ANN ARBOR, Mich. (CBS DETROIT) – The Ann Arbor Fire Department has acquired a new product to disable solar panels during structural fires.
It’s called PVStop, and it acts as a liquid blanket to instantly shut down solar panels. Ann Arbor Fire Chief Mike Kennedy said the product will help firefighters safely contain blazes.
“When we have a fire in a building, we want to turn off the power,” said Kennedy. “And so, we can turn off the power from DTE, but the solar power will continue to energize the house. This gives us an ability to completely shut off any electrical generation from that solar array.”
When solar power remains on during a fire, arcs can still occur, which could cause additional fires.
Developed in Australia, PVStop is currently used in countries across Europe and Asia, including England and Singapore, but it’s relatively new to the U.S. market.
Kennedy said the product costs $450 per canister, which is equivalent to a single use. AAFD acquired two canisters of PVStop two weeks ago.
“We believe we’re one of the first, if not the first, department in Michigan that has it,’ said Kennedy. “And with the amount of solar that’s in the city of Ann Arbor, if anyone has it, it would make sense for us too.”
According to the manufacturer, PVStop does not damage solar arrays. Instead, it can be peeled off solar panels after it’s used.
Until now, the Ann Arbor Fire Department had to layer large tarps over solar panels to try and cut power during fires, which were prone to sliding off the panels and therefore posed more danger to firefighters on rooftops.
Still, Kennedy said fires involving solar aren’t very common.
“Fortunately, we don’t have a lot of issues involving solar,” he said. “It’s one of those (instances) that are pretty rare, but when we have them, they’re a big deal.”
Six fire engines and around 40 firefighters tackled a house fire on Garth Road in Cricklewood.
A small part of the ground floor and the roof of an end-of-terrace house was damaged by fire. A detached outbuilding was destroyed by the blaze. There were no reports of any injuries.
Station Commander Steve Pringle, who was at the scene, said: “Firefighters used one of the Brigade’s 32-metre turntable ladders to deploy PV Stop on to solar panels on the roof of the property.”
Incidents involving solar panels are especially dangerous as it’s difficult to isolate the electrical current they generate if they are damaged or involved in a fire. When tackling fire involving solar panels, crews run the risk of receiving electric shocks as the current can travel down water jets and hoses. PVStop works by blocking the sunlight that powers solar panels, so the process of converting light into electricity is stopped. The panels are then de-energised and the risk of electrocution is greatly reduced so crews can get closer and prevent fire spreading from a roof to the rest of the building.
The Brigade’s 999 Control Officers took 16 calls to the blaze.
The Brigade was called at 1317 and the fire was under control by 1507. Fire crews from West Hampstead, Mill Hill, Park Royal and Holloway fire stations attended the scene.
The fire is believed to have been accidental and caused by resistive heating in an extension lead.
Firefighters’ top tips for electrical device safety
Try to keep to one plug per socket, especially for high powered appliances like washing machines.
Always check that you’re using the right fuse.
Be lead safety savvy – cable drum extension leads should always be completely unwound to avoid overheating, and be careful not to overload extension leads.
Always make sure electrical appliances have a British or European safety mark when you buy them.
Keep electrical appliances clean and in good working order.
Don’t buy cheap counterfeit chargers for items that use lithium batteries, and never leave phones or laptops plugged in to charge overnight
Four fire engines and around 25 firefighters tackled a house fire on Ferrymead Avenue in Greenford on 9th August.
Part of the roof of a semi-detached house was damaged by fire. There were no reports of any injuries. London Fire Brigade confirmed that they rescued a pet snake from a first-floor bedroom.
A spokesperson from London Fire Brigade (LFB) said via their website: “PVStop, which is a black liquid polymer coating designed to cover solar panels like a liquid tarpaulin, was used to isolate power to ten solar panels.”
“It works by blocking the sunlight that powers solar panels, so the process of converting light into electricity is stopped. The panels are then de-energised, and the risk of electrocution is greatly reduced so crews can get closer and prevent fire spreading from a roof to the rest of the building.”
The Brigade was called at 4:25pm and the fire was under control by 6:58pm. Fire crews from Southall, Northolt, Ealing and Wembley fire stations attended the scene.
