PHOTOVOLTAICO vs VVF

UNI 9177

  • The UNI 9177 standard is currently in force (Annex C to note prot. 6334 of 4-5-2012 of the Ministry of the Interior). This defines the fire resistance and reaction tests for the materials making up photovoltaic modules, based on specific safety standards. Following these tests, the materials are divided into classes that guarantee the modules' compliance. It is important to emphasize that only in Italy does a regulation of this type exist that identifies the fire resistance classes of photovoltaic modules, which belong to classes 1 and 2. The materials are assigned to the following classes (each demonstrating a different fire behavior): 0: non-combustible materials 1: non-flammable combustible materials 2: combustible materials that are difficult to ignite. The value increases as the materials' participation in combustion varies. This implies that the lower the class, the better a combustible material's fire behavior. If it is intended to take into account the external fire resistance class of roofs and roof coverings and the fire reaction class of the photovoltaic module (case 3/a of Annex B), the following combinations can be considered, in general, acceptable:
  • roofs classified as Froof and PV panel of class 1 or equivalent fire reaction;
  • roofs classified as Broof (T2, T3, T4) PV panel of class 2 or equivalent fire reaction, top layers of roofing (waterproofing and/or insulation packages) classified as Froof or F installed on EI 30 roofs and PV panel of class 2 or equivalent fire reaction.

    • Broof Coverings

    ALL ABOUT PV FIRE PREVENTION

    Legislative Decree No. 144 of September 23, 2022 (Official Gazette No. 223 of September 23, 2022), in Article 16 of Fire Prevention Procedures, establishes that, following the ongoing energy emergency, in order to facilitate the installation of photovoltaic and solar thermal systems on the roofs and facades of buildings serving activities subject to fire prevention inspections for the assessment of complete project documentation, if required after installation, the deadlines are reduced from 60 to 30 days until December 31, 2024.

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    WORSENING IF:

    Photovoltaic systems are not among the activities subject to fire prevention controls pursuant to Presidential Decree no. 151 of August 1, 2011, "Regulation simplifying the rules governing fire prevention procedures, pursuant to Article 49, paragraph 4-quater, Legislative Decree no. 78 of May 31, 2010, converted with amendments by Law no. 122 of July 30, 2010." Generally speaking, the installation of a photovoltaic (PV) system, depending on its electrical/construction characteristics and/or installation methods, may increase the existing fire risk. For the building served, this increase could result in: - interference with the combustion product ventilation system (partial/total obstruction of translucent elements, impediments to the opening of exhaust vents); - obstruction to the cooling/extinguishing operations of combustible roofs; - risk of flames spreading outside or inside the building (presence of pipes on the roof of a building divided into multiple compartments - change in the speed of fire spread in a single-compartment building). NO ASSURANCE IF: The installation must be carried out in such a way as to prevent the spread of a fire from the photovoltaic generator to the building in which it is incorporated. This condition is considered met if the photovoltaic system, incorporated into a construction project, is installed on non-combustible roofing and/or façade structures and elements (Class 0 according to Ministerial Decree 26/06/1984 or Class A1 according to Ministerial Decree 10/03/2005). It is also equivalent to place a layer of fire-resistant material of at least El 30 and non-combustible (Class 0 according to Ministerial Decree 26/06/1984 or Class A1 according to Ministerial Decree 10/03/2005) between the photovoltaic modules and the support surface.

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    PHOTOVOLTAIC SYSTEMS - FIRE PREVENTION REGULATIONS

    Don't despair, there's a solution to everything... maybe!!! Download the attached document.

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    MODULO: Installazione impianti fotovoltaici

    Installazione impianti fotovoltaici (da 07/02/2012)

