In recent weeks, many states have seen a sharp increase in the number of new cases of COVID-19. According to the Johns Hopkins University Coronavirus Resource Center, Arizona, Texas and Florida are seeing record numbers of new cases in the last two weeks. Many other states are seeing rising trends as well.
At the end of March, I wrote a post about the impact the COVID-19 pandemic may have on occupant load factors. Nearly four months later, I believe it's clear that the pandemic has changed the way we work and gather as a society, at least for the foreseeable future. In response to the pandemic, nearly every state has placed restrictions on gathering and assembly spaces, typically requiring them to operate at no more than 50% of their original capacity. This 50% reduction has included airlines, restaurants, public transit systems, and casinos, just to name a few. As I've thought more about social distancing and occupant load factors in the last few weeks, I've been considering if this percent reduction actually makes sense. First, lets review how building or space capacities are typically determined... For the purposes of egress, occupant load factors found in IBC Chapter 10 (and also NFPA 101 Chapter 7) are used to determine the minimum number of occupants that need to be considered when sizing the means of egress. A denser occupant load factor results in more people per unit area and a greater egress width. But the occupant load factors found in IBC Table 1004.5 are used to determine the minimum occupant load that needs to be accommodated by the means of egress. The IBC specifically allows the occupant load to be increased beyond the number established by Table 1004.5, so long as there is sufficient egress capacity and the load does not exceed 1 occupant per 7 square feet (IBC 1004.5.1). The posting of the occupant load that you see near the main exit from restaurants, entertainment venues and other assembly occupancies is often reflective of an increased occupant load beyond Table 1004.5. So when a State or County Government orders restaurants to operate at 50% capacity, does this automatically result in the minimum six feet of social distancing recommended by the CDC? Maybe. It all depends on how the 100% capacity number was determined. If the restaurant's (or other business's) occupant load was originally based on a denser load factor, such as 1:15 for tables and chairs seating, even a 50% reduction in capacity is unlikely to result in social distancing. It's even more unlikely if that 100% capacity was based on an increased occupant load, beyond what IBC Table 1004.5 requires. Instead of starting with a percent reduction in capacity, it may be more effective to use occupant load factors to determine a maximum capacity for a building or space during pandemic social distancing conditions. Using the CDC guidelines, 6 feet of distance between people results in 1 person for 36 square feet (or perhaps 1 person per ~28 square feet using a 3 foot radius measurement). Assuming occupants can be evenly distributed through the space (a potentially big assumption), this method would allow for social distancing, regardless of the posted occupant load or exit capacity of a space.
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October 2020 Update: I am moving all calculators to the Tools menu at the top right of the screen. I have also added in a slider bar to allow for varying frontage amounts (see the new tools page for this function).
After several weeks of working on this, I'm excited to release a beta version of the 2015 IBC Allowable Height, Area and Number of Stories Calculator. Take a look and let me know what you think! A few notes:
After countless requests from clients to verify if a particular system is required to be on emergency or standby power, I decided to write them all down in a single location. While IBC Chapter 27 does have a list of the required systems, I often find myself going to the separate sections referenced from 2702. This cheatsheet has already saved me some time...I'm hoping it does the same for you!
I'm currently working on a large, multi-family apartment building that includes several-hundred dwelling units. The building is four stories tall and each story has multiple exits. The building is divided up by several fire walls for allowable area purposes, so the exits are a combination of exit stairs and horizontal exits.
In a recent discussion, the AHJ indicated that he thought Emergency Escape and Rescue Openings complying with IBC 1030 were required for each bedroom in the building. On past projects, I have not seen this required in buildings where each story has two or more exits, so I decided to do a deep dive into the code requirements. For years, architect clients have asked me for solutions to mitigate a dead end corridor condition. As a quick reference, dead ends are limited to 20 feet, except in Groups B, E, F, I-1, M, R-1, R-2, R-4, S and U with a full NFPA 13 sprinkler system, where the limit is increased to 50 feet (2015 IBC 1020.4).
For architects and engineers designing parking garages, two questions commonly arise when determining whether the garage should be an open or enclosed garage. These questions are:
In starting The Building Code Blog a few months ago, one of my main motivations was to answer frequently-asked code questions in a medium that is widely-accessible. Providing clear code direction to a contractor or architect is impactful, but providing code insights to hundreds or thousands of people in the AEC community is even more impactful. In my work on the blog and elsewhere, I hope to provide that further-reaching impact.
To that end, I have partnered with Joe Meyer to launch a new initiative, CodeCalls.org. With the COVID-19 pandemic impacting billions around the world, many cities are seeing an unprecedented change in the concentration of people.
In many urban areas, once crowded streets and public gathering spaces are now deserted. Major cities around the US have closed non-essential businesses, rendering office and conferences rooms vacant for the time being. Congested highways where cars formerly crawled along during rush hour are now empty. After getting some great feedback on the egress cheat sheet post, I have put together another cheat sheet. This time, we're looking at all the situations where the IBC allows you to have a single exit (or access to a single exit) from a room, space or story.
For most architects and engineers who deal with life safety compliance on a regular basis, the main "distance" requirements in a building are quite familiar. Most folks in the life safety world can tell you that the common path limit for business occupancies is 100 feet or that the travel distance limit for assembly occupancies is 250 feet, without needing to refer to the code.
But I've also found that certain occupancies are less common in my day to day project work (do you know the Group H-5 travel distance limit off the top of your head)?? So whether you're just starting out in the world of life safety or you've been doing it for years, hopefully you find this cheat sheet helpful! |
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