LFB added, “The cause of the fire is believed to have been accidental and involved a solar panel.”
Four fire engines and around 25 firefighters tackled a flat fire on Kilburn Park Road.
Four solar panels on the roof of a residential block were damaged by fire. Around 20 people left the building before the Brigade arrived. There were no reports of any injuries.
The Brigade’s 999 Control Officers took 10 calls to the blaze.
PVStop, which is a black liquid polymer coating designed to cover solar panels like a liquid tarpaulin, was used. It works by blocking the sunlight that powers solar panels, so the process of converting light into electricity is stopped. The panels are then de-energised, and the risk of electrocution is greatly reduced so crews can get closer and prevent fire spreading from a roof to the rest of the building.
The Brigade was called at 1100 and the fire was under control by 1139. Fire crews from North Kensington, West Hampstead, Paddington and Soho fire stations attended the scene.
The fire is believed to have been caused by electrical resistive heating.
London firefighters used a new glue like liquid to save a school in Twickenham from burning down and they are the first crews in Europe to use this unique scientific breakthrough.
Crews were called to a fire at a school in Hampton Road in Twickenham and the specialist glutinous gear called PVStop prevented serious damage to the roof of the building by preventing the fire spreading to the solar panels.
PVStop is a black liquid coating designed to cover solar panels, like a liquid tarpaulin, which is sprayed onto the panel using an extinguisher or from the head of an aerial appliance.
Operational Policy Watch Manager George Mahoney said: “The fire started in an extractor fan on the ground floor and spread into the void of the roof, where the school had solar panels. Without crews quickly applying PVStop, the fire could have very quickly spread to the solar panels which in turn could have compromised the roof of the school.
“Incidents involving solar panels can be especially dangerous as it’s difficult to isolate the electrical current they generate if they are damaged or involved in a fire and PVStop works by blocking the sunlight which powers them so the process of converting light into electricity is stopped.
“Science and quick thinking of firefighters really saved this school”
“The panels are then de-energised and the risk of electrocution is greatly reduced so crews can get closer and prevent fire spreading from a roof to the rest of the building.
”A combination of science and the quick thinking of firefighters really saved this school from significant damage.”
Part of the ground floor toilet area in the two-storey school building and part of the roof were damaged by the fire, but damage to the solar panels was prevented by the use of the liquid.
The liquid, which is environmentally friendly and non-toxic, has been distributed to eleven of the Brigade’s aerial appliances.
Operational Policy Watch Manager George Mahoney continued: “This is the first time PVStop has been used operationally in Europe. It has been used once in Australia, where it is manufactured.
“It was great to see this in action for the first time and it was successful – it prevented the fire spreading and has saved the school the cost of having to replace the solar panels.
“We had spoken to crews about PVStop just this week as with the heatwave we had been expecting it.”
The Brigade was called to the fire at 1308 on Thursday (19 July) and the fire was under control at 1528. Four fire engines and around 25 firefighters from Twickenham, Southall and Richmond fire stations attended the scene.
Around 40 pupils and 15 members of staff left the building before the Brigade arrived. There were no reports of any injuries.
The Brigade’s Fire Investigators believe the cause of the fire was an electrical fault in an extractor fan.
In Part 1 of this article featured in the last edition we discussed the rise of solar energy from a cottage industry just a few decades ago to becoming a genuine mainstream electrical source. We discussed how legislation, safety and fire training have failed to keep up with the rapid expansion of this alternative energy source. We then moved on to discuss training objectives and offered some basic education in the differences between AC and DC electricity, how solar PV panels work, the different types of solar PV systems and finally the upcoming battery storage revolution.
With this foundation of knowledge in place we will now move on to discuss what goes wrong with solar PV systems, the dangers faced by fire and emergency services personnel, discuss the recent attempts to make solar PV systems safer and introduce you to a new product which offers a simple solution to this growing and complicated problem.
How Do Solar PV Systems Fail?
There are a number of reason why PV solar systems fail, ranging from physical damage and component failure to poor manufacture and workmanship.
