CERTIFICATION AGENCY INTERPRETATION
Our NGBS Interpretation documents provide recommendations on technical and verification issues related to NGBS Green certification
File Under: Chapter 7: Energy Efficiency
NGBS 701.4.3.4 is a mandatory practice that specifies maximum air leakage rates for windows, skylights, sliding glass doors, and swinging doors. The NGBS requires fenestration products to be tested in accordance with NFRC 400 or AAMA/WDMA/CSA 101/I.S.2/A440 by an accredited, independent laboratory, as well as listed and labeled. This practice applies to fenestration in any building seeking NGBS Green certification: single-family; townhomes; multifamily; and mixed-use buildings.
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File Under: Chapter 8: Water Efficiency
The 2020 NGBS Chapter 8 included a new practice that states that buildings with a pool and/or spa must have a dedicated meter to measure the amount of water used by the pool and/or spa. The wording of the practice is unambiguous – it states a pool and spa shall have a dedicated meter (see below). However, the ICC 700 National Green Building Standard® was printed without the obligatory "M" that designates when specific practices are mandatory. This has created some confusion about what is required for compliance.
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File Under: Chapter 3: Scope
The 2020 NGBS Section 3 Compliance Method establishes compliance criteria for different building types and details which compliance path should be used. Chapters 5-10 are for buildings generally pre-construction and Chapter 11 is for existing buildings.
Green practices for existing buildings are specifically governed by § 305 – Green Remodeling. The certification path's name being an activity [remodeling] rather than a building type [existing building] has led to confusion and unnecessary limitations on the NGBS's use. This has led Home Innovation to formally acknowledge § 305 as applying to existing buildings and as certification agency, adopted the label "Existing Building" for certifications under § 305 – Remodeling.
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File Under: Chapter 3: Scope
The 2020 NGBS has a handful of practices that specify they are intended for multifamily, multi-unit, or multifamily buildings. On reflection, homes and townhomes should also be eligible for these practices. Incorporating these practices can provide sustainability benefits to the environment and residents regardless of building types. Further, because eligibility for the practices is written inconsistently and without using defined terms, they are subject to interpretation. Home Innovation will allow certain practices containing the terms "multifamily" or "multi-unit" to be used to earn points toward certification for homes and townhomes as described in this interpretation.
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File Under: Chapter 7: Energy Efficiency
Grade I insulation installation is mandatory for NGBS compliance. The 2020 NGBS specifically states that "Insulation installation other than Grade I is not permitted" and devotes an entire page to the batt insulation installation criteria to ensure that it is done correctly. Yet, this green building practice, which is seemingly so simple, is by far the most common practice requiring corrective action as identified by Verifiers and has singularly thwarted more buildings from earning NGBS Green certification than any other specific green practice.
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File Under: Chapter 13: Commercial Spaces
The 2020 NGBS was the first version to allow mixed-use buildings to earn certification for both the residential and commercial/retail portions of the building. NGBS Chapters 5–10 outline compliance for new multifamily buildings and the residential portion of mixed-use buildings; Chapter 13 provides a Prescriptive compliance path for non-residential areas.
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File Under: Chapter 11: Existing Building
Verifiers working on existing mixed-use buildings, where there is no planned renovation to the existing commercial space(s) have asked if Home Innovation allows certification of the entire building, not just the residential portion of the building. The answer is yes, there is a path for certification of the whole building as discussed below.
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File Under: Chapter 3: Scope
The 2020 NGBS Scope and Administration allows for the certification of "Accessory Structures." In the 2020 NGBS Definitions section, the Accessory Structure definition aligns with the ICC International Building Code (IBC) and the ICC International Residential Code (IRC), but also confers the Adopting Entity flexibility in what buildings are treated as accessory.
The 2020 NGBS Green VRG Part I sets out the Conformance Criteria for Accessory Structures. In short, it allows Accessory Structures to attain a conforming designation if compliant with NGBS criteria.
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