February 6, 2012

Solar Energy Industries Association 575 7th Street, N.W., Suite 400Washington, D.C. 20004

Att’n: Christine Covington, Manager of Trade & Competitiveness

Re: Preliminary, Limited-Scope Analysis of UL 1703 / UL 790 Photovoltaic System Fire Classification Tests

Dear Ms. Covington,

Following is my initial, limited-scope commentary on work done to date by the UL 1703 Standards Technical Panel (STP), toward the goal of revising UL 1703 to conform to new requirements in the 2012 International Building Code (IBC). The 2012 IBC is published but not yet adopted in most Authorities Having Jurisdiction (AHJ’s). When adopted, a new section of the 2012 IBC, Section 1509.7.2, will require rooftop mounted photovoltaic (PV) systems to have a fire classification not less than the fire classification required for the roof assembly. Under current standards, only the PV panel or module is rated with a fire classification of Class A (best), Class B, Class C, or unrated.

The UL 1703 standard incorporates two of four fire tests found in UL 790 – the Burning Brand test and the Spread of Flame test. Preliminary fire classification tests for PV systems have been conducted by Underwriters Laboratories, in collaboration with Solar America Board for Codes and Standards, as funded by the U.S. Department of Energy.

Preliminary testing for UL 790 Spread of Flame test has been conducted in a manner that finds nearly every existing common configuration of rooftop rack-mounted PV system “non-compliant” with the spread of flame test. Simply stated, the UL 1703 Standards Technical Panel is proceeding on a path that will render nearly all existing rack-mounted rooftop PV systems illegal until such time as the industry develops new products and new methods of installation to pass the test.

Solar companies across America have been working diligently to decrease the installed cost of solar PV systems, while maintaining a high level of safety. Rapid advancement and adoption of solar technologies is a matter of national importance. We are gravely concerned that the current path of the UL 1703 Standards Technical Panel will have a devastating impact on the solar industry.

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It appears that a limited number of solar companies have been engaged in this process. We believe representatives of most solar companies are unaware of the negative impacts of these changes. We believe even some of those companies with representatives observing this process might simply be in “wait and see” status. We are concerned those companies might believe they can wait until UL 1703 is revised and finalized, then begin testing to see what they need to do, without realizing these tests will render their entire rack-mounted product line illegal to install in its present form.

As the new code sections that triggered revisions to UL 1703 are found in the International Building Code, there is no question the commercial sector of the solar industry will be impacted first. I believe this process will also impact the residential sector of the solar industry, as many residential buildings are required to have a minimum fire classification for roof assemblies. In my opinion, this is inevitable.

The solar industry has an exceptional safety record. Brief research of historic fire events discloses only eight or nine rooftop fire events involving PV systems. Seven of these events are cited in a report by the U.S. Fire Administration. Another report published by the California State Fire Marshall adds only one more known rooftop fire event involving a PV system. Of those known events, only three occurred on commercial buildings. Statistics maintained by Solar ABCs indicate as of the third quarter of 2011, over 196,000 PV systems were installed in the United States.

Underwriters Laboratories is a reputable organization widely trusted with improving the public health and welfare. We believe this is a case where the test method currently used by UL is not reflective of the real-world risk based on historic data. We believe the current application of the UL 790 spread of flame test for PV systems is flawed, and is not an appropriate method for assessing the risks associated with extremely rare rooftop fires on buildings with a rack-mounted PV system.

We respectfully request support from SEIA, members of SEIA, and all other stakeholders in the solar industry to actively engage in this process now. The following pages include a detailed discussion of our observations to date.

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BACKGROUND

The 2012 International Building Code (IBC) is the first edition of the IBC to include provisions specific to solar PV systems. Fire classification provisions were added to IBC Chapter 15, Roof Assemblies and Rooftop Structures. The first step to including PV systems was to revise the definition of Rooftop Structures in 2012 IBC Section 202.

ROOFTOP STRUCTURE. A structure erected on top of the roof deck or on top of any part of a building.

The previous definition of rooftop structure in the now-current 2009 IBC includes only enclosed structures. Examples include Penthouses, Tanks, Cooling Towers, Towers, spires, domes, and cupolas. The word enclosed was removed from the definition in order to include rooftop PV systems. There were no proposals to regulate any type of non-enclosed rooftop structure other than solar PV systems.

Chapter 15 of the 2012 IBC was revised with the following new sections applicable to rooftop, rack-mounted PV systems only (BIPV systems are covered in a different section).

