LEED v4.1 Revisions Point to the Future of Building Commissioning
The U.S. Green Building Council recently released version 4.1 of LEED. In it, one will find many important updates to the rating system. I recently cross-referenced the guidelines and standards related to commissioning in LEED v4 versus LEED v4.1. What might initially appear to be minor changes to referenced documents may actually give us a glimpse into big changes on the horizon for how we approach building commissioning.
LEED v4 Commissioning
In LEED v4 Building Design and Construction (BD+C), the Fundamental Commissioning and Verification prerequisite defines the commissioning process scope as follows (my highlights):
Complete the following commissioning (Cx) process activities for mechanical, electrical, plumbing, and renewable energy systems and assemblies, in accordance with ASHRAE Guideline 0-2005 and ASHRAE Guideline 1.1–2007 for HVAC&R Systems, as they relate to energy, water, indoor environmental quality, and durability.
Requirements for exterior enclosures are limited to inclusion in the owner’s project requirements (OPR) and basis of design (BOD), as well as the review of the OPR, BOD and project design. NIBS Guideline 3-2012 for Exterior Enclosures provides additional guidance.
(The prerequisite language goes on to define the Cx process activities as indicated.)
The LEED v4 BD+C Enhanced Commissioning credit goes on to offer the following regarding the Envelope Commissioning (also referred to as Building Enclosure Commissioning or BECx) option, which also references ASHRAE Guideline 0-2005 and NIBS Guideline 3-2012:
Fulfill the requirements in EA Prerequisite Fundamental Commissioning and Verification as they apply to the building’s thermal envelope in addition to mechanical and electrical systems and assemblies.
Complete the following commissioning process (CxP) activities for the building’s thermal envelope in accordance with ASHRAE Guideline 0–2005 and the National Institute of Building Sciences (NIBS) Guideline 3–2012, Exterior Enclosure Technical Requirements for the Commissioning Process, as they relate to energy, water, indoor environmental quality, and durability.
(The credit language goes on to define the Cx process activities as indicated.)
The following is a brief definition of each referenced document.
Cx Referenced Documents in LEED v4
ASHRAE Guideline 0-2005: The Commissioning Process
Think general CxP. In 2000, ASHRAE and NIBS joined to develop a universal Cx process - this document was the result of that effort. Guideline 0-2005 defines the procedures, methods, and documentation requirements describe each phase of the project delivery and the associated CxP from pre-design through occupancy and operation, without regard to specific elements, assemblies, or systems. The CxP guideline procedures include the Total Building Commissioning Process (TBCxP) as defined by NIBS in its Guideline 3-2012.
ASHRAE Guideline 1.1-2007: HVAC&R Technical Requirements for the Commissioning Process
Think HVAC&R Cx. Guideline 1.1-2007 represents a revision of ASHRAE Guideline 1-1996 (which replaced the original Guideline 1-1989), which contained both general commissioning process requirements and HVAC technical requirements. The technical CxP requirements for different building systems are now defined in individual discipline technical guidelines separate from the universal commissioning process requirements that are defined in Guideline 0-2005. Although Guideline 1.1 focuses upon HVAC&R systems, a successful total building commissioning process will carefully validate interfaces and possible interferences between all building systems.
NIBS Guideline 3-2012: Building Enclosure Commissioning Process BECx
Think BECx. NIBS Guideline 3-2012 was the culmination of the work from the NIBS Building Enclosure Technology and Environmental Council (BETEC). Guideline 3-2012 fosters an impartial review of building envelope components and provides recommendations for the BECx process. The document clarifies that BECx services should validate the design and ensure that the performance of the building enclosure meets the OPR.
LEED v4.1 Commissioning
Contrast the LEED v4 criteria with that of the emerging LEED v4.1 BD+C Beta Guide. The LEED v4.1 BD+C Fundamental Commissioning and Verification prerequisite defines the commissioning process similarly but with different references (my highlights):
Complete the following commissioning (Cx) process activities for mechanical, electrical, plumbing, and renewable energy systems and assemblies, in accordance with ASHRAE Guideline 0-2013 and ASHRAE Guideline 1.1–2007 for HVAC&R Systems, as they relate to energy, water, indoor environmental quality, and durability.
