In order to accomplish this continuity, it is important to be able to draw a continuous line through the full height of the exterior wall section without lifting your hand from the paper. The next step is to ensure continuity from top of parapet to the bottom of the footing for all 3 barriers, despite openings, penetrations, material changes etc. These 3 barriers need not always be separate – sometimes they come together as in an insulated glazed window wherein the IG plays the role of all 3 barriers. E.g., the ply sheathing is the air barrier, building paper is the weather resistive barrier and insulation is the thermal barrier.
Vapor barriers are best avoided in all climates except the coldest regions.
In order to do this, the different layers in the building skin are (theoretically speaking) divided into weather barrier, air barrier and thermal barrier. Building science involves studying the flow of heat, air and moisture across all 6 sides of the building enclosure – the walls, roof and slab. While BECx begins in schematic design, the work can essentially be boiled down to building science + building testing. Hence BECx is officially “Building Enclosure Commissioning” not “Building Envelope Commissioning.”īuilding Enclosure Technology & Environment Council AIA also provides a standard contract for BECx services The NIBS team decided early on that the “E” in BECx would stand for “enclosure” not “envelope” as the latter sounds too much like stationary. ASTM E 2813-12 specifically addresses BECx but is not free. ASHRAE Guideline 0-2005 talks about Cx in broad, general terms and is applicable to both HVAC as well as Building Enclosure Cx. It provides a detailed list of all the activities performed at each stage and explains the roles and responsibilities of the BECxA in every phase.
NIBS guideline 3, available for free online National Institute of Building Sciences = NIBS lays out the full scope of BECx across all phases of a project, starting from early design (Schematic Design or perhaps even Predesign) to end of construction and then into the occupancy phase. LEED v4 has really cast a spotlight on Enclosure Commissioning or ‘BECx’. But what is “Enclosure Commissioning” or “Envelope Commissioning,” and what about LEED Envelope Commissioning? Its scope is vast and skills and knowledge required are pretty intensive as well. Most of us have heard of Commissioning (Cx) as it deals with HVAC equipment and digital controls. Listed below are a number of tasks are recommended to satisfy the requirement for commissioning and to maximize the impact of Building Envelope Commissioning on the project outcome.What is Envelope Commissioning or Building Enclosure Commissioning (BECx)? Further, in our experience, the success of the building Envelope is highly dependent on appropriate selection and design of building Envelope systems and component. The Owner's Project Requirements must be clearly articulated early in the design process early alignment of the project's Basis of Design with the Owner's Project Requirements provides clarity for the designers to more effectively begin the design process, resulting in fewer design changes and greatly improves the project's chances of meeting expectations. To help ensure that the Owner receives the project that they are paying for, Blue Quality Services recommends that the Commissioning Authority be engaged early in the design development phase of the project.
Envelope Commissioning should include foundations and basement construction, vertical enclosure assemblies (walls, windows, doors, connections to existing buildings, sunscreens), and roofing systems.
Building Envelope Commissioning utilizes the Commissioning Process to verify that the design meets the owner’s requirements and that the systems and components are installed and perform according to the construction documents. Building Envelope Commissioning is a pro-active, systematic process that facilitates communication between owners, designers, and contractors.