bpva pv and fire guide

Photovoltaic's and Fire

A Guide from the BPVA

2011

Photovoltaic's and Fire Guide 2011

Contents ¡  An Introduction to PV & Fire – Slide 4

¡  Photovoltaic Fire fighting, Emergency Assistance & Safety for Fire Fighters - Slide 19 §  Building Code Requirements and Other Regulations for Photovoltaic Systems – Slide 34 §  Electrical Requirements for Fire Protection and State of the VDE Standardisation – Slide 63 §  Technical Rules - Planning, Installing and Maintaining Photovoltaic Systems in Compliance with Fire Protection Requirements – Slide 92


Contents

§  Fire Protection from the Insurer’s Point of View – Slide 115

§  Technical options for the disconnection of solar generators in the

event of damage - an overview and evaluation – Slide 127

§  Standard Requirements for the Fire Protection of PV Systems

and Outlook – Slide 159


History First spectacular fire: PV system with wooden subframe and bitumen roof in Bürstadt on the 21st of June 2009


History Fire in a room gets out of control Official statement by fire officer-in-charge:

§  After putting out the fire, glowing embers behind the wood panelling §  Flue gas ignition, retraction from the building

§ “PV system is not the cause for the entire damage […], but it did make the extinguishing work difficult” (uncertainty because of potential danger) §  “Horror as we held the newspaper in our hands in the morning […] statements taken out of context”

§  Press release DKE*: Fires in the vicinity of PV systems can be promptly extinguished by the fire brigade if the safety distances [..] according to DIN VDE 0132 are met.


Does the fire brigade extinguish fires in buildings with PV systems? (press examples)

There is a basement fire in a single-family house. However, what the 27 year old and his colleagues do not know: there is a photovoltaic system on the roof, which cannot be readily switched off. Depending on the solar intensity, it produces up to 900 volts of DC current – a current of only 120 volts is life threatening. Furthner stepped on a bare cable. The result: a burnt musculature, heart problems and movement disorders. He only recovered weeks later.

Owners of houses with rooftop solar systems need to be aware that the fire brigade may not be able to protect their homes in the event of a fire. This has already happened in a number of cases. In the East Frisian village of Schwerinsdorf, the volunteer fire brigade allowed a one-family home equipped with a solar power system to burn down after a small fire in a room earlier this year.

Directing water jets onto the modules, members of the fire brigade risk a fatal electric shock. If in doubt, they prefer merely to contain the fire and to let the house burn down, as happened in February in the East Frisian village of Schwerinsdorf.

One fireman has already suffered a major electric shock when extinguishing a fire.


Fire fighters had an increasing number of problems extinguishing

buildings with large-scale, closed photovoltaic systems

History


Request by the Committee of the Conference of Interior Ministers AFKzV

Committee of fire brigade affairs, civil protection and civil defence of the working group of the Conference of Interior Ministers

The chairman- Hessen c/o Hessian Ministry of the Interior and Sport, Friedrich-Ebert-Allee 12, 65185 Wiesbaden

Dear ladies and gentlemen,

In its meeting on the 17th/18th of March 2010 under Item 16, the AFKzV dealt with the requirements for photovoltaic systems from the perspective of preventative fire protection and made the following decision:

“1. The AFKzV takes notice of the report on photovoltaic systems.

2. For the protection of persons, the AFKzV requires a switch to be installed directly on the individual photovoltaic modules or on a suitable position where the maximum permissible voltage of 120 volts (DC) is not exceeded. The shutdown should take place automatically for the occurrence of faults in the system or when the building’s power supply is shut down in the individual case of deployment.


Photovoltaic Fire Prevention and Fire Fighting Project The project was initiated and organised by the interdisciplinary working groups at the BSW kick-off meeting in Frankfurt on the 18th of November 2009: fire brigade, fire protection experts, DGS, BSW, building authorities, planners, installers and the photovoltaic industry. Project Framework Photovoltaic fire prevention and fire fighting

Three working groups: 13th Jan. 2010 WG 1: Safety of fire brigade forces

WG 2: Product components WG 3: Planning and installation


Analysis of Shutdown Facilities Development of a decision matrix for components to shut down photovoltaic generators - Ralf Haselhuhn Assessment criteria: 1. Technology clearly documented and traceable

marketable product when is it applicable suitable for all new and existing systems meets standards

2. Safety reliability, warranty period

location free of electric current automatic shutdown in the case of power outage remote controlled shutdown functional capability display

3. Handling realisable through technical firms, training?

acceptance and revisions required additional expense in planning and installation

4. Costs equipment costs, additional costs

additional planning and installation costs earnings loss


German Fire Brigade Association (DFV) §  DFV - Publication of the maps used for safe extinguishing by the fire fighters on photovoltaic systems

§  DFV equips fire brigades with over 33,000 photovoltaic maps

§  Nationwide awareness campaign on the subject of “fire brigade and photovoltaic systems.”


DFV Position Paper Fire brigade requires shutdown mechanism on photovoltaic systems The safety of fire fighters must be placed in the foreground Related DGS statement from the 10th of November 2010

DGS statement regarding the DFV position as well as the DGS position regarding fire protection problems

The DGS supports the position of the German Fire Brigade Association (DFV), subject to http://www.feuerwehrverband.de/photovoltaik.html The reservations result from the fact that technical solutions for safely shutting down photovoltaic modules in the case of a fire while simultaneously ensuring the long term security of the system are not yet ready for the market and the relevant normative product requirements have not yet been developed.

German Fire Brigade Association


Brochure On The Technical Rules

First presentation of the brochure as a part of the 26th OTTI photovoltaic symposium in March of 2011. Resulted from the work of interdisciplinary working groups involving the fire brigade, fire protection experts, planners, installers and the photovoltaic industry organised by the BSW. Brochure on the technical rules issued together by the BSW, DGS, Central Association of the German Electrical and Information Technology Trades (ZVEH), Occupational Fire Brigade of Munich and the Confederation of Technical Planners and Experts in Preventative Fire Protection e.V. (BFSB). Agreed with the Consortium of the Heads of the Occupational Fire Brigades in Germany (AGFB Bund).


Additional work of the DGS photovoltaic technical committee for fire protection problems §  Collaboration in creating the DKE/VDE standard for application

regulation E VDE-AR-E 2100-712 “Minimum requirements for the DC area of a photovoltaic system in the case of fire fighting or technical assistance” starting in 2010

§  Comments on "Planned DIBT (German Institute for Structural Technology) publication for solar panel systems" for the solar industry in cooperation with the BSW (including structural fire protection regulations), December 2010 to March 2011

§  Comments on the provision draft VdS3145, April 2011 “Technical guidelines for photovoltaic systems” from the General Association of German Insurers (GDV),

§  Comments on RAL-GZ 966 – draft of the quality and testing provisions for solar energy systems (including fire protection), May 2011

§  Public information: various technical articles in professional journals on the topic, also at www.dgs-berlin.de/download and at www.dgs-berlin.de -> Fields of Work -> Advisory Opinions


Joint project for the “Assessment of the risk of fire in photovoltaic systems and the creation of safety concepts to minimise the risk”

Supported by: Federal Ministry for the Environment, Nature Conservation and Nuclear Safety due to a decision by the German Bundestag Munich Fire Brigade Associated Partners: Bern University of Applied Sciences College of Engineering and Computer Science Laboratory for photovoltaics, Prof. Dr. H. Häberlin


Open Problems structural Measures:

§  Requirements for structural regulations: “Hard roofing” as well as the use of materials with a minimum classification of building material class B2 “normal flammability” according to DIN 4102

§  Building inspection test certificate of older glass film modules from the company Shell Solar certified as B2; newer certificates were not provided

§  Fire tests according to IEC 61730 and UL790 Roof Coverings do not allow classification into building material classes according to DIN 4102 or DIN EN 13501 and thus do not meet the German building regulations


Open Problems technical Measures:

§  Tests and testing procedures regarding the function, safety and long-term durability of “DC fire switches,” whether generator switches or module switches, are not yet developed

§  Triggering for fire fighters must be comprehensible

§  Activation with semiconductor elements is not yet normatively permitted

§  Development of a product standard for shutdown solutions and their certification

§  Shutdown solutions must allow measurements of the strands and modules during installation and troubleshooting must be enabled (EN 62446)


Open Problems arc Problems:

Causes for arc formation: Defects in components: particularly on modules, cell connectors, module junction box … Defects during the installation: module connector, conduits, junctions layout, installation location The insulation aging, in particular the cable insulation Unsuitable fuses and execution of the DC distribution box


Photovoltaic Fire fighting, Emergency Assistance & Safety for Fire Fighters

Overview

¡  Hazards for fire fighters

¡  Examples

¡  Foaming attempts by the Munich Fire Brigade

¡  What has been done so far?