Physical Damage
Physical damage to solar PV systems can be due to a number of factors. Weather events such as hail, lightening, fire, storm damage (such as fallen branches) flooding and water ingression are all well document causes of system damage. Vermin attack such as chewed wiring and nesting are other less considered causes of system damage. It is also worth noting that even when a solar PV system is seriously damaged, broken, shattered, burnt or inundated with water, it can still produce potentially lethal amounts of DC electricity.
Component Failure
In Australia hundreds of solar PV system failures (and fires) have been caused by faulty DC isolation switches. It must also be remembered that solar PV systems are comprised of delicate electronic componentry that generates electricity. When mounted on roofs and exposed to constant UV and both freezing and boiling hot conditions, 365 days a year, over time they will naturally deteriorate. As such solar PV systems should be periodically checked and maintained. However because of the installation location of most solar PV systems (on roofs) they are out of sight and out of mind; very few systems are maintained regularly or adequately. Finally, the vast majority of solar PV systems are relatively new (less than 10 years old). As these systems age, the number of incidents relating to component failure will escalate on an increasing scale.
Poor Manufacture & Workmanship
In the year 2000 there were 8 companies producing solar panels globally. In 2005 there were 20 companies producing solar panels globally. In 2007 there were 846 companies producing solar panels in China alone! Expertise is not earned overnight and one of the challenges of the exponential expansion of solar technology over the past decade has been a shortage of skilled labour, both on the manufacturing and installation sides of the industry. Without adequate legislation or regulation to keep abreast of growth, there are a large number of solar PV system installations that are sub-standard and a lesser number that should be considered unsafe or dangerous. Neither governments nor industry sources are properly equipped to manage or audit the existing and growing number of solar PV system installations and it has fallen upon fire and emergency services agencies to reactively manage and mitigate these risks as they are encountered.
The DC Danger Zone
As discussed earlier, as long as solar panels are exposed to light, they cannot be turned off and like any electrical generator or source that is live, must be considered dangerous. Even with an isolation switch installed at the solar PV system inverter, the solar panels on the roof and the electrical wiring leading down to the inverter and completely live and producing potentially lethal amounts of DC electricity. In professional terms this is known as the “DC Danger Zone”.
Unlike traditional sources of electricity solar PV systems cannot be switched off or isolated effectively. If the panels or wiring leading to the inverter are faulty and arcing, the solar panel frame, metal roof or metal guttering all have the potential to be conducting lethal amounts of electricity that can ignite fires or electrocute unsuspecting emergency services personnel, electrical technicians or the general public if they come into contact with a conductor (via a ladder or unbroken stream of water etc). Up until now there has not been an emergency response protocol or strategy that has adequately mitigated these threats.
Recent Rules, Regulations and Technologies
In recent times Governments and Industry have attempted to address the issues surrounding the DC Danger Zone with limited success.
DC Isolators
In Australia, roof top isolators are a legislated requirement. They were implemented with the intention of turning the panels off in the event of a short circuit or similar emergency. Although well intentioned, switching is an AC electricity solution and is not suitable for DC electrical applications. Every time DC is switched, it arcs on the circuit board and has the potential to set the switch alight. Since legislation was passed in 2011, there have been hundreds of solar PV related fires in Australia as a direct result of faulty isolation switches and literally tens of thousands of DC isolations switches have been recalled as a consequence of these incidents. Isolation switches on solar PV arrays is a bad idea and has created more problems than it has solved. This legislation seems set to be reversed in the near future.
Anti Arcing Equipment
In a further attempt to improve safety, Standards have now incorporated anti arcing devices in all newly installed inverters. This standard solves one problem in that it shuts down the inverter and disconnects the load from the solar panels, allowing the panel wiring to enter into open circuit voltage, extinguishing any “series arcing” occurring. But in the case of a parallel arcing fault, it can allow the full amount of the power available to be poured into the fault, fuelling the arc and making the arcing fault much worse!
The Red Zone Above Indicates the DC Danger Zone.
Rapid Shutdown/Micro-inverter Panels
Micro-inverters are a hot topic, especially in the United States where there has been a legislative push to make micro-inverter solar PV panels the standard (over string panels). Micro-inverter solar PV panels are being marketed as a safer alternative to string array solar PV panels as a small (micro) inverter is installed directly underneath each individual panel, converting the DC electricity to AC electricity directly under panel and allowing electricity to be shut down directly below the panel. Note however that the panel itself can still not be shut down when exposed to light and still has the potential to arc potentially lethal DC voltage directly onto the panel frame, metal roof and guttering.
