Cx Monitor: LEED v4- Commissioning Changes in the USGBC’s Newest Green Building Rating System
Project teams pursuing certification under the LEED® v4 Building Design and Construction rating system should carefully examine their commissioning process and scope, as the updated rating system includes several new requirements and options for building commissioning. Following is a selection of significant changes in commissioning requirements, based on information currently available within the LEED v4 BD+C reference guide. As project teams prepare for new LEED v4 projects, this information will provide an overview of changes affecting scope, systems, timing, and contracting specific to the commissioning process.
LEED v4 has placed an increased emphasis on bringing the entire team to the table earlier in the design process. As a result, updated guidelines require that the Commissioning Authority (CxA) be engaged by the end of the Design Development phase.
Requirements related to CxA experience and employment have been further clarified. CxA experience must span at least two projects with a similar scope of work, and experience must begin in early design phase and extend through at least 10 months of occupancy.
Similar to previous versions of LEED, the CxA performing fundamental commissioning may be a qualified employee of the owner, an independent consultant, an employee of the design or construction firm who is not part of the project’s design or construction team, or an independent subcontractor of the design or construction team. The CxA is always required to report findings directly to the owner.
If a project is smaller than 20,000 SF, the CxA responsible for fundamental commissioning may be a qualified member of the design or construction team. This has been reduced from previous versions of LEED, which cited a cut-off point of 50,000 SF.
COMMISSIONING SCOPE CHANGES
LEED v4 introduces a number of changes to the scope of work for the CxA. These scope changes affect the breadth, duration, and types of commissioning agents required for LEED v4 projects.
Fundamental Commissioning and Verification Scope Updates
Changes to the commissioning prerequisite will require an increased scope of work for the CxA, as compared to previous versions of LEED. Updated requirements state that construction checklists must be developed by the CxA. Additionally, exterior enclosure criteria must be included in the Owner’s Project Requirements (OPR) and Basis of Design (BOD), as well as the CxA review of the OPR, BOD, and project design.
For each LEED v4 project, a Facility Requirements and Operations and Maintenance Plan must be prepared by the CxA, including the following details:
- Sequence of operations for the building
- The building occupancy schedule
- Equipment run-time schedules
- Setpoints for all HVAC equipment
- Set lighting levels throughout the building
- Minimum outside air requirements
- Any changes in schedules or setpoints for different seasons, days of the week, and times of day
- A systems narrative describing the mechanical and electrical systems and equipment
- A preventive maintenance plan for building equipment described in the systems narrative
- A commissioning program that includes periodic commissioning requirements, ongoing commissioning tasks, and continuous tasks for critical facilities
Enhanced Commissioning Options
Up to 6 points are available under the updated enhanced commissioning credit, spread across 3 different options:
- Option 1, Path 1: Enhanced Commissioning (3 points)
- Option 1, Path 2: Enhanced and Monitoring-Based Commissioning (4 points)
- Option 2: Envelope Commissioning (2 points)
Enhanced Commissioning Scope Updates
The creators of LEED v4 have attempted to bridge the gap between the design and construction process and building occupancy within several areas of the rating system. As a result, the enhanced commissioning credit now includes a requirement for the development of an ongoing commissioning plan.
This new enhanced commissioning option requires the development of monitoring-based procedures, including the identification of points that will be measured and evaluated. Scope must include both energy and water-consuming systems. This credit also requires as-needed updates to the systems manual, including explanations for any modifications to the original design.
The following items must be included in each monitoring-based commissioning plan:
- Roles and responsibilities
- Measurement requirements (meters, points, metering systems, data access)
- The points to be tracked, with frequency and duration for trend monitoring
- The limits of acceptable values for tracked points and metered values
- The elements used to evaluate performance, including conflict between systems, out-of-sequence operation of systems components, and energy and water usage profiles
- An action plan for identifying and correcting operational errors and deficiencies
- Training to prevent errors
- Planning for repairs needed to maintain performance
- Frequency of analyses in the first year of occupancy (at least quarterly)
The new option for envelope commissioning will require teams to fulfill the requirements of EA Prerequisite Fundamental Commissioning and Verification as they apply to the building’s thermal envelope. The scope of work must include energy, water, indoor environmental quality, and durability; referenced standards are ASHRAE Guideline 0–2005 and the National Institute of Building Sciences (NIBS) Guideline 3–2012, Exterior Enclosure Technical Requirements for the Commissioning Process.
The changes in commissioning criteria for LEED v4 are significant. Owners and project teams should consider these differences with respect to their planning process. SSRCx is available as a resource to assist in determining the potential impact to a project’s scope, system and consultant requirements, and fees. We look forward to successful LEED v4 projects with our clients and industry partners.