¡  Forecast and protection goal

Electric Accidents

In the case of damages to PV systems, for the course of action the following rules are to be observed: DIN VDE 0132 “Fighting fire and technical emergency assistance for electrical systems” GUV-I 8677 “Electrical hazards at the scene of a fire” Terminology definitions: AC = alternating current voltage, DC = direct current voltage

Sun energy – usage forms

Solar heat: Warmth from the sun

PV system: Power from the sun Grid connected PV systems (Supply of generated power in the network of the power supplier) remote PV systems (Isolated operation). They work with accumulators. (Frequency: < 1%)

Hazards for fire fighters

¡  In the case of fire:

¡  Hazard through toxic inhalation

¡  Hazard through falling parts

¡  Hazard of spreading

¡  In the case of fire and water damage:

¡  Hazard through electrical shock

Fire development

Jet pipe clearance (DIN 14365-CM)

All over the country …

Noise protection wall on the highway

Warning sign

Overview plan for the fire department

The lines pictured in red always carry voltage!

PV Living area, stable, garages, DC connector equipment

Closed roof areas

Foaming and summary

§  Lathering of the PV module with Low-expansion foam, medium expansion foam, CAFS

§  Measuring of the voltage curve

§  Best results with CAFS: Voltage reduction to 47%

§  Maximum length of time until voltage is back to 100%: maximum 5 minutes

§  Conclusion: Not suitable as a possibility for

“Connection” of PV systems

Safety for fire fighters

Protection goal: Avoidance of contact voltage larger than 120 V DC in application Possible solutions: Safe laying of lines, spray gel, “fire department switch”, safety device, intelligent modules and junction boxes Realization The solutions are partially still in development Standardization and accordingly commercial launch Where will which technology be necessary?

Pocket card and information

Building Code Requirements and Other Regulations for Photovoltaic Systems

What regulations are to be observed from a building code perspective when planning and constructing photovoltaic systems?

§  Applicable building code …

§  In the lecture, Model Building Regulation MBO 2002

What regulations are to be observed from a building code perspective when planning and constructing photovoltaic systems?

§  Applicable building code … §  Applicable directive for wiring systems …

Regulation

¡  BSW brochure for “Fire protection-oriented planning, installation and maintenance of photovoltaic systems”

¡  Currently “State of technology and science”

Building Regulation

§  The erection of photovoltaic systems does not require a building permit

§  Nevertheless, the provisions of building regulations are to be observed

§  Non-compliance counts as a misdemeanour, which can be punishable with up to 250,000 euros

What is to be observed from a building code perspective when planning photovoltaic systems?

What is to be observed from a building code perspective when planning photovoltaic systems?

§  The existing building permit is to be observed (e.g.) - Where are the inner fire compartments? - Minimum spaces

§  Is there a fire protection concept for the building?

- If yes, then it is to be observed and supplemented

What may I do and where?

Distance of photovoltaic modules to the perimeter and firewall Perimeter 1.25 m

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View

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§ 32 Roofs

(1) Roofs must be resistant (for a sufficiently long time) against an external fire from flying sparks and radiating heat (hard roofing).

MBO § 32 Roofs

(5) Roof overhangs, eaves and roof structures, translucent roofing, dome lights and skylights are to be arranged and constructed in such a way that a fire cannot spread to other parts of the building and adjacent properties.

MBO § 32 Roofs

The following must be at least 1.25 m away from firewalls and from any walls that are permitted in lieu of firewalls 1. … 2 Dormers and similar roof structures made from flammable materials, unless these walls provide protection against the fire spreading.

Types of Firewalls

Flammable materials or components may not bridge these areas!

Do not bridge the firewall!

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View of the roof

Do not bridge the firewall!

View of the roof Cross section

OK Roof

Hall airspace

Cable

MG 3 mortar

+ 0.3 OK Roof

Inverter and Generator Junction Box

¡  Installation in the stairs and exit area of single and two-family homes is to be avoided

¡  Unprotected installation in stairwells of apartment buildings and auxiliary buildings is not permissible!

Inverter and Generator Junction Box

§  Do not install inverter directly on wooden walls

§  Keep the immediate area clear of flammable materials

§  Metal plate as a shield between the inverter and wooden wall is unsuitable

§  Beware of exhaust heat from the inverter as well as the air exchange - spontaneous combustion

§  Install e.g. a calcium silicate plate (d 15 mm) between the inverter and flammable base; maintain a circumferential clearance of 10 cm.

§  Highly flammable materials must not be present in the vicinity

Protection of the Fire Fighters §  ≤ 1 m around the

object “unprotected” DC conduit

§  Other conduit that cannot be switched off is protected by:

§  - Concealed wiring

§  - I 90 channel DIN 4102

red, maximum extent of the unprotected area

green, protected area

inside of the building: fire-resistant DC conduit

Why I_90 DIN 4102 or Concealed Wiring?

¡  Tamper-proof

¡  No maintenance required

¡  Durable and reliable for a long time

¡  Additional insulation for everyday protection

¡  No switches necessary in the case of a fire

¡  A faster deployment of fire fighters is possible

¡  Safer DC conduit, even after a fire

Switch in the DC Conduit

§  At least 2 switches are necessary in order to turn off the current in the main DC conduit

§  If there is only one DC switch on the photovoltaic system, then there is a discharge from the inverter to all DC lines

§  If there is a DC load disconnecting switch before or in the inverter, then current flows from the photovoltaic system to the string

Roof Access for the Fire Brigade

Go over the north side of the roof

North side has no panelling/structures

South side


Go over the front side “required window”


Go over the dormer


Panelling/structures on both sides of the roof with no other access option

Go over the fire break


Flat roof or mono-pitch roof without access options via windows, etc. Go over the fire break

Roof Access for the Fire Brigade Go over the outer fire breaks

Labelling for the Fire Brigade

§  House connection box §  Building’s main distribution board

§  ≥ DIN A 6

§  Reference sources Electricity company Insurance BSW Solar

MBO 2002 – Model Building Regulation Construction Consortium

Version from November 2002

§ 3 General Requirements

Systems are to be arranged, constructed, modified and maintained in such a way that the public safety and order, in particular life, health and the natural bases of life, are not endangered.

§ 14 Fire Protection

Structural systems are to be arranged, constructed, modified and maintained in such a way that the occurrence of a fire and the spread of fire and smoke (fire propagation) are prevented. The rescue of people and animals, as well as effective fire extinguishing work (note: in compliance with VDE 0132), is also to be possible in the case of a fire.

§ 30 Firewalls

(1) As space-separating elements at the edge of buildings (building perimeter) or for subdividing buildings into fire compartments (inner firewall), firewalls are to prevent the spread of fire to other buildings or fire compartments for a sufficiently long time.

MBO 2002 – Model Building Regulation - cont § 30 Firewalls

(2) Firewalls are required as an end wall of a building ... if these end walls are constructed on the property line or at a distance of up to 2.50 m away from the property line, unless there is a guaranteed distance of at least 5 m to the existing buildings or to the future buildings permitted according to the building regulations,

§ 30 Firewalls

as an inner firewall to subdivide extended buildings at intervals of not more than 40 m,

as an inner firewall to subdivide buildings used for agriculture into fire compartments of not more than 10,000 m3 gross volume

as a building’s end wall between residential buildings and attached buildings used for agriculture, as well as an inner firewall between the residential part and the agricultural part of a building.

MBO 2002 – Model Building Regulation - cont § 30 Firewalls

(7) Building components with flammable building materials may not be transported across firewalls …

§ 30 Firewalls

(8) Openings in the firewalls are not permissible. They are only permitted in the interior firewalls if they are limited to the number and size required for use. Openings must have fire-resistant, sealed and self-closing closures.

Electrical Requirements for Fire Protection and State of the VDE Standardisation

Application Regulation VDE-AR-N 4105

This is a VDE application regulation in the sense of VDE 0022 in simultaneous compliance with the procedure described in VDE-AR-N 100. It was recorded under the aforementioned number in the VDE specifications following the implementation of the approval process decided by the VDE committee and was announced in the trade journal etz Elektrotechnik + Automation.