1509.7 Photovoltaic systems. Rooftop mounted photovoltaic systems shall be designed in accordance with this section.

1509.7.2 Fire classification. Rooftop mounted photovoltaic systems shall have the same fire classification as the roof assembly required by Section 1505.

1509.7.4 Photovoltaic panels and modules. Photovoltaic panels and modules mounted on top of a roof shall be listed and labeled in accordance with UL 1703 and shall be installed in accordance with the manufacturer’s installation instructions.

Section 1509.7.2 is the trigger for revisions to UL Standard 1703. Section 1509.7.2 references Section 1505, which references UL 790 and Table 1505.1.

1505.1 General. Roof assemblies shall be divided into the classes defined below. Class A, B and C roof assemblies and roof coverings required to be listed by this section shall be tested in accordance with ASTM E 108 or UL 790. In addition, fire-retardant-treated wood roof coverings shall be tested in accordance with ASTM D 2898. The minimum roof coverings installed on buildings shall comply with Table 1505.1 based on the type of construction of the building.

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In Table 1505.1, the first horizontal row of entries includes the construction type of a particular building. Roman numerals I (one) through V (five) indicate Type I (one) through Type V (five) construction, based on the materials used in construction (for example, concrete, steel, wood), and whether they are combustible or noncombustible. The suffix A or B indicates whether building components are required to be protected from fire or unprotected (for example, 1-hour fire rating or non-rated). Generally speaking, the larger a building, the more likely it will be required to have a lower construction type and protected construction assemblies. For example, single-family home are almost always Type VB (type five, non-rated).

The second horizontal row of entries in the table indicates the minimum required fire classification for the roof assemblies and roof coverings. As stated in UL 790, Class A, B, and C roof coverings are effective against severe, moderate, and light fire test exposures, respectively.

As stated in UL 790, “These fire test methods do not provide a basis to compare expected performance under all actual fire conditions but they do provide a basis for comparison of the response of roof coverings when subjected to fire sources that are described herein.”

It is important to be aware that more-stringent fire classification requirements for roof assemblies can be found in statewide amendments to the IBC or in municipal ordinances established by individual AHJs, as discussed in the following section under “scope.”

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It is interesting to note the original code change proposal was submitted with the statement: “The code change proposal will not increase the cost of construction.” Members of the committee approved these new code requirements with modifications to the originally proposed language. The underlying premise was there would be no additional cost to industry.

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SCOPE OF 2012 INTERNATIONAL BUILDING CODE

As the new code sections that triggered revisions to UL 1703 are found in the International Building Code, there is no question the commercial sector of the solar industry will be impacted first. This specifically includes all nonresidential buildings and multi-family housing with three or more dwelling units.

Some stakeholders have expressed a belief that fire classification of PV systems will not apply to one- and two-family dwellings and townhouses, as those buildings are within the scope of the International Residential Code (IRC). For this discussion, it is important to review the scope of the 2012 IBC, which states the IBC applies to all occupancies, including one- and two-family dwellings and townhouses that are not within the scope of the IRC.

The International Building Code (IBC) is a model code that provides minimum requirements to safeguard the public health, safety and general welfare of the occupants of new and existing buildings and structures.

The IBC applies to all occupancies, including one- and two-family dwellings and townhouses that are not within the scope of the IRC. The IRC is referenced for coverage of detached one- and two family dwellings and townhouses as defined in the Exception to Section 101.2 and the definition for “townhouse” in Chapter 2. The IBC applies to all types of buildings and structures unless exempted. Work exempted from permits is listed in Section 105.2.

The IRC includes primarily prescriptive code requirements. For example, requirements for structural engineering calculations are not found in the IRC. Therefore, we use the IBC every day for qualifying single-family homes for the added load of PV systems.

We believe fire classification of rooftop mounted PV systems will ultimately impact the residential sector of the solar industry as well as commercial sector. Many residential buildings are already required to have a minimum fire classification for roof assemblies, owing to state or local amendments to the IBC.

For example, the requirements for fire classification of roof assemblies are amended in Chapter 7A and Chapter 15 of the 2010 California Building Code (CBC). In particular, every structure in California within a very high fire hazard severity zone must have a roof covering that is at least Class A, per the following amendment to Section 1505.1.

1505.1.1 Roof coverings within very high fire hazard severity zones. The entire roof covering of every existing structure where more than 50 percent of the total roof area is replaced within anyone-year period, the entire roof covering of every new structure, and any roof covering applied in the alteration, repair or replacement of the roof of every existing structure, shall be a fire-retardant roof covering that is at least Class A.

