April 26, 2019
As solar photovoltaic (PV) technology matures, it is increasingly being integrated into building construction and used to replace conventional materials in parts of the building envelope such as roofs, curtain walls and windows. As conventional roof 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 the 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 part of a structural or non-structural component of a building such as a curtain wall, facade, atrium or skylight
BIPV testing and certification requirements
BIPV 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 photovoltaic shingles and BIPV roof panels. Testing and evaluation include electrical, temperature, mechanical loading, wind 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.
Currently, BIPV systems and their mounting means for roofing systems are evaluated separately for compliance to several standards:
- UL 1703, Standard for Safety of Flat-Plate Photovoltaic Modules and Panels, and
- UL 790, 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, 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 makes it far easier for code authorities to determine compliance with the applicable electrical and building codes.
The recently published UL 7103, Outline of Investigation for Building-Integrated Photovoltaic Roof Coverings, brings together all the testing standards required for BIPV by the model installation codes. UL 7103 includes additional requirements to address concerns regarding these unique products and their specific labeling (marking) requirements.
Building-integrated photovoltaic (BIPV) modules and panels intended for mounting integrally to the structural or protective surfaces of a building are certified by UL under the category code number (CCN) QHZK for Building-integrated Photovoltaic Modules and Panels.
Product listings for QHZK can be found using the UL Product iQ Database. Access is free with a one-time registration.
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.
Product installation concerns for PV panel systems include:
- Utility compatibility and interaction
- Environment, e.g., indoor, outdoor, hazardous location, etc.
- Maximum number of modules affecting voltage, current and short-circuit
- Fire exposure ratings
- Wind and snow loading
- Mounting and attachment
- Grounding and bonding
- Shading
Since BIPV is designed to directly replace roofing material, a BIPV system must be evaluated not only as a PV module but also as a roofing material with additional model code required testing such as:
- Fire resistance
- Impact testing
- Wind resistance
- Wind driven rain
- Environmental testing for conditions like temperature and humidity
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 these products or their listing, please contact John Taecker at [email protected].
Author: John K. Taecker, UL Senior Regulatory Engineer, Codes and Regulatory Services, Distinguished Member of Technical Staff