Duplication (even for internal purposes) is not permitted. ICS 29.160.40 Generators connected to the low-voltage distribution network – Technical requirements for the connection to and parallel operation with low-voltage distribution networks Dipl. Ing. Andreas Habermehl

DKE VDE DIN ZVEH Application Regulation VDE-AR-N 4105 4 Mains Connection 4.1 Principles for Establishing the Network Connection Point … If power generating and consuming systems are located on a piece of property, then the supply terminals for the power generating system and for the power consuming system should be arranged in immediate vicinity to one another. The supply terminal for the power consuming system is to be provided with a sign indicating the location of the supply terminal for the power generating system. Power generating systems that are installed on different properties, each with its own mains connection, are generally not permitted to be connected together to one network connection point on the operator’s network. Power generating systems that are installed on a building with several mains connections may be connected together to one network connection point on the operator's network (label the supply terminals as described above). The owner of a terminal point is to permanently label each separate supply terminal for the power generating system with the inscription “Disconnection point between the power generating system and supply network.”

DKE VDE DIN ZVEH Application Regulation VDE-AR-N 4105 7 System Operation 7.1 General … In the case of danger, fault or threatening loss of network security, the network operator is entitled to immediately disconnect the power generating system from the network or to reduce the active power output of the power generating system. If the agreed maximum connection power is exceeded, then the network operator is entitled to separate the power generating system from the network. To do this, the network operator may demand the system operator to install corresponding technical equipment that separates the power generating system from the operator’s network if certain limit values are exceeded (e.g. maximum apparent connection power). If the network operator discovers major defects on the power generating system that are related to the safety of persons or the system, then he is entitled to separate these system components from the network until the defect is corrected.

DKE VDE DIN ZVEH DIN IEC 60364-7-712

Contents Page 712 Photovoltaic (PV) power supply systems………………………………8 712.1 Area of application……………………………………………………....8 712.2 Normative references……………………………………………………8 712.3 Terms……………………………………………………………………8 712.13 Basic principles………………………………………………………….8 712.4 Protective measures……………………………………………………10 712.41 Protection against electric shock………………………………………10 712.410 Protective measure: automatic shutdown of the power supply………..10 712.414 Protective measure: protection through SELV and PELV low voltage..10 712.421 Protection against fires caused by electric operating materials………..10 712.43 Protection against overcurrent…………………………………………11 712.433 Protection against overload on the DC side……………………...……11 712.434 Protection against short-circuit currents……………………………….11 712.44 Protection against interference voltages and measures against electromagnetic influences…….11 712.444 Protection against electromagnetic disturbances………………………11 712.511 Compliance with standards…………………………………………….13 712.512 Operating conditions and external influences………………………….13 712.513 Accessibility……………………………………………………………14 712.515 Discharging electrostatic charge……………………………………….14 712.52 Cable and wiring systems……………………………………………...14 712.54 Earthing systems, protective conductor and protective equipotential bonding………………...14 Attachment A (informative) System information……...………………………………15 Attachment B (normative) PV sign……….…………………………………………...20

Protective Measure: Automatic Shutdown of the Power Supply

Requirements for the Fault Protection

712.411.3.0.1 The PV (photovoltaic) power supply cable / line must be connected (through the associated protective device) to the supply side of the protective equipment for the automatic shutdown of the power supply, which supplies the consumables. 712.411.3.2.1 The residual current protective device used for the fault protection of the PV power supply circuit must be type B (according to IEC 62423), unless there is simple separation between the DC and AC voltage side of the PV inverter or the PV inverter cannot feed DC fault currents into the electrical system due to its design.

DIN IEC 60364-7-712

712.421 Protection Against Fires Caused By Electric Operating Materials If there is an error in the insulation on the DC side, an automatic warning must be given in order to alert the operating personnel or the system owner. 712.421.1 If there is not a simple separation between the AC side and DC side, then a functional earthing on the DC side is not allowed. An earth fault on the DC side must be detected and the inverter must be separated from the AC side. 712.421.2 I If there is not a simple separation between the AC side and DC side, and there is no direct functional earthing on the DC side with low impedance, then a device for earth fault detection must be installed on the DC side.

DIN IEC 60364-7-712

E DIN IEC 60364-7-712 (VDE 0100-712):((2011-03)) Attachment B (normative)

PV Sign In Germany, it is mandatory to attach the following sign to indicate the presence of a photovoltaic system. It must be attached at the interconnection point of the electrical system, e.g. house connection box, building’s main distributor, and it can also be used for identification on electric current distribution boards. The sign must be at least DIN A6 in size.

DIN IEC 60364-7-712

Nozzle Spacing (According to VDE 0132)

Nozzle DIN 14365-CM (N)

Low-voltage ≤ AC 1.0 kV ≤ DC 1.5 kV

High-voltage (H)> AC 1.0 kV > DC 1.5 kV

Spray jet 1 m 5 m

Full jet 5 m 10 m

Abbreviation N-1-5 H-5-10

Solutions: VDE Application Regulation (Draft)

Draft April 2011 E VDE-AR-E 2100-712

This is a VDE application regulation in the sense of VDE 0022 in simultaneous compliance with the procedure described in VDE-AR-N 100. It was recorded under the aforementioned number in the VDE specifications following the implementation of the approval process decided by the VDE committee and was announced in the trade journal etz Elektrotechnik + Automation. Duplication (even for internal purposes) is not permitted. ICS “Minimum requirements for the DC area of a PV system in the case of fire fighting or technical assistance”


Preface…………………………………………………………………………………...3 1 Area of application………………………………………………………………4 2 Normative references……………………………………………………………4 3 Terms and abbreviations………………………………………………………...5 4. General principles……………………………………………………………….5 5. Identification of systems and wiring…………………………………………....5 6. Structural and organisational installation measures…………………………….5 6.1 Laying PV DC lines in the building that are protected against fire……………..5 6.2 Laying DC lines outside of the building………………………………………...6 6.3 Metallic shielded wiring………………………………………………………...6 7. Device for switching, separation or short-circuiting in the DC area of a PV system...6 7.1 General…………………………………………………………………………..6 7.1.1 Basic functions…………………………………………………………………..6 7.1.2 Release signal function………………………………………………………….7 7.2 Devices for isolating the line or the PV generator……...…….…..…………….7 7.3 Devices for short-circuiting the line or the PV generator...........……………….8 7.4 Devices for switching off the PV module………………………..………..……8 7.5 Devices for short-circuiting the PV module…………………….……….…...…9 References……………………………………………………………………………….9 Attachment A (normative)……………………………………………………………..10 Attachment B (informative)……………………………………………………………11


1 Area of Application This application regulation applies for the planning and construction of photovoltaic systems on or in buildings. The requirements of DIN VDE 0100-712 (VDE 0100-712) apply for erecting low-voltage systems for photovoltaic (PV) power supply systems. The requirements of DIN VDE 0132 (VDE 0132):2008-08 apply for fire fighting and assistance near electrical systems. The building law requirements valid in each individual federal state are to be met, e.g. with regard to fire protection. In the case of damage (such as a fire on the building), storm damage or collapse of the supporting structure, the protective measures (doubled or reinforced insulation in the DC area of the PV system) could be affected by several errors that can occur simultaneously. The DC voltage can remain after the AC network has been shut off.


Visibility can be so limited (e.g. due to smoke from a fire) that people cannot comply with the safety distances from electrical systems, which are required in VDE 0132. This application regulation summarises the specifications with recommendations for being able to prevent hazardous contact voltages when the protective measure fails (doubled or reinforced insulation: e.g. in the case of a fire). Insulation faults, which can simultaneously occur at different places in the DC area, are to be taken into account. The insulation fault in the DC area causes damage to the insulation on cables and wires (basic and fault protection). This application regulation does not describe any testing requirements for products that can result from the protection target, such as

§  Overvoltage category §  DC switching capacity §  Fulfilment of a separation function §  Environmental conditions.


General Principles In a hazard analysis, the measures are selected that are required to achieve the specified “protection target.” This application regulation can be agreed between the planner, installer and the future PV system operator by means of this hazard analysis, building law requirements or requirements of the property insurer. In the process, the type of building, its usage, the collection of people in the building, or rooms and locations with irreplaceable, high-value goods are to be taken into consideration. When installing PV systems, no dangerous contactable DC voltages may occur in the building so that fire fighting or technical assistance in the electrical system can take place safely. This can be implemented via technical, structural or organizational measures.

5. Identification of Systems and Wiring A sign in accordance with Attachment A must provide information regarding the existence of a photovoltaic system. It must be attached at the interconnection point of the electrical system, e.g. house connection box, building’s main distributor, and it can also be used for identification on electric current distribution boards. An overview plan in accordance with Attachment B must be attached at the interconnection point of the electrical system, e.g. house connection box, building’s main distributor, and must provide appropriate information regarding the type and location of the photovoltaic system components, such as the live wires that cannot be switched off, live wires that are protected against fire, photovoltaic generator, position of the DC disconnection device. If needed, the existing fire brigade plan may require revision according to DIN 14095.