A map of California Fire Hazard Severity Zones is shown on the following page.

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TESTING BY UNDERWRITERS LABORATORIES (UL)

In coordination with Solar ABCs, staff of UL has conducted UL 790 spread of flame tests with varying configurations of PV panels mounted above test specimens representing roof assemblies. Results of these tests have been reported through Solar ABCs during presentations at Stakeholder Meetings.

Most of the tests have been conducted with a solar panel mounted parallel to the roof assembly in the test apparatus, in the configuration industry often refers to as a “flush mount.” According to tests conducted by UL, the worst-case height above the roof is 5 inches. This finding is particularly disturbing, as 5 inches is a very common height above the roof for a typical flush mount PV system. A typical height range of approximately 4 inches to 8 inches above the roof surface provides adequate space for flashing and weather sealing, as well as leveling of the rack system when roof surfaces are experiencing differential deflection.

The sheer number of potential module, rack, roof, configurations will make it nearly impossible for module manufacturers to comply with the proposed UL testing requirements. Manufacturers will need to ensure that systems perform at classification levels under a myriad of permutations such as:

1. Roof Slope – (Minimum of 4 configurations) Flat, Low Slope, Medium Slope and Steep Slope

2. Roof Covering – (Minimum of 3 configurations) – Noncombustible, Class A and Class C

3. Module Orientation – (Minimum of 3 configurations) - Parallel to roof, Positive tilt toward leading edge, negative tilt toward leading edge.

4. Module Distance from Roof Surface – (Minimum of 4 configurations) – Directly mounted to roof surface, 1-4” from roof surface, 4-8” from roof surface, >12” from roof surface.

5. System distance from Leading Edge of Roof (Minimum of 3 configurations) – Flush with leading edge, 6-18” from leading edge, >18” from leading edge.

By multiplying the above possible configurations, a manufacturer might be required to perform dozens, and if taken to an extreme conclusion up to 400 individual tests just to determine spread of flame fire rating for modules in very common installation configurations.

Work done to date has lead to more questions than answers.

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PUBLICATIONS

Two publications on this topic have been made available on the Solar ABCs web site.

In April 2010, Solar ABCs published a white paper titled Flammability Testing of Standard Roofing Products In the Presence of Standoff-mounted Photovoltaic Modules. A Solar ABCs Interim Report. The authors of this report are listed as Andrew Rosenthal, Larry Sherwood, Bill Brooks, Pravinray Ghandi, and Bob Backstrom.

http://www.solarabcs.org/about/publications/reports/flammability-testing/index.html

In May 2011, Solar ABC’s published a white paper titled Impacts on Photovoltaic Installations of Changes to the 2012 International Codes. A Solar ABCs White Paper. Collaborators on this report include Stephen Barkaszi, Christine Covington, Mark Graham, Dennis Grubb, Colleen O’Brien, Lorraine Ross, and John Taecker.

http://www.solarabcs.org/about/publications/reports/2012Codes/index.html

A white paper has been published by Tom Meyers, C.B.O., titled Fire Classification of Photovoltaic Systems Used as Roof Top Structures, dated March, 2011. This white paper contains additional background information on this topic from a code-development perspective.

STAKEHOLDER MEETINGS

Solar ABCs has hosted stakeholder meetings to make available to interested parties information about their ongoing efforts to comply with 2012 IBC requirements. These meetings are announced on the Solar ABCs web site and elsewhere, in the interest of transparency.

Unfortunately, it is often difficult to distribute this information to the right audience. It is difficult to fully capture the attention of busy people in industry, especially when there is so much work to be done. We believe most people in the solar industry are unaware of the widespread ramifications of the proposed revisions to UL 1703.

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UL 1703 STANDARDS TECHNICAL PANEL (STP)

The UL Standards Technical Panel (STP) is a “balanced” panel of stakeholders representing different sectors of industry, consultants, and enforcement personnel. The UL 1703 STP is presently charged with crafting the revisions to UL 1703 to incorporate new requirements of the 2012 IBC.

The UL 1703 STP is striving to move forward with a sense of urgency under the belief that failure to complete revisions in a timely manner could lead to a shut-down of industry. Staff of UL and some members of the UL 1703 STP believe revisions to the standard should be completed as soon as possible, to give industry an opportunity to begin testing and therefore to begin product development.