    in attività soggette al DPR151

    SCIA con dichiarazione di non aggravio

    BORDER LINE SITUATIONS - WHERE TO INSTALL AN EI30 LAYER

  • Ventilated roofs employ advanced roof insulation technology and are primarily used for the construction of habitable attics. They consist of a panel of insulating material made of closed-cell sintered expanded polystyrene (EPS). They are self-extinguishing, non-toxic, hygienic, and durable. They are shaped with protruding supports to create ventilation channels and are bonded to a sheet of cross-laminated long-fiber phenolic plywood (OSB/3). The OSB/3 sheet is pre-treated with anti-mold, anti-woodworm, and water-repellent resins. It is highly resistant to compression, walkable during installation, and impervious to the weight of commonly used roofing materials (terracotta tiles, concrete tiles, Canadian shingles, etc.). The special shaping of the insulation panel allows for the creation of a ventilation chamber between the insulation and the phenolic wood, which serves as a support for the roofing. The constant and consistent circulation of air created within the panel removes heat from the roof covering, protecting the underlying layers from overheating. This ventilation increases and strengthens the insulation's properties by expelling heat from the roof ridge, thus reducing the temperature in the rooms below by 8-10°C. In addition to the risk assessment, which must be conducted "taking into account the external fire resistance class of the roofs and roof coverings and the fire reaction class of the photovoltaic module," other assessments aimed at demonstrating achievement of the guide's objectives are admissible. If the external fire resistance class of roofs and roof coverings and the fire reaction class of the photovoltaic module are to be taken into account (case 3/a of Annex B), the following combinations can generally be considered acceptable:
  • roofs classified as Froof and PV panel of class 1 or equivalent fire reaction;
  • roofs classified as Broof (T2, T3, T4) and PV panel of class 2 or equivalent fire reaction;
  • top covering layers (waterproofing and/or insulation packages) classified as Froof or F installed on EI 30 roofs and PV panel of class 2 or equivalent fire reaction. The classification of roofs and roof coverings must refer to the applicable conformity attestation procedures (CE marking) or, in their absence, the manufacturer's declaration based on a test report issued by an Italian laboratory authorized pursuant to the Ministry of the Interior Decree of 26 March 1985, or another laboratory recognized in one of the European Union countries or countries party to the EEA Agreement. For the purposes of assessing the external fire resistance class of roofs and roof coverings, please note that the first version of UNI CEN /TS 1187 was published in February 2012, replacing UNI ENV 1187:2007 cited in the technical guide. For information purposes, please note that European Commission Decisions 2001/671/EC (OJ L 235 of 4 September 2001) and 2005/823/EC (OJ L 307 of 25 November 2005) report the classification system for the external fire resistance of roofs and roof coverings. For the purposes of assessing the reaction-to-fire class of photovoltaic panels, please note that a specific resolution was issued on 28 March 2012 by Area V of the DCPST - Fire Reaction Sector, regarding the methods for carrying out reaction-to-fire tests on PV panels (Annex C). The resolution requires laboratories to issue a specific test certificate indicating the use "PHOTOVOLTAIC PANEL". The test certificate is related to the panel itself and not to the place of use. Risk assessments must be signed by qualified technicians registered in the Ministry of the Interior's registers.

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  • Verifying the installation of an EI 30 panel under photovoltaic panels on a roof with the following stratigraphy:
  • Roofing: insulated corrugated sheet metal
  • Insulation: Polyurethane (PU) Rock wool (5 cm) requires analyzing various regulatory and technical aspects. Here are the main points to consider: 1. Verification of EI 30 Fire Resistance EI 30 indicates a 30-minute fire resistance in terms of tightness (E) and thermal insulation (I). The EI 30 panel must be certified according to current regulations (e.g. UNI EN 1365-2 for roofing). Its installation under photovoltaic panels must guarantee continuity of passive fire protection. 2. Compatibility with the Roof Stratigraphy Corrugated sheet metal: the presence of a cavity under the sheet metal can influence behavior in the event of a fire. PU Rock Wool: Polyurethane is combustible and could promote the spread of fire, while rock wool is non-combustible and helps protect against fire. It is necessary to verify whether the installation of the EI 30 panel creates thermal bridges or discontinuities in protection. 3. Local Regulations and Requirements Check compliance with local fire regulations (e.g. Ministerial Decree 03/08/2015 in Italy for activities subject to the Fire Brigade). If the photovoltaic system exceeds 20 kW, specific compartmentation requirements may be required. 4. Installation and Fixing The EI 30 panel must be adequately anchored to the structure to maintain its fire barrier function. Consider safety distances between the PV panels and the EI 30 panel to avoid overheating. 5. Possible System Approval It is recommended to verify whether the complete system (roofing EI 30 panels PV system) has already been tested and certified as a single solution. If certifications are not available, specific tests may be required to ensure compliance. Risk assessments must be signed by qualified technicians registered with the Ministry of the Interior.

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