Attachment B (Informative)

Overview plan for the fire brigade (example)


6. Structural and Organisational Installation Measures

6.1 Laying PV DC Lines in the Building that are Protected Against Fire

In a building, the PV wiring system in the DC area must be laid in a fire-protected area. The fire resistance of the wiring system complies with the respective valid state building code. If no fire resistance grading is required by the state building code, the PV DC wiring system must at least be fire resistant and be labelled as a fire retardant PV wiring system. This can be achieved, for example, through the following measure:

Laid flush according to MLAR 2005,Fire protection channels and shafts according to EN 1366 of DIN 4102

An unprotected area of a maximum of 1 m around the inverter is permissible and is to be labelled accordingly in the documentation for the fire fighters.


7. Device for Switching, Separation or Short-Circuiting in the DC Area of a PV System

7.1 General 7.1.1 Basic Functions

When switching off the inverter or if the supply voltage fails, then the equipment for switching, separation or short-circuiting outside of the building or before the area to be protected must operate automatically in the direction of the inverter.

A device or combination of several devices for switching, separation or short-circuiting is suitable if (due to of their response) the output side voltage between an active component and earth and the voltage between active components is smaller than 120 V DC (harmonic-free), or the sum of all output side, short-circuit currents in the same output side DC system is smaller than 12 mA DC or the energy within the same output side DC system is lower than 350 mJ.

Regardless of the device for switching, separation or short-circuiting, only the DC system on the output side can be considered as activated.

The continuous current-carrying capacity of the device for switching, separation or short-circuiting must at least be designed for 1.25 times the value of / SC STC at the junction.

The device for switching, separation or short-circuiting must revert into a secure condition if an internal error occurs (fail-safe principle), e.g. short-circuit in the case of a fault with a short-circuit device. If this is not ensured, then the functionality of the device must be monitored daily.

If a device for switching, separation or short-circuiting responds at the line end, then (if necessary) a device (e.g. line diode, line fuse in the same line) must prevent return current from the inverter or return current occurring from parallel lines, which affects the functionality of the device for switching, separation or short-circuiting.


7.2 Devices for Isolating the Line or the PV Generator

There must be an isolating device at the line or generator end or at the building entrance, which can be controlled by an external enabling signal.

These isolating devices must ensure a defined lasting activation at the line end, generator end or building entrance.

The isolating device must meet the requirements for a control unit according to DIN EN 60947-3 (VDE 0660-107) or according to DIN EN 60947-2 (VDE 0660-101).

The device must be separable from the DC side in order to carry out maintenance work at the input of the isolating device.

A DC load-disconnecting switch according to DIN VDE 0100-712 (VDE 0100-712) is then no longer required.


Fig. 1: Exemplary design of an isolation device at the generator end


7.3 Devices for Short-Circuiting the Line or the PV Generator

There must be a short-circuiting device at the line or generator end or at the building entrance, which can be controlled by an external enabling signal.

This short-circuiting device must ensure (with negligible impedance) a defined lasting short-circuit at the line end, generator end or building entrance. In the short-circuited state, it must therefore be ensured that the voltage across the short-circuiting device is not larger than 120 V DC.

The requirements for temperature tests on short-circuiting devices can be derived from the DIN EN 61215 (VDE 0126-31) or DIN EN 61646 (VDE 0126-32) requirements for bypass diodes.

The short-circuiting device can be a semiconductor without an isolation function, if the typical failure mechanisms ensure a short circuit.


Fig. 3: Exemplary design of a shutdown device in the module connection box


7.4 Devices for Switching Off the PV Module

There must be a shutdown device in or on the module connection box, which can be controlled by an external enabling signal.

This shutdown device must ensure a defined lasting short-circuit at the module output, the module connection box output or the output of an external connection box.

The requirements for temperature tests on shutdown devices can be derived from the DIN EN 61215 (VDE 0126-31) or DIN EN 61646 (VDE 0126-32) requirements for bypass diodes.

The shutdown device can be a semiconductor without an isolation function, if the typical failure mechanisms ensure a short circuit.


Fig. 2: Exemplary design of a short-circuiting device at the generator end


7.5 Devices for Short-Circuiting the PV Module

There must be a short-circuiting device in or on the module connection box, which can be controlled by an external enabling signal.

This short-circuiting device must ensure a defined lasting short-circuit (with negligible impedance) at the module output, the module connection box output or the output of an external connection box. In the short-circuited state, it must therefore be ensured that the voltage across all of the connected short-circuiting devices is not larger than 120 V DC.

The requirements for temperature tests on short-circuiting devices can be derived from the DIN EN 61215 (VDE 0126-31) or DIN EN 61646 (VDE 0126-32) requirements for bypass diodes.

The short-circuiting device can be a semiconductor without an isolation function, if the typical failure mechanisms ensure a short circuit.


Fig. 4: Exemplary design of a short-circuiting device in the module connection box


Only technically feasible options are described in the application regulation. How the solutions are to be achieved is tied with the conditions formulated in the application regulation. The solutions should first be presented to the professional public in order to later be capable of putting them back up for discussion in AK 221.1.4_373_2011

DKE Press Release From March 2011 (German Commission for Electrical Engineering, Electronics and Information Technology in DIN (German Industry Standard) and VDE (Association of German Electrical Engineers))

Fighting Fires Near Photovoltaic Systems VDE / DKE Recommendations

13 April 2011

In coordination with experts from professional associations, fire brigades, research institutes, network operators and the industry, the DKE (German Commission for Electrical Engineering, Electronics and Information Technology in DIN and VDE) is providing recommendations for the correct behaviour in the case of a fire with photovoltaic systems (PV systems). Fire brigades can promptly extinguish burning PV systems or fires near PV systems if the safety distances (according to DIN VDE 0132) to live components are maintained. The standard DIN VDE 0132, “Fire fighting near electrical systems,” provides mandatory safety distances for persons who are responsible for rescue measures or fighting fires in or near electrical systems. This is for their protection as well as that of others.

In general, the distances to open damaged lines are to be maintained. For low-voltage networks, the safety distance to live components is one metre. When using nozzles (i.e. fire brigade fittings carrying extinguishing water), one metre is to be maintained for a spray jet and five metres for a full jet. In the darkness, photovoltaic systems in moonlight (even if it is a full moon) and artificial light (e.g. halogen lamps) cannot produce currents or voltages dangerous to fire fighters. Thus, photovoltaic systems pose no electrical hazard in the darkness. This was confirmed by independent testing.

Contrary to the popular belief that fire fighters must first activate the DC load disconnecting switch on the PV system before they can begin extinguishing the fire, it is to be noted that fire fighters may immediately begin with the fire extinguishing if the preventative measures (in particular the safety distances to live components as according to DIN VDE 0132) are adhered to. The “DC switch” is a switch on the convert unit, which is provided for maintenance technicians if they must work on the converter. A body of experts from DKE is currently working on determining additional structural or switching measures for constructing the DC area of a photovoltaic system. A corresponding draft is to be presented to the professional public in 2011.

DKE Press Release From March 2011

(German Commission for Electrical Engineering, Electronics and Information Technology in DIN (German Industry Standard) and VDE (Association of German Electrical Engineers)) “Contrary to the popular belief that fire fighters must first activate the DC load disconnecting switch on the PV system before they can begin extinguishing the fire, it is to be noted that fire fighters may immediately begin with the immediate fire extinguishing if the preventative measures (in particular the safety distances to live components as according to DIN VDE 0132) are adhered to.”

Technical Rules Planning, Installing and Maintaining Photovoltaic Systems in Compliance with Fire Protection Requirements

Disclaimer

The slides show selected aspects of the technical rules of “planning, installing and maintaining photovoltaic systems according to fire protection requirements” created as a part of the “PV fire prevention and fire fighting” project. Nevertheless, no liability is assumed for the accuracy of the contents and the suitability of the information in individual cases. Therefore, it is essential to carefully review the circumstances and regulations to be observed in the case of an actual specific project. The information and recommendations presented in the technical rules are based on the installation scenarios and legal frameworks in Germany. They were agreed with the Consortium of the Heads of the Occupational Fire Brigades in Germany (AGFB Bund). The technical rules were created with the support of the Federal Solar Industry Association (BSW Solar), National Association of Technical Planners and Experts in Fire Prevention (BFSB), Occupational Fire Brigade of Munich (BF Munich), German Association for Solar Energy (DGS) and the Central Association of German Electrical and Information Technology Trades (ZVEH).