At the December 14, 2011 stakeholder meeting in Northbrook, Illinois, we requested development of prescriptive solutions included within UL 1703. If the standard includes prescriptive solutions, then conformance with those solutions could result in UL 1703 certification without specifically requiring further testing. Staff of UL has recommended against including prescriptive solutions within UL 1703 at this time, citing a concern for delays that would prevent companies from initiating testing. Staff recommended the revisions to the Standard be completed first, without prescriptive solutions, leaving open a possibility that prescriptive solutions could be included in yet another revision to UL 1703 in the future.

POSSIBLE MITIGATIONS STUDIED BY UL

During the course of conducting PV system spread of flame tests, testers at UL recognized that existing rack-mounted configurations were uniformly failing the spread of flame test.

During preliminary testing, three possible mitigations were investigated. We believe all three of these possible mitigations are problematic. It is imperative for industry to understand the challenges presented by the present application of the UL 790 spread of flame test.

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Mitigation 1: Install roof-mounted flat PV panels in direct contact with the roof surface, such that flame cannot enter between PV panel and roof surface.

In preliminary testing by UL, a flat PV panel installed in direct contact with a flat roof surface was found to be “compliant,” as the test flame was not allowed to come in direct contact with the roof surface. In the test, the leading edge of the PV panel / roof interface was protected with a fire sealant. The test specimen included a very flat roof covering material. This mitigation does not appear to have much value for several reasons:

1. Not all roof covering materials are flat. Thermoplastic membranes such as Polyvinyl Chloride (PVC) and Thermoplastic Olefin (TPO) are generally found only on “flat” roofs, not on pitched roofs. Pitched roof coverings generally have variable depth or various profiles for architectural relief. This mitigation would not be possible on tile roofs or metal roofs of any kind.

2. Most “flat” roofs are not designed to be monoslope flat roofs. Roofs are designed for slope to drainage. Monoslope roofs with a roof pitch in only one direction are usually limited to small roof planes. Most roof surfaces have variable direction of pitch, including cricketing or other devices to direct rainwater runoff to scuppers or downspouts.

3. Roof framing systems deflect and are not flat. Roof framing members deflect when load is applied, even when that load is only self-weight. Code-allowable deflection depends on application, and is expressed as a percentage of the unsupported span of framing members. For example, if the deflection limit is L/240 (length in inches divided by 240), the allowable deflection for a member with length of 15 feet is (15 ft x 12 in./ft ) / 240 = 0.75 inches. Even roofs with code-allowable deflection are not flat enough to install modules in direct contact.

4. Differential deflection can vary along the length of one mounting plane. Roofs with significant differential deflection can take on a “wavy roof” appearance.

5. Deflection of roof framing members can vary over time owing to short-term loads such as wind, or seasonal loads such as snow.

6. A PV panel installed in contact with the roof surface creates an unvented, concealed space that promotes moisture problems leading to decay of framing systems.

7. While zero-clearance rack-mounting systems do exist in the marketplace, their installed cost is approximately $1.00/W to $1.50/W more than traditionally framed modules. These zero-clearance systems cannot be effectively installed on roofs experiencing differential deflection.

8. The majority of framed modules require a space between the roof and the module as detailed in their user manual. Their UL listing requires that the modules be mounted in accordance with their user manual, so we have a clear contradiction.

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Mitigation 2: Provide a fire barrier to prevent test flame from entering between PV panel and roof surface.

In preliminary testing by UL, a steel fire barrier was installed in such a manner as to provide a fire barrier at the leading edge of the PV panel near the flame. This method was found to be “compliant,” as the flame was not allowed to pass between the PV panel and the roof assembly.

UL first prepared preliminary tests for a fire barrier attached to the frame of the PV panel. Realizing the PV panels are dependent on airflow beneath the panels for cooling, additional tests were performed with a detached fire barrier and the PV panel set back from the leading edge of the test specimen.

This mitigation appears to have value, but appears to be problematic for several reasons:

1. If the fire barrier is attached to the module frame and surrounds an array for the entire perimeter, this creates an enclosed, unvented space. In hot climates the temperatures under the module could be extreme. In cold or wet climates the space beneath the panels might be prone to moisture problems and rot.

2. If the fire barrier is held at some distance away from the array to allow venting beneath the panels, the barrier could act as a water dam, trapping leaves and debris. This could lead to accumulation of increased fire load (fuel) when dry, and could lead to moisture problems and rot when saturated.

