As of Spring 2024, the NCARB ARE 5.0 exams now reference the 2021 International Building Code for code related questions. 

ARE 5.0 code questions can cover a large portion of your exams. Up to 22% of both the Programming and Analysis (PA) and Project Planning & Design (PPD) question and up to 14% of Project Development and Documentation (PDD) question. Everyone will go into the ARE 5.0 exams with some weaknesses, but I highly recommend that the building code NOT be one of yours!

The tough part is that there are a LOT of things to know about the building code. While you will never be able to know all of it, if you start by learning the ten things I cover in this post you'll be off to a good start. These are all very efficient topics, meaning you'll probably see them over and over again on the different exams.

2021 IBC STUDY RESOURCES

I always recommend studying directly from the primary resources, i.e. the books and resources listed in the NCARB ARE 5.0 Guidelines. You probably have the physical book in your office, but the 2021 IBC is always available for free online as well.

I also really love the 2021 International Building Code Commentary. It's about $10/month from the ICC website and has plain language explanations and lots of sample calculations for all the different code sections. Very very useful as a study resources.

And finally there's the Francis Ching book, Building Codes Illustrated: A Guide to Understanding the 2021 International Building Code. Super useful and classic Ching graphical descriptions of various code requirements. I used that book as part of my studies. That last link is an Amazon affiliate link, meaning I might get a commission if you end up buying the book after using the link.

IMPORTANT THINGS TO KNOW ABOUT THE 2021 IBC

Ok, let's get to it! Study these things first, and then keep going!

FIRE SEPARATION OF MIXED USE OCCUPANCY IN THE 2021 IBC

In a building with multiple occupancies, like Business Offices (B), Retail (M) and Residential (R) you may need to provide walls and other building elements between the occupancies that can resist fire. The time, in hours, that the walls must be able to resist fire can be found in Table 508.4 Required Separation of Occupancies.

This is a concept you'll see on multiple exams, both in the planning exams (PA and PPD) and in the construction/detailing exam (PDD). You do not have to memorize this table, but you SHOULD memorize the number (so you can quickly find it on the exam) and LEARN how to use it.

Check out this video on how to determine the required fire separation using the table. That video references an older version of the code, but the process is the same.

In the 2018 IBC and earlier the bottom left of the table was blank because those spaces would have been the same as their opposite on the top right. Many people confused the – to mean No Separation Required, or Not Allowed, so in the 2021 version the table is completely filled in, even though the information is duplicated.

Quick Explanation of 2021 Fire Separation:

– Find your first occupancy code (A, E, R, etc.) along the left column in the chart. You could also start on the top row, it doesn't matter. You can find the occupancy definitions in the 2021 IBC Chapter 3: Occupancy Classification and Use
– Find your second occupancy in the row along the top
– The number where the column and row intersect is the required fire separation, in hours. An ‘N' means there is no separation required, or 0 hours. An ‘NP' means that those two occupancies are not permitted to be next to each other, regardless of how many hours of separation you provide.

Dead End Corridors

A dead-end corridor is a hallway the leads only to an exterior wall with no exit. A window does not count as an exit. The maximum distance of a dead end corridor is 20ft, though there are always exceptions, like certain occupancies and whether or not the building has sprinklers. The link takes you to Chapter 10 of the IBC, read Section 1020.5 for specifics of dead end corridors.

An office, a school, an apartment building and a retail store are a few of the occupancies that allow a 50 foot dead end corridor if the building is equipped with a sprinkler system.

The hallway on the bottom right of this image, with the dimension is an example of a dead end corridor. Image is from my PPD-PDD Study Assignments Course, if you want to practice a bit.

COMMON PATH OF TRAVEL

The IBC defines common path of travel as, “that portion of the exit access travel distance measured from the most remote point within a story to that point where occupants have separate and distinct access to two exits or exit access doorways.”

In real words, you measure from the furthest corner in a room to the point where someone could egress two different ways. Marty Huie has a good video about Common Path of Travel. While that video is really old at this point, the concept is the same.

The maximum distance of the Common Path of Travel is set in the 2021 IBC Table 1006.2.1 Spaces With One Exit or Exit Access Doorway, which also has restrictions for spaces with only one exit.

Note that Common Path of Travel is not the same as the maximum egress distance, which is is found in Table 1017.2 Exit Access Travel Distance.

Door Locations and Max Projection into Corridors

With a few exceptions, doors must swing in the direction of egress, meaning doors from rooms will swing out into corridors people are trying to use for egress.

The 2021 IBC limits the amount of this swing in Section 1005.7 Encroachment. A lot of the things you need to know about the IBC are in Chapter 10 Means of Egress!

