SIST-TP CEN/TR 18326:2026

Report on installation scenarios, available test methods and national legislation to be considered for the fire performance classification of roof systems with above roof mounted PV modules

This document describes installation scenarios and available test methods and national legislations to be considered when determining the external fire performance of roof systems, when combined with BAPV.

Rapport sur les scénarios d'installation, les méthodes d'essai disponibles et la législation nationale à prendre en compte dans la classification des performances au feu des systèmes de toiture équipés de modules photovoltaïques montés en surimposition

Poročilo o scenarijih namestitve, razpoložljivih preskusnih metodah in nacionalni zakonodaji, ki jo je treba upoštevati pri razvrščanju požarne učinkovitosti strešnih sistemov z nadstrešnimi PV moduli

Ta dokument opisuje scenarije namestitve in razpoložljive preskusne metode ter nacionalne zakonodaje, ki jih je treba upoštevati pri določanju zunanje požarne odpornosti strešnih sistemov, ko so kombinirani z BAPV (Building-Added Photovoltaics - fotonapetostni sistemi, dodani zgradbam).

General Information

• Status: Published
• Public Enquiry End Date: 30-Mar-2026
• Publication Date: 15-Jun-2026
• ICS: 13.220 - Protection against fire
• ICS: 13.220.50 - Fire-resistance of building materials and elements
• ICS: 27.160 - Solar energy engineering
• Technical Committee: POZ - Požarna varnost
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 11-Jun-2026
• Due Date: 16-Aug-2026
• Completion Date: 16-Jun-2026
• Directive: Harmonized Standard305/2011 - Regulation (eu) No 305/2011 of the European Parliament and of the Council of 9 march 2011 laying down harmonised conditions for the marketing of construction products and repealing council directive 89/106/eec
• Ref Project: CEN/TR 18326:2026 - Report on installation scenarios, available test methods and national legislation to be considered for the fire performance classification of roof systems with above roof mounted PV modules

Overview

SIST-TP CEN/TR 18326:2026 provides a comprehensive examination of installation scenarios, fire performance test methods, and national legislation relevant to the external fire performance classification of roof systems equipped with above-roof mounted photovoltaic (PV) modules. Developed by the SIST and stemming from work done within CEN/TC 127 on fire safety in buildings, this technical report primarily addresses Building Attached PV (BAPV) systems, reflecting their growing use across Europe.

The report offers a summary of current testing practices, guidance, and regulatory approaches. It includes an analysis of the responsibilities of various stakeholders involved in planning, installing, and maintaining PV installations, emphasizing the critical role of fire safety in the era of expanding renewable energy infrastructure.

Key Topics

• Installation Scenarios: The document reviews common BAPV mounting configurations, covering both flat and pitched roof installations. It highlights the significance of design parameters such as module distance from the roof, arrangement, orientation, and type of mounting structure, all of which can influence fire performance.

• Fire Performance Classification: It investigates the impact of PV modules on the external fire resistance of roofing systems. This includes a review of the applicable standards, like EN 13501-5 for classification and CEN/TS 1187 for test methods, noting the lack of harmonized European approaches for BAPV-roof combinations.

• Available Test Methods: The report describes current methods for assessing fire exposure and reaction, such as those outlined in IEC 61730, CLC/TR 50670, and ongoing national initiatives. It also outlines differences in assessment criteria, including the spread of flame and roof penetration resistance.

• National Legislation: A comparative overview of national regulations is provided, highlighting varying requirements on PV module placement, distances from roof penetrations and fire barriers, and the adoption of glass-backed modules or specific roofing systems for assurance.

• Stakeholder Responsibilities: The responsibilities of designers, installers, and operators are discussed, especially regarding regulatory compliance, ongoing maintenance, and risk mitigation.