3. Performance of PV arrays is dependent on airflow beneath the panels to provide natural cooling. A decrease of natural cooling negatively impacts the temperature rating of the panel. Efficiency decreases and production decreases. Panel manufacturers might need to recertify their panels, and PV installers might need to install more panels to reach energy production goals.

4. Whether attached to the PV panel frame or free-standing on the roof surface away from the panel frame, preliminary tests indicate the bottom edge of the fire barrier must fit tight to the roof surface. Roof covering materials are found in many different shapes, profiles, and configurations. Roof surfaces are not uniformly flat. It is extremely difficult to imagine a fire barrier that can withstand a 1400 degree flame for ten minutes, yet is flexible enough to be shaped to various profiles of roof coverings.

5. The fire barrier method likely leads to installations that are prone to moisture problems and rot. Code officials are keenly aware of rot problems caused by enclosed, unvented spaces, such as the rafter bays of a vaulted ceiling.

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Mitigation 3: Install rack-mounted PV system high above the roof surface.

Preliminary tests found some PV systems to be “compliant” if the PV panel in the test apparatus is held high enough above the roof assembly that there is little concentration of heat. In other words, the test flame encounters a roof surface similar to if the PV system did not exist.

This proposed mitigation might have value for tall rack-mounted systems held high above the surface of a flat or low-slope roof. It is expected to have value for the rare case of a solar support structure located above a rooftop parking lot. However, for a majority of rack-mounted rooftop PV systems, this mitigation does not appear to have much value for several reasons.

1. This mitigation was first described as having PV panels 12 inches above and parallel to the roof. It is highly unlikely any PV systems will be installed 12 inches above and parallel to the roof, as this type of installation is not aesthetically pleasing and is rejected by most building owners.

2. Architects and building owners care about the aesthetics of solar PV installations. We must sell and install our PV systems as aesthetically pleasing systems in many applications where they are visible from yards, streets, or highways.

3. Some local Authorities Having Jurisdiction (AHJs) and some Homeowners’ Associations (HOAs) apply stringent aesthetic standards during the course of their review of PV systems. For example, the City of Manhattan Beach in California can be expected to request a reduction of PV system height of all systems on all flat roofs, owing to preservation of the view-shed toward the Pacific Ocean.

4. Aesthetics is extremely important when looking at the costs of customer acquisition. PV is still at a point in its growth where public perception is extremely important for adoption. Having arrays mounted 12” above the roof will drive away a large percentage of customers and at least double this cost.

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SOLAR INDUSTRY SAFETY RECORD

On the basis of historical information, the solar PV industry has established an outstanding safety record. As the fundamental premise of the UL 790 spread of flame test is mitigation of risk from rooftop fires involving PV systems, it is informative to review existing historical data. First, we are interested in the quantity of PV system installations. As of the 3rd quarter of 2011, over 196,000 PV systems were installed in the United States.

Number of Installations (Annual)2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 Q1-Q3

Residential 507 1,748 3,183 4,085 5,980 6,652 8,445 13,132 17,008 29,418 48,118 35,592 Non-Residential162 93 269 498 870 1,062 1,128 1,463 1,943 2,275 4,499 7,626 Utility 19 24 22 25 17 4 2 2 19 143 59 71Total 688 1,865 3,474 4,608 6,867 7,718 9,575 14,597 18,970 31,836 52,676 43,289

Number of Installations (Cumulative)2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 Q1-Q3

Residential 507 2,255 5,438 9,523 15,503 22,155 30,600 43,732 60,740 90,158 138,276 173,868 Non-Residential 162 255 524 1,022 1,892 2,954 4,082 5,545 7,488 9,763 14,262 21,888 Utility 19 43 65 90 107 111 113 115 134 277 336 407 Total 688 2,553 6,027 10,635 17,502 25,220 34,795 49,392 68,362 100,198 152,874 196,163

from Larry Sherwood/IREC SEIA/GTM Research

We found two publications highlighting known fire events that involved rooftop PV systems.

The first publication, by the Fire Protection Research Foundation, is titled Firefighter Safety and Emergency Response for Solar Power Systems, May 2010.

http://www.nfpa.org/assets/files/PDF/Research/FFTacticsSolarPower.pdf

The second publication, by the California State Fire Marshall, is titled Fire Operations for Photovoltaic Emergencies, November 2010.

http://osfm.fire.ca.gov/training/pdf/Photovoltaics/Fire%20Ops%20PV%20lo%20resl.pdf

In these two publications, we find mention of only eight fire events that involved a rooftop solar PV system. Notes from these two reports are merged into the following single list of known fire events involving rooftop PV systems.

