What is compartmentalization?
Multifamily developers are familiar with this 20-letter word. But, it sometimes creates confusion. What exactly does it mean and when is it used?
Also known as single-unit blower door testing, compartmentalization is the process of sealing up gaps and openings between adjacent units.
Here are the 5 questions I hear most often in regard to multifamily air sealing and compartmentalization:
1. Is compartmentalization required?
The IECC requires whole-building sealing, but does not require compartmentalization. Compartmentalization is a Passive House requirement. Each unit must meet or exceed 0.30 ACH50. It is also a requirement of LEED BD+C: Homes | v4 – LEED v4.
2. How is compartmentalization accomplished?
The residential International Energy Conservation Code (IECC), ENERGY STAR, LEED, Green Communities and Passive House all use blower door testing to demonstrate tightness of building envelope and individual dwelling units. Air sealing has often left up to the trades, but increasingly stringent tightness targets require builders to look at air sealing from the very beginning of the design process.
Most HERS raters and BPI professionals are qualified to perform compartmentalization testing. Due to fewer walls exposed to the outside, results typically show relatively low leakage compared to whole building or single-family home testing.
3. What are the benefits of compartmentalization?
There are important benefits to sealing each individual unit, including:
- Improved Comfort. Compartmentalization reduces hot/cold drafts and sound transfer between units.
- Better Air-quality. With a tightly sealed unit, there is greater particulate control. Especially, in cases of higher concentrations of outdoor air pollution, such as buildings located near freeways or in cities with poor air quality.
- Odor control. Less transfer from neighboring units, including cigarette smoke and cooking odors.
- Enhanced Safety. During fire, reduced transfer of smoke and hot gasses between units that helps fires spread.
- Construction Quality Control. By testing each unit, pre-drywall, possible workmanship flaws are exposed and able to be addressed.
- Energy Savings. Lower electric bills, due to fewer leaks and reduced energy demand.
4. What are the challenges of compartmentalization?
With improved air tightness, ventilation design becomes especially important with compartmentalization, especially in taller buildings, due to the inherent air pressure differences and opportunities for air infiltration. With properly designed ventilation, and well-sealed ductwork, each unit will have balanced air.
What are the costs of compartmentalization?
Costs are broken down into testing and application.
Testing: Single-unit tests are less expensive than whole-building tests because they require significantly less equipment and personnel. For example, a whole-building test of 50-units, using five blower door setups and six technicians, costs approximately $6,000, or $120 per apartment. Single-unit testing for compartmentalization may only cost $28 per unit, or approximately $1,500 for a 50-unit building.
Application: The main challenge with significant leakage reduction is searching for holes that may not be visible to the eye. This means hours spent between the caulk gun, testing, and possibly retesting. This means, the biggest expense is time, labor, and possible delays. At AeroBarrier, our goal is to remove this expense, and guarantee the blower door results – the first time!
Recently, AeroBarrier was used on Harlem’s first Passive House certified multifamily project, Perch. I received a call from the Architect, Chris Benedict, stating there were challenges achieving the stringent Passive House leakage requirements for compartmentalization, or 0.30 CFM50 Pa/sqft.
By using AeroBarrier, Perch achieved less than the Passive House requirement of .30 ACH50.
When we spoke with Chris, she said, “I was excited to not have to follow the caulk guys around, unit by unit, searching for holes. With AeroBarrier, this step was eliminated, saving money and countless hours. Needless to say, the developer was very pleased.”
Chris cited the benefits of compartmentalization, saying “You’re not getting the smells, the noise, or bugs and mice running back and forth between apartments, because the apartments are literally sealed from each other. Also, the units have exceptional temperature control compared to a typical New York City apartment which is very leaky.” Benedict notes, “When the windows are closed you can barely hear the garbage trucks and the traffic and other things going on outside. That is a huge added bonus”
Contact me for all of your compartmentalization questions
Are you building a multifamily project to the stringent standards of Passive House, WELL Standard, LEED, or ENERGY STAR Multifamily Hi-Rise? Or, do you simply want additional information about AeroBarrier or compartmentalization? I am here to help. Please send me a direct message. If you have a comment about this article, please enter it below and start the conversation.
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