When fully open, like beyond 90 degrees…close to parallel with the wall, a door can only project 7″ into a corridor. While the door is being opened (swinging through 90 degress) it can't reduce the width of the corridor by half.

You have to account for this when placing doors, so often times you will see them recessed into alcoves so that they can be fully opened and not reduce the required width of the hallway. I recommend remembering 7″ and “reduced by half”.

RAMP SLOPE

There used to be a ramp slope vignette on the old Building Design and Construction systems exam. That exam is now part of Project Planning and Design and Project Development and Documentation, so you may see ramp slope questions on more than one exam.

You can read all about ramps in the 2021 IBC Section 1012 (Still in the egress chapter!)

First, you need to understand that a ramp is defined by the slope of a sloped walking surface. If the slope of a walkway is less than 1:20 it's just a sloped surface, and doesn't require a handrail or landing. If the slope is steeper than that it is considered a ramp, and must meet the requirements of a ramp.

Side Note: You should also understand slopes, as it comes up in code and site planning things. I have a post about Slope Math, which in turn has links to a video on slope math as well. Both of those are based on information in my PA Study Course.

Anyway, a ramp can have a maximum slope of 1:12, which is the same as saying 8.3% or 1″ in 12″ or 1 ft per 12 ft. Those are all the same things, just written in four different forms. Remember that 1:12 is steeper than 1:20, as you might go up 1 foot over a 12 foot run instead of 1 foot over a 20 foot run.

The maximum rise is 30″ before you are required to have a landing, so if you have to go up more than 2.5 feet (30 in) you'll need a landing mid way.

That landing (and others) have to be at least as wide as the ramp and at least 60″ long. Minimum width is 36″ though this is absolute minimum and the ramp may have to be wider due to requirements of Section 1020.2

USE AND OCCUPANCY CLASSIFICATION

Chapter 3 Use and Occupancy Classification is where the different Occupancy Groups are defined.

These are the most general classification of the use of a building, like Assembly, Business, Educational and Factory, etc.

You don't need to memorize these, but it's good to understand what the general definitions of these groups implies. You also may be asked to choose an Occupancy Group based on a description of what the space is used for. In that case it would be helpful to refer to Chapter 3 to make a determination of what the best Group is.

It will be good to have a general understanding of the different residential groups R1 vs R2 vs R3.

And remember, M is for Mercantile, which is what we call Retail!

Somewhat related to Occupancy Classification is…

Maximum FLoor Area per occupant load

You will likely be asked about egress sizes for things like doors and corridors, and this is usually based on the Occupant Load of a space. This is found in Table 1004.5 Maximum Floor Area Allowances Per Occupant.

Two important things to know about this table. First is that the “Function of the Space” does not perfectly match the Occupancy we just discussed above. The Occupancy is a general description of the use of a building, and is used to determine things like fire separation and building height and area. Occupant Load is about what's happening in any one specific room, and the list is a lot longer.

The other important thing to really understand this table is that it's not telling you how many people are allowed in a room. It's telling you how much egress you have to provide.

For example, the occupancy load factor for Classroom Area is 20 net. If you have a classroom that is 1000 sf, you must provide egress for 50 people. You can not have a 1000 sf classroom but claim only 15 people will be using it. I have more info on this topic in my post about How to Round Code Requirements.

QUICK EXPLANATION OF OCCUPANT LOAD

– Find the function of your space in the left column, then find the occupant load factor in the column on the right.

– Divide the net or gross square footage of the room or spaces in your question.

– The resulting number (the quotient!) is the number of occupants you have to account for when determining your egress sizes.

ATRIUMS

Atriums are covered in 2021 IBC Section 404 Atriums and defined in Chapter 2: “An opening connecting two or more stories other than enclosed stairways, elevators, hoistways, escalators, plumbing, electrical, air-conditioning or other equipment, which is closed at the top and not defined as a mall. Stories, as used in this definition do not include balconies within assembly groups or mezzanines that comply with Section 505.”

They're basically saying an open space that's more than one story tall that's not obviously some kind of chase. An elevator shaft is clearly not an atrium.

The biggest thing to know about atriums is the fire and smoke protection requirements. This is handled in Section 404.6 Enclosure of Atriums. With some exceptions, an atrium needs to be surrounded by a 1-hour fire barrier..

FIRE WALLS, BARRIERS, PARTITIONS

Speaking of Fire Barriers, it's important to understand the difference between the three primary fire resistant wall types you will encounter, Fire Walls, Fire Barriers and Fire Partitions.

The key difference is not the number of hours, but the construction of the walls with relation to the floor, roof and ceilings. These are all covered in Chapter 7 Fire and Smoke Protection Features. Make sure to read the subsections on Continuity.