We are aware of one more residential fire in California that started within a residence and involved the rooftop PV system.

Fire events involving solar systems can be divided into three main categories. In two of these categories, the PV system is the victim of a fire started elsewhere. Fire can start inside a building and spread to the roof, or fire can start on a roof without being caused by the PV system. In the third category, a system fault can make the PV system the source of the fire.

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Summary of known fire events involving rooftop PV systems:

Date Location SummaryFeb. 2008 Long Beach, CA Commercial fire at Convention Center with fire on

two modules. The modules involved were field repaired by the manufacturer representative. Damage limited to the modules.

May 2008 San Francisco, CA Commercial fire at University of San Francisco. Fire started at the array and extinguished by maintenance personnel.

June 2008 Sedona, AZ Residential content fire, starting inside the home. PV system was destroyed. Firefighter received an electric shock (non life threatening) that was first attributed to the PV system but later attributed to the utility power supply.

Jan. 2009 Torrance, CA Residential fire started at PV modules two weeks after the system was installed. The modules were “do-it-yourself” of questionable installation quality. Minimal damage to the residence.

Feb. 2009 California (might be duplicate record ofthe Torrance event)

Residential fire. PV system caught fire due to an electrical malfunction. Damage was limited to the rooftop system components.

Mar. 2009 Simi Valley, CA Residential fire started in a shingle module of an integrated roof BIPV system. Not rack-mounted.

Apr. 2009 Bakersfield, CA Commercial fire on big box retail store. Fire may have started in the PV conduit or the array. Fire was confined to the solar modules and was kept from penetrating the store’s roofing materials.

Apr. 2010 Maryland Residential fire – older PV system. Fire started at modules. Reports are debris beneath modules may have been involved in the cause of the fire.

Nov. 2010 Glendale, CA Residential fire started within the residence, and fully engulfed the home. Residence was total loss.

From the events listed above, we can see there are only three known fire events involving commercial rooftop PV systems. One of the residential events involves Building Integrated PhotoVoltaic (BIPV) shingles, not a rooftop mounted PV system.

Considering there are only seven or eight fire events involving rooftop mounted PV systems known to the Fire Protection Research Foundation and the California State Fire Marshall, and there are over 196,000 PV systems installed, we can see the rooftop mounted segment of the solar industry has an excellent safety record. If our primary interest is in commercial rooftop systems, there are only three known fire events out of approximately 22,000 PV systems.

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UL 790 SPREAD OF FLAME TEST METHOD

Following the present path of the UL 1703 Standards Technical Panel, it seems the primary challenge for the PV industry is to develop and design PV systems and PV products to be found “compliant” with the spread of flame test. It seems necessary to design to the test.

1509.7.2 Fire classification. Rooftop mounted photovoltaic systems shall have the same fire classification as the roof assembly required by Section 1505.

This new section in the 2012 IBC requires a fire classification of rooftop mounted photovoltaic systems. Therefore, it seems reasonable that we expect to see testing and fire classification of a particular PV panel installed on a particular rooftop racking or mounting system. It is therefore interesting to learn that under the current test method the mounting hardware does not seem to influence the results of the spread of flame test. The test results are primarily influenced by only one factor – the geometric relationship of the PV panel to the roof assembly in the test apparatus.

It is important to recognize that under the current test method and in certain configurations a noncombustible panel (in lieu of a real PV panel) installed on a noncombustible mounting system over a sample roof assembly will routinely fail the spread of flame test. Conversely, a solar PV panel on a noncombustible mounting system over a noncombustible deck will also fail. This result is owing to a channeling effect of fire through a confined space that concentrates heat and facilitates the spread of flame.

Regardless of the manufacture of the PV panel and regardless of having noncombustible mounting hardware, nearly all existing rooftop mounted PV systems will be illegal to install, until or unless the PV industry can develop new products and new systems that can survive a blast of fire for 10 minutes without significant damage. Or perhaps industry will abandon rack-mounted PV systems only because they cannot pass the UL 1703 / UL 790 spread of flame test as currently conducted.

The tests conducted to date by UL appear to be a re-classification of a roof assembly in the presence of a rooftop mounted PV system, rather than a fire classification test of the PV system itself. For example, in the case where the PV panel is placed high above the roof surface, the flame of the test apparatus will still be directed over the top of the roof assembly specimen. In this case, keeping the PV panel away from the flame is a likely means of achieving a “compliant” PV system, as the flame passes over the top surface of the roof covering material the same as it did without the PV panel in place.

