LEED v4 vs LEED 2009 : les principales différences

All versions of LEED have shared similar intensions during this time, but LEED v4’s framework for achieving green-building goals – unveiled in 2013, and the newest version of LEED – takes a slightly different approach.

LEED v4 was reviewed and broken down into positives and negatives by technical advisory groups. Over its three-year development process, the U.S. Green Building Council (USGBC) received 23,000+ public comments and released six drafts. The final draft was approved by 86% of the consensus body.

One of the biggest differences when comparing and contrasting LEED v4 vs. LEED 2009 - its most recent predecessor - is the rating system and dependency on project type. In LEED v4, there are 21 rating system adaptations, which can be divided across five broad categories:

1.       Building Design & Construction (BD+C)
2.       Interior Design & Construction (ID+C)
3.       Operations & Maintenance (O+M)
4.       Neighborhood Development (ND)
5.       Homes 

Core credit categories have also changed in LEED v4 vs. LEED 2009. Since LEED's beginning, there have been five core credit categories where points can be earned:

1.       Sustainable Sites
2.       Water Efficiency
3.       Energy & Atmosphere
4.       Materials & Resources
5.       Indoor Environmental Quality

With LEED v4, a credit category for Location & Transportation was added to all rating systems, placing more emphasis and attention on reducing main contributors to global warming: transportation. The Location & Transportation category includes strategies to reduce costs, pollution and resource depletion related to daily commutes.

LEED v4’s System Goals

New to LEED v4, a list of LEED system goals was created (also referred to as "impact categories") to guide point allocation for each credit. Impact categories answer this question: "What should a LEED project accomplish?"

The seven different system goals are:

1.       Reverse contribution to global climate change
2.       Enhance individual human health and well being
3.       Protect and restore water resources
4.       Protect, enhance and restore biodiversity and ecosystem services
5.       Promote sustainable and regenerative material resources cycles
6.       Build a greener economy
7.       Enhance social equity, environmental justice and community quality of life

While all of these goals were implied in previous versions, stating them clearly and concisely helps explain what the USGBC actually wants to achieve with LEED.

Using the Integrative Process

In LEED v4, USGBC added a credit in nearly all rating systems to encourage the use of the integrative process. This requires all team members to be actively involved during a project, allowing them to work together to discover unique ways to reduce costs and material usage, and minimize environmental impact.

For example, choosing a paint color with a higher reflectance value may allow you to reduce the number of lighting fixtures in a room while still maintaining adequate lighting levels.

Following traditional building practices, choosing a paint color would’ve happened after the lighting systems were designed and installed. Using the integrative process, however, the designer and contractor are actively involved and working together – along with other team members – to meet desired objectives and come up with economical, energy-saving ideas.

The integrative process also requires an iterative process, which is used from the very beginning of a project through to building occupancy. It involves conducting research, sharing data, receiving feedback and repeatedly refining a project's design until its sustainable goals are met. To optimize building performance and meet the project's stated goals, building-system tweaks may be necessary even after a building is occupied.

Systems Thinking and Feedback Loops

Another key concept of LEED v4 vs. LEED 2009 is systems thinking, which follows the principle that the only truly sustainable system is a closed system. For example, a tree sheds its leaves in the fall. The leaves decompose and fertilize the tree's roots. The tree then drops seeds, which grow into new trees. Those trees, in turn, shed their leaves - and the process repeats until external forces interfere.

Instead of closed systems, most building processes are open systems: For example, resources, such as water, come in and waste goes out. LEED stresses the importance of converting as many processes as possible to closed systems.

Systems are affected by feedback loops – information flows that allow a system to organize itself (think about your air-conditioning system, for example, which turns on and off based on room temperatures and your predetermined settings).

In a negative feedback loop, systems self-correct and stay within a set range. In a positive feedback loop, energy is taken from a system's output and reapplied to the input, producing more of the system's output. The concept of population growth is an example. As more people are born, these people will give birth to future generations (and so on). In a built environment, negative feedback loops equate to a more sustainable building.

Leverage Points

Lastly, when comparing LEED v4 vs. LEED 2009, you'll notice that LEED v4 incorporates leverage points. A system's leverage point is the point at which a small change can potentially yield a big result. For example, when an automobile driver receives instantaneous feedback on his miles per gallon, he can change his driving habits to drive in a more fuel-efficient manner.

Applying this concept to the built environment, it's important to continually measure energy consumption, water usage and material usage. If this information is shared with building occupants, many will instinctively change their behavior to reduce things like energy and consumption beyond even the original building design.  

What Comes After LEED v4

In this newest version, changes to the LEED Materials & Resources credit were also made that directly impact products used in the built environment - including cable and connectivity. This credit category underwent a major overhaul, transitioning from a material-deselection approach to one that encourages product transparency.

Because LEED is an ever-changing program, the next step for LEED is LEED v4.1. It's not a full version change, but an incremental update. LEED v4.1 will simplify the rating system and streamline project scorecards and requirements.

Belden will pay close attention to the changes that occur as part of LEED v4.1 and will adapt quickly - and keep you informed. In the meantime, if you have any questions about LEED product selection or green buildings, our team is ready to help. You can reach us at sustainability@belden.com or visit our LEED webpage.