Overview

§  Brief introduction of BSW Solar

§  Creation of the technical rules

§  Planning, constructing and maintaining the PV systems – Principles

§  The four basic rules of planning, installation and maintenance in compliance with fire protection requirements:

§  Structural fire protection §  Protection from exposed voltages in the building §  External access for extinguishing §  Information and signs for fire fighters

§  Conclusion and outlook

Tasks Representation of interests of the German solar industry in the fields of photovoltaics and low-temperature solar thermal energy Vision A globally sustainable energy supply, large parts of which are to be provided by solar energy Activities Lobbying, political consulting, public relations, market observation, standardization, quality assurance Experiences Active for more than 25 years Members Over 850 companies from the solar energy industry: suppliers, manufacturers, system vendors, wholesalers, skilled workers, consultants and others Registered Office Berlin

Federal Solar Industry Association

Creation of the Technical Rules

¡ Causes: public discussions, uncertainties of all those involved, contradictory statements

¡  11/2009: Experts workshop

¡  03/2010 – 01/2011: “PV Fire Fighting and Prevention” workshop

¡ Objective: Bundling the responses on the topic; development of packages of measures

¡  Persons involved: fire brigades, fire protection experts, component manufacturers, planners, technicians, insurance companies and associations, professional association

Planning, Constructing and Maintaining the PV Systems – Principles (a)

§  Constructing and affixing the substructure etc. according to EN 1991

§  Electrical installation inter alia according to DIN VDE 0100-712, DIN VDE 0100-410

§  Lightning protection according to DIN VDE 0185-305 parts 1-4

§  Commissioning test etc. according to DIN VDE 0100-600, DIN EN 62446 and BGV A3 § 5

§  Labelling and documentation, technical approval and briefing etc. according to DIN EN 62446, § 633 BGB (German Civil Code), § 12 VOB/B

§  Maintenance etc. according to DIN 31051, DIN VDE 0105-100 and BVG A3

Planning, Constructing and Maintaining the PV Systems – Principles (b) The following risks apply with electrical wiring systems:

§  A fire, caused by the electrical system §  Flammable wires (fire load) §  Spread of the fire (thermal transfer)

A fire caused by …

Effe

ct,

Favo

ured

by,

R

emed

y

… the electrical system … other technical or structural systems

Personal & property damages

Damage from inadmissible shutdowns

Encroachment on the electrical system

Personal and property damages

Fire Load The flammable insulation feeds the fire.

Reducing the amount of wiring systems, the type of wire installation (e.g. under plaster),installation of wires insulated by minerals

Spread of Fire Since flammable cables and wires (wiring systems) run through the building, the fire can spread through them.

Fire barriers according to DIN 4102 or sample systems, the type of wire wiring system guidelines

Technically correct planning and construction as well as maintenance and servicing

1.  Structural fire protection – preventing the spread of fire

2.  Protection from exposed voltages in the building

3.  External access for fire extinguishing 4.  Information and signs for fire fighters

The Four Basic Rules – Brief Overview

Essential objective: preventing the spread of a fire to adjacent fire compartments

1. Structural Fire Protection (a)

Mechanisms of a fire spreading

Flying sparks

Bur

n th

roug

h

Thermal radiation Fi

rew

all

Firewall

Fire compartment

Structural Fire Protection (b)

§  It generally applies that: the function of firewalls and building separation walls must not be diminished.

§  Requirements from the building regulations: Characteristic of the “hard roof” as well as the use of materials with a classification of at least building material class B2 “normal flammability” according to DIN 4102

§  Spacing of roof structures to firewalls depends on their fire behaviour Different designs of firewalls

Fire

wal

l

Fire

wal

l Projection Roof cladding Roof cladding

1. Structural Fire Protection (c)

§  Activation of the DC cable at the building lead-in

§  Installation of the inverter at the building lead-in

§  Laying the DC cables in a fire-protected manner

§  In the future: direct disconnection of the voltage at the module

2. Protection From Exposed Voltages in the Building (a)

Protection target:

§  There must be strictly no risk of exposed DC voltages in a burning building due to the installation of PV systems in order to ensure that fire fighting and the rescue of persons inside the building can be carried out safely.

§  Implementation through: §  Structural or §  Technical and §  Organisational measures

Option 1 §  Safe installation of non-disconnectable DC lines in the building by:

§  Underground installation (according to MLAR) §  Sheathing the DC lines with fire protection cladding §  Installing the DC lines in fire protection channels and ducts

2. Protection From Exposed Voltages in the Building (b)

2. Protection From Exposed Voltages in the Building (c)

Please note:

Wiring in existing shafts is to be labelled. Disused chimney shafts are to be regarded as installation shafts according to building regulations.

Non-disconnectable DC lines within a building longer than 1.0 metre should be installed with fire protection

red, maximum extent of the unprotected area

green, protected area

inside of the building: fire-resistant DC conduit

2. Protection From Exposed Voltages in the Building (d)

Option 2

Installation of DC lines outside of the building. Please note:

DC conduits are to be recognisable by fire fighters (e.g. “Overview plan for fire fighters”)

No damage may occur during operation

Installation of DC lines away from the entrance areas for fire fighters or protected installation

Installation of the DC lines away from areas where pools of water form

2. Protection From Exposed Voltages in the Building (e) Option 3

Inverter in the outside area or directly at the building entrance. This means: there are only freely switchable AC lines in the building

Please note:

Inverters are to be placed away from escape routes and entrances for fire fighters

Inverters are to be installed protected from the weather

The necessary IP protection class is to be observed

2. Protection From Exposed Voltages in the Building (f)

Option 4

DC isolator switch in the string or main line.

Please note:

§  Long-term reliability in reasonable weather conditions

§  Fail-safe behaviour of the switch

§  Secured against restarting

§  Actuator on the house connection

§  Recognisability of the switching state

§  Identification of the switch and the disconnected areas

§  Simultaneous connection of inverter load-disconnecting switch due to the risk of discharge currents

§  …

3. External Access For Extinguishing (a)

Prerequisite for fire fighting:

§  Fire fighters must have access to the source of the fire

§  Internal access: protection from exposed voltages in the building

§  External access: access to the roof structure

Escape routes

§  Are primarily for escape and rescue

§  Also serve as access paths for fire fighters

Minimum requirements for accesses and distances are to be observed

§  A safety distance of one metre away from live components is to be guaranteed (according to DIN VDE 0132)

§  E.g. size of the “required window” is 90 cm clear width and 120 cm clear height

3. External Access For Extinguishing (b)

Various access points to the roof structure

Use fire breaks if both halves of the roof are covered or it is a mono-pitch roof with no gable window

Access via the open north side Access via the gable window

PV generator

3. External Access For Extinguishing (c)

Various access points to the roof structure

Smaller flat roofs without other access points – Fire breaks on the longer side

(a fire break is recommended for a partial system width of up to a

maximum of 20 metres)

For larger flat roofs, there should be an access point for each fire compartment (usually 40x40 metres) around the generators. Route passage widths should not be narrower than one metre.

4. Information and Signs for Fire Fighters

§  Guarantee a quick overview for fire fighters

§  At the house connection

§  Informational sign

§  Overview plan for the fire fighters

§  Supplement the existing fire brigade plans to include the PV installation

Conclusion

¡  Simple measures allow for the planning, installation and maintenance of photovoltaic systems according to the fire protection requirements

¡  There is currently no known solution that answers all of the questions for all installation situations → Close inspection of the installation situation by the planners and technicians is required

¡  Planners and technicians are encouraged to apply the recommendations from the technical rules for proper fire protection planning, installation and maintenance

¡  Emotional topic → Working with care and expertise

Outlook §  Further dissemination and use of the technical rules

§  Missing answers to individual questions are currently being normatively processed or worked on by the industry

§  The industry is working on solutions regarding the free switchability of the DC circuit

§  → Testing requirements are required in order to prevent the subsequent dismantling of unsuitable solutions

§  Requirements of the building regulations:

§  “Hard roofing” as well as the classification of at least building material class B2 “normal flammability” according to DIN 4102

§  Planning, Installing and Maintaining Photovoltaic Systems According to Fire Protection Regulations

Fire Protection from the Insurer’s Point of View

Causes of Damage to Photovoltaic Systems

Number of Claims:

14% - pressure from snow

26% - overvoltage

9% - storm 2% -

theft

2% - hail

3% - malicious

intent

2% - fire

42% - other damage

12% - pressure from snow

14% - overvoltage

25% - storm

8% - theft

3% - hail

1% - malicious intent

26% - fire

11% - other damage

Main Cause for Damages - Defective Quality

What are the causes?: §  The technology is brought up to the roof:

§  Does the roof hold the photovoltaic system? §  What damage can occur during installation?

§  The country needs new technology: §  Is information available about the features of photovoltaic systems

(e.g. inverter, DC current, electrical parameters)?

§  Several trades from one source: §  The solar panel system owner should simultaneously be a roofer,

electrician, lightning protection specialist and construction expert. Is that possible?