Requirements for exterior enclosures are limited to inclusion in the owner’s project requirements (OPR) and basis of design (BOD), as well as the review of the OPR, BOD and project design. ASTM E2947-16: Standard Guide for Building Enclosure Commissioning provides additional guidance.
(The prerequisite language goes on to define the Cx process activities as indicated.)
The Enhanced Commissioning credit states the following for the Building Enclosure Commissioning option:
Fulfill the requirements in EA Prerequisite Fundamental Commissioning and Verification as they apply to the building’s enclosure in addition to mechanical and electrical systems and assemblies.
Complete the following commissioning process (CxP) activities for the building’s thermal envelope in accordance with ASHRAE Guideline 0–2013 and ASTM E2947-16: Standard Guide for Building Enclosure Commissioning, as they relate to energy, air and water tightness, indoor environmental quality, and durability.
(The credit language goes on to define the Cx process activities as indicated.)
The following is a brief definition of the revised referenced documents.
Revised Cx Referenced Documents in LEED v4.1
ASHRAE Guideline 0-2013: The Commissioning Process
Again, think general CxP. The 2013 edition of the guideline addresses changes to project delivery systems resulting from the evolution of whole-building commissioning in the life cycle and sustainable measurement and verification processes. Among other updates, the 2013 edition emphasizes the role of the owner in clearly documenting the Owner's Project Requirements so they may be transferred to design criteria and construction documents in a way that provides consistency and continuity throughout the scope of the project.
ASTM E2947 - 16a (2016): Standard Guide for Building Enclosure Commissioning
Replaces NIBS Guideline 3-2012 for BECx. The guide provides procedures, methods and documentation techniques that may be used in the application of the building enclosure commissioning (BECx) process. This guide provides recommendations for the enclosure commissioning process from its project planning through design, construction and occupancy and operation phases. The BECx process outlined in the document uses performance-oriented practices and procedures to verify that the project is achieving the OPR throughout the delivery of the project. The process is recommended to begin during the pre-design phase and continues through the occupancy and operations phase. The process includes specific tasks during each project phase.
This guide is complementary to ASTM E2813 and is aligned with ANSI/ASHRAE/IES Standard 202 and ASHRAE Guideline 0. ASTM E2813 and is aligned with ANSI/ASHRAE/IES Standard 202 are not referenced in the current iteration of LEED v4.1. However, defining these documents in context may prove instructive for anyone considering codifying the commissioning process.
Other Critical Cx Documents
ANSI/ASHRAE/IES Standard 202-2018: Commissioning Process for Buildings and Systems
ASHRAE/IES Standard 202 uses normative language to define the commissioning process: the roles of the principle agents and stakeholders, and a framework for developing design documents, specifications, procedures, documentation, and reports. It also describes the general requirements for a training program for continued successful system and assembly performance.
ASTM E2813 - 18 (2018): Standard Practice for Building Enclosure Commissioning
Practice E2813, as it is often referred to, is intended to serve as a concise, authoritative, and technically sound practice for building enclosure commissioning that establishes two levels of BECx: Fundamental and Enhanced. The 2018 edition includes a mandatory OPR development guideline, mandatory BECx performance testing requirements, and requires an independent design review during the design phase of both Fundamental and Enhanced BECx.
Why are these new Cx documents important?
In a big-picture sense, these new and revised Cx documents revolve around an industry move toward defining commissioning in such a way that it can be incorporated into codes and standards. Model codes and standards (which are often adopted as the basis for codes) require normative language; however, "guidelines" such as ASHRAE Guideline 0-2013 are written in non-normative language. As such, codes and standards cannot reference a guideline for content.
ASHRAE Standard 202 was developed to address the need for a commissioning process defined using normative language. Authorities having jurisdiction now have access to appropriate commissioning content for codes. However, it will likely take several years before owner awareness, general practice, and enforcement catch-up.
But make no mistake—total building commissioning is on the path to becoming codified and enforceable.
