LEED Midrise Certification
Last year, I petitioned the USGBC Technical Committee on Homes and received the green signal to pursue LEED certification for a 32 story apartment tower in San Francisco’s Transbay neighborhood. Midrise V 2010 allows certification for residential buildings of 4 to 12+ stories with exceptions made for taller buildings on a case-by-case basis. Residential projects certifying under LEED V 4 are required to use Midrise for buildings with 4 to 8 stories. Buildings with 9 to 12 stories have a choice between Midrise V4 or NC V4 with many exceptions being granted for use of the Midrise system for buildings taller than 12+ stories. Indeed, USGBC has been under tremendous pressure by developers to allow use of LEED Midrise certification for high-rises, instead of the NC system.
As I got more familiar with the LEED Midrise rating system, I was struck not only by how much better suited it was to residential occupancies, but also the considerably reduced documentation and related soft costs.
Given LEED’s reputation in the marketplace as being heavy on documentation and increasing construction costs, most developers and architects shy away from considering it. So I want to take this opportunity to shed light on a rating system that really flies in the face of these assumptions.
With the LEED Midrise certification system we have an opportunity to provide the public with housing that is certified green without the associated cost markup. And it can be applied to apartment buildings, condominium conversions, mixed use, assisted living facilities, student housing, etc.
Here are a few instances where LEED Midrise (V 2010) differs from LEED BD+C (V 2009):
- Home size adjustment: In this, the credit threshold is “adjusted” based on size of homes and number of bedrooms. So sprawling homes are “fined” for excessive resource consumption, but small homes with multiple bedrooms (i.e. any room that can potentially be used for sleeping) are rewarded by lowered certification thresholds. In my Midrise project, the certification threshold was lowered by 6 1/2 points. This meant platinum certification required 83.5 points in lieu of 90 points!
- Points are awarded for housing density.
- Points are awarded for water efficient and energy star appliances and fixtures
- No tracking of costs during construction for Materials credits, just using the “right” materials earns points.
- No tracking of waste hauls throughout construction. Simply upload the statement from your waste hauler that provides percentage of diversion.
- No tracking and logging of adhesives, sealants, paints, etc. through construction.
- Preoccupancy flushout is a total of 48 hours in lieu of having to provide 14,000 CFM of air per SF at 60% relative humidity.
In addition, there is little (if any) documentation that needs to be produced by project team members specifically for LEED credit purposes. In most or all cases, they simply upload the drawings they have already produced for permitting purposes.
So what about some of the harder or unusual aspects of LEED Midrise certification? Let’s discuss those as well.
- EPA Multifamily Testing and Verification protocols: This is a prerequisite in the Energy category and is incredibly tedious and time consuming to boot. So the USGBC offers a simpler alternative which requires a combination of HVAC Cx, HERS Rater inspection of insulation and a “thermal enclosure checklist”. This checklist is a list of items that need to be sealed such as recessed lights, electrical and plumbing penetrations, etc. The checklist also includes a list of places that the HERS rater needs to inspect in order to confirm that the insulation is in direct contact with an air barrier such as sheetrock.
- Blower Door test: This requires the HERS Rater to test the units to ensure that they do not exceed an air leakage rate of 7 ACH50. This testing is accomplished via a blower door test and there is usually a sampling rate of 1 in 7 to 1 in 10 used to limit the number of units tested. This leakage rate is not too ambitious and is in keeping with what can be expected for new construction.
So the scope of the HERS Rater in considerably expanded in a LEED Midrise project and thereby equates to some added costs over a non-LEED project. Projects permitting under the new 2013 Energy Code, will already have HERS Raters on board to verify certain aspects of their HVAC equipment. This prerequisite creates some overlap between the Energy Code requirements and those of LEED.
I hope this article helps convince architects, developers and building owners to give LEED certification a second look. The bottom line is that LEED Midrise certification gives you an opportunity to differentiate your housing complex with a nationally recognized brand and provides the consumer with independent, third party certified green housing at a cost much lower than that of LEED BD+C.
Who is Healthy Building Science?
Environmental Testing Services at HBS
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