Fire Walls

Fire Walls are covered in Section 706 Fire Walls. They are required to extend from the foundation to 30 inches above the roof. Yes, all the way from the foundation to above the roof. A fire wall can be used to separate one structure into two separate buildings, as far as the code is concerned. They will be rated between 2-4 hours, depending on the Occupancy Groups. See Table 706.4

Fire Barriers

Fire Barriers are covered in Section 707 Fire Barriers. They must be built from the floor to the underside of the deck above (vertical continuity) They are used for many of the key separations, like separating occupancies, protecting exits, protecting atriums (see above) and more.

Fire Partitions

Fire Partitions are covered in…Section 708 Fire Partitions. See the pattern? These offer the least amount of protection of the three. They are generally used to corridors or other interior spaces. They must go from the floor to the underside of the deck above -OR- from the floor to a rated ceiling.

Mezzanines

Mezzanines are basically free space. They don't count against the floor area or stories limit, but they come with some restrictive requirements.

Of course, there are exceptions, per usual code is relaxed when you add sprinklers or more exits.

Keep in mind the goal of the mezzanine (per the intent of the code) is to allow a smaller space above, and open to, the space below. Like a reading room above a library stack and etc.

Not considering exceptions, a mezzanine can be a maximum of 1/3 the area of the room it is in, and has to be open and accessible from that room (mezzanine walls are max 42″ high).

These requirements are relaxed if the occupant load of the mezzanine is fewer than 10 people or there are two or more exits from the mezzanine. There are other exceptions, but these are the big two. Read more about mezzanines in the 2021 IBC Section 505 Mezzanines and Equipment Platforms.

Maximum building height and area

I personally feel this topic gets more than it's fair share of press. The amount of time people spend studying for, and stressing about building height and area doesn't seem to match up with how much this stuff is actually on the exams. BUT, it's good to know and even better, it got EASIER in the 2015 IBC..which was two codes ago from where we are now. Anyway…

Allowable Building Height

There are two height limitations, actual height in feet, and number of stories. You can now read these entirely from tables, with no calculations or formulas or adding 20 feet etc.

Maximum height in feet is in the 2021 IBC Table 504.3 while maximum height in stories is one section down.

To find your height limits start with your Occupancy (see earlier in this post or Chapter 3) in the rows along the left. As you move to the right, use the top half of the row if your building does not have sprinklers and the bottom half if it does. Continue to the right until you intersect your building's Construction Type.

A couple things to note:

Construction Type is found in Chapter 6 Types of Construction. The different types, I through V are worth knowing, and can generally be described by the materials that are allowed to be used, with Type I required to be made of non-combustible material and Type V allowing anything.

The A and B below the construction types is generally referred to as Protected or Non-Protected, even though these terms, to the annoyance of many, are not actually defined in the code. And big thing to note, it does NOT have to do with sprinklers. It is a fire protection rating of the assemblies and building elements themselves. You can find the minimum requirements for these ratings in Chapter 6 as well, see Table 601 Fire-Resistance Rating Requirements for Building Elements.

And finally, note that while we started with our occupancy and then found the max height based on some facts we already knew about the building, the process of designing the building is usually the opposite. You start with your occupancy, then figure out how tall you need it to be and from that height you see the possible options for what combination of sprinklers and construction type will allow you to achieve that height. And the more you add sprinklers, build with non-combustible materials and protect your various walls and assemblies with higher fire ratings, the more you will be allowed to build.

Allowable Number of Stories

This works the same as Building Height. See Table 504.4

Allowable Building Area

This is a big one. It still requires a formula, but it's less involved than it was before. See Section 506 Building Area.

To start, find your Allowable Area Factor in Table 506.2. This part works the same as with the Building Height example we just did above. Find your Occupancy on the left, then read across to find your Allowable Area Factor in the portion of the row that matches your sprinkler condition and the column that matches your construction type. On the ARE all this stuff should be given to you.

Then you need to go to Section 506.2.1 and 506.2.2 to find your specific area increase formula, depending on if you have a single occupancy building or a mixed occupancy building.

All the variables you need to plug in are listed below the formula. And perhaps when I get more energy I'll update this post with an example or two showing how to do the math!

EXCEPTIONS

OK, bonus tip here. There are exceptions to pretty much everything I've covered above. It's good to know they exist and what their purpose is.

In your studies focus on the exceptions that relate to sprinklers, exits, and number of people. Pay less attention to things like 505.2.3 Exception 4 which allows equipment platforms in Industrial facilities to be glazed on all sides. That's way too specific, but if you actually get that question on the exam and miss it because I told you don't worry about it…sorry?

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