§  Completion by a deadline, §  The photovoltaic systems must be connected to the network by a

deadline. Are the systems being installed with the required quality under this time pressure?

Photovoltaic Systems – Technical Guide (VdS 3145) §  Support for planners, builders and operators

§  Collaboration with the Verband der Elektrotechnik Elektronik Informationstechnik e.V. (Association of Electrical Engineers, Electronics and Information Technology) (VDE)

§ Content:

§ Selection and assembly of PV modules and their assembly systems (mechanical)

§ Structural fire protection

§ Selection and construction of electrical components

§ Protection against lightening strikes and overvoltages

§ Activation or equivalent measures for facilitating fire fighting services

§ Protection against theft

§ Commissioning

§ Operation

§ Publication in July 2011

Distances to Firewalls (MBO)

- § 32 Roofs (5)

“Roof overhangs, eaves and roof structures, translucent roofing, dome lights and skylights are to be arranged and constructed so that a fire cannot spread to other parts of the building and adjacent properties. The following must be at least 1.25 m away from walls that are permitted in lieu of firewalls

1. Skylights, dome lights and openings in the roof, if these walls are not at least 30 cm over the roof…”

- § 30 Firewalls (2)

“Firewalls are required

as a building’s end wall,”…”if these end walls are constructed on or at a distance of up to 2.50 m from the property line”

(replacement for firewall)

Distances to Firewalls (Guide VdS 3145)

Minimum distances to firewalls:

PV module protruding above the upper roof of the firewall → 2.5 m distance

or there is special evidence for the restriction of the risk of fire. Otherwise maintain a 0.5 m distance

Firewall

§  No building over firewalls with PV modules §  PV wiring:

§  Wiring compartments §  Fire protection casing

§  (permission from the local building authority is required) §  Materials used must be suitable for outdoor use

Additional Details Regarding Fire Protection

§  Separation of module surfaces through module-free strips

§  Building material requirements for PV modules on in-roof and facade systems

§  minimum standard flame-retardant material (B2)

§  ground floors without and multi-storey industrial buildings with automatic fire extinguishing systems → minimum flame-retardant material (B1)

§  non-flammable material (A) with industrial buildings with floor space > 2,000 m2 (MIndBauRI) and high rises (MHHR)

Fire Protection – Electrical Components

Planning and construction according to DIN VDE 0100-712 Inverter installation (underground, minimum distance to flammable materials, avoid storage of highly flammable substances) Wiring

earth and short circuit protected wiring suitable fastening of the wiring do not lay over sharp edges separate installation of DC power lines usage of PV cables (type PV1-F) protect wires from rodents chewing on them do not run wires through rooms with highly flammable substances.

Fire Fighting

§  Labelling of the building

§  Recommendations for action by the DFV and other fire brigade associations (www.solarwirtschaft.de/brandvorbeugung)

Jet pipe DIN 14365-CM

Low-voltage (N) AC voltage up to 1kV or DC voltage up to 1.5 kV (≤AC 1kV or ≤DC 1.5 kV)

High-voltage (H) AC voltage over 1kV or DC voltage over 1.5 kV (>AC 1kV or > DC 1.5 KV)

Spray jet 1 m 5 m

Full jet 5 m 10 m

Facilitating the Fire Fighting Conditions

§  Activation of the DC cable at the building lead-in §  Installation of the inverter at the building lead-in §  Laying the DC cables in a fire-protected manner §  In the future: direct disconnection of the voltage at the module

Building lead-in

Laying the DC Voltage Lines in a Fire-Protected Manner

§  Laying lines in an electrical installation shaft or channel with a fire resistance grade from I 30 to I 90 (depending on the required fire resistance endurance, but at least I 30). In doing so, the shaft or channel must be attached to the inverter at least 1.0 m from the building feed-in,

§  Modelled after MLAR (guidelines in fire protection concerning power supply cable layouts), the cables may be laid in slots that are sealed with at least 15 mm thick mineral plaster or with 15 mm thick plates made of mineral building materials,

§  Laying lines on the building’s exterior,

§  Combination of the aforementioned variants.

Technical options for the disconnection of solar generators in the event of damage – an overview and evaluation

Preliminary remarks

§  How can PV systems be connected without voltage?

§  Are there any solutions already on the market?

§  Where does the need for action exist?

Main Cause for Damages – Defective Quality

§  PV systems are rarely the cause of fire

§  Mostly quality defects in the components (module, oscillator) and in the mounting §  Electric accidents are rare during installation

§  Additional safety components???

§  Quality in the component design and manufacture!

§  Qualification of the installers!

§  Final inspection and regular inspections

§  “conventional” fires of houses with PV systems will increase statistically

§  The fire department can and does extinguish them! (Thiem, Staffelstein 2010) §  Additional safety components??? §  Current research project for fire protection at TÜV Rheinland (Technical Inspection Association Rhineland) and Fraunhofer Institute for Solar Energy Systems §  Involvement of the fire department, insurance companies, surveyors,

manufacturers, traders, planners, installers, … §  Goals: customized solutions, engineering standards

Main Cause for Damages – Defective Quality

Protection goal I:

§  Personal security inside the building

Protection goal II:

§  Personal security outside the building/ on the generator / on the module

under voltage no voltage

oscillator electrical supply meter

house connection network

Example for disconnection: PV system on the house roof

§  Extremely high reliability (MTBF, FIT-rate) required

§  Life cycle / Availability of replacement parts > 30 years

§  Internal consumption < 0.1 % rated power (< 0.2 W @ rated power = 200 W)

§  Costs < 10 Euros @ rated power = 200 W

Technical / financial parameters for disconnection measures

Distances to Firewalls (Guide VdS 3145)

[Diagram, left to right:

Oscillator without voltage [red square]

PV generator, DC splitter, DC main,

DC isolator, oscillator, AC mains] DC main without voltage* [red square]

String without voltage (< 120 V) [red square]

Module without voltage [red square] Automatic disconnect during disruption to main [red square]

Reliability in operation [green square]

Energy loss [green square]

Simple ability to retrofit [grey square]

Effort / Costs [green square]

Availability [green square]

* The input capacitor of the oscillator,

Protection goal I: inside building** [green square]

usually a high capacity model, can be hazardous! Protection goal II: Generator [red square] ** Dependent upon the instalment of DC lines in the building

Conventional PV system without DC side disconnection measures

Oscillator without voltage [green square]

DC main without voltage [green square]

Film-forming spray gel to create an artificial night String without voltage (< 120 V)

[green square]

Module without voltage [green square]

[Image] Automatic disconnect during disruption to main [red square]

Prevento®Solar Reliability in operation [green square] Trolley 40 for secure depositing of Energy loss [green square] Prevento®Solar on photovoltaic Simple ability to retrofit (fire service) [red square] panels Effort / Costs (fire service) [red square]

Availability (fire service) [red square]

Protection goal I: inside building ?

Protection goal II: Generator ? Source: http://www.profireinigung.de/AUB/News/Solar.pdf

Covering of the solar generator with opaque gel

Prevento®Solar Film-forming spray gel tocreate an artificial night

[Diagram, left to right: Oscillator without voltage

[green square] PV generator, DC splitter, DC main, oscillator] DC main without voltage*

[red square] String without voltage (< 120 V) [red square]

Module without voltage [red square] Automatic disconnect during disruption to main [green square]


Energy loss [yellow square]

Simple ability to retrofit [green square]

Effort / Costs [green square]


* An automatic DC isolator will advantageously Protection goal I: inside building

[red square] separate the input capacitor from the DC mains. Protection goal II: Generator

[red square]

Automatic (fail safe) DC isolator in or before the oscillator

Automatic short circuiting devices on the output of the DC splitter

Automatic short circuiting device on the input of the DC splitter [Diagram, left to right: Oscillator without voltage

[green square] PV generator, DC splitter/building entrance, DC main, oscillator, AC mains] DC main without voltage

[green square] String without voltage* [red square]

Module without voltage [red square] Automatic disconnect during disruption to main [green square]


Energy loss (diode) [yellow square]


Effort / Costs [yellow square]

Availability [red square]

* If string is disconnected, Protection goal I: in the building

[green square] the full voltage is available at the joint! Protection goal II: Generator*

[red square]

Automatic short circuiting device on the input of the DC splitter

Automatic DC isolator on the output of the DC splitter (“Fire department switch”)

Automatic DC isolator on the output of the DC splitter

[Diagram, left to right: Oscillator without voltage [green square]

PV generator, DC splitter/building entrance, DC main,

oscillator, AC mains] DC main without voltage [green square]

String without voltage (< 120 V) [red square]

Module without voltage [red square]

