UL 1703 Fire Classification

 

NEW UL 1703 FIRE CLASSIFICATION REQUIREMENTS TAKE EFFECT JAN 1, 2015

Recent changes to the California Building Code (CBC) and the California Residential Code (CRC) require all “PVsystems” permitted after January 1, 2015 be tested, listed, and identified with a fireclassification per UL 1703.

CBC 1505.9 states: “Effective January 1, 2015, rooftop mounted photovoltaic systems shall be tested, listed and identified with a fire classification in accordance with UL 1703.”

CRC R902.4 states: “Effective January 1, 2015, rooftop mounted photovoltaic panels and modules shall be tested, listed and identified with a fire classification in accordance with UL 1703.”


Until recently, the only fire rating system used for rooftop PV systems focused the fire testing on PV modules as stand alone components. In early 2013, UL 1703 revised the fire classification requirements and now evaluates flammability characteristics of the "PV system" which includes the PV module, roof rack, and the roof. Starting January 1, 2015, installers are advised to utilize PV systems (racking and modules) that are tested and listed to the current version of UL 1703. It is also advised that the permit applications include documentation showing the proposed PV system complies with the Class A, Class B, or Class C requirements described below. Testing for the revised UL 1703 fire classification is performed by one of the Nationally Recognized Test Labs (NRTL's). Currently, the NRTL's that offer UL 1703 fire testing are UL, TUV, CSA, and Intertek.

UL 1703 fire classification requirements: On November 25, 2014 the California State Fire Marshal issued Information Bulletin 14-011 , which states "Where Class A or Class B roofing is required, the photovoltaic solar system (photovoltaic panels with the rack support system) shall have a Class A or Class B rating, respectively." Roofs are classified for fire resistance using a scale of A, B, C or unclassified. Class A roofs are the most fire resistant and are frequently required in areas sensitive to wild fires particularly in "Wildland Urban Interfaces" or WUI's. In some cases, entire jurisdictions like Oakland have mandated all residential structures have class A roofs. In previous versions of UL 1703, modules carried their own fire rating. This method of classifying modules as stand-alone components will be discontinued at the end of 2016, and now only has significance for areas with class C fire rating requirements for roofs as explained below. You may also wish to download this free report by Bill Brooks/NREL on UL 1703 for more detail. 

Class A Roofs

Buildings and structures requiring Class A roofs must use PV systems that have been tested, listed and identified with Class A fire classification in accordance with UL 1703. 

Please note: Modules with a Class A fire rating are no longer valid in California. California now requires that the "PV system" carry a fire rating. The "PV system" consists of the racking system AND the module as an assembly.

 

Class B Roofs

Buildings and structures requiring Class B roofs must use PV systems that have been tested, listed and identified with either a Class A or Class B fire classification in accordance with UL 1703. 

Please note: Modules with a Class A fire rating are no longer valid in California. California now requires that the "PV system" carry a fire rating. The "PV system" consists of the racking system AND the module as an assembly.

 

Class C Roofs

Until January 1, 2017, the California State Fire Marshal mandates that buildings and structures requiring Class C roofs use modules or systems that meet one of the following UL fire ratings (see this Informational Bulletin for more detail):

  • Use PV modules having a Class C rating under the previous version of UL 1703 (2002 edition with revisions through April 2008)
  • Use PV modules having a having a Class C rating complying with UL 790 (2004 edition with revisions through October 2008)
  • Use PV systems that have been tested and listed for Class A, Class B, or Class C fire rating per the most recent version of UL 1703 (2002 edition with revisions through October 2013)

Roof Attachments

Roof mounts (standoffs, stanchions, L-feet, tile hooks) are not considered in the current UL 1703 fire rating system unless the maximum span of the mount is required to be less than 40", or if the PV system requires/specifies a specific make/model of roof attachment.

 

Steep Slope Air Gap

In steep slope testing, the roof to module default air gap is 5". The 5" gap has been demonstrated to produce the most efficient thermal chimney effect in fire testing, therefore, if a PV racking system achieves a Class A fire rating using the default 5" air gap, and there is no roof attachment specified, installers can use any roof attachment and space the array at any air gap and retain the Class A fire rating. If the testing of the PV system was performed at a air gap other than 5", the installer must match the specified or air gap to retain fire classification.

 

Leading-Edge Deflectors

Leading edge deflectors (aka shields or skirts) may be used to help slow the spread of flame and achieve a better fire rating. Deflectors can reduce the perimeter air gap and thereby reduce the chimney effect. If deflectors are used in the testing to achieve a fire rating, they must be installed to retain that fire rating.


Module "Typing" for Fire Classification

Testing PV systems with every make/model of PV module was deemed impractical and unnecessary since PV modules with comparable construction characteristics have comparable flammability characteristics. Therefore, the new UL 1703 fire classification developed a system of "typing" PV modules to simplify testing and fire classification. This means that racking systems will not require fire testing with every make and model of PV module used with their racking systems. 

Using this method of "typing", a module manufacturer can list their module as a specific "type" for purposes of listing to the new UL 1703 fire classification. If a PV rack with a "type 1" module achieves a Class A fire rating, the installer can use any other "type 1" module and retain the fire classification. This "typing" option requires PV panel manufacturers classify their modules through evaluation by a NRTL, and many have already done so. Please contact your module supplier to verify if the modules you specify have been "typed" for UL 1703 fire classification.

Using "typed" modules is not mandatory and testing can be performed using only specified make(s)/model(s) of modules that are not "typed", however, installers must use the specific make(s)/model(s) of PV module(s) shown in the system fire classification to retain the fire rating.

 

The 15 existing module types are shown in the table below:

The 15 module "types" for UL 1703 system fire classification

Which manufacturers have fire classified PV systems? There are many racking manufacturers that have completed fire classification testing or are in the process of completing their testing, including those listed on the CALSEIA tested product list. Unfortunately there is no convenient comprehensive list of fire classified systems available, but CALSEIA has developed a database of UL 1703 fire classified systems as a service to California solar installers.  Manufacturers can add their PV fire rated system(s) at the link below.

 

What documentation is needed to validate UL 1703 fire classification for PV systems (racking and modules)?

Certificate of compliance from a Nationally Recognized Test Lab (UL, Intertek, TUV, or CSA) that includes all of the following information

    • PV racking system makes/models
    • Tested for Low Slope or Steep Slope?
    • Successfully tested to UL 1703 Oct 2013 or later
    • Fire class rating A, B or C
    • Acceptable PV module “TYPE” or specific makes/models of PV modules.
    • Installation manual

 

What documentation is needed to validate UL 1703 fire classification for PV modules?

Certificate of compliance from a Nationally Recognized Test Lab (UL, Intertek, TUV, or CSA) that includes all of the following information

    • PV module makes/models
    • Successfully tested to UL 1703 2013 or later
    • Module “type” for UL 1703 Oct 2013 or later  fire classification
    • Installation manual