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?
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.
State and Local Goverments requiring a 50% reduction in capacity is a step in the right direction if the goal is to promote social distancing in public spaces. But it might not be enough.
Instead of cutting the original capacity of a space in half, it may be more effective to apply a 1:36 or 1:28 occupant load factor to the area in question and consider this the maximum permitted occupant load for that space.
What do you think? Has the 50% reduction in capacity been effective in achieving social distancing in your area? What other ways could governments help to promote social distancing?
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.
This project is under the 2015 IBC, but I have also included the 2018 language below, as this seems to further clarify the requirements.
In the 2015 language, the first sentence seems to indicate that for a Group R-2 occupancies, the emergency escape requirements apply when triggered by Table 1006.3.2(1) or 1006.3.2(2). As I described in a recent cheat sheet for single exits, these tables are allowances for having a single exit or access to a single exit from a story. In this case, every story has multiple exits, so the provisions of these tables do not apply. The 2018 IBC makes this even clearer.
The AHJ on this project is pointing to the second sentence from the 2015 IBC 1030.1, stating that all sleeping rooms below the fourth story require the openings. The second paragraph from the 2018 IBC has similar language.
In my opinion, the first sentence of IBC 1030.1 essentially functions as scoping language for the rest of the requirements. Since this project does not meet the conditions described in this scoping sentence, the rest of the requirements do not apply and the openings are not required.
Emergency Escape and Rescue Openings: What Do You Think?
In a Group R-2 building where each story has multiple exits, are emergency escape and rescue openings required?
Let me know your thoughts in the comment box!
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).
Up until recently, my normal suggestion has been to place a cross-corridor door to break up the length of any one corridor segment to less than 50 (or 20) feet. This has been accepted in numerous jurisdictions and also validated by an ICC staff opinion that I requested on the topic. In many cases, I have seen the cross corridor door on magnetic hold opens, to release upon activation of the fire alarm system
But on a recent project, a local AHJ has taken the stance that a cross corridor door does not mitigate a dead end condition. I scheduled a meeting with the AHJ to explain how this has been done on other projects and to share the ICC interpretation, but they were reluctant to budge. After some negotiations, the AHJ allowed the door, but insisted that it not be held open and also required a large "Not an Exit" sign on the door itself.
I have drawn up a similar situation in the image below. The corridor is serving a Group A occupancy, so the dead end limit is 20 feet. The added door is shown in red.
Dead End Corridors: What Do You Think?
Do cross-corridor doors mitigate the 20 foot dead end limit? Do you think they should be permitted to be held open?
Let me know your thoughts in the comment box!
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:
When Can a Parking Garage Be Considered Open?
Parking garages must meet all of the requirements of 406.5 to be considered open. In most cases, the limiting factor for an open vs. enclosed garage is meeting the opening requirements for natural ventilation.
To achieve natural ventilation, an open parking garage must (IBC 406.5):
One additional point is that these opening calculations are for the free area of the openings. If a screen or other form of cover is applied to the opening, the free area ratio of the screen must be multiplied by the area of the opening to determine the free area.
What are the differences in code requirements for an open garage vs. an enclosed garage?
Key differences in the code requirements are:
Where open garages are naturally ventilated, closed parking garages require mechanical ventilation complying with the International Mechanical Code (IMC). Mechanical ventilation alone can add hundreds of thousands or even millions of dollars to a project.
Open parking garages are not required to be sprinkler protected. Enclosed parking garages require sprinkler protection in accordance with NFPA 13. If the garage is not maintained above 40 degrees Fahrenheit, a dry-pipe sprinkler system is required by NFPA 13. Both open and enclosed garages typically require standpipe systems.
Enclosure of Vertical Openings
Stairs serving an enclosed parking garage are required to be enclosed with rated construction similar to any other vertical opening in a building. In an open parking garage, enclosure of vertical openings, including stairs, is not required. In both cases, the vehicle ramps connecting levels are not required to be enclosed.
Height and Area
For an open parking garage used exclusively for parking (with an exception for a small office and waiting area at grade), the number of tiers and area is permitted to comply with IBC 406.5.4, which is an increase over the allowable height and area limits in IBC Chapter 5. The numbers in IBC Table 406.5.4 can be further increased when the garage has open sides on at least ¾ of the building perimeter. Enclosed garages cannot take this approach and must comply with the limits set forth in Chapter 5.
