Can the envelope commissioning (to earn the 2 points) be carried out by company of the facade execution?

Yes. Quite often it is not the Cx authority who implements the test, they just oversee their implementation.

doesn't the BECxA need to be a "qualified INDEPENDENT member of the design or construction team"?  That language is actually from the v4.1 reference guide, but I think the intent in v4 is the same.  I think in this case, the LEED reviewer may question the independence of the facade installer as there is an apparent conflict of interest.

Hi folks - Was there a resolution here?  Can the facade installer be the BECxA, if the Mech CxA is the lead and provides oversight?

In the scenario above the facade installer is not functioning as the BECxA. Cx in general is an oversight function. So even if the facade installer does the testing they are not functioning as the Cx if the Cx is overseeing the test. 

Ah, thanks for the clarification, Marcus!
So, in a slight twist.... We have a client who would like to use the Envelope Consultant company as the BECx. Would this be allowed, if, for example, a) the BECxA were an individual not participating in the envelope consulting, or b) the general CxA were providing oversight for any envelope testing performed by the envelope testing company?

"The CxA may be a qualified employee of the owner, an independent consultant, or a disinterested subcontractor of the design team." Best practice is always to use an independent consultant as it removes even a perception of confilct of interest. That said for a) I think the case for allowing this would be similar to having the MEP firm do HVAC commissioning as long as it is not the same people doing the HVAC design, so I assume it would be allowed. Option b) would most certainly be allowed as I described above assuming that the Cx either created or had significant input into the creation of the functional testing procedure. 

There is a difference between what is allowed by LEED and what is a best practice or even a reasonable idea. In general I would expect that if the same firm that does the design also does the Cx that they are automatically incentified to find less wrong and since they both come from the same culture, processes, etc. they are also less likely to find anything wrong. The whole idea behind Cx is to bring a different perspective and set of experiences to the design and its testing relative to it. So if this was my client I would try to talk them out of hiring the same firm to do both the design and the BECx.

Yes, completely agree - thank you!

I just want to remind everyone that "Commissioning" is not the same thing as "testing."  Building Enclosure Commissioning is a process described by ASTM E2947-16 (or NIBS Guideline 3-2012 if you're not using v4.1), with references to ASHRAE Standard 202 and Guideline 0. If you are starting to think about BECx during installation, you're way too late - it starts at pre-design (ideally).  Even the ill-defined BECx scope in LEED includes a BECx design review, which many believe is the most important step in the BECx process. So, even if the HVAC CxA is overseeing facade testing performed by the installer, you need to ask who did the design review?  If the answer is the installer, the HVAC CxA, or the Architect, then there's a problem.

Thanks Lyle!