Is this really a test of a rooftop mounted photovoltaic system, as required by 2012 IBC Section 1509.7.2? Or this a re-classification of the roof covering in the presence of solar, which does not appear to be required by Section 1509.7.2?

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FINDINGS AND CONCLUSIONS

We should find uniform agreement the rapid advancement and deployment of solar PV systems is a matter of national importance. In partnership with federal, state and local government, utilities, trade organizations, and investors, the solar industry has spent years working to increase demand and drive down the cost of distributed solar power generation.

One fundamental goal of the PV industry is to achieve grid parity – to drive down cost such that solar customers will still save money even when incentives are no longer offered. So far, the solar industry has done an excellent job of driving down cost to keep pace with downward-ratcheting incentives. The incentive system is working as intended.

The solar industry has an outstanding fire safety record, with only eight or nine known fire events involving rooftop solar PV systems out of approximately 200,000 systems installed. Circumstances of known fire events have lead to revised electrical code requirements and new fire code requirements. New and revised code provisions already in effect have already made buildings with rooftop mounted solar PV systems safer for building occupants and first responders.

Recent code cycles have included a volume of proposals for code changes unprecedented in the history of the solar industry. Current proceedings for proposed changes to the 2014 National Electrical Code include 164 different proposals, 47 of which originate from industry forums, with the remainder from public comments. Fifteen proposals were written to specifically address firefighter safety. Additional regulation for solar PV systems has already been written into the 2012 editions of the International Fire Code, International Building Code, and International Residential Code.

Many of these code change proposals are apparently written without regard for a cost/benefit analysis. The authors of some proposed code changes appear to write proposals without technological boundaries. The 2012 IBC requires fire classification according to a standard that does not exist in a suitable form, and preliminary development of that standard fails nearly all rack-mounted systems until or unless industry develops products and systems that do not yet exist. This situation calls into question whether 2012 IBC Section 1509.7.1 is enforceable.

Industry has not yet developed a fire-proof rooftop rack-mounted PV system, and it does not seem reasonable or necessary to do so.

Given the current path of the UL 1703 STP, estimates of monetary cost of compliance are in the range of $1.00 to $1.50 per Watt. Additional, indirect cost is difficult to quantify, as it would be based on the negative impact of unintended consequences, as discussed below. Photovoltaic system costs can be expected to spike back up, even though incentives are ratcheting downward. The cumulative cost of conformance with this fire test method as presently conducted is disproportionate to the expected real-world risk.

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It is likely some smaller solar companies will not have the resources to respond to these new requirements. We can expect some small solar companies to go out of business.

The primary concern of fire test staff at UL appears to be the channeling effect that results in spread of flame in the test apparatus. Most building code concerns over fire channeling effects are related to concealed spaces internal to a building, such as shafts, plenums, laundry chutes and floor/ceiling assemblies. These concealed spaces are inaccessible to firefighters. Rooftop mounted PV systems are directly accessible to firefighters. Existing fire incident data indicate all known rooftop fires were quickly extinguished by firefighting personnel. In all known events with fire originating on the rooftop, fire damage was limited to localized areas of the rooftop, and rooftop fires were extinguished before the fire could penetrate the roof covering.

No other type of rooftop structure is required to survive direct application of a 1400 degree test flame for ten minutes. The spread of flame test is designed to direct a test flame with air current over the top of a surface. If we are to direct a test flame directly at a rooftop structure, or in-between a rooftop structure and a roof surface, should we be testing other types of rooftop structures and vertical projections above a roof surface? Should we be fire testing skylight wells, wood-framed dormers, penthouses, tanks, towers and spires? Most of these rooftop structures could spread fire, even without a channeling effect, yet the solar PV industry is singled out.

Staff of UL and some members of the UL 1703 STP believe failure to complete revisions to UL 1703 in a timely manner could lead to shut-down of the solar industry. We believe it would be more catastrophic to industry to complete the revisions based on the current path, resulting in a finding that nearly all existing rooftop rack-mounted PV systems are “non-compliant,” and therefore illegal to install. These proceedings have industry-wide ramifications. The solar industry has worked hard to build a reputation as providing clean, safe, distributed power generation. Claims to challenge the safety of the rooftop segment of our industry are being advanced. These claims are based not on the industry’s safety record and actual fire incident data, but on the results of theoretical tests in a laboratory. There are some who might with to use this information to denigrate the solar industry to advance a different agenda.

