Managing fire risk related to photovoltaic (PV) systems on buildings

IEC TR 63226:2021 is intended for use as guidance for reducing fire risks in general and for site-specific needs for buildings with PV systems. In addition to the general recommendations, technical, installation, and maintenance measures can be selected to reach the intended safety level of the PV system and building, depending on the results of a risk assessment. This document contains general information about building related risks and includes measures for reducing those risks. These measures are not general requirements or recommendations. They are explained as a guide for selecting suitable measures depending on the on-site needs.

General Information

Status
Published
Publication Date
17-Feb-2021
Current Stage
PPUB - Publication issued
Completion Date
18-Feb-2021
Ref Project

Buy Standard

Technical report
IEC TR 63226:2021 - Managing fire risk related to photovoltaic (PV) systems on buildings
English language
27 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

IEC TR 63226
Edition 1.0 2021-02
TECHNICAL
REPORT
colour
inside
Managing fire risk related to photovoltaic (PV) systems on buildings
IEC TR 63226:2021-02(en)
---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
Copyright © 2021 IEC, Geneva, Switzerland

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form

or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from

either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC

copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or

your local IEC member National Committee for further information.
IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC

The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes

International Standards for all electrical, electronic and related technologies.
About IEC publications

The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the

latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC online collection - oc.iec.ch

The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the

variety of criteria (reference number, text, technical publications previews. With a subscription you will always

committee, …). It also gives information on projects, replaced have access to up to date content tailored to your needs.

and withdrawn publications.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 000 terminological entries in English
details all new publications released. Available online and
and French, with equivalent terms in 18 additional languages.
once a month by email.
Also known as the International Electrotechnical Vocabulary
(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc
If you wish to give us your feedback on this publication or
need further assistance, please contact the Customer Service
Centre: sales@iec.ch.
---------------------- Page: 2 ----------------------
IEC TR 63226
Edition 1.0 2021-02
TECHNICAL
REPORT
colour
inside
Managing fire risk related to photovoltaic (PV) systems on buildings
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160 ISBN 978-2-8322-9395-9

Warning! Make sure that you obtained this publication from an authorized distributor.

® Registered trademark of the International Electrotechnical Commission
---------------------- Page: 3 ----------------------
– 2 – IEC TR 63226:2021 © IEC 2021
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

3 Terms and definitions ...................................................................................................... 7

4 Risk evaluation ................................................................................................................ 7

4.1 General ................................................................................................................... 7

4.2 Site selection .......................................................................................................... 7

4.3 Aspects for building risk evaluation ......................................................................... 7

4.3.1 Roofing materials............................................................................................. 7

4.3.2 Building construction ....................................................................................... 8

4.3.3 Building contents ............................................................................................. 8

4.3.4 Use of building................................................................................................. 9

4.3.5 Building type considerations regarding financial risks ...................................... 9

4.4 Measures for supporting firefighter and rescue service operations .......................... 9

4.4.1 General ........................................................................................................... 9

4.4.2 Response times of emergency responders and available apparatus............... 10

4.4.3 Geometry, height, accessibility of building ..................................................... 10

4.4.4 Coordination with fire alarm systems ............................................................. 11

4.5 Other organizational aspects................................................................................. 11

4.5.1 Briefing fire services in on-site specific aspects ............................................. 11

4.5.2 Harmonize measures with fire protection measures of building ...................... 12

4.5.3 Harmonize measures with owner, user and building and inventory

insurance ....................................................................................................... 12

5 Technical PV system design measures for fire prevention ............................................. 12

5.1 General ................................................................................................................. 12

5.2 Initial PV system design considerations to minimize risk ....................................... 12

5.2.1 General ......................................................................................................... 12

5.2.2 Ventilation ..................................................................................................... 12

5.2.3 Accumulation of flammable material............................................................... 13

5.2.4 Cabling .......................................................................................................... 13

5.3 Arc-fault detection ................................................................................................. 13

5.4 Earth-fault detection.............................................................................................. 14

5.5 Automatic shutdown after first fault ....................................................................... 14

5.6 Coverboard ........................................................................................................... 14

6 Technical PV system design measures for supporting firefighter and rescue

service operations ......................................................................................................... 15

6.1 General ................................................................................................................. 15

