FIRE SAFETY OF PV SYSTEMS
INSIGHTS AND
RECOMMENDATIONS
FIRE Safety of PV systems
2/18
© Fronius International GmbH
Version 01/2020
Business Unit Solar Energy / System Technology
Fronius reserves all rights, in particular rights of reproduction, distribution, and translation.
No part of this work may be reproduced in any way without the written consent of Fronius. It must not be saved, edited, reproduced, or
distributed using any electrical or electronic system.
You are hereby reminded that the information published in this document, despite exercising the greatest of care in its preparation, is
subject to change and that neither the author nor Fronius can accept any legal liability.
Gender-specific wording refers equally to female and male form.
.
.............................................................................................................................................................................
FIRE Safety of PV systems
3/18
TABLE OF CONTENTS
1 Introduction .....................................................................................................................................4
1.1 Objective ...........................................................................................................................................4
1.2 Fire and PV Systems: Fact and Fiction ............................................................................................4
1.3 Risk of Fire vs. Risk for Firefighters ..................................................................................................5
2 Failure Analysis ..............................................................................................................................6
2.1 Germany ...........................................................................................................................................6
2.2 United Kingdom ................................................................................................................................8
3 DC-Connectors – Necessity and Error Source ............................................................................9
3.1 Installation Errors ..............................................................................................................................9
3.2 Mismatching DC-Connectors ......................................................................................................... 10
3.3 Power Optimizers – a Dangerous Safety Measure ....................................................................... 11
4 PV fire – Tackling the Improbable .............................................................................................. 13
5 Recommendations & Conclusion .............................................................................................. 14
5.1 Recommendations to Reduce the Risk of Fire .............................................................................. 14
5.2 Additional Measures to Reduce the Risk for Firefighters .............................................................. 15
5.3 The Embedded Safety of Fronius Products ................................................................................... 16
6 Literature ...................................................................................................................................... 17
.............................................................................................................................................................................
FIRE Safety of PV systems
4/18
1 INTRODUCTION
Recently, unsubstantiated safety concerns were created by the media about the safety of PV systems, despite
photovoltaics being an extremely safe technology. Rumors about burning houses that cannot be extinguished
or firefighters who do not fight a fire if PV is involved put rooftop PV systems in a light they do not deserve. In
fact, PV systems are of a very high safety level when it comes to preventative fire protection as well as
operational safety and security in the case of fires. Many recent analyses of fire incidents related to PV, like
those from TÜV Rheinland and Fraunhofer ISE (Sepanski et al., 2015), BRE (2017b), and IEA PVPS (2017)
show that components of PV systems are tested according to very stringent safety and reliability test protocols
during the manufacturing process. This ensures they fulfill electrical safety requirements of various national
and international codes and standards. Additionally, aspects like the creation of fire compartments,
accessibility, functional integrity, and mechanical safety have to be considered in planning, construction, and
operation. Modules that act as a part of a roof (building integrated PV) have to fulfill the same fire resistance
tests as the roofing material.
According to the International Energy Agency Photovoltaic Power Systems Program (IEA PVPS), “PV systems
do not pose health, safety or environmental risks under normal operating conditions if properly installed and
maintained by trained personnel as required by electric codes.” (IEA PVPS 2017; p. 2).
1.1 Objective
The aim of this paper is to evaluate and display the actual situation concerning fire incidents including a PV
system in selected countries and to derive if there is a significant contribution of building related PV systems
to the risk of fire. Although PV is a very safe technology and incidents are rare, this analysis should highlight
the most common reasons for arc faults and therefore possible fire incidents. Based on the findings of this
failure analysis in selected countries, suitable measures for reducing the already small fire risk induced by PV
systems are derived.
Although low voltage electricity has been a part of almost every building for decades now, and fire fighters
know how to deal with it, a certain precariousness exists in the public when it comes to the topic of extinguishing
a PV related fire. By analysing different operation tactics and strategies as well as safety measures to reduce
the risk of electrocution for firefighters, this paper provides recommendations on how to act in the event of a
fire.
1.2 Fire and PV Systems: Fact and Fiction
As mentioned in the introduction, rumours about rooftop PV systems and their handling in the case of fires still
exist. By analysing customer feedback, headlines as well as relevant literature (Sepanski et. al. 2015), the
following points have been identified, representing the variety of incorrect information that circulates in the
public domain:
/ Firefighters do not extinguish a fire in buildings with a rooftop PV system
/ A rooftop PV system massively increases the risk of fire
.............................................................................................................................................................................
FIRE Safety of PV systems
5/18
/ A rooftop PV system massively increases the risk of injuries during an emergency for firefighters
/ Module level shutdown reduces the risk of fire
/ It is not possible to extinguish a fire caused by PV
/ A rooftop PV system greatly increases the possibility that a building gets struck by lightning
Next to the objective defined in Chapter 1.1, the listed points should be analysed critically, to check if there are
realistic statements that confirm or invalidate those rumours.
1.3 Risk of Fire vs. Risk for Firefighters
Before going into detail regarding the analysis of PV related fire incidents, a distinct definition is necessary
regarding the risks related to a fire.
When talking about the safety of PV systems, possible risks relating to a fire that may occur can be divided
into two categories:
/ Risk of fire: This risk describes the probability that a fire occurs. The
higher the probability, the higher the risk that a fire occurs.
/ Risk for emergency responders: This risk describes the probability that a firefighter or other
emergency personnel is injured during a rescue or fire fighting mission.
These two categories are both important when talking about increasing the safety of PV systems.
Taking appropriate measures to reduce the risk of fire directly reduces the risk for emergency responders, as
no fire means no risks for the emergency responders, and therefore this should be the top priority as far as PV
fire safety is concerned. This conclusion is not always applicable the other way around. Measures that directly
affect the risk for emergency responders, like module level shutdown for example, often do not contribute to
reducing the risk of fire, but could instead lead to an increased risk of fire as will be discussed in Chapter 3.
In its commitment to increase the already high level of safety concerning fire protection, Fronius sets the focus
on decreasing the risk of fire, which directly influences the risk for emergency responders, therefore making it
a sustainable and more beneficial approach.
.............................................................................................................................................................................
FIRE Safety of PV systems
6/18
2 FAILURE ANALYSIS
Figure 2: Type of error – allocation for Germany (data from
Sepanski et. al. 2015)
Figure 1: Error source – allocation for Germany (data from
Sepanski et. al. 2015)
As mentioned in the introduction, this chapter will give an overview about fire incidents involving building
related PV systems in selected countries.
2.1 Germany
Germany is one of the oldest PV markets worldwide, and the biggest in Europe. In 2015, TÜV Rheinland in
cooperation with Fraunhofer Institute for Solar Energy Systems (ISE) published a report about fire incidents
involving building related PV systems until 2013 and their causes. This detailed analysis showed that 430
instances of fire/heat damage were officially reported, whereof 210 were triggered by the PV system itself.
Compared to the 1.3 million PV systems installed in total as of 2013, this equates to 0.016% of all PV systems
installed in Germany (Sepanski et. al. 2015). The following figures show an allocation of the fire incidents to
various types of error and error sources.
The analysis showed that more than 70% of the errors are based on external influences or installation failures
(see Figure 2). Whereas only 17% of the errors resulting in fire are based on product failure (see Figure 2) and
only 10% of the errors occur in the inverter (see Figure 1).
A detailed fault analysis pointed out the most common reasons for serial arc faults, which are the main causes
of fire incidents involving PV systems. These reasons are listed in Table 1, and sorted according to component
and likelihood of occurrence.
.............................................................................................................................................................................
Loading...