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Manufacturers of flat solar PV panels should be concerned about a need for redesign of PV panels to meet fire classifications for certain racking systems and certain roof covering products. They should also be concerned about their products being deemed “non-compliant” and therefore illegal to install in most rooftop applications. Manufacturers of panels should also be concerned about lost energy production of panels without adequate ventilation, and whether their panels can meet temperature rating requirements.

Manufacturers of solar PV racking systems should be concerned about having their entire rooftop rack-mounted product line deemed “non-compliant,” and therefore illegal to install.

Solar integrators should be concerned about continued ability for supply chain to acquire products that meet the volume demands of their sales. Integrators should also be concerned about continued ability to satisfy the plan review, permitting, and inspection requirements. Delays associated with compliance are likely to develop at the worst possible stage near the end of a design project when customer expectations are greatest. Delays near the end of commercial projects can place project financing or incentives in jeopardy. Critical deadlines could be missed, resulting in cancelled projects, lost sales, and extremely poor customer experience. System costs will increase, and system performance is likely to decrease. It is likely a greater system size could be required in order to meet the same system energy production. Maintenance issues such as roof leaks will likely be increased. Customer acquisition could become more difficult and costly.

The roofing industry, the insurance industry, and code enforcement personnel should be concerned about water and ice damming, moisture accumulation, and inability to see concealed problems before major damage occurs. If using a fire barrier mitigation, extreme conditions would likely be created between the solar panel and the roof covering. Unvented, concealed spaces could prematurely age roof coverings, and could encourage moisture damage and rot. Even if vented, routine observation and maintenance are inhibited.

Solar Thermal Manufacturers and Integrators should be watching these proceedings. These issues could impact solar thermal systems in the future. It is important to note the configuration deemed “non-compliant” and therefore illegal according to the present application of the spread of flame test is not unique to the solar photovoltaic applications. Solar thermal systems also include flat panels installed above and parallel to a roof surface. Although solar PV systems are the subject of increased regulation today, we can only expect solar thermal systems will be burdened by similar regulations in the future.

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RECOMMENDATIONS

We recommend targeted outreach to critical stakeholders in the solar industry. It is not sufficient to wait for more stakeholders to become aware of this situation. We must actively pursue the attention of critical stakeholders and raise their awareness.

SEIA should become more actively involved in determining precisely what is required by 2012 IBC Section 1509.7.2, and in shaping revisions to the UL 1703 Standard. We recommend engaging experts to advocate for the solar industry on these issues, and recommend a source of funding be developed. We also recommend initiating a search for consultants. The consultant base should include a fire protection engineer and/or other fire scientist.

We recommend the present application of the UL 1703 / UL 790 spread of flame test be called into question. We should question whether it is necessary or justified to deem nearly all existing rooftop rack-mounted PV systems “non-compliant,” and therefore illegal to install, given the solar industry’s safety record. We should question whether a spread of flame test that does not direct the test flame over the top of the PV panel is really a test of a PV system, as required by Section 1509.7.2. If a test flame encounters a roof surface or a detached fire barrier rather than a PV system, how is that a fire classification test of a PV system?

As new code Section 1509.7.2 is the trigger for revisions to UL 1703, then UL 1703 should be revised to meet the code provision, not revised to exceed the code provision.

We should question whether 2012 IBC Section 1509.7.2 is enforceable, given the extreme negative impact on industry, and given revisions to UL 1703 are not complete. Section 1509.7.2 was approved by the code committee bearing a statement that “The code change proposal will not increase the cost of construction.” This is clearly a false statement.

Far more research is needed. Under the present path of the UL 1703 STP, our design efforts will become focused on passing a fire test in order to develop rack-mounted systems that are legal to install under the 2012 IBC. Nearly 100 percent of PV systems will never experience a fire event during the life of the system. However, 100 percent of rooftop systems subject to these requirements are likely to experience negative impacts of unintended consequences during every day of normal operation. We must fully understand these negative impacts before we can optimize solutions.

More time is needed for industry to respond to these concerns. Prescriptive solutions are needed. During the December 14, 2011 stakeholder meeting in Northbrook, IL, staff of UL suggested it is possible for UL to provide additional research and testing toward the goal of developing industry solutions. UL staff indicated funding of this additional research and testing would be beyond the scope of their present contract. Funding mechanisms for industry solutions should be explored.

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