Automatic disconnect during disruption to main [green square]


Energy loss (control) [yellow square]


Effort / Costs [yellow square]


Protection goal I: inside building [green square]

Protection goal II: Generator [red square]

¡ 

¡  [Diagram, left to right: Oscillator without voltage [green square]

¡  PV generator, DC splitter/building entrance, DC main,

¡  oscillator, AC mains] DC main without voltage [green square]

¡ 

¡  String without voltage (< 120 V) [red square]

¡ 

¡  Module without voltage [red square]

¡ 

¡  Automatic disconnect during disruption to main [green square]

¡ 

¡  Reliability in operation [green square]

¡ 

¡  Energy loss (control) [yellow square]

¡ 

¡  Simple ability to retrofit [green square]

¡ 

¡  Effort / Costs [yellow square]

¡ 

¡  Availability [green square]

¡ 

¡  Protection goal I: inside building [green square]

¡ 

¡  Protection goal II: Generator [red square]

Automatic DC isolator on the input of the DC splitter

Thermal / mechanical isolator in many positions in the system

Safety devices for photovoltaic systems

The invention involves a safety device for photovoltaic systems which separates the individual solar panels of a photovoltaic system from each other electrically in cases of danger. It is intended not only for the open space but also for equipment mounted on roofs for protection from fire or for mechanical effects, which for example can be caused through falling trees or motorized vehicle accidents. The safety device includes two electrical contacts (3), which through an isolated fuse body (4), are spaced apart. This is shock and warmth sensitive in such a way that it is destroyed during exposure to considerable mechanical forces and during extraordinary heat influxes. The contacts (3) are connected via an existing separating electrical fastener made out of a pin (10) and a socket (9). Between the two ends of the fuse body (4) a pressure spring (5) is clamped. In cases of danger the fuse body (4) shatters or is separated. The spring (5) pushes the contacts (3) away from each other and the pin (10) is pulled out of the socket (9). The spring (5) subsequently drops out. Through this the electric current is safely opened.

Safety devices for photovoltaic systems

Patent application DE 10 2008 027 189

Thermal / mechanical isolator in many positions in the system

Several automatic isolators within the strings

Module integrated DC/DC converter without isolation function

Module integrated DC/DC converter with isolating/short-circuiting function

Module integrated oscillator (AC module) with isolating function

Conventional oscillator airtight with solar generators

Series switch with safe isolation in every module

Short-circuiting device in every module

Solar energy extraction system

(57) Summary: Solar energy extraction systems are built out of one or more parallel chains (strings) of photovoltaic (PV) modules and are inducted over the oscillator in a low voltage network. According to the invention it is intended that every PV module (1 through 400) is assigned to a switching element (A) on the output side, which is controlled from an enabling signal (FG) so that with a missing enabling signal (FG) the assigned PV module is free of voltage and activated by the existing enabling signal (FG) (Figure 6).

The new BFA-BOX from SolteQ The fire safety disconnection

A safety box per module and a control centre, which simultaneously serves as an emergency hand alarm … that’s all! (Patent filed)

§  1 – 20 solar modules can be switched in a row, module switch,

§  live signal sender, network oscillator, fire department switch

The new BFA-BOX from SolteQ

Double use of an “active bypass diode”

§  Main goal: Reduce the creation of heat in the bypass operation

§  - Additional functions such as module disconnection can be additionally

§  implemented in the future. Two products (without disconnection) available

The new BFA-BOX from SolteQ

Short circuiting devices in every module

Summary

¡  Implement the customized solutions of assigned tasks

¡  Utilize “conventional” options

¡  Critical evaluation of the necessity and the effectiveness of additional safety measures

¡  Normative targets of the tasks to be fulfilled and the respective testing requirements, no preference for any particular concrete solution

¡  Development of further concepts and products if required

Standard Requirements for the Fire Protection of PV Systems and Outlook

Contents

Standard Requirements

Fire prevention and fire-fighting for PV systems

§  Fire and PV – differentiation of requirements

§  Arc risks

§  External fire

§  Active fire-fighting

Research Activities

Current research activity

§  Structure and contents of the R&D project: fire risk for PV systems

§  Current work packet

Fire Prevention and Fire-Fighting for PV Systems Differentiation of requirements

§  A differentiation of requirements is necessary for the technical differentiation of and holistic approach to fire situations in PV systems:

Arc risk Risk of a fire occurring as a result of the PV system. External fire Fire extinguishing risk

An external and non-intrinsic fire influencing the building and PV system

Minimisation of hazard and protection for fire fighters during operations.

Attempts at the deliberate ignition of arcs under different electricity/voltage combinations.

Arc risk Requirement for igniting arcs

Arc ignition Arc ignition No arc ignition Ignition limit

Derived through tests at TÜV Rheinland (Technical Inspection Association Rhineland) – influences on the ignition of arcs:

§  Temperature, pressure, moisture (RH)

§  Dimension/material of the electrodes (differences in conductor cross-section, el. resistance)

§  Combination of different electricity-voltage values (arc ignition varies on the different electrodes)

§  Surrounding material determines the “life span” of the arc

§  Conductor must be completely separated at the affected junction.

General triggers in reality: bad solder connection (cold solder joint), loose connections, corrosion, earthing errors, defective insulation (this applies to the whole system).

Arc Risk Requirement for igniting arcs

§  IEC Safety Standard 61730-1: flammability rating for polymeric materials

§  Test methods like reverse current test, bypass diode test, ground continuity test, wet leakage current test, etc. (according to IEC 61730-2)

§  FprEN 50548:2011 Junction boxes for photovoltaic systems

§  EN 50521:2008 Connectors for PV systems, safety requirements & tests

§  TÜV Rheinland internal specification: 2 Pfg 1169/08.2007, requirements for cables for use in PV systems

§  VDE 0100-712 Erection of low voltage installations, part 7-712: Requirements for industrial premises and special locations and installations – solar photovoltaic (PV) power systems

§  DIN EN 62305-3 Supplemental Sheet 3 Lightning and surge protection for PV power systems

Arc risk - Minimising and avoiding risk

Arc Risk Minimising and avoiding risk §  Preventative fire protection begins with the manufacture of materials

and ends with the expert and correct installation of the systems at the site. A permanently secure and risk-reduced PV system depends on these requirements.

Arc risk Minimising & avoiding risk

PV module

manufacturer

Computer

retailer, installer etc.

Quality control of the

products

Installation instructions, system monitoring etc.

Possibility: arc detection

systems for arc deactivation

Process monitoring: quality assurance measures for the

production of modules

PV module/component qualification, IEC

qualification (e.g. by TÜV Rheinland)

Certification process

Risk minimisation as a network of multiple mechanisms

§  Can weak points with the potential risk of igniting an arc be identified in a PV system?

Yes. However, these sources of error can be avoided with high quality products and expert installation.

§  What are the necessary requirements for igniting an arc? Defective contact points and junctions in the system as well as electrical and material-specific conditions at the affected position.

§  Which measures must be implemented for minimising and avoiding risk?

General awareness of the specific sources of error must be achieved. In particular, qualitatively high value products that are able to maintain under electrical, thermal and thermo-mechanical influences during their life cycle (>25 years). A professional installation and the avoidance of secondary errors in the construction of the PV system.

Arc risk

- Applied test methods for investigating the resistance of PV modules and components against the influence of fire from the outside:

- IEC 61730-2 and ANSI/UL 1703 with UL 790 (spread of flame and burning fire)

Module-specific Fire Tests – External Fire IEC 61730-2 and ANSI/UL 1703 with UL 790

§  Spread of flame (gas flame) and burning fire (wooden pallets)

§  The test method is derived from the UL790 standard. Fire load test for roofs.

§  Three different classes can be tested:

Class A/B: Burner capacity 369-387 kW Flame impingement 10 min Pallet A: 2000g, B: 500g Class C: Burner capacity 316-334 kW Flame impingement 4 min Pallet C: 10g


§  No glowing or burning part of the PV module may fall from the test station

§  The flame propagation may not exceed the following values:

-  Class A - 1.82 m -  Class B - 2.40 m -  Class C - 3.90 m

§  The lateral flame propagation is limited

Additionally in the ANSI/UL 1703: §  No burn-through with ratholing on

the PV modules §  No constant burning of the PV

module in the burning fire test



Module damaged by heat

Expanded test methods from the building sector with requirements for roofs: §  Classification with EN 13501-5 & ENV 1187 as European testing standard

for roofs §  ENV 1187: Test methods for external fire exposure to roofs

§  With regard to fire tests for roofs (ENV 1187), there is no universal standard that is generally applicable in all EU countries.

