Hello! I have a question regarding the inclusion of Vestibules (double entrances to buildings to prevent heat loss), in a Court House building project we’re working on. This project is located in a 3C climate zone, with a built surface area of 30.000 sqft aproximately, 3 stories above ground and 1 underground, and is being certified for LEED v4.
The main building entrance (for the general public and with the highest use frecuency) has a vestibule which complies with the requirements described in ASHRAE 90.1-2010, section 5.4.3.4 Vestibules. However, there are about 7 other doors that connect to the outisde of the building that don’t consider vestibules, and we’re not sure whether they should be implemented as they're not main building entrances. These include: door in the underground floor to enter from the parking lot into the building (only for workers), doors on the second and third floor that connect office spaces to outside terraces (only for workers), and a secondary building entrance on the ground floor only for workers.
Based on the Exceptions for section 5.4.3.4, we think point b, "Doors not intended to be used as a building entrance”, could be applied to the other entrances, as they’ll have considerably lower usage than the main building entrance; however, we're unsure if we're understanding the criteria correctly for the exceptions, and if there are any additional criteria or ways to identify whether the other entrances should have vestibules (for example, being able to define it based on usage frecuency).
Any help would be kindly appreciated! Thank you!
Jamy Bacchus
Associate PrincipalME Engineers
20 thumbs up
June 12, 2023 - 1:07 pm
This may not fully overlap with your question. It sounds like you're in CA and thus under Title 24--I'm not sure if you're under 2019 or 2022. If the local code doesn't require vestibules you can apply LEED ID 10426 and take a possible hit on your energy results.
https://www.usgbc.org/leedaddenda/10426
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5868 thumbs up
June 12, 2023 - 4:12 pm
It sounds to me like the other two entrances for workers only from the parking lot and the ground floor are building entrances that should comply. The terrace doors are not building entrances. The definition - "building entrance: any doorway, set of doors, turnstile, vestibule, or other form of portal that is ordinarily used to gain access to the building by its users and occupants." The term "main building entrance" does not reside in the standard and therefore does not matter.
Jamy Bacchus
Associate PrincipalME Engineers
20 thumbs up
June 29, 2023 - 5:09 pm
* My comment was based on CZ 3C which is California here. Later on I saw you had noted "Chile". But the general note on vesibules and the deduct might still apply to folks reading this thread.
Christopher Russell-King
ArchitectConsultora Pasiva Ltda.
6 thumbs up
November 20, 2023 - 2:40 pm
Hi Marcus and Jamy, thank you for your replies and clarifications!
I have an additional question reagrding this topic: if we have a building entrance in the underground floor that connects the underground parking space to an unconditioned hallway, but this hallways has a staircase that connects directy to a conditioned space on the floor above, would this building entrance also require a vestibule? (This stair case does not have doors). Any help or recomendation is greatly appreciated! Thank you
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5868 thumbs up
November 27, 2023 - 11:53 am
Sounds like there is a connection between unconditioned space and conditioned space. According to Section 5.4.3.4 only entraces between conditioned space and the exterior are required to have vestibules.