Building Enclosure Commissioning
What is the “building enclosure?”
The building “enclosure” also known as building “envelope” or building “shell” consists of all the exterior faces of the building, such as foundations, exterior walls and roof. The enclosure manages everything that might get into and out of a building: water, wind, light, sound, air, pests, and people. How the foundations, walls, and roof are put together (i.e. constructed) makes all the difference to how well the building performs—and for how long.
What is “Building Enclosure Commissioning?”
The building materials that make up the enclosure are developed by many different companies and have varying physical and chemical properties. These materials are assembled piece by piece on the construction site by hundreds of different tradespeople working for several different sub-contractors, and often with minimal coordination. This work is performed under all possible weather conditions with the intention of meeting a certain level of performance. However, this performance cannot be verified until the construction is complete and the building is fully enclosed. At that time, to access a non-performing or inappropriately installed building material becomes very expensive. Thus the most reliable means to achieve building performance targets is have an expert with in-depth knowledge of the enclosure be involved in the design and the construction process. During construction the Building Enclosure Commissioning Agent can visually check a statistical sampling of work and also test the enclosure components and systems to ensure they meet the desired level of performance.
This process is by which the design and constructed performance of the building enclosure are validated to meet the defined objectives, is known as Building Enclosure Commissioning or BECx and the person designated to perform this role is known as the Building Enclosure Commissioning Authority, Building Enclosure Commissioning Agent, or BECxA.
Commissioning (Cx) vs. Building Enclosure Commissioning (BECx)
Cx or Commissioning is typically interpreted as commissioning of the mechanical or HVAC systems of the building. But in reality the commissioning process can be applied to many different building systems including the enclosure, plumbing system, electrical system, lighting etc. ASHRAE Guideline 0 – 2013 provides the standard procedure that can be followed to commission any building system and forms the basis for other system specific guidelines.
The Future of Building Enclosure Commissioning…
Right now, BECx is being used primarily for large federal building projects; in the private sector, universities, hospitals, and other owners with a focus on durability are starting to include it in contracts as well.
In LEED version 4, BECx is in the Enhanced Commissioning credit. As with other types of commissioning, the Building Enclosure Commissioning Agent should ideally be involved throughout the design and construction process and may conduct a variety of activities—from reviewing enclosure design against the owner’s objectives to observing construction, performing field testing, completing checklists, and verifying corrective actions. So far, the LEED BECx requirements are fairly vague, and it does not appear likely that any field-testing will be required.
Detailed expectations from USGBC on what constitutes acceptable BECx will go a long way toward ensuring that all projects get good value from BECx and that providers are competing on a level playing field.