Fire Resistance Ratings of Exterior Walls
Both open and enclosed parking garages are required to comply with the exterior wall rating requirements of IBC 602. However, per Footnote C to IBC Table 602, open parking garages with a fire separation distance of 10 feet or greater are not required to have a fire-resistance rating. Enclosed parking garages do not have this exception and would require a 1-hour exterior wall unless the fire separation distance is 30 feet or greater.
An open parking garage must meet the minimum requirements for both area of openings and perimeter of openings to allow for natural ventilation. If a parking garage does not meet these requirements, it is considered an enclosed garage and must be provided with mechanical ventilation, sprinkler protection, and it must also meet the other requirements listed above.
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.
Joe and I met last year at the NFPA conference in San Antonio, and have since discovered a shared vision for developing resources and tools that benefit a wide range of people in the AEC community. Joe is an accomplished author and blogger at MeyerFire.com, where he regular writes and develops tools for the for fire protection community. He also recently launched his own practice, where he focuses on fire suppression and fire alarm design.
What is CodeCalls.org?
We are all about positive IMPACT for the fire protection community. This website is aimed at bringing together code officials, designers & contractors in a collaborative environment where local requirements can be met.
The site will compile some common local requirements, such as type of fire department connection or level of hydraulic safety factor, in an easily accessible database.
We know that better communication can help contractors in the bidding process and help code officials get their needs met to better serve the community and their own first responders.
What's the Goal?
Phase 1 is a test case for viability.
Our goal is to gather local requirements that covers jurisdictions that combined account for 70% of an area's population.... and we want do to it in 30 days.
To start, we are only compiling data for Indiana.
Indiana has a healthy mixture of urban, suburban and rural jurisdictions, so it presents a great test case to validate the concept. If we get enough momentum for Indiana, we feel confident in pursuing the project for larger coverage.
In order for the project to provide a practical positive experience for designers and contractors, we feel that a designer or installer needs to find the information they need at least 70% of the time. Otherwise, with too sparse or scattered information we won't get the positive feedback loop that we need to keep the project viable.
If you're an engineer, designer or installer, why should you contribute?
For one - this is a way to clarify local requirements that will help in more fair and consistent bidding. Second - we'll thank you by crediting your contribution with a link from the local listing directly to your company's website. If someone is looking for a local contractor or design outfit, they can search a ZIP code and immediately have contact information to you, the person who they know is already familiar with the local requirements.
If you're a jurisdiction, why should you contribute?
Simple - get your needs met. Are you tired of providing the same plan-review comments? Tired of answering the same basic questions in phone calls and emails? This platform is an easy way to clarify the gray areas of code and simply make your requirements more clear to those who are seeking them.
If you are outside of Indiana, we hope to expand quickly. Assuming we get a strong response from jurisdictions in Indiana, we plan to rapidly move to other states!
You can contribute starting now at CodeCalls.org/contribute-data.
About twice a year, I receive a question from an architect regarding safety glazing. Where is it required? Can I provide a different type of glass? Is this manufacturer/model acceptable? Without fail, I always end up revisiting the International Building Code (IBC) to review the requirements before answering the question. So in an effort to save me (and hopefully you) time in the future, I have compiled a quick reference guide for safety glazing. All references are to the 2015 IBC.
Practically, safety glazing refers to glass panels or other materials that are manufactured to reduce the likelihood of breaking and to minimize the safety risk if the material does break. From a code compliance standpoint, safety glazing refers to any glazing that meets the requirements of IBC 2406.
Glass panes are the most common safety glazing material, but the IBC also recognizes plastic, glass block, and louvered windows as potential options. The IBC does not provide any requirements for the process used to manufacturer safety glazing, it only provides performance requirements. Therefore, both tempered and laminated glass assemblies can qualify as safety glazing, if they meet the IBC 2406 requirements.
IBC 2406.4 identifies 7 locations as hazardous locations that require safety glazing:
Additionally, glazing located in fire-protection rated or fire-resistance rated glazing installed in fire door and window assemblies is required to be safety glazing (IBC 718.104.22.168 and 716.6.3).
When safety glazing is required, the most common design option is manufactured glazing panels that are either laminated or tempered. Safety glazing panels are required to be tested to either CPSC 16 CFR Part 1201 or ANSI Z97.1 and must be identified through a label or other means of designation. There is an exception that allow forms of safety glazing other than tempered glass to not be labelled when approved by the AHJ.
When tempered glass is used, the glazing must be identified by a manufacture’rs designation that is, “acid etched, sand blasted, ceramic fired, laser etched, embossed, or of a type that once applied, cannot be removed without being destroyed.”