§  Outline of the ENV 1187 in -1…-4 in four parts, with adequate classification according to EN 13501-5 with BROOF (t1…t4).

§  ENV 1187-1, comparable to DIN 4102-7: Fire behavior of building materials and components. Determination of resistance against flying sparks and radiating heat. According to German building regulations, hard roofing is required in addition to Building Material Class E (standard combustibility) according to EN 13501-1 and DIN 4102-7 for roofs.

Module-specific Fire Tests – External Fire EN 13501-5 and ENV 1187

Module-specific Fire Tests – External Fire EN 13501-5 and ENV 1187

§  The tests differ: different incendiary devices, roof slopes and general implementation methods (test duration, additional sources of radiation, wind flow).

§  The incendiary devices are also applied to material impacts on the roofs. In the case of PV modules, these are, in particular, joints, seals, and eave and ridge terminations.

Incendiary devices in ENV 1187 tests Application of ENV 1187 tests in Europe Source: In Plastics magazine, 2nd release, 2007

Module-specific Fire Tests – External Fire EN 13501-5 and ENV 1187 Classification criteria for ENV 1187-1, among others:

§  External and internal flame spread up <0.7 m, down <0.6 m

§  Maximum permissible scorch mark, external and internal <0.8 m

§  No burning parts falling down from the surface

§  No burning/glowing parts that influence the roof construction

§  No opening after fire >25mm2

§  …

Active Fire-Fighting Presentation of the situation in the media Since 2009, the number of articles and television newscasts on the topic of photovoltaics and fire has increased, including in the specialised media:

- “… Fire brigade leaves houses with solar roofs to burn …” – Welt Online 08/2010

- “… Roofs with PV systems have their hazards ..." – Badische Zeitung 08/2010

- “… Fire brigade is not equipped to deal with solar roof fires... " – Badische Zeitung 09/2010

- “… Extinguishing fires is risky …” – Photon 01/2011

- “Harmless or risk of fire? ...” – Sonne, Wind und Wärme 2010

- “Earth, Fire, Water and Solar …” PV magazine 04/2009

- “… Photovoltaic system makes installation much more difficult …” – local newspaper

- “Hot hot steel” – Regenerative Energien 03/2011

The core messages emphasise the electric shock risk defective PV systems pose to fire fighters during operations.

§  It’s the fire brigade’s job to extinguish fires! Safety regulations for fighting electrical system fires are defined according to VDE 0132 – Fire-fighting and technical assistance with electrical systems. They also apply to PV systems.

§  Extinguishing electrical system fires is routine for the fire brigade.

§  However, fire brigades need to know that there is a second energy or power source in the building.

§  Associations, the PV industry and standards bodies deal with this topic and address the entire industry including manufacturers, suppliers, dealers and technicians etc.

Active Fire-Fighting Representation of the situation

Fire extinguishing safety Derivation of overarching measure

§  The goal of the PV industry must be the guarantee of safety for humans and the environment when using a PV system. PV systems must not represent an additional source of incalculable risk for fire fighters -> This is a clearly defined objective.

§  General: minimising risks as far as possible for protection against

electric shock (not only for fire fighters) while taking into account all technical, structural and organisational possibilities.

§  Select fire-proof DC lines.

§  Obtainment of the highest quality standard for the product and installation according to valid standards for avoiding PV system fires.

§  Constant improvement of quality as well as the development and modification of products and measures to comply with technical and organisational requirements.

Fire extinguishing safety Installation measures

§  Compiled using AK 221.1.4 of the DKE: fire brigade sign. Download or order stickers from the homepage of the Bundesverband Solarwirtschaft (BSW).

§  Fire brigades must know that there is a PV system on the roof.

Fire extinguishing safety Installation measures §  Recommendation of the BSW expert

commission:

§  A site map helps fire fighters. Easy to recognise where live parts are located in the affected property.

§  The site map for fire fighters and the systems plan should be stored in a weather-proof area in the main distribution board or at the supply point.

§  Active information distribution: district and regional fire brigade association, all captains of the professional fire brigades, all fire brigade schools as well as the numerous employees within the Association of German Fire Brigades – they each received 50 folding cards.

Fire extinguishing safety Installation measures ¡  Currently, a BSW work group, assisted by the fire brigades, PV industry

representatives, technicians, insurers and institutes, is creating and publishing an informational brochure for fire brigades.

¡  It contains recommendations for dealing with damage to energy producing solar systems.

Jet tube DIN 14365 CM

Low voltage (N), AC voltage up to 1kV or DC voltage up to 1.5 kV (≤ AC 1 kV or ≤ DC 1.5 kV)

High voltage (H), AC voltage over 1kV or DC voltage over 1.5 kV (> AC 1 kV or > DC 1.5 kV)

Spray jet

1m 5m

Full jet

5m 10m

Fire Protection for PV Systems Structure and contents of the R&D project §  In the field of application of photovoltaics, three requirement types,

among others, can be named in the area of fire protection for the purpose of technical differentiation:

Arc risk Risk of the PV system causing a fire

External fire

Fire extinguishing risk

§  Identification of safety risks and current preventative measures

§  Risk minimisation and determination of expanded counter measures

§  Risk minimisation, prevention and arcs, increasing safety for fire brigade fire fighters

Influence of an external and non-intrinsic fire on a building and PV system.

Minimisation of hazard and protection for fire fighters in case of actions inside the building

Fire Protection for PV Systems Structure and contents of the R&D project

¡  Physical and data analytical evaluation of arc risks

¡  Investigation of fire risks triggered by materials

¡  Aging and weathering of electrical connections (module … GAK)

¡  Arc detection and extinguishing

¡  Determination of risk to fire fighters

¡  Identification of safety risks and current preventative measures

¡  Risk minimisation and determination of expanded counter measures

Fire Protection for PV Systems Structure and contents of the R&D project §  Risk analysis and categorisation of errors with regard to arcing

§  Risk analysis of PV components with regard to the potential influence of arcs

§  Expanded guidelines for project planning and installation

§  Derivation of quality standards for electrical joints

§  Derivation of an adjusted test method

§  Definition of requirements for arc detectors

§  Testing arc detectors

§  Complete support of the fire brigade (distribution of information, extinguisher tests etc.)

§  Definition of requirements for organisational and technical solutions for the manufacture of an electrically safe system status

§  Identification of safety risks and current preventative measures

§  Risk minimisation and determination of expanded counter measures

Current Research Activities Components-related work packets §  Investigations using deliberate arc ignitions with artificial ageing

(of modules and components) – early detection of arc risks:

§  Comparability of tests using accelerated ageing with real data

§  Development of requirements for ageing tests, submission to standards bodies

§  Creation of a risk analysis based on the test series for critical joints

§  Development of test methods parallel to production

§  Possible definition of quality standards for joints

Current Research Activities Components-related work packets

§  Definition of requirements for arc detectors and switching and deactivation devices in case of fire:

§  Conceptualisation of technical devices (type of detection, type of deactivation...)

§  Definition of requirements with regard to:

§  Functionality, reliability

§  Sensibility

§  Response and deactivation times

§  Resistance to environmental influences (moisture, temperature, UV …

§  Electrical and electromagnetic susceptibility (e.g. return current carrying capacity)

§  Validation by way of adapted tests, submissions to standards working groups

+++ Current Work Packets +++

Questionnaire and inspection of conductivities

Questionnaire

In the context of arc and extinguishing safety, cases are categorically investigated with incidents and cases of damage. The evaluation and analysis should result in expanded fire prevention methods .

Distribution of catalogues in June. Addressees: project planners, technicians, experts, insurers …

Inspection of conductivity of extinguishing agents, protective clothing etc.

Specific proof of fire fighter safety in compliance with safe distances during extinguishing measures pursuant to VDE 0132. Inspection of conductivities of the extinguishing agent from predefined distances (at 1 kV).

Summary and Discussion Preventative fire protection and fire-fighting are complex subjects.

The prevention of fires caused by PV systems can only be guaranteed with high quality materials and products as well as the correct expert installation.

Safety standard IEC 61730 for modules, as well as other production oriented standards for components, can be used to detect early damage.

Failure rate

Early failures

Coincidental failure

Wear-out failure

Type test for PV module

Intensification or adjustment of test methods with regard to specific application situations as part of additional risk minimisation.

Summary and Discussion

Complete support of fire fighters and end users for protection against electric shock when fighting fire and defective systems. Any increase of safety potential by way of safety systems on the module, string or field level using short-circuiters or isolators must comply with adequate product standards and requirements.

Adequate means adjusted to a specific application situation, accessibility, availability, functionality, temperature and weather requirements and long-term durability. A corresponding product standard will need to be developed in accordance with these requirements.

Thank you for your attention

bpva pv and fire guide

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