Applications

SIST-TP CEN/TR 18326:2026 is a valuable resource for a range of users involved in PV and roofing industries, including:

• Architects and Designers: Guiding design decisions to ensure that the integration of PV modules meets relevant fire safety regulations.
• Installers and Contractors: Assisting with correct installation approaches, selection of mounting systems, and understanding national requirements to reduce fire risk.
• Product Manufacturers: Informing development of PV modules and mounting systems that comply with evolving fire performance standards.
• Regulatory Authorities: Aiding the creation and harmonization of fire safety standards and codes for roof-mounted PV systems.
• Insurance and Risk Assessors: Providing insight into best practices for minimizing fire-related incidents in buildings with BAPV systems.

This guidance is particularly important for large-scale or industrial PV installations, where rooftop fire spread could have severe consequences.

Related Standards

Key standards referenced and discussed within the report include:

• EN 13501-5: Fire classification of construction products and building elements – Part 5: Classification using data from external fire exposure to roofs tests.
• CEN/TS 1187: Test methods for the exposure of roofs to fire from outside.
• IEC 61730 Series: Photovoltaic (PV) module safety qualification (covering construction and testing).
• IEC 63027: DC arc detection and interruption in PV power systems.
• IEC 62446-2: Requirements for testing, documentation, and maintenance of grid-connected PV systems.
• CLC/TR 50670: External fire exposure to roofs in combination with photovoltaic arrays – Test method(s).

National guidelines and specifications from countries like France, the Netherlands, Italy, and Slovenia are also referenced, demonstrating the diverse landscape of fire safety regulation for above-roof PV systems.

Keywords: fire performance of PV modules, above roof mounted PV, roof system fire safety, fire resistance classification, BAPV fire risk, photovoltaic installation standards, external fire exposure testing, national building regulations for PV roofs.

Standards Content (Sample)

SLOVENSKI STANDARD
01-julij-2026
Poročilo o namestitvenih scenarijih, razpoložljivih preskusnih metodah in
nacionalni zakonodaji, ki jih je treba upoštevati pri razvrščanju požarne odpornosti
strešnih sistemov s fotonapetostnimi moduli, nameščenimi nad streho
Report on installation scenarios, available test methods and national legislation to be
considered for the fire performance classification of roof systems with above roof
mounted PV modules
Rapport sur les scénarios d'installation, les méthodes d'essai disponibles et la législation
nationale à prendre en compte dans la classification des performances au feu des
systèmes de toiture équipés de modules photovoltaïques montés en surimposition
Ta slovenski standard je istoveten z: CEN/TR 18326:2026
ICS:
13.220.50 Požarna odpornost Fire-resistance of building
gradbenih materialov in materials and elements
elementov
27.160 Sončna energija Solar energy engineering
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TR 18326
TECHNICAL REPORT
RAPPORT TECHNIQUE
June 2026
TECHNISCHER REPORT
ICS 13.220
English Version
Report on installation scenarios, available test methods
and national legislation to be considered for the fire
performance classification of roof systems with above roof
mounted PV modules
Rapport sur les scénarios d'installation, les méthodes
d'essai disponibles et la législation nationale à prendre
en compte dans la classification des performances au
feu des systèmes de toiture équipés de modules
photovoltaïques montés en surimposition

This Technical Report was approved by CEN on 17 May 2026. It has been drawn up by the Technical Committee CEN/TC 127.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 18326:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Overview of installation scenarios and fire classifications . 6
4.1 General. 6
4.2 External fire performance and classification of roof systems . 7
4.3 Components and mounting and fixing parameters of PV modules . 7
4.3.1 General. 7
4.3.2 Supporting structure of BAPV modules . 8
4.3.3 Dimensions of PV modules and arrangement of arrays . 8
4.3.4 Ancillary equipment . 8
4.4 Fire performance of the BAPV modules including their supporting structure . 8
4.4.1 General. 8
4.4.2 Fire performance of PV modules: standardized assessment methods and
requirements . 9
4.5 Fire performance of roofs in combination with BAPV modules . 9
4.5.1 General. 9
4.5.2 Fire sources and requirements for roofs combined with BAPV in case of fire . 9
5 Current proposals, and tests for assessment of roofs combined with BAPV . 10
5.1 CLC/TR 50670:2016 . 10
5.2 Further activities in Europe . 10
6 Conclusions . 11
Bibliography . 13

