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Kevin Ahern

By: Kevin Ahern on January 30th, 2019

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Building Classification Types: What You Should Know When Planning Your Commercial Project


International Building Code, or IBC, requires that all buildings and structures be classified under specific categories. These building classification types affect the building and fire code enforcement, and by doing so, influence the structure and design of the building.

While the owner of the building can provide input on the structure, the building's designated category influences the building's size, number of exits, routes toward exits and other variables.

Commercial building owners must understand these categories and their purpose, so they can make the right decisions when designing their commercial structure. Knowing how these categories and codes influence the commercial building design can have a big impact on owner satisfaction, especially during the design phase of a construction project.

Use and Occupancy

The use and occupancy category defines the specific use of every commercial building. There are ten main use and occupancy groups. Each group is divided into subgroups, and every building has a group and subgroup. The specific subgroup that the building falls under depends on the risk to the occupants. The higher the risk to occupants, the lower the subgroup number.

Use and Occupancy
Group Subgroup Building Use
Assembly Groups A-1, A-2, A-3, A-4, & A-5 Religious or civic gathering
Business Group B Professional office
Educational Group E K-12 schools
Factory/Industrial Group F-1 & F-2 Manufacturing/fabrication/packaging
High Hazard Groups H-1, H-2, H-3, H-4 & H-5 Hazardous materials
Institutional Groups I-1, I-2, I-3 & I-4 Assisted living, hospitals, and prisons
Mercantile Group M Display and sale of merchandise
Residential Groups R-1, R-2, R-3, R-4 Housing, apartments, and hotels
Storage Groups S-1, S-2 Storage of non-hazardous materials
Utility & Miscellaneous Group U Accessory structures

The way a commercial space is used affects how many people will typically gather in that space at one time. Placement of furniture and equipment is also affected by the space's use.

Also, to ensure that people can use the space for its purpose and leave safely in the event of an emergency, exits are placed around the building. The placement of exits depends on the use category.

For example, an assembly area will have fire doors placed in specific locations around the building, based on the idea that there will be many people gathered in the building at one time. Doors will be positioned to ensure that many people can exit at once, safely and efficiently. A warehouse space may contain fewer people at any given time, and thus may have different exit requirements.

These requirements, and those similar to them, are why it's important to hire a knowledgable contractor. Property owners who are unfamiliar with the exit requirements may rely on their contractor to tell them how a building can be constructed to conform to building standards.

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Type of Construction

The construction type identifies the type of materials used to build a structure. The different types are as follows:

  • Type 1 – Frequently called fire resistive construction, in which building elements are of non-combustible materials.
  • Type 2 – Frequently called non-combustible construction. Again, building elements are made of non-combustible materials.
  • Type 3 – Frequently called ordinary construction. Some walls are of non-combustible materials or fire-retardant wood framing, while interior building elements are of combustible or non-combustible materials.
  • Type 4 – Frequently called heavy timber (HT) construction. Some walls are of non-combustible materials or fire-retardant wood framing, while other building elements are of unconcealed solid or laminated wood members that meet minimum dimension requirements.
  • Type 5 – Frequently called wood frame construction. For this type, walls and elements are made from any materials permitted by the code, combustible or non-combustible.

Accurate classification of a commercial building is crucial. There are many resources online that discuss construction type and use and occupancy. Commercial structures are required to conform to building standards in order to be permitted. If the building does not meet code requirements, it may never be finished.

Table 601 in the IBC states that materials referenced above include the primary structural frame, interior and exterior walls (including non load-bearing walls), and the roof and floor. All building elements are required to have a fire-resistance rating between 0 and 3 hours, depending. This rating indicates how long a building can be on fire and also retain structural integrity.

A building can utilize more than one construction type, if needed. Commercial property owners can work with their construction contractor to ensure that their building is properly categorized.

In addition, commercial buildings that do not conform to building standards can put people at risk. This is why building codes exist in the first place: to ensure that everyone who uses public facilities and modern structures are safe from fire and other potential hazards. Without accurate classification, the risk to the public could be significant.

Work With a Professional

Working with a reputable professional construction contractor company is critical to the success of a commercial construction project. If you're a commercial property owner who will soon be starting your own commercial construction project, now is the time to get in touch with a commercial contractor.

Working with a knowledgable professional can help ensure that your commercial construction project will be a success. Whether you're knowledgable about building classification types or not, your commercial construction contractor will help you determine what category and type fits your commercial structure.

Are you planning a commercial construction project in the coming months? What have you done to start your project? Leave your comments in the box below.

At Litchfield Builders, we're happy to walk you through the commercial construction process. We'll answer any questions you might have about building classification types and other related inquiries.

Call us today to set up a consultation to discuss your upcoming building project.

For more information about commercial construction, check out our free publication, Sustainability & Green Building in Commercial Construction.

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About Kevin Ahern

Kevin is the Co-Founder of Litchfield Builders, an award-winning, industry leader with a reputation for managing projects others shy away from. They are known for their high-quality work, customer service, and reliability and though still relatively small in size, Litchfield Builders now competes with some of the areas largest firms in both the residential and commercial arenas.