(The Consequences of Constructing Three Walls and Two Doors)
10/04/2019
Now that I’ve made it to Week Two, I would first like to thank everyone for the support they gave, via text, email, comments, etc. it really meant a lot to hear from everyone. I am also proud to present the second post for the Video + Blog series “What the Hell is Architecture?” A series that will present Case Studies, Code Commentaries, How-To Videos, and anything else that comes to mind to try and get the word out on what Architecture, Engineering and Construction ACTUALLY is. (Something the industry has done a poor job of enlightening the public on)
This week we are going to review a Code Analysis that was done for a client. This project was done at another firm, so the names have been changed to protect the innocent. Hopefully this will garner a little insight into the process and effort involved in reviewing the Building Code, and ensuring that your project is code compliant, as well as being handicap accessible. Attached is a list of all the Code Provisions referenced in this review.
Is an Elevator Required?
A quick synopsis of the project, a nonprofit organization had a group home building for people who are developmentally disabled. The building is an L-Shaped Floor plan and has two floors, a ground floor and a basement, and there were six single user bedrooms on the ground floor and some offices and a recreation room in the basement. The client wanted to build two more bedrooms in the basement, and not only wanted to confirm this was legal, but also wanted to know if it could be done without building an elevator, which would have cost too much and would have prevented these bedrooms from being added.
The Code is Not A Checklist
A common misconception people have is that whenever something is being designed there is just a checklist of rules and dimensions that need to be met for a building to be handicap accessible, or to confirm that it meets the building code. That is not the case, in fact the building code is a series of Code Documents, not to mention certain conditions require OTHER standards to be met. This project specifically not only required The International Building Code, but also required to follow NFPA (National Fire Protection Association) standards. However, to keep this from being obnoxiously long, we will just look at the code review for the IBC. (International Building Code)
Existing Building
Our first course of action is to get a couple of statistics about the exiting building. The first being the Square Footage of the basement, which is 2,655 SF. Both floors already have an Automatic Sprinkler system installed in the ceiling, which is a separate exercise to confirm whether it is required or not in other projects, that luckily, we don’t need to do for this project. We then need to calculate the Occupant Load, which is the maximum amount of people this Basement can handle. We do this dividing the Square Footage of the floor (2,655) by the Occupant Load, a number we get from a table in the IBC. From this table, we find that a Residential Building usage has an Occupant Load of 200 Square Foot per user. So, by dividing 2,655 by 200, we find the Occupant Load to be 13 people.
Level of Work
While all the building statistics we just figured out were calculated with the IBC, we first start reviewing the International Existing Building Code, also known as the IEBC. Another misconception about the Code, it is not a linear book you just read, you must jump between multiple books at multiple times, not to mention that fact you can’t review the chapters in order.
Based on what scope of work a project has, will determine which sections of the code will need to be followed in existing buildings. There are three levels of alteration; One, Two and Three. Level One is very minimal construction, limited to the removal or replacement of finishes. Level Two being any reconfiguration of space, as well as the addition or removal of windows, doors and walls. And Level Three being any work that exceeds over 50 percent of the building area.
The construction of new bedrooms will trigger the threshold of being Level Two, but since it will not account for over 50 percent of the Square Footage, it will not be considered Level Three. So not only will all this work need to conform with Level Two alteration requirements, it will also need to conform with Level One.
Emergency Escape Windows
Most of the Level One requirements are less stringent than Level Two, however there is one provision that needs to be met, the new bedrooms will need to have Emergency Escape and Rescue Openings for Group R-4 Occupancy Spaces. We determine what the occupancy of this building is by looking through the Occupancy Definitions in the IBC. Since we have more than 5, but less than 16 people living in the building it is considered Group R-4. There are also two “conditions” for this group that refer to the speed at which the users can escape if a fire were to break out. Since this is a developmentally disabled group home, it is considered “Option 2.”
The IEBC refers you to the IBC for what the minimum dimensions of these openings must be, which is simply a window with a clear opening of 5.7 square feet, with at least one of the window dimensions being at least 20 inches. These dimensions must be maintained when the window is opened. The existing windows did not meet this dimension as they were double hung windows, (Which meant only half of the window area can be opened for exiting) however the window opening in the wall itself would meet these requirements if a casement window (Large, single pane window that can swing open) was installed. Therefore, the existing windows need to be replaced.
Changing How the Space Is Used
The next determination we need to make is what Occupancy Classification the new Basement layout provides. In this case, we are not changing the Classification of the space, it is still considered Residential. However, as we are changing it from a recreational space to bedrooms, it is still a change of occupancy. In fact, as the Alterations are less than 50 percent of the area, the new bedrooms are not required to be Type B Sleeping Units. Type A and Type B units refer to how accessible the space is. Type A is a fully accessible unit; with proper turning radius clearances, specific door hardware, lowered shelves and counters, etc. to allow for wheelchair usage. While type B is an adaptable unit, which is not as accessible as Type A, but can be converted into such; removable base cabinets and wood blocking installed in the walls for future grab bars.
This Change in Occupancy is an important distinction, as alterations that affect an area containing a primary function must be made fully accessible. However, there is an exception that states that when Type B units would be added to an area where none existed before, the route is not required to be fully accessible. This is intended to prevent building owners from being penalized when adding units to a floor above or below an accessible floor where no elevator was before. So, while our initial question of “Is an Elevator Required?” is answered, we are not done yet.
