Party Walls

The sunset date for LEED 2009 project registration has come and gone and all new LEED registrations (or existing registrations that will not submit for preliminary review before June, 30 2021) will fall under the V4 rating system. We are still seeing a trickle of requests for LEED 2009 compliance support for projects that were registered before the October deadline, but those are becoming few and farther between. At the same time, design and construction teams are still wondering what the differences are between the rating systems. So, we are highlighting a few changes to the commissioning requirements in LEED V4 BD&C about which Architects and Developers should be aware.

Major changes to Commissioning requirements for LEED V4  

1. Contract CxA Early in Design Development Phase Fundamental Commissioning (i.e., prerequisite!) now requires a review of the Design Development (DD) documents and requires the Commissioning Authority (CxA) be contracted before the end of the DD phase. We recommend project teams use the Conceptual or Schematic Design sets to secure a CxA contract early in the design process. V2009 only required a design review for Enhanced Cx.

2. Over 20,000 sf = Third Party CxA
   If the facility is over 20,000 square feet an independent third party CxA is required as defined by Table 1 in the EAp1 Credit language (excerpted below). It would be anticipated that projects in which the HVAC designer is also the CxA will become even more limited. V2009 Third Party CxA cut off was 50,000 sf.

3. Building Envelope Design Review
   The building envelope strategy and goals must now be included in the OPR and BOD. The CxA must complete a technical review of the building envelope during the fundamental commissioning design review. LEED does not detail the focus of this review, but our approach typically includes review of the roof and wall sections and details. V2009 did not include any Building Envelope Cx requirements.

4. Includes Electrical Service & Distribution
   Electrical Service and Distribution Systems are now included in the Cx scope. This broadened scope addition is generally limited to items related to LEED credits, such as energy metering demand response provisions, as well as power failure response of other Commissioned systems. The V2009 commissioning scope items remain in the V4 scope. These include HVAC&R, Automatic Temperature Controls, Lighting and Daylighting Controls, Renewable Energy Systems, and Domestic Hot Water Systems.

5. More Points for Enhanced Commissioning
   Three to six points are available for enhanced commissioning under three options/paths listed here:>Enhanced “Option 1 Path 1” for 3 points. This is similar to V2009 enhanced Cx requirements with some clarified requirements. This option includes: verifying design includes requirements for systems manual and owner/occupant training; reviewing submittals; verifying systems manual development and owner training are effectively completed; and, developing an on-going commissioning plan.>Monitoring Based Commissioning “Option 1 Path 2” for 1 additional point. This is simplest to accomplish on projects with full building automation systems. We find it easiest to assess this credit once the controls detail is developed.>Envelope Commissioning “Option 2” for 2 points. This requires adding to the envelope design review required in the Fundamental scope (as outlined in §3 above) and including the envelope in the construction phase commissioning scope. This typically requires mockup testing to be built into the specifications and additional site inspections performed by a member of the commissioning team with expertise in building enclosures.

   LEED V2009 provided up to two points for Enhanced Commissioning.

6. Fundamental Commissioning is More Involved
   The fundamental commissioning prerequisite has grown to include some formerly enhanced commissioning steps, including the design review, and O&M Plan (a scaled down version of the systems manual), as well as a new requirement to transition the Owner’s Project Requirements into the Current Facilities Requirements (CFR) at the end of construction to align requirements of the initial project team with the operation team’s requirements.

Who can be the Commissioning Authority?

The question clarified back in 2006 has been re-clarified within the EAp1 credit language. Besides the reduced square footage requirements for an independent CxA discussed above, the credit language clarifies that multiple CxAs can be engaged for different portions of the commissioning scope (i.e., Envelope, Electrical, Fundamental, Enhanced, MBCx, etc.) as long as one CxA oversees and coordinates all deliverables provided by the CxA team. The table below clarifies who can be the CxA.

* For data centers only: with computer room peak cooling loads less than 2,ooo,ooo Btu/h or a total computer room peak cooling load less than 6oo,ooo btu/h(175 kW), the CxA may be a qualified employee of the design or construction team.

In addition to the three points awarded for the Enhanced Commissioning Credit, project teams can elect to pursue one or two additional points for Monitoring Based Commissioning and Envelope Commissioning.

Monitoring Based Commissioning (1pt)

Monitoring Based Commissioning (sometimes referred to as On-going or Continuous Commissioning) takes the 10 month warranty review requirement to the next level by regularly reviewing energy and key control system data points to assess building performance often using predictive algorithms to identify system deficiencies. As shown in the figure below, the concept is to reduce the building’s energy consumption by identifying and addressing system deficiencies as they occur as opposed to months or years later when the building is retro commissioned. The credit requirements are similar to the Measurement & Verification credit in that a plan needs to be developed and contracted to implement the process for at least one year post construction.

Source: LBNL, 2012, Evan Mills, “Monitoring-Based Commissioning: Benchmarking Analysis of 24 University”

Envelope Commissioning (2pt)

This credit continues the Envelope design review into the construction phase to review submittals and to physically inspect and test envelope components to verify that they meet the design requirements for air tightness and thermal performance. The process is outlined in ASHRAE Guideline 0-2005 and NIBS Guideline 3-2012 “Exterior Enclosure Technical Requirements for the Commissioning Process” as it relates to energy, water, indoor environmental quality, and durability. This might include enhanced performance testing of mockups and/or large scale tests, such as whole building blower door testing, and can potentially add a significant cost. However, such tests can be very valuable in providing assurance to ownership that the quality of the installed envelope meets the facility’s needs.

By Kevin McDonald, Energy Engineer