In retrofit applications, it may not be desirable to replace existing glazing with new safety glazing panels. There are various film products available that can be applied to existing glazing that will satisfy the code requirements for safety glazing. Some examples include products by 3M, Llumar and Gordon Glass.
If using this option, it’s important to determine who applies the label to the glazing once the film is applied. If the installing contractor is applying a label after the film is installed, check with the local authority to verify that this will be acceptable. Since the IBC has fairly stringent requirements on safety for identification of the safety glazing, some AHJs require a permanent label that is etched in to glass.
There are 7 distinct hazardous areas where the IBC requires safety glazing. Technically, any product that meets the requirements of IBC 2406 can be considered safety glazing, but the most common products are tempered and laminated glass. Be sure to verify that the product you select has been tested in accordance with CPSC 16 CFR Part 1201 or ANSI Z97.1
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.
Yet in certain locations, the crowds of people are growing.
For example, cities across the US are seeing a rise in temporary emergency shelters. Many hospitals are expanding with new temporary patient sleeping areas, and homeless shelters are expanding to arenas, convention centers and other large facilities to accommodate a drastic increase in occupants. In Alaska, one homeless shelter has taken over a sports arena and is housing double the number of people originally expected. In Arizona, one homeless shelter has moved to a head-to-toe sleeping mat arrangement to allow for some level of social distancing while still accommodating as many people as possible. You can find similar stories across the country.
So what does this mean for calculating occupant loads?
In the long term, it's impossible to say for sure. Things could very well go back to normal once the pandemic ends, leaving the nature of occupant loading strategies unaffected. But on the other hand, does COVID-19 change how we work and gather as a society? Will there be a sharp increase in the number of employees working from home when this is all over? Or separately, does the pandemic go on for quite some time such that we have to asses things differently as new buildings are designed in the coming months or years?
Occupant Load Factors Meet Social Distancing
With the current CDC guidelines, the recommendation for social distancing involves maintaining 6 feet of separation from other individuals. Six feet of separation in both direction results in each occupant of a building taking up 36 square feet of space.
So how might this impact an occupant load calculation?
Here's one example: a 750 square foot conference room with tables and chairs would normally be assigned an occupant load of 50 (using a factor of 15 square feet per occupant), but following the CDC guidelines, no more than 20 occupants should be in the room.
Another example is a 500 square foot classroom, which would normally be assigned an occupant load of 25 (using a factor of 20 square feet per occupant). But following the CDC guidelines, no more than 13 occupants should be in the room.
As long as the CDC guidance and government direction is in place, any gatherings or meetings that are still occurring will likely be smaller and less dense than normal. And with most schools around the US canceled and many meetings moving to a virtual format, there's a good change that many conference rooms and classrooms are vacated completely.
But what about locations where the crowds are increasing?
Let's take the temporary emergency shelter as an example.
As more and more people are impacted by COVID-19 and the demand for emergency shelters increases, staff members of these locations are already facing the growing tension of trying to accommodate more people while still maintaining some level of social distancing.
During Hurricane Katrina in 2005, the field of the Superdome in New Orleans was converted to an emergency shelter for displaced local residents. As you can see from the image below, the field was densely packed with sleeping cots. For families, cots were pushed together with no space in between and each group of cots was only 1-2 feet away from the next group.
Now compare this to a recent photo from a temporary emergency shelter in Alaska, where there is at least 6 feet of space between each sleeping cot.
Assuming the pandemic continues and the number of people forced into shelters grows, the challenge of this tension will also grow. With a limited amount of space and resources, is it better to limit the occupant load in order to maintain social distancing? Or should shelters attempt to help more people at the expense of housing people closer together?
The world is facing an unprecedented situation in the current COVID-19 pandemic. In the short term, major cities are seeing a complete desertion of many offices, public spaces and streets. Yet emergency facilities such as hospitals and shelters are seeing a sharp increase in occupants.
For life safety consultants like me, this raises the question: how does this impact occupant load strategies?
While I'm hopeful that the pandemic ends soon and life returns to normal, I also have a small inkling that COVID-19 will have some change on how we work and gather as a society in the future. Maybe it will be an increase in the number of people working from home. Perhaps large public gatherings look different in the future. At this point, it's impossible to say for sure.
What are your thoughts? Have you seen occupant loads change drastically in your community? Do you expect the pandemic to change how we gather together in the future? Please share your thoughts in the comments section!
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.
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