6.2 Initial PV system design considerations to minimize risk ....................................... 15

6.2.1 General ......................................................................................................... 15

6.2.2 DC cable lengths and routing ......................................................................... 15

6.2.3 DC cabling marking ....................................................................................... 15

6.2.4 Access pathways and escape routes ............................................................. 15

6.2.5 Caution board ................................................................................................ 15

6.3 Generator/string-level shutdown ........................................................................... 15

6.4 Module-level control, ELV-systems, distributed array protection ............................ 16

6.5 Cable routing measures ........................................................................................ 17

---------------------- Page: 4 ----------------------
IEC TR 63226:2021 © IEC 2021 – 3 –

6.6 Fire-resistant cable raceways................................................................................ 17

7 Installation and commissioning ...................................................................................... 17

7.1 General ................................................................................................................. 17

7.2 Important installation requirements impacting risk ................................................. 17

7.3 Commissioning procedures ................................................................................... 18

7.4 Documentation – clear installation, owners, fire services and maintenance

manuals for PV equipment .................................................................................... 18

8 Operation and maintenance ........................................................................................... 18

8.1 General ................................................................................................................. 18

8.2 Inspection of electric system ................................................................................. 18

8.3 Inspection of mounting structure and building influence ........................................ 19

8.4 Inspection of pathways ......................................................................................... 19

8.5 Cleaning ............................................................................................................... 19

8.6 Thermography....................................................................................................... 19

8.7 Recommendations for empty buildings or systems not under supervision .............. 19

9 Corrective measures after fire ....................................................................................... 19

9.1 General ................................................................................................................. 19

9.2 Measures to avoid safety risks or further damage ................................................. 19

9.3 Safety inspection .................................................................................................. 20

9.4 Measures to bring PV system into a safe state ...................................................... 20

Annex A (informative) Analysis from fire incidents in PV systems ......................................... 21

A.1 General ................................................................................................................. 21

A.2 Component where fire started ............................................................................... 22

A.3 Cause of incident .................................................................................................. 23

A.4 When did incidents occur? .................................................................................... 25

Bibliography .......................................................................................................................... 26

Figure 1 – Cable routing related to pathways ........................................................................ 11

Figure A.1 – Number of identified incidents and severity of effect on surroundings for a

total of about 400 fire reports ................................................................................................ 21

Figure A.2 – Distribution of fire reports depending on mounting type ..................................... 21

Figure A.3 – For cases of damaged buildings only: distribution of fire reports

depending on mounting type ................................................................................................. 22

Figure A.4 – Counts of system section where fire started ...................................................... 22

Figure A.5 – Counts of component where fire started ............................................................ 23

Figure A.6 – Distribution of identified causes of fire incidents ............................................... 23

Figure A.7 – Number of incidents over operation system age ................................................ 25

Table A.1 – Number of incidents with a certain damage ........................................................ 21

---------------------- Page: 5 ----------------------
– 4 – IEC TR 63226:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MANAGING FIRE RISK RELATED TO PHOTOVOLTAIC (PV)
SYSTEMS ON BUILDINGS
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international

co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and

in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,

Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their

preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with

may participate in this preparatory work. International, governmental and non-governmental organizations liaising

with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for

Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all

interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence between

any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.

5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent

rights. IEC shall not be held responsible for identifying any or all such patent rights.

The main task of IEC technical committees is to prepare International Standards. However, a

technical committee may propose the publication of a Technical Report when it has collected

data of a different kind from that which is normally published as an International Standard, for

example "state of the art".

IEC TR 63226, which is a Technical Report, has been prepared by IEC technical committee 82:

Solar photovoltaic energy systems.
The text of this Technical Report is based on the following documents:
Draft TR Report on voting
82/1500/DTR 82/1553A/RVDTR

Full information on the voting for the approval of this Technical Report can be found in the

report on voting indicated in the above table.

This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

---------------------- Page: 6 ----------------------
IEC TR 63226:2021 © IEC 2021 – 5 –

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct understanding

of its contents. Users should therefore print this document using a colour printer.