This is not a new technology, micro-inverter panels have been around for over 20 years. Apart from the perceived safety improvement versus string array panels, micro-inverter panels also have the advantage of having better shade tolerant properties than string array panels. The disadvantages of micro-inverter solar PV panels is that they are very expensive, up to three times the cost of a standard string array solar PV panel. Also, inverters are sensitive and delicate electronic components and do not like heat. This is why standard inverters are generally installed inside garages or on the shady sides of properties. By miniaturizing the inverter and installing them directly onto the back of each solar panel, micro-inverters are being exposed directly to the elements and high operating temperatures. As a result, the life expectancy of micro-inverter solar PV panels is greatly reduced versus standard string array solar PV panels.
Finally, we have noticed recently that in order to reduce the price of micro-inverter solar PV systems, manufacturers have started designing “micro-inverter” systems with 1 inverter to every 2 panels and even 1 inverter to every 4 panels. In essence these are now micro-string arrays rather than true 1 to 1 micro-inverter arrays. Micro-inverters are another step towards improved solar PV system safety, however they are not financially viable for most applications, are prone to failure and because of the prohibitive cost are now being watered down to a less than ideal solution.
Mitigating the dangers of the DC Danger Zone
With over 40 years of experience in the solar industry, The Australian Company Solar Developments recognised the need to find a simple, fast and economical solution to tackle the broad and complex risks associated with the DC danger zone. A solution that isolated the power at the source (the solar panel surface) thus eliminating all the complexities in the downstream componentry. The result of this search is PVStop, a global innovation developed by Luke Williams, one of the founding directors of Solar Developments and the inventor of PVStop. Luke is a CEC (Clean Energy Council) accredited renewable energy system designer and has been working in the Australian solar industry since the early 1970’s.
How does PVStop work?
PVStop is a state-of-the-art polymer film technology. Delivered from a pressurised cylinder similar to a fire extinguisher, it acts as a “liquid tarp” covering the solar panel surface and switching off the solar PV system in seconds, rendering the entire solar PV system safe.
With a delivery range of over 10 meters the product can be applied from the ground or from an elevated platform, eliminating the need to climb on to rooftops and operate at height. It can be utilised in all weather conditions and is touch dry within a matter of minutes, creating a waterproof coating that insulates the solar panels and protecting the panels from fire, heat and impact damage. The coating is also non-flammable and fire retardent and is capable of extinguishing the panels if they are on fire. In addition, the coating is non-conductive and anti-arcing, which is essential as its primary function is to isolate the power generated by solar PV systems. The coating also encases any nano-particles released in the event that the panels are damaged or during salvage operations. At the completion of an incident, the dry coating can simply be peeled off the solar panels like a latex sheet without causing any damage to the solar PV system or surrounding structure. The coating is non-carcinogenic, can be safely handled and disposed of with normal garbage waste
Reducing risk factors for emergency services and electrical technicians
The exponential growth of the solar industry has led to a commensurate rise in the number of solar system incidents encountered by fire and emergency services agencies. Ten years ago fire and emergency services agencies rarely encountered incidents involving solar PV systems; today incidents involving solar PV systems are encountered on a weekly basis. As the only safe, fast and reliable solution to isolating the power produced by solar PV systems, PVStop has rapidly come to the attention of fire and emergency services organisations both in Australia and abroad and is currently undergoing testing and review by a number of these services.
The broader picture around solar safety.
Products such as PVStop are only one component of the much broader solution required around solar energy and battery storage. Fire and emergency services require new and innovative training resources and fast adoption of new procedures as new products become available to solve new problems. New legislation is also needed to remove the responsibility wholly from fire and emergency services and place more onus on industry and system owners to install systems with more integrated safety solutions. The solar battery storage revolution is just getting started as is the wide adoption of electric vehicles and their integrated battery storage systems. These are the next challenges that are faced by the fire and emergency services industry, but that’s a topic for another article!
The growth of solar photovoltaic (PV) systems has been exponential for the past two decades. In the last 10 years especially, the world has seen solar PV evolve from a pure niche market of small scale applications towards becoming a genuine mainstream electricity source.