European foreword
This document (CEN/TR 18326:2026) has been prepared by Technical Committee CEN/TC 127 “Fire
safety in buildings”, the secretariat of which is held by BSI.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
Introduction
Photovoltaic systems (PV) on roofs can be part of the roofing system (Building Integrated PV systems,
BIPV) or mounted on top of a roof (Building Attached PV, BAPV). Above roof mounted PV systems are
increasingly used. In most European countries the fire performance of roof integrated PV systems
(BIPV) is tested in the same way as for roof systems. Whilst additional guidance is required in CEN/TS
1187 to ensure a unified approach to testing BIPV systems, this is not the subject of this TR, which
addresses only BAPV systems.
Above roof PV modules (BAPV) are usually not considered as construction products. Therefore no
harmonized standards until now have been developed by CEN for assessing the fire performance of
these installations alone or in combination with the roofing system below.
PV modules in general are regulated under the low voltage directive (LVD 2014/35/EU)014/35/EU). It
covers health and safety risks for electrical equipment, in order to make sure that the requirements are
the same across Europe for products placed on the market. The European Committee for
Electrotechnical Standardization (CENELEC) is responsible for standardization in electro-technical
engineering field.
Statistics show an increased risk of fire on roofs with BAPV or BIPV. A major cause is with the electrical
connections and these have been mitigated by adhering to CENELEC standards. Nevertheless, risks
remain and PV installations can lead to the outbreak of fire and can contribute to the spread of fire on
and within the roof.
A general assessment of all scenarios for BAPV mounting and fixing above roof systems procedures is
needed.
This document addresses the fire performance of roofs fitted with BAPV modules. It considers the
performance of the PV panels themselves, their method of mounting and the roof system they are
mounted above. There are many variables and for the mounting system these include material, design,
inclination and spacing between the PV modules and the roof covering.
Consideration is needed with regards with creation of Exap Rules due to the complex nature and
number of variations within the construction.
1 Scope
This document describes installation scenarios and available test methods and national legislations to
be considered when determining the external fire performance of roof systems, when combined with
BAPV.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN ISO 13943:2017, Fire safety - Vocabulary (ISO 13943:2017)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN ISO 13943:2017 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
3.1
PV modules
PV Array
mechanically integrated assembly of modules or panels and its support structure
3.2
external fire performance
fire performance in case of external fire exposure
3.3
fire performance
response of a material, product or assembly in a fire
Note 1 to entry: It is often important to understand how materials, products or assemblies behave in real fires as
opposed to in fire tests under controlled conditions. Improved fire performance can be exhibited in a variety of
ways. For example, longer times to ignition, lower heat release, lower flame spread or lower smoke release could
all be evidence of improvements in fire performance.
[SOURCE: Fire Vocabulary]
3.4
pitched roof
roof with an inclination angle of at least 10°
3.5
flat roof
roof with an inclination less than 10°
3.6
roof covering
uppermost waterproofing part of a roof
Note 1 to entry: This layer can comprise single layer or multiple layer coverings.
[SOURCE: CEN/TS 1187]
3.7
roof pitch
inclination of the rafters to the horizontal (pitched roofs) or the inclination of the roof surface to the
horizontal (flat roofs)
3.8
fire penetration
appearance on the underside of the specimen of any sustained flaming or glowing due to combustion,
including the occurrence of any flaming droplets falling from the underside
3.9
roof
roof covering and sealing system including any insulating layers or vapour barriers normally provided
together with their supporting elements including attachment (glued, mechanically fastened, etc.), that
are intended to provide a weatherproof surface
3.10
continuous deck
element with a continuous supporting function in which the gap between adjacent elements is not
