The documentation requires a composite STC of 50 between Office / Conference Room and Hallway / Stairway. At a wall with a door, this will require a wall with four total layers of GWB and an STC-45 door. Is the intent here similar to LEED for Schools where the main partition is what is important and an entry door and window are assumed and can be ignored?
Footnote 1 seems to indicate that the underlying goal is "Normal speech privacy (except at corridor walls with doors)". Does this mean that the required STC values can be ignored at "corridor walls with doors", or is there another standard that should be applied here?
Larissa Oaks
Specialist, LEEDUSGBC
LEEDuser Expert
67 thumbs up
January 21, 2014 - 12:37 pm
Hi Matthew,
The entry door and windows cannot be ignored, they should be considered when determining the STC of the wall assembly.
Matthew Azevedo
January 21, 2014 - 1:09 pm
How are you expected to achieve STC 50 at corridors for offices in a practical sense? You'd need a STC 45 rated door and no windows with a 2+2 wall, which is completely impractical in an office building due to the cost of the doors. If this credit is going to require the elimination of glass fronts for offices and conference rooms (which are often needed to get LEED credits for daylighting) and even simple vision lites I can't see anyone pursuing it.
Additionally, in most offices the door will comprise more than 10% of the entry wall's area, making it impossible to achieve STC 50 even with a rated door and no glazing.
Larissa Oaks
Specialist, LEEDUSGBC
LEEDuser Expert
67 thumbs up
January 31, 2014 - 11:09 am
Hi Matthew,
I think you have a few options. The intent of the sound isolation requirements is to meet or exceed a normal speech privacy level. Since the speech privacy is a combination of STC and background noise, you could meet the credit intent with a lower STC rating by providing increased background noise.
Additionally, depending on the design and office culture, you may be able to justify a lower level of speech privacy between the enclosed offices and the adjacent corridor or open office space. Some potential reasons:
1. Full privacy is not required as sensitive conversations are not occurring in these spaces.
2. Design has incorporated spaces with Normal (or higher) level of speech privacy for sensitive/private conversations (i.e. HR meetings, executive offices, etc.)
3. Office culture promotes open dialogue and collaboration so some lack of privacy is OK.
4. Adjacent space is a corridor and is transient. People aren’t eavesdropping outside of offices, they are just passing by.
5. Adjacent space may be open office but people are seated at a distance that provides additional attenuation (and/or there are screening elements that act as sound barriers/absorbers).