---------------------- Page: 7 ----------------------
– 6 – IEC TR 63226:2021 © IEC 2021
INTRODUCTION

PV systems provide electric energy in an environmentally beneficial way. They work silently,

without pollution or other emissions and can be mounted nearly anywhere in close proximity to

where people use electricity including living, working and sleeping facilities. However, since

they contain electrical equipment, they share a similar risk of causing damage on both the DC

side and on the AC side of an installation as any electric or electronic equipment.

This document is about fire prevention measures and additional measures for supporting

firefighters. In general, PV systems are considered safe when relevant product and installation

standards are applied. But even for PV systems installed according to relevant safety standards,

there is a remaining risk that a fire is caused by the PV system. Additional measures are

considered to further improve the situation at special locations, independent of whether the PV

or an external event is the source of a fire. Also the restrictions to firefighters facing damaged

PV systems in case of fire are considered in general.

At some locations or buildings there are greater needs due to higher risks. For such locations

additional requirements often apply. This is why building and fire codes often vary based upon

risks to safety. Also in the installation standards there are additional requirements for fire safety,

for example IEC 60364-4-42 or IEC 60364-5-51. In case of higher risks regarding fire, people's

safety, and financial risks, additional measures are reasonable depending on the building itself.

This document is designed to assist PV designers and insurance companies to select suitable

measures to address the on-site specific needs of special locations. This document contains

measures for reducing risks in general and depending on the on-site conditions.

General information is provided to further reduce fire risks of PV systems. Also, information is

given how to handle PV systems after a fire.
---------------------- Page: 8 ----------------------
IEC TR 63226:2021 © IEC 2021 – 7 –
MANAGING FIRE RISK RELATED TO PHOTOVOLTAIC (PV)
SYSTEMS ON BUILDINGS
1 Scope

This document, which is a Technical Report, is intended for use as guidance for reducing fire

risks in general and for site-specific needs for buildings with PV systems. In addition to the

general recommendations, technical, installation, and maintenance measures can be selected

to reach the intended safety level of the PV system and building, depending on the results of a

risk assessment. This document contains general information about building related risks and

includes measures for reducing those risks. These measures are not general requirements or

recommendations. They are explained as a guide for selecting suitable measures depending

on the on-site needs.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 Risk evaluation
4.1 General

It is recommended to perform a risk evaluation, to identify, if additional measures are needed

and which measures are reasonable in order to reach the intended safety level. Such a site-

specific evaluation can help the needs of all stakeholders to be covered without putting

unnecessary requirements on all PV systems.
4.2 Site selection

The selection of the site can have a major impact on the recommended measures. The designer

should evaluate if the proposed building or part of the building is the best choice for a PV

installation. Shifting to another part of the building, to another building or to a ground installation

can be a reasonable step to avoid additional measures.

The fire zones and the position of fire protection walls should be evaluated. The PV array should

not provide a fire path (bridge) between adjacent fire zones.
4.3 Aspects for building risk evaluation
4.3.1 Roofing materials

Roofing materials have an impact on how much damage an exterior fire will cause to a building.

In some countries, for example USA, building codes require fire ratings of roofing systems

---------------------- Page: 9 ----------------------
– 8 – IEC TR 63226:2021 © IEC 2021

based upon the occupancy of the building. Buildings, where people assemble, such as theatres

and churches, require a higher level of roof fire ratings than warehouses. Both are susceptible

to exterior fires, but the assembly occupancy has a higher risk to human life and is therefore

required to have a more fire-resistant roof.

Roofing materials are tested for certain fire withstand capabilities. However, these product

characteristics may not be sufficient to withstand the energy from an arc or fire caused by a

fault. If a roofing material is capable of being ignited by an arc or fire caused by a fault,

additional measures may be taken into account. Additionally, the presence of PV modules in

close proximity to roofing materials may trap or radiate heat from a rooftop fire causing

additional roof damage. The higher the fire resistance of the roofing system, the less likely a

rooftop fire will cause widespread damage.

Depending on the occupancy of the building and the financial risk of loss for the building, it may

be necessary to upgrade a roof system's fire resistance when a PV system is installed on the

roof or use additional measures to reduce the fire risk. If the cost of upgrading the fire resistance

of the roof or additional equipment is too high, then other installation locations should be

considered that require less investment.

