The installation of a photovoltaic system serving an activity subject to fire prevention controls undoubtedly involves a change to the fire risk assessment drawn up by the qualified technician.
To facilitate the installation of photovoltaic systems on the roofs of buildings serving activities subject to fire prevention controls, given the high number of requests for the ongoing energy emergency, the legislator with the Legislative Decree 144/2022 (GU no. 223 of 23 September 2022), in art. 16 established that in the event that, following the installation of these types of systems, the evaluation of the fire prevention project is necessary, the terms for the binding opinion of the Fire Brigade. are reduced, until 31 December 2024, from sixty to thirty days, in order to streamline the bureaucratic process.
Changes to subject activities
Photovoltaic systems are not included among the activities subject to fire prevention control as they are not included in the list in Annex 1 of the Presidential Decree. 151/2011.
However, the installation of a photovoltaic system serving an activity subject to fire prevention controls undoubtedly involves a change to the fire risk assessment drawn up by the qualified technician, whose management is regulated by the Ministerial Decree. 7 August 2012, which provides for differentiated obligations depending on whether the changes are:
- « Not substantial » (it is sufficient to declare them when certifying periodic renewal).
- «Without worsening» the pre-existing fire safety conditions (a new certified notification of commencement of activity must be submitted).
- With worsening of the pre-existing fire safety conditions (a new project examination must be submitted).
Evaluation of changes
The evaluation of the type of modification is carried out by the designer through a risk assessment aimed at identifying the most suitable solutions to achieve the fire safety objectives.
The professional will be able to take into account the technical solutions contained in the DCPREV prot notes. n. 1324 of 7 February 2012 and n. 6334 of 4 May 2012, although they must not be considered as prescriptive indications.
"Photovoltaic system serving an activity subject to fire prevention controls" means a system incorporated into the subject activity, independently of the end user, or a system whose modules fall, even partially, within the volume delimited by the cylindrical surface. vertical having as its generator the plan projection of the building, including overhangs and eaves.
Fire prevention requirements
If the fire risk assessment reveals a worsening of the pre-existing fire safety conditions, examination of the project must be requested (for category B and C activities) from the Provincial Fire Brigade Headquarters and, once the works are completed, it must be presented the certified Report of commencement of activity before the start of the activity.
However, if no worsening of the pre-existing fire safety conditions emerges, the application must be updated with the presentation of the Scia.
In case of presentation of the Scia without prior approval of the project, the documentation must be integrated with the risk assessment.
Case of «increased risk»
The installation of a photovoltaic system can lead to an increase in the pre-existing level of fire risk for the business served, depending on the electrical and construction characteristics and methods of installation.
In evaluating this possible "increased risk" for the legislator, the following aspects must be taken into consideration to allow the identification of the obligations set out in the art. 4, paragraph 6, of the Presidential Decree. n. 151/2011:
> Interference with the combustion product ventilation system such as, for example, partial/total obstruction of translucent elements, impediments to the opening of the vents.
> Obstacle to cooling or extinguishing operations on combustible roofs.
> How the fire spreads in a building of the flames outside or towards the inside of the building (presence of pipes on the roof of a building divided into several compartments, modification of the speed of spread of a fire in a single compartment building) .
> Safety of maintenance operators.
> Safety of rescue operations workers.
From a safety point of view, it must be taken into account that it is impossible to de-energize the system in the presence of sunlight.
This constitutes an element of attention not only during the construction and maintenance phase of the photovoltaic generator, but also in the event of an emergency intervention.
For the purposes of fire prevention, PV systems must be designed, built and maintained in a workmanlike manner.
Where the systems are carried out according to the technical documents issued by the CEI (standards and guides) and/or by the international standardization bodies, they are considered to have been carried out in a workmanlike manner.
All components must comply with applicable community or national provisions.
The installation must be carried out in such a way as to avoid the spread of a fire from the photovoltaic generator to the building in which it is incorporated.
This condition is considered respected if the photovoltaic system is installed on non-combustible structures and roofing elements (Class 0 according to the Ministerial Decree 06/26/1984 or Class A1 according to the Ministerial Decree 03/10/2005).
The interposition between the photovoltaic modules and the support surface of a layer of fire-resistant material of at least EI 30 and non-combustible is also equivalent.
Alternatively, a specific assessment of the risk of fire spread may be carried out.
In addition to the risk assessment, other assessments aimed at demonstrating the achievement of the objectives of the guide are eligible.
In the DCPREV note n.6334 of 04/05/2012 the different methods for satisfying the safety requirement relating to the risk of fire spread were summarized.
If it is intended to take into account the external fire resistance class of roofs and roof coverings and the reaction to fire class of the photovoltaic module (case 3/a of Annex B), the following can generally be considered acceptable pairings:
> Roofs classified Froof and PV panel class 1 or equivalent reaction to fire.
> Roofs classified as Broof (T2, T3, T4) and PV panel class 2 or equivalent reaction to fire.
> Final roofing layers (waterproofing and/and insulation packages) classified Froof or F installed on EI 30 roofs and class 2 PV panels or equivalent reaction to fire.
The location of the modules and electrical conduits must also always allow the correct functioning and maintenance of any smoke and heat evacuators (EFC) present, as well as taking into account, based on the fire risk analysis, the existence of possible fire transmission routes (skylights, chimneys, etc.).
In any case, the modules, ducts, inverters, panels and any other equipment must not be installed within a radius of 1 m from the EFCs.
Furthermore, in the presence of vertical fire compartmentation elements, placed inside the activity underneath the support surface of the photovoltaic system, the same must be at least 1 m away from the projection of these elements.
The PV system must also have the following characteristics:
> Be equipped with an emergency control device, located in a marked and accessible position which determines the isolation of the electrical system, inside the compartment in relation to the power sources, including the photovoltaic system.
> In the event of the presence of gases, vapours, flammable mists or combustible dusts, in order to avoid the dangers caused by electrical ignition, it is necessary to install the direct current part of the system, including the inverter, outside the classified areas pursuant to Legislative Decree 81/2008 - annex XLIX.
> In places with danger of explosion due to the presence of explosive material, the photovoltaic generator and all other direct current components constituting potential ignition sources must be installed at the safety distances established by the applicable technical standards.
> The components of the system must not be installed in places defined as "safe places" pursuant to Ministerial Decree 30/11/1983, nor be an obstacle to escape routes.
In-depth analysis by the eng. Matteo Pierotti