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Cx Monitor: Building Enclosure Commissioning (BECx)

Building enclosure (or envelope) commissioning (BECx) is a process by which the performance of a facility is evaluated and verified against the specific quality requirements of the owner. The commissioning team in charge of BECx is involved throughout the entire project, from the pre-design phase through the operations and maintenance phase. From the start, the commissioning team works with the owner to develop the Owner’s Project Requirements (OPR), which will take into consideration parameters which the building enclosure must meet: climate, loads, and reflection of the life cycle expectations of the building.

The key systems of an enclosure are:

  • Fenestration
  • air barrier
  • vapor barrier
  • roofing
  • cladding
  • waterproofing
  • insulation
  • sealants

These control the flow of moisture, air, heat, and vapor — the primary elements of environmental separation, all of which must work together to ensure a building’s durability. Environmental separation encompasses anything that could escape or infiltrate the building: heat flow, air flow, insects, light radiation, solar radiation, fire, etc. In some climates, for example, occupants might notice that their buildings get an infestation of lady bugs in the Fall. That’s a building envelope problem.

But it’s more than just bugs. An air leakage problem can lead to condensation and moisture transfer, which can lead to mold or other problems. In fact, until you ensure the performance of a building enclosure system, you can’t ensure the performance of other systems like HVAC.

According to data from the American Contractor’s Insurance Group, building envelope accounts for 70% of construction industry defect claims. A defective building envelope can lead to energy losses, costing the owners money year after year. In fact, like all commissioning, the inclusion of building envelope commissioning at the outset of the project can save not only headaches in the future, but cost in finding and correcting the issues, or worse, the cost and disruption of having to repair damaged interiors and completely replace elements of the occupied building.

After determining the owner’s project requirements (OPR), the BECx team is involved in design peer reviews (by evaluating them against the OPR), creating the building envelope commissioning specifications, and updating the commissioning plan accordingly. Then the real fun begins. During the construction phase of a project, the BECx team will often use on-site mock-ups to determine that the planned construction and materials will meet the intended performance requirements.

Outside of building

A series of tests can then be conducted, testing for water leakage, air leakage, and durability.

Occasionally, if there are factors prohibiting the use of on-site mock-ups (like weather), the mock-ups are created in an off-site laboratory, where additional testing can also take place, like those for seismic reactions and thermal cycling.

Site visits are made to document the progress of enclosure construction and to identify and correct observed and potential deficiencies. Testing is also performed on the actual building throughout the construction phase to verify that enclosure systems and transitions between systems are installed correctly and perform as intended.

In the final operations and maintenance stage, post-construction verifications take place, including infrared scanning and whole building air leakage tests. The verification process is what keeps people honest and ensures that the building envelope was installed as planned according to the owner’s needs and requirements, helping to ensure durable buildings that keep the energy savings where they should be and owners happy.

If you would like more information on building envelope commissioning services or would like a personalized BECx presentation, please contact Media Relations at