PV & Fire Is it safe?

Transcription

1 PV & Fire Is it safe? Steve Pester Principal Consultant, BRE BIPV Conference UK 2012 Part of the BRE Trust

2 Warning some of these slides may be a bit scary! BRE Global fire experts: Martin Shipp & Steven Manchester Part of the BRE Trust

3 Many new sustainable technologies have fire safety implications Modular construction Timber frame Structural Insulated Panel Systems Engineered joists Cladding systems

4 Any energy-handling device can cause fires

5 What could go wrong with PV? PV is simple in concept

6 The PV Fire Questions: Can PV cause fires? Can PV exacerbate hazards during a fire caused by something else? Does PV present new risks to fire fighters?

7 Causes Arcs potential to cause fires Electrical shorts or poor connections can cause very hot arcs, both inside panels and between conductors DC arcs do not tend to self-extinguish

8 Arc fault example -Early failure in LA -One week operation -Did not meet installation standards -No certification on this system

9 Other sources of ignition Component break-downs & inverter fires Same as any other electrical device very uncommon Good quality inverters have built-in safety devices Fires caused by PV appear to be rare at present!

10 Exacerbation of existing fires Glass potential to exacerbate existing fires Glass can fall from PV panels when broken Restricted access to roof? Toxic substance release? Appears to be unfounded 1100 deg. C needed unconfined fires normally less than this

11 New risks to fire fighters Fire fighters may not recognise PV system lots of different types Shocks through fire hose jets? DC electrics cannot be completely switched off on most systems AC detectors will not detect DC No official guidance yet in the UK for fire-fighters Feedback from BRE conference (2011) was that hazards are manageable with prior knowledge

12 What is Industry doing to address fire risks?

13 Main methods of managing the risks Safe PV System 5. Monitoring & Maintenance 4. Inspection & Testing 3. Safe Installation 2. High Quality Components 1. Safe Design

14 Microgeneration Certification Scheme (MCS) Industry owned Independent Quality Mark Certification is great step forward (but is not a panacea )

15 PV Installer Technical Standard (MIS3002) New version about to be released Calls up new MCS Installation Guide Safety-related features: Wind loading calculations Cable & component ratings When and how to use safety devices All installations must comply with: BS7671 (Wiring Regs) Building Regulations

16 MCS Product Standards for PV PV Modules - MCS 005 specifies test standards: Module robustness & electrical standards: IEC or CE marking Separate module safety qualification: IEC 61730

17 New MCS standard for pitched roofs Pitched Roof Installation Kits - MCS 012 (mandatory 2013) Building envelope requirements of PV & Solar thermal mounting kits address: Wind load tests Rain ingress tests Fire resistance testing

18 Test Methods ISO CEN BSI ASTM NES DIN AFNOR Etc..

19 Guidance for fire fighters No official guidance yet in the UK for fire-fighters Office of the Chief Fire and Rescue Adviser Fire & Rescue Services actively considering BRE publication on Fire & Renewables

20 Fire and Rescue Notification For roof-mounted systems: Signage to alert Fire Services mandatory in new Installer Guide Mounted next to the supply isolator in the building Discussions on national database and/or local registration by installers

21 Procurement pointers for designers Modules MCS 005 build quality & performance CE mark basic electrical safety IEC Photovoltaic (PV) module safety qualification Manufactured in ISO9001 certified facility consistent products Also wise to check for the double insulation (class II) mark

22 Inverters (central and string types) Currently only mandatory standards are: CE marking EMC Directive Low Voltage Directive Connection guidelines & type testing G83 type testing (small systems) G59 installation or type tested products MCS Installation standard requires: Matching of input voltage & power ratings

23 Some other devices may help to reduce risks Micro-inverters and DC optimisers Local & remote Fire-fighter's switches Arc fault detection few products available yet

24 Inspection, Testing & Documentation International standard, to be called up in MCS: IEC 62446: 2009 Grid connected PV systems minimum requirements for system documentation, commissioning tests, and inspection Amongst other things: Inspection schedule Insulation resistance of the d.c. circuits Continuity test of protective earthing

25 Maintenance Low maintenance - no moving parts Compliant designs are very safe Annual cleaning, electrical test & inspection typical Expect at least 30 years service from well designed and installed systems

26 Getting it into perspective UK Stats: 300 people per year die in fires (lots of minor injuries) 3000 die in trips and falls 5000 die from hospital-related infections To date, no known deaths caused by PV.

27 Summary 1 Any innovation may introduce new risks which need to be managed Many of the new eco-technologies have risks to be managed Any energy-handling device needs special precautions Certification of products and installers contributes to safety Some of the concerns may be unfounded; others may need a response work continues.

28 Summary 2 - Guidance For designers, there are some simple pointers for safe procurement decisions & installation practices There is now good technical design and installation guidance for systems <50kW. Following this is the best way to manage the risks Code of practice required for larger systems No formal fire fighters guidance in UK yet BRE can help via consultancy, training, testing & certification

29 If designed & installed correctly, PV is not a big fire risk

30 Questions? Fire consultancy & test: BRE Renewables Consultancy: Tel: +44 (0) Steve Pester: MCS Installers & Products: Tel: +44 (0)