I'll let you figure out how to read the title (you may want to cover your children's ears for one of them), but the following post will cover some helpful practical info I've recently learned the hard way. Basically, there are a set of figures and data that must be consistent across various LEED credits. This isn't a big problem, but it's very easy for separate trades (civil, landscaping, architect, electrical) to be working from different sets of drawings with slightly different figures. If everyone finishes their documentation with different numbers, someone is going to end up doing their work over, which is a huge annoyance and waste of every one's time.
Though the following may seem obvious for those working on simple projects, determining a site boundary gets much more complex once you add multiple buildings or on a nebulous site, i.e. a campus or master-planned development. Your boundary may end up changing over time, and it's really only important that these numbers are nailed down before everyone starts their final documentation, but at the same time I like to keep them updated so I can do back of napkin calculations over the course of the project to make sure we're on the right track and no nasty surprises emerge (e.g. "Oh yeah... we're going to need another 2 acres of open space"). Please note the proper use of both i.e. and e.g. in the above paragraph... I had to look up the usage to make sure I got it right!
The Reasonable Project Boundary's Impact
Some of you may be lucky enough to work on a clearly defined site with easy to understand boundaries. I have yet to be so lucky. Even the single buildings I'm working on seem to always be in a campus or master planned setting. As a result, there is no clear boundary and LEED allows you to determine a 'reasonable' one. More on that later... This is probably the most important item to define early on, as it will affect SSc2 (development density), SSc5.1 (protect habitat), SSc5.2 (open space), SSc6.1 and 6.2 (stormwater quantity and quality), SSc7.1 (heat island, non-roof), SSc8 (light pollution), and WEc1.1 and 1.2 (water efficient landscaping) calculations. Once the building is sited, it quickly becomes difficult to make changes. What makes it even more critical to determine is the fact that typically these credits are typically divided among four design team members: the architect, civil engineer, electrical engineer, and landscape architect. Even in the ideal world of total integrated design, at some point these folks are each going to be putting the finishing touches on the LEED documentation at their desk all alone. It's critical that if one party makes changes that the others are made aware and can adjust accordingly!
When Do I Need a Reasonable Project Boundary?
Again, if you have a single building on a "normal" site none of the following should apply to you. When the calculations call for volume and rate of stormwater leaving the site or allowable footcandles a 15 feet from the site boundary you're stuck with what you have. When your building is in the middle of a master planned development where your 'site' drains to retention facilities a block or two over and you're stuck with site lighting standards that run along the edge of your 'property' things get much more complex. Even though the stormwater is leaving the area around my building, it's not a drain (HA!) on the local infrastructure, and that lighting doesn't trespass on anyone, it's just to light a sidewalk that connects my building to one next door... Why should my project's rating be punished for good design that just happens to span large distances?
It's for issues such as these that the USGBC drafted the slightly helpful LEED-NC Application Guide for Multiple Buildings and On-Campus Building Projects(AGMBC), which provides (not enough) guidance on how you can mitigate these issues. Essentially, you're allowed expand your site boundary to include large-scale measures such as those mentioned above. I've written about a few other multiple buildings issues here
How Do I Determine a Reasonable Project Boundary?
This is where things get confusing. Though it's briefly mentioned in the AGMBC, it wasn't clear to me how this really works until I received some clarification from a VERY HELPFUL certification coordinator at the USGBC. This is in reference to a project where we have multiple buildings being certified within a larger masterplan:
Given that there are several buildings within one development you may choose to take the multi-building/campus approach when applying for particular credits, especially related to site issues. In that case you would have a larger campus/development site boundary and then separate buildings within that boundary. By following the AGMBC, it allows for these different boundaries (campus boundary vs. project boundary within campus) that may apply for different credits. The campus boundary must be consistent for all credits for which the campus boundary applies and project boundary must be consistent for all credits for which that boundary applies. It is up to the project team how to determine these boundaries for your particular projects whether by drainage plain, or some other means. However things such as open space and walkways may not be counted for more than one LEED building unless taking an aggregate approach.
As you can see, what we're really talking about here is TWO boundaries... one for the campus and one for the project. Before I tell you what we're doing in this regard, it's very important that I tell you that they have not yet been approved as correct by the USGBC review team at this point. I will be sure to update this post when that happens.
This picture is meaningless, but it looks like an upside-down man and I figured... What the hell? There's too much text in this post anyway.
We decided that instead of using the entire development as our campus boundary, the area that feeds into a set of retention ponds would mark our campus, as that completely contains the all of the buildings that are seeking certification. As such, the stormwater documentation for all buildings will be identical. On one edge we extended the boundary to include some of the lighting we are installing along road that our buildings front. If we used the stormwater boundary one or two lights (out of many) would 'trespass' onto the adjacent site, but since it's still all internal to the larger development I don't feel guilty. On the whole, it's still a responsible development. The only reason we didn't set the whole development as the campus boundary is because it would be difficult to pull complete stormwater data for everything. Our engineers were doing calculations on the area we've included already.
Our project boundaries were determined by the amount of open space needed to satisfy requirements for each building. I can hear many of you thinking about what a sham this is... that we're just setting boundaries in a point-mongering mentality. Though in a literal sense you're technically correct, it's important to note that the vast majority of the area surrounding our buildings is vegetated open space, a feat that was accomplished through the use of multi-story structured parking (at great expense to the owner) in an area that is generally characterized by large swaths of surface parking. Again, we have met the intent of the credit, and I feel that on the whole we're well within our rights to claim the space.
To get to this point took a lot of back and forth between civil engineers, electrical engineers, and the project architect. We had to set a boundary, examine it from all sides, and reset the rest to that which is the best fit. Where on a 'normal' project I would suggest that materials selection and procurement is going to be your most frustrating task, on multiple buildings projects it's clearly these site issues that get to be a hassle. We've known all along that we're doing the right thing, it's just a matter of putting it in an acceptable framework to meet the credit requirements.
Working on other projects has made me realize that how you determine these boundaries will be driven by different factors for different situations. PLEASE share your experiences with the world by leaving a comment!
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