Innovative Solar Designs Drive Standards and Code Development

Author: John K. Taecker, UL Solutions Senior Regulatory Engineer, Codes and Regulatory Services, Customer Experience Distinguished Member of Technical Staff

As part of the design of net zero energy buildings to address climate change, architects and builders utilize renewable on-site generation. Traditionally, solar photovoltaic (PV) panels have been installed on top of existing roofs or on the ground. PV technology continues to mature and is increasingly being integrated into building construction and used to replace conventional materials in parts of the building envelope such as roofs, exterior wall coverings, curtain walls and fenestration. As conventional installation costs continue to increase and PV prices decrease, building-integrated photovoltaics (BIPV) are growing in popularity.

Architects are now integrating PV technology into their designs for aesthetic value and to help building owners reduce energy costs with environmentally friendly electric generation. BIPV is a way to achieve compliance with energy conservation codes and sustainability requirements and helps in earning a LEED building certification.

What is BIPV?

BIPV are PV modules that are integrated into a building and have been designed following the basic requirements for both photovoltaic products and construction materials, or the components and cladding they are intended to replace. BIPV products are intended for mounting integrally to the structure or protective surfaces of a building in one of two primary installation methods:

• As a roof, or as a major component of the roofing system of a building
• As an exterior wall covering or fenestration, such as a curtain wall, facade, atrium or skylight

BIPV testing and certification requirements

Testing and certification is required by the International Residential Code (IRC) (sections R905.16 and R905.17) and the International Building Code (IBC) (sections 1507.17 and 1507.18) for BIPV shingles and roof panels. The scope of testing and certification include electrical, temperature, mechanical loading, UV and corrosion resistance, wind and rain resistance, impact, and fire tests. The product’s output wiring system is also investigated for conformance with the provisions of the National Electrical Code^® (NEC), including Article 690 Solar Photovoltaic (PV) Systems.

In the 2015 and 2018 editions of the IRC and IBC, BIPV systems and their mounting means for roofing systems are required to be evaluated separately for compliance to several standards:

• UL 1703, the Standard for Safety of Flat-Plate Photovoltaic Modules and Panels, and
• UL 790, the Standard Test Methods for Fire Tests of Roof Coverings, and
• Either ASTM D3161 Standard Test Method for Wind-Resistance of Steep Slope Roofing Products (Fan-Induced Method) or UL 1897, the Standard for Safety  Uplift Tests for Roof Covering Systems

The results of evaluation to these various requirements may be captured in separate certification reports that must be reviewed to determine compliance with all model code requirements. Having one standard to address all aspects of concern for BIPV safety and code compliance would make it far easier for code authorities to determine compliance with the applicable electrical and building codes.

Thus, UL 7103, Outline of Investigation for Building-Integrated Photovoltaic Roof Coverings, was developed to combine all the testing standards required for BIPV roofing systems by the model installation codes, and to include additional requirements to address concerns regarding these unique products and their specific labeling (marking) requirements. The 2021 editions of the IBC and IRC require BIPV roofing systems to be listed and labeled in accordance with UL 7103.

Currently, the model codes do not contain requirements for BIPV systems that are used as either exterior wall coverings or fenestration. IBC Chapter 14 and IRC Chapter 7 contain the applicable requirements for exterior wall coverings and exterior wall assemblies. Code change proposals have been made for the 2024 editions of the IBC and IRC (FS150-21 and RB240-22) to provide guidance for these BIPV systems. These proposals require BIPV exterior wall coverings and fenestration to be listed and labeled in accordance with either UL 1703 or both UL 61730-1, the Standard for Photovoltaic (PV) Module Safety Qualification—Part 1: Requirements for Construction, and UL 61730-2, the Standard for Photovoltaic (PV) Module Safety Qualification—Part 2: Requirements for Testing, and to also comply with other provisions that apply to exterior wall coverings or fenestration, including fire tests and weather protection.

Safety considerations for BIPV

Safety certification for BIPV products is more stringent than certification for conventional PV modules. The NEC, IBC and IRC require that all PV products installed on or around a building must be certified by a Nationally Recognized Testing Laboratory (NRTL) in accordance with the applicable standards. Because of these model code requirements, all BIPV products are subjected to the same electrical certification, performance and safety testing standards as conventional PV modules and more.

Installation concerns for BIPV systems include:

Since BIPV is designed to directly replace roofing material, a BIPV roofing system must be evaluated not only as a PV module but also as a roofing material. UL 7103 requires testing for:

BIPV certifications

Building-integrated photovoltaic (BIPV) modules and panels intended for mounting integrally to the structural or protective surfaces of a building are certified by UL Solutions under the product category for Building-integrated Photovoltaic Modules and Panels, QHZK.

Product certifications (listings) for QHZK can be found using UL  Product iQ^®, available at www.ProductiQ.ul.com. Product iQ^® is complimentary to use, but does require a simple one-time registration.

Integration of PV systems into building products and architectural designs is growing. Certification to a single, all-inclusive standard provides a solid foundation upon which to certify BIPV technologies and deliver confidence in the safety and performance of new BIPV products for architects, installers and code authorities.

For more information related to product or system listing (certification) from UL Solutions, please contact ULRegulatoryServices@ul.com.