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Hi everyone, I’m Pam Cole and welcome to this episode on vestibules sponsored by the
US Department of Energy’s Building Energy Codes Program.
We will be bringing you the inside scoop on the national
model energy codes, the latest news on building efficiency practices, and tips on making compliance
easier while saving money and energy. Today, we’ll be taking a look at vestibules, when
they are required, how they work, and how they can
reduce your energy bill.
The entrance behind me is called a vestibule, which is defined as a completely enclosed,
unconditioned space, that separates the inside entrance
of a building from the exterior. What an unconditioned space
means is a space that is not heated and/or cooled. Now the primary intent behind the
requirements of a vestibule is to reduce infiltration for areas
that have doors that have a high volume of pedestrian traffic.
These doors are typically used by the general public to enter public spaces, unlike doors
that are classified or employee use only. Vestibules
can reduce infiltration losses and gains from wind and stack
effect by creating an airlock entrance. The term infiltration means air leaking into and
out of a building that can be a major contributor to heat loss
and gains.
Vestibules must be designed so that the doors leading into and out of the vestibule do not
open at the same time. This allows a person to enter the
vestibule and the doors shut behind them. The person then
can exit the vestibule. This creates and airlock entry reducing infiltration.
So when is a vestibule required? Unless any exemptions apply, it’s on primary entrance
doors leading into a space that is greater than or equal
to 3,000 square feet. Now how do you determine the 3,000
square feet area? Basically you’re taking the entrance into a building and calculating
the floor area from floor to ceiling partitions and if there are
corridors or hallways that lead off of the space that you’re
entering, if there’s not an enclosed door that separates those areas then you would
include that floor area as well. Now some possible exemptions
that apply to that are doors not intended as a building
entrance such as mechanical or equipment room, other doors that lead from a guest room, dwelling,
or sleeping unit, and doors that are directly
opening to a space that is less than 3,000 square feet. And then
also, you also have doors that are for vehicular movement, material handling, or for employee
use only. So how is compliance determined during plan
review and final inspection? Verify that doors which
separate the conditioned space from the exterior and that lead into spaces that are greater
than or equal to 3,000 square feet contain a vestibule.
Also, you must verify that those doors leading into and
out of the vestibule do not open at the same time, and also meet the requirements of the
Americans with Disabilities Act Accessibility Guidelines
for buildings and facilities. You must also determine and
verify that that the building components, that separate the conditioned part of the
building from the vestibule, meet the building thermal envelope
requirements that would be applicable within the
project’s location. And then lastly, if the building is exempt from having a vestibule
installed on that building, that you truly are determining that
the space from the entrance to the building is less than
3,000 square feet.
Vestibules provide a means for businesses to save energy and decrease their energy bills.
Managers can maintain control of the indoor climate, maximizing
customer and worker comfort. Speaking of which, it’s
a little warm out here, so I’m going to head inside. I hope you enjoyed this episode,
and for more information, go check out our easy to use
compliance tools for residential and commercial buildings, and
send us feedback or podcast requests at energycodes.gov. I’m Pam Cole, and on behalf of DOE’s Building
Energy Codes Program, thanks for watching.