This has been driven by a number of factors. When solar photovoltaic (PV) systems were first recognized as a promising renewable energy technology, governments started implementing programs such as feed-in tariffs to provide economic incentives to invest in solar projects. As a consequence, cost of solar declined due to improvements in technology and economies of scale, even more so when widespread production ramped up in China. Another factor has been the rising cost of grid electricity in first world countries and the lack of reliable grid electricity in third world countries. In conjunction with these trends, popular sentiment has shifted towards finding clean, sustainable and affordable energy sources for the future wellbeing of the planet.
Deployment of photovoltaics will continue to gain momentum on a global scale and solar PV is set to become an increasingly popular competitor to conventional energy sources. In fact, grid parity has now been reached in around 30 countries with predictions that 80% of countries will be at parity by the end of 2017. To quantify this in numerical terms, cumulative PV power capacity is nearing 200GW (gigawatts) which is the equivalent of nearly 1 billion solar panels installed globally. A figure that is forecast to reach 2.5 billion solar panels by the end of 2017.
Legislation, safety and training
Due to the exponential growth of the solar industry globally and its rapidly evolving technology, standards and legislation have not been able to keep pace with solar innovation. There are very few true experts in this new frontier and it is becoming increasingly obvious that there is a significant gap in the safety protocols surrounding the use of solar. There is an urgent need for better training programs to educate the various industries that are impacted by the increasing popularity of solar.
The knowledge gap
Firefighter awareness of solar PV systems, being able to identify the different types of solar PV systems and gaining a basic operating knowledge of these systems are paramount to effectively mitigating a fire event involving solar PV systems. Taking this back one step further, it is also essential that firefighters are aware of both Direct Current (DC) electricity and Alternating Current (AC) and the differences between the two electricity types.
Training objectives
Firefighters cannot be expected to be electrical engineers, so a training program needs to be tailored to equip firefighters with the necessary tools to make accurate and informed decisions when dealing with incidents that involve solar PV systems. So what information do firefighters require and what are typical questions that are asked?
Firefighters need to understand the different types of electricity, the nature of DC electricity and how it works in solar PV systems. Why would you want to turn solar systems off? How do you turn one off? What goes wrong with them? How does presence of a solar PV system impact your first response procedure? These are just a few of the questions that need to be answered.
Physiological Effects of DC Electricity Table of the physiological effects of DC electricity taken from the AS/NZ Standard
Understanding the animal
Let’s start with electricity basics; Watts = Volts x Amps. A Watt is a unit of power, this is the indicator of how much power is available (or how badly it can hurt/injure you). Remove either Volts or Amps and you have no Watts (meaning no power/electricity).
Alternating Current (AC) is created by a rotary alternator. Electrons flow and vibrate backwards and forwards creating a frequency. The voltage and frequency varies from country to country, but in most regions the voltage is typically either 220- 240 Volts – AC (220V-240V) or 110 Volts – AC (110V). Frequency is typically 50Hz (50 cycles per second) or 60Hz (60 cycles per second). Because of this positive and negative alternating frequency, if you come into direct contact with the electrical current your muscles will contract and release, potentially allowing you to break free of the electrical current.
Direct Current (DC) is the type of electricity that is generated by all solar PV systems. The electrons only flow in one direction and so do not produce a frequency. Direct Current (DC) travels in one direction only, from the source to the load. Due to this, if you come into direct contact with the electrical current your muscles will contract and lock, there is no opportunity to break free of the electrical current. If you do try to break the load (wire short circuit, switch or even your skin) from the source, the current arcs very badly, either setting fire to or burning the load. From a physiological perspective, given the same voltage and amperage, Direct Current (DC) will not allow you to break contact and will cause much worse deep cell damage than Alternating Current (AC) (excluding high voltage/high amperage equipment which is just plain deadly from either an AC or DC source).
To dispel the myth that voltage alone is dangerous let’s use the example of a Taser. A Taser produces 50,000 volts, but only 0.0021 amps (105 Watts). Once contact with the body occurs the voltage drops, delivering an actual electrical charge to the body of between 7-26 watts. It will incapacitate an adult but causes no long term physiological effects. In contrast a typical domestic solar array will produce anywhere between 4kw (4000 watts) and 6kw (6000 watts) which is lethal.
