Retrofitting Building Enclosures to Improve Energy Consumption

21 Feb 2023

An introduction to the BECx process

The airtightness of building enclosures, or envelopes, directly affects the building's energy consumption. The less efficient the airtightness of an enclosure, the more energy the building uses. Airtightness also affects indoor air quality (IAQ) and improves moisture management for the building. In this blog, we're going to look at the building enclosure commissioning (BECx) process that is followed when retrofitting building enclosures.

Existing buildings represent a huge opportunity to reduce energy use and the building's carbon footprint. Most existing buildings were built before any mention of air barriers or enclosures or air control requirements were made in the International Building Code. But these requirements are becoming mandatory and must be met when a building is altered or remodeled. The Department of Energy is also providing funding opportunities to underwrite the cost of jurisdictions implementing IECC 2021 energy code.

The reason for this is that buildings with reduced air leakage can provide energy savings of 10-40% depending upon climate zone, in turn reducing carbon footprints and contributing to decarbonization. These are crucial elements when we talk about environmental, social, and governance (ESG) reporting, which has increasingly become an area of focus for real estate investors: according to real estate investment management firm JLL, the question of ESG is raised in 80% of conversations around properties. Investment risk and climate risk go hand-in-hand in the building and construction industry.

Retrofitting enclosures is best done through the BECx process. This is a formal process that begins with the establishment of the owner's project requirements (OPR) most important and endeavors to confirm that the exterior enclosure and those elements intended to provide environmental separation within a building or structure meet the expectations of the owner as described in the OPR, and as defined by the contract documents. It is during this step of the process that everything that will be accomplished during the project is established, with measurable results based on performance requirements. This way everyone on the team knows what is expected and is held accountable to the project's outcome.  

BECx is a five-phase process that includes:

Pre-Design Consulting

• Work with Building Owner to develop Owner's Performance Objectives (OPO)
• Development and acceptance of initial Commissioning Plan
• Evaluate design concepts against OPO and Architect of Record's design intent

Design Phase Services

• Develop and document commissioning specification, establish commissioning team, and identify responsibilities
• Review project drawings and specifications
• Develop design concepts with the Architect of Record
• Perform final review of bid/tender documents
• Develop construction checklists
• Coordinate Pre-Bid Meetings and briefing of construction management team

Pre-Construction Phase

• Review construction sequencing and scheduling
• Verify material/assembly compatibility
• Evaluate submittals and shop drawings
• Coordinate Pre-Construction Commissioning Meetings
• Oversee construction of mock-up and perform testing with documentation, observations, comments, and recommendations
• Perform material testing of alternative materials
• Perform hygrothermal computer modeling (WUFI & THERM)

Construction Phase

• Finalize Commissioning Plan based on mock-up testing
• Verify and document field QA/QC programs
• On-site review and field testing of installations
• Integration of RFIs and change orders to the Commissioning Plan
• Provision and follow-up of on-going deficiency lists
• Attendance at relevant site meetings
• Coordination of Commissioning Plan items to relevant parties
• Resolve disputes related to building enclosure performance

Operations & Maintenance Phase

• Finalization of project commissioning record with warranties and close-out documentation
• Verify applicable training procedures of building maintenance personnel
• Update and distribute Commissioning Report

To learn more about the opportunities and challenges of retrofitting buildings, download my recent presentation, Existing Building Opportunities: Retrofitting Enclosures to Improve Energy Conservation, Indoor Air Quality, and Moisture Management. It explores the history and state of the practice for enclosure design, energy code/existing building code/sustainability requirements and market impacts, enclosure investigation techniques, and present case studies about successful building enclosure retrofits.