greater than 0,5 mm ((5,0 ± 0,5) mm in the case of wooden planks with plain edges)
[SOURCE: CEN/TS 1187]
3.11
roof system/assembly
continuous deck, if present, (and any supporting structure as/if needed), insulation and intermediary
layers, through to and including the roof covering
Note 1 to entry: The roof system/assembly includes all layers e.g.: insulation and the Air Vapour Control Layer
(AVCL) etc.
3.12
roof system plus PV modules
combination of roof systems and PV modules plus installation systems (BAPV)
4 Overview of installation scenarios and fire classifications
4.1 General
Solar modules systems convert solar energy into electrical energy. They can be located on the ground,
or attached to the exterior of building structures such as facades or roofs.
On buildings they are either integrated into the outer face of the building (Building Integrated, BIPV) for
example roofs or facades or attached to the existing building envelope (Building Applied BAPV) for
example on roofs. This document only covers above roof mounted PV systems (BAPV).
Since harmonized methodologies to assess the fire performance of roof systems in combination with
above roof PV modules for the external fire scenario(s) do not exist, their approval follows a variety of
non-harmonized assessments and test methods. In most cases, approval is supported by guidance or
legislation. In addition, a number of insurance methods, guidelines and recommendations are in place.
There is a need to understand the rationale behind these rules, including fire statistics and evidence
from testing.
To evaluate fire performance of the combination of PV modules interacting with roof systems, a general
assessment of PV design, of performance of PV in fire and a general assessment of all scenarios for PV
mounting and fixing above roof systems procedures is needed. The following parameters are relevant
for fire performance:
— Fire performance (and classification) of roof systems;
— Fire performance of the solar modules;
— Fire performance of the electrical infrastructure and accessories (cables, connector boxes etc.);
— Fire performance and geometry of mounting and fixing systems.
For defining a test scenario and a basis for the assessment criteria, information from real fires should be
studied to determine:
— The cause of the fire (external and or autoignition of the PV installation);
— Remedial actions.
4.2 External fire performance and classification of roof systems
Within CEN/TC 127, standards have been developed to assess the external fire performance of roofs.
The scenario of burning brands (for example from a neighbouring building, a wildfire or a chimney),
wind and radiation, are well defined for roofing assemblies through the classification standard of
EN 13501-5 and the associated 4 test methods in CEN/TS 1187. Member states choose which of these
four tests, plus the associated requirements and classifications, they wish to adopt. They also choose the
building types to which these apply. The ignition sources and other test parameters as well as sample
sizes and assessment criteria are different for each test.
4.3 Components and mounting and fixing parameters of PV modules
4.3.1 General
PV modules contain combustible and non-combustible materials.
BAPV modules may be composed of the following layers:
— Mainly Glass on top of the module;
— Crystalline semiconductor cells embedded in a flexible polymeric layer;
— A rear side which can be glass or a polymeric layer (glass backed modules or foil backed modules);
— The outer edges are sealed with a polymer, and often an aluminium frame is used around the
module.
4.3.2 Supporting structure of BAPV modules
The supporting structure may be made of metal (for example aluminium) or from plastics (fibre
reinforced plastics). In addition, a number of different mounting or ballasting fixing are used.
The supporting system can also include shields to prevent dirt and leaves building up or to shield the
underside from the wind.
The supporting structure of the BAPV can also influence the fire behaviour of the combined system, key
parameters being:
• Slope: PV modules can be parallel to the roof or inclined to it. Inclinations vary from 0° to 45;
• Distance of the PV modules from the roof: parallel PV modules are usually close to roof surface (few
centimetres, between 5 to 10); inclined PV modules structures have bottom of PV modules 10 to
20 cm from roof surface;
• The distance between PV modules;
• Orientation of differen
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