For buildings covered with exposed flammable roofing materials, additional safety measures

should be considered to help prevent fire ignition. Flammable roofing materials include many

common roofing materials such as bitumen, asphalt, tar paper, and various polystyrene and

polyisocyanurate insulating materials. Higher fire-rated roofing systems that incorporate the

most flammable polystyrene insulating materials normally include what is referred to as a cover

board between the roof membrane and the insulation to prevent a fire on the membrane from

involving the flammable polystyrene materials beneath the membrane.

All roofs in Europe – with or without PV – must comply with fire resistance classes according to

CEN/TS 1187. There are four different regions with four different tests within Europe. Generally,

the requirements are separated into building-integrated PV (BIPV) where PV modules need to

comply with the same requirements as the roof skin and building-applied PV (BAPV) with lower

requirements related to fire resistance such as ignitability.

Building products and building materials in Europe are classified according to the EN 13501

series, for example class E. Ignitability (e.g. in Germany for BAPV "normal ignitability" is

required by building codes – DIBt) is tested according to ISO 11925 (all parts).
4.3.2 Building construction

Not only is the roof construction important to the fire risk of a building, the entire building

construction is also important. Buildings constructed of concrete, brick, and stone are more fire

resistant than steel or wood structures. The concern with building construction types may be

accelerated building collapse or propagation of fire to adjacent structures.
4.3.3 Building contents

In the case of buildings that warehouse flammable materials, these contents can add

significantly to the risk of loss should the fire originate inside the building or penetrate the roof

and get into the building. Examples of flammable contents are polymeric materials, butter, and

wood-based products. Should the fire engage these contents without adequate fire sprinkler

systems to control the fire, contents fires are capable of destroying buildings, even those with

good fire-resistant construction. The contents of buildings such as warehouses may change

over the lifetime of the building and may require that the risk evaluation be revised based on

the change of contents.
---------------------- Page: 10 ----------------------
IEC TR 63226:2021 © IEC 2021 – 9 –
4.3.4 Use of building
4.3.4.1 General

Building use can play a major role in the risk profile of a project. The financial risk of a fire is

closely related to the risk to human life and the risk to structures and building contents. A barn

housing hay for livestock may be a low risk, particularly if the livestock is not housed in the

structure. A warehouse storing consumer electronics may have a higher financial risk in case

of fire. Thus a building full of people, such as a theatre or a shopping mall, has a much greater

financial risk than either of the previous examples given the threat of loss of human life. These

building types generally require more sensitive fire alarm and fire suppression equipment to

help mitigate these risks. A PV system installation should take into account these varying levels

of risk due to building use, especially with respect to the operation times (daylight) of the PV

system, and employ the highest safety levels for buildings with the highest risks.

4.3.4.2 Building type considerations regarding risks to humans

Where risks to humans are involved, fire prevention measures and measures supporting

firefighter safety are important (e.g. hospitals). Additionally, firefighters need quick access to

the fire location to extinguish and avoid the spread of fire in the early stages of a fire before it

becomes a problem for the people inside the building regardless of whether the PV was the

cause or not. In order to access the fire, firefighters may need to open parts of the roof,

depending on the location of the fire. Where this area is covered by PV modules, there is already

a time delay, caused by removing modules and mounting structure.

Firefighting tactics vary from country to country. Therefore, measures for supporting firefighter

activities should be chosen accordingly.
4.3.5 Building type considerations regarding financial risks

Additional safety measures may be selected according to the financial risks involved with losses

at a particular building and place of business. This includes costs for any building contents and

inventory as well as costs for interruption of the facility operations. For instance, a

manufacturing process that is critical to the production of a particular product may require a

high level of safety since the loss of facility production could interrupt the production of the final

product. Facilities that have redundant manufacturing options would be a lower risk to the

production. Also, the value of stored products will impact whether the facility has a higher or

lower financial risk in the event of a fire. Safety measures should be selected based on the level

of risk. Often the insurance company will determine the classification of risk.

In order to address financial risks, fire prevention measures are recommended as well as

measures supporting firefighters. Damages and losses can be reduced when quick access to a

fire location is enabled. This allows firefighters to extinguish the fire quickly and avoids the

spread of fire in an early stage. In order to access the fire, firefighters often need to open parts

of the roof. Where this area is covered by PV modules, there is additional time delay, caused

by removing modules and mounting structure.
4.4 Measures for supporting firefighter and rescue service operations
4.4.1 General
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.