Solar panels come in a huge variety of sizes and power outputs, anything from 1 watt through to modern panels of up to 315 watts.
A solar panel consists of many individual solar cells joined in series. Each solar cell produces 0.6 volts DC (at 25°c) no matter what size they are. The size of the solar cell determines the amperage that the solar cell produces. The larger the solar cell, the higher the amperage. The output of a typical modern solar panel is 250 watts.
These panels are then joined in series (also referred to as a string) to increase the voltage. Domestic solar panel strings are limited to an output of 600V and industrial/commercial strings are limited to 1000V , this is due to a number of factors such as the high cost of circuit breakers and isolators rated at over 1000W and also due to the potential problems associated with high voltage stress(HVS). Larger commercial and industrial solar PV Systems typically consist of multiple strings run in parallel to increase power output.
Types of solar systems
There are 3 types of solar PV systems. Firefighters need to be able to identify the three types of systems in order to determine the most appropriate risk assessment and isolation procedures (to be discussed in more detail shortly)
Grid Interactive System
A grid interactive system is a solar PV system that is connected to the utility grid. Any excess power that is produced beyond the consumption of the connected load (ie household usage) is fed/sold back to the utility grid. This allows the property owner the ability to earn feed-in tariff credits from the utility grid provider.
Standard net metered grid interactive solar system
Off Grid System
An off grid system is a solar PV system that is not connected to the utility grid. An off grid system requires a number of additional components (compared to a grid interactive system) such as a battery storage system to store excess power, a regulator, a mains disconnect and a generator to support the system if power is depleted from the battery storage system.
Standard dc coupled off grid solar system
Hybrid System
This third (and most recent) solar PV system type provides the best elements of both the grid interactive system and the off grid system. The convenience of a grid connected system, including the ability to earn feed in tariff credits with the extra flexibility of a battery storage system. This means that even during a power blackout, you still have electricity (more on the implications of this later). There is also a growing financial incentive; the ability to store your own power (through the battery storage system) and relying much less on the utility grid. In effect the utility grid adopts the function of the generator in the off grid system. Power from the utility grid is only utilized when power is depleted from the battery storage system.
Standard grid storage/hybrid solar power system
The battery storage revolution
With the “best of both worlds” scenario that hybrid solar PV systems offer, virtually every grid interactive solar PV system currently installed will adopt a battery storage system within the next 5 to 10 years. According to studies by the CSIRO in Australia, it is forecast that up to half of all electricity generated will be on site (homes, businesses and communities) within the next few decades. These battery storage systems (or energy storage systems) will hold the same amount of potential energy as a 44 gallon drum of fuel. They will be mounted within garages next to normal household possessions, next to parked cars (many of which will have similar battery storage systems as well). They will not always be easily accessible and currently there is no legislation around the location, installation or signage of the mains disconnect. The implications for fire and emergency services personnel globally are significant!
In part 2 we will continue on to explain why solar PV systems fail, the DC Danger Zone, recent rules, regulations and technologies, and give you an overview of a new product PVStop which is designed to mitigate the dangers associated with the DC Danger Zone and offer first responders with a solution when encountering incidents involving solar PV systems.
This article first appeared in Fire Australia, Issue 2, 2019.
Photovoltaic (PV) systems, commonly known as solar panels, are a growing challenge for the fire and emergency services. For personnel, this can be responding to a solar panel fire, attending to storm or flood damage or encountering a property that has a faulty or substandard solar system installed. Solar panels pose a serious risk to personnel safety due to their capacity to circulate electricity even when switched off.
Statistical evidence published by the Clean Energy Regulator warns that solar panels represent a serious national safety issue. This is supported by the increasing number of solar panel incidents reported by fire and emergency service agencies through the Australian Incident Reporting System.
Solar panel systems are emerging as a new and growing incident category, yet current standard operating procedures still do not adequately address the increasingly obvious safety gaps. Fire and emergency service crews are likely to face solar panel incidents on a daily basis in the near future, but without adequate tools, procedures or training, dangerous scenarios may become more common and increasingly put lives at risk.
