting, or mechanical and electrical system changes), the change in occupancy alone classifies it as an Alteration.
This is important because for Alterations, 11B-202.4 provisions apply. This states that “When alterations or additions are made to existing buildings or facilities, an accessible path of travel to the specific area of alteration or addition shall be provided.” The Division of the State Architect (DSA) has an Advisory that says that “When a building or facility undergoes a change of occupancy, the entire building or facility (or portion thereof) is considered the area of alteration. The entire building or facility (or portion thereof) must be upgraded to comply with current accessibility requirements for new construction.”
The priorities of the Path of Travel upgrades are primary entrance, toilet and bathing facilities, drinking fountains, public telephones, and signs. See Section 11B-202.4 for more information, including many listed exceptions.
More and more cities require drawings documenting the existing non-conforming conditions, in addition to the new proposed work. This gives them a reference document for future remodels, and allows the plan checker to have all the information needed for negotiating with you which pieces should be upgraded, which might include elements that were in compliance when built, but that don’t meet the current code.
So the bottom line is that if a client comes to you just wanting help with a change of occupancy, do your research, talk to the building official about what accessibility upgrades they might reasonably require before your client just gets a Zoning approval for a change of occupancy and starts moving in.
