Building Envelope Commissioning

The language used for BECx does make it pretty confusing. To get the 2 points for BECx requires that requirements in the EA Prerequisite for Fundamental Commissioning and Verification (as they apply to the building’s thermal envelope) be met, that the requirements of EA Credit for Enhanced Commissioning - Option 2 Envelope Commissioning be met, and that the commissioning process be performed in relation to energy, water, indoor environmental quality, and durability in accordance with NIBS Guideline 3 (Building Enclosure Commissioning Process). NIBS GL 3 is just that...a guideline, so I go by what LEED notes in the document and the reference guide and then perform those tasks in accordance with the Guideline. But where it gets confusing is that some of the tasks stem from Cx and aren't relevant to BECx. So this is my interpretation:

• OPR and BOD review
• Peer review (1 required but GL 3 recommends 3 reviews)
• Cx or BECx plan
• BECx specification
• construction checklists
• submittal review
• site visits to observe construction and testing
• Final report
• Warranty review
• Training
• Lessons learned workshop

Other items not listed by LEED but recommended include mockup construction and testing review and participation in preinstallation meetings.

I've also been wondering what people's experience has been with actual LEED reviews of BECx.  My thought is that you should only do the tests that are appropriate for your climate (eg. no spray rack test in a desert), but sometimes I get nervous about LEED reviewer's ability to make common sense judgement calls about situations that stray from the standard application.

Agree- the intent of testing is not to just do another test but to verify that the installation meets the OPR. So if the owner doesn't care about water tightness (which could be the case in a desert climate), then water infiltration testing would not be required. The BECxP should use his/her professional judgement about what kinds of tests and how many tests should be performed to verify that the construction meets the performance requirements. He/she must also be able to weigh in on (with the owner) which performance requirements are beneficial/appropriate, and which ones might not be, in his/her review of the OPR.

Thank you, Elizabeth.

1. Does anyone have RFP/brief to appoint the CxA for BECx?

2. I am working on a LEED V4 BD+C for Data Center, unfortunately Client has appointed a Commissioning authority who has no capability for additional 2 points BECx and now client wants Main contractor to appoint another CxA just for BECx. Will this be accepted by USGBC? please advise.

Thanks

It is standard practice for the BECx to be a different company than for the MEP systems. However, the same rules apply to their qualifications and independence. You give very little detail, but I would not think anyone working for the contractor would be acceptable or prudent. Why not have the BECx work as a sub to the CxA currently in place? My old firm did not have envelope skills, but we were able to team with some great companies over the years.

Thanks Elizabeth. You noted "Other items not listed by LEED but recommended include mockup construction and testing review and participation in preinstallation meetings." 

This testing can have huge cost implications and the credit information is unclear as to what is required. NIBS Guideline 3 is a bit jumbled and, while it has a lot of potential information, is neither clear nor helpful the way it is currently written.

How do we get 'bottom line' input regarding what is required? Based on NIBS G3 it sounds like either mockup or in-place testing is acceptable. What testing is required? Dynamic and static air and water infiltration? Thermal continuity? Air barrier continuity? Glazed systems? Opaque systems? Doors and entrances? The list can go on. The BECx folks I've spoken with often aren't sure what will or will not comply with the LEED credit. They have a laundry list of items that can be tested and are willing to do whatever the building owner is willing to pay for. 

Any clarity would be greatly appreciated.

It depends on your project's needs whether mock-up or on-site testing takes place. We are frequently involved in both - testing systems extensively in mockup before accessibility becomes an issue and mistakes are repeated. As a matter of fact, we witness spray rack tests in the Arizona desert. Tucson, AZ has monsoons with wind-driven rains as well as Winter rains. Makes for a pretty lush desert.

Note: v4.1 references ASTM E2947-16: Standard Guide for Building Enclosure Commissioning, rather than NIBS.

...and ASTM E2947-16 says: "While both levels of BECx require first installation mock-ups as a minimum requirement, enhanced BECx requires either a preconstruction laboratory mock-up or on-site free standing building mock-up to be tested."

Has anyone tried to use Passive House verification as a BECx agent? Do we really need to hire a seperate BECx agent for LEED and one a PH Verifier for PHIUS? 

I think it would depend on the qualifications and experience of the person with Passive House certification. Cx Providers have significantly different training and examinations than those required for PH credential. You might get lucky and find one who can do both but take a look at a site like BCxA.org to fully understand the Cx process.