Exiting the Basement
We have determined that an elevator is not required, however the users of the bedrooms in the Basement need to be able to exit safely in the event of a fire. We first need to determine how many exits are required, as we currently only have one exit. At first glance the basement appeared to have two exits, with one leading to a patio and an unenclosed stairway to the upper floor, however an exit cannot be considered a legal exit unless it is a far enough distance from other exits, which these two exits were not, therefore we only have one exit. The IEBC refers us to the IBC to see how many exits are required based on occupant load. Based on the table and our occupant load, we can have a single exit, (As well as a provision in the IBC that allows Group R-3 and R-4 to have a single exit) and if the space has Automatic Sprinklers installed, (Which it does) the maximum Common Path of Travel is 125 feet. The Common Path of Travel is the maximum distance allowed from a junction where someone can choose which exit to pursue, to the exit. In this case we only have one exit, so it is the distance from the furthest point from the exit to the exit, which we are well below the maximum distance.
While we are well within the Common Path of Travel distance maximum, we need to confirm we don’t exceed the Dead-End Corridor requirements. Based on the code, we cannot have a Dead-End corridor that exceeds 50 feet, what this means is that somebody cannot travel more than 50 feet towards a dead end. Currently, the basement exceeds this dimension. To help avoid that, we can place a wall and locked door somewhere in the corridor to shorten this Dead-End dimension, with the added benefit of creating a private room for storage or usage by the staff.
Fire Protection
The code states that when you have a Change of Occupancy, which we do, and this change is not separated from the building, then the entire building must meet all the fire requirements of the portion of the building being altered. We will discuss shortly what the new bedrooms need in terms of fire resistance, but what this simply means is that due to the open stairway, the entire building is not separated, which would require that the entire basement floor and the upper floor to be constructed to the fire requirements of the new construction. This would be very expensive and require a lot of construction, so we will propose to separate the bedrooms from the rest of the building with a fire rated wall and door, the users do need a path to the exit, so we will construct this new wall to allow an exit pathway.
Because we are creating a Change of Occupancy that is an equal or lower hazard category, which we determine from a table in the IEBC, the existing Exterior and Interior walls will be compliant, however in order to maintain the fire barrier required, existing walls will need to be extended all the way to the roof deck above. Newly constructed elements will have to comply with the IBC however.
What is the Fire Rating?
So far, we determined that the new bedrooms need to be fire rated and separated from the rest of the building, but what is the fire rating required? The IBC requires Exit Passageways to have Walls, Floors and Ceilings to have minimum construction of 1-hour fire resistance. For those who are not familiar with Fire-Resistance Ratings, they refer to how many hours an element can withstand a fire. Any new walls can simply be constructed to meet this fire rating; however, the challenge is the existing ceiling and floor structure above makes this difficult.
Because we cannot alter the floor structure above the existing wood joists, there are no UL assemblies (Standard assemblies that have been tested and proven to meet certain fire resistance ratings) that can be constructed with the existing wood joist construction. This requires us to build a horizontal shaft wall assembly below the existing structure. For those who are not familiar, a horizontal shaft wall can be thought of as building a fire rated wall, that is overhead like a ceiling. The newly constructed horizontal shaft wall must not violate the minimum ceiling height that is required, which is normally 7’-6” per the IBC, however there is an exception that allows dwelling units and sleeping units within a residential occupancy space that allows for a ceiling to be 7’-0”. Due to the tight height of the existing basement, this required the existing ceiling to be removed and the existing sprinkler heads to be relocated.
Closing
At first glance, adding some bedrooms to an existing Basement may have seemed to be a small project, but there is always more that needs to be considered. While an elevator is not required to be installed, in order to construct these new bedrooms, a few things need to be completed first.
- Existing windows need to be removed and replaced.
- Existing ceiling needs to be removed.
- Existing doors in the exit path need to be removed and replaced.
- A new wall and door need to be constructed to shorten the Dead End distance.
- A new wall and door need to be constructed near the exit door.
- Existing walls need to be extended to the underside of the floor deck above.
- A new horizontal shaft wall needs to be constructed at the minimum height.
- Existing sprinklers need to be relocated to accommodate the new layout.
All of this is still cheaper than an elevator, however if construction had started and these items are raised, the cost would have quickly skyrocketed out of control. This was a small project, and only touched on two of the International Code books. There are roughly fourteen International Code Books, countless handicap accessible standards to meet, as well as auxiliary code standards. (All of which we had to gloss over to keep this from becoming obnoxiously long)
The moral of the story is this…whenever you are building, removing, or reconfiguring something. TALK TO AN ARCHITECT.
Any last minute surprises a code official or building inspector will have for you will only cost more time and money.
If you feel I missed the mark or am misinformed on any aspect of what I wrote, please let me know.
If you did enjoy the post or have any ideas or questions you would like to see or hear about in the upcoming posts and videos in this series, please let me know that as well.
Thank you all and have a great day.
- Bryan Toepfer, AIA, NCARB, CAPM
- Principal – Architect
- TOEPFER Architecture, PLLC
- Direct: 518.443.9366
- http://www.toepferarchitecture.com
- btoepfer@toepferarchitecture.com
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