Working amongst damaged and live solar tiles is potentially fatal. Photo: Fire and Rescue NSW
Sobering statistics
Solar panels have experienced a staggering 5,000% increase in Australia over the past ten years. Approximately 20% of Australian homes now have rooftop solar, and the ever-growing number of commercial, industrial and solar farm installations have seen the number of PV systems across the nation surpass two million.
In December 2018, Federal Energy Minister Angus Taylor made headlines when he warned his state counterparts that lives are at risk from unsafe or substandard solar panel installations. Quoting figures produced by the Clean Energy Regulator, he stated that up to one quarter of all rooftop units inspected posed a severe or high risk. Extrapolated against the current number of two million national rooftop installations, this equates to potentially 500,000 unsafe or substandard installations across Australia.
Solar panels damaged by hail pose a safety risk to fire and emergency service personnel. Photo: Stewart O’Regan
The danger zone
The primary risks associated with solar panels are electric shock and electrocution. As long as solar panels are exposed to light, they will continue to produce potentially lethal amounts of direct current (DC) electricity, known within the industry as the ‘DC danger zone’. This means anyone operating near a solar panel system during daylight hours is always engaging with live electrical equipment.
To put the risk of solar panels into perspective, a domestic 240-volt AC power outlet is usually rated at ten amps and provides 2,400 watts of power. The average size of a residential solar PV installation is five kilowatts, usually configured in multiple strings of up to 600 volts per string. With up to ten amps available, the average residential solar PV array can produce up to 5,000 watts of power. Residential installations of up to ten kilowatts are now common, while commercial installations can be upward of several hundred kilowatts, and generation plants can exceed 100 megawatts or more.
Tarping solar panels is an outdated and dangerous practice. Photo: Stewart O’Regan
Deadly mistakes
One of the challenges surrounding solar panel safety is the simple fact that the technology is relatively new and has grown so quickly. There are very few true experts in the field of solar safety and authorities are only just starting to recognise the knowledge and safety gaps. As a result of this, emergency service personnel are at risk of making fatal errors on the job.
For example, the practice of ‘tarping’ damaged solar panels is extremely dangerous and operates in clear breach of standard operating procedures, which state that crews should assume the solar power system and surrounding area is live. Standard operating procedures mandate an exclusion zone of at least three metres be established around any damaged solar panel components, and the exclusion zone be increased to eight metres if the components are in contact with conductive materials.
The December 2018 Sydney hailstorms highlighted that this dangerous practice is still being utilised as agencies struggle to adapt and come to terms with responding to incidents involving solar panels. Tarping solar panels is an outdated but persistent practice that is done with good intentions but is ultimately a dangerous solution.
Unanticipated risks: fire and ice
Following the same storm event in Sydney, a new and previously unanticipated risk was highlighted when hail damage to solar panels led to secondary fire incidents. One example was in the Sydney suburb of Moorebank, where a factory’s roof top solar panel system had sustained heavy hail damage. Although power had been subsequently isolated, hot and sunny conditions returned and, three days later, the damaged panels began arcing and sparked a significant roof fire that put the entire factory at risk.
There are still many rooftops across Sydney with hail-damaged solar panels. Some owners remain oblivious to the fact that these systems present a significant ongoing fire risk until the solar panels are disconnected and removed.
Hail damage to a solar panel array of a Moorebank, NSW factory sparked a significant roof fire. Photo: Tacca Plastics Pty Ltd
Toxic problem
Sandwiched between the protective glass, frame and back sheet of the solar panel, solar cells present no risk to health, but once a panel burns and the solar cells are exposed, the burning panels can be highly toxic and dangerous to humans. Solar cells contain the carcinogens cadmium telluride and gallium arsenide, as well as the potentially lethal phosphorous. Inhalation of these toxic nano-particles cause silicosis of the lungs and should be treated with the same precautions as asbestos. Self-contained breathing apparatus (SCBA) should always be utilised in incidents involving burning solar panels.
The full scope of solar panel risk
With solar panels now installed on one in five buildings across the country it is important to consider the broader range of incidents involving structures and fire. For every incident initiating from a fault in the solar panel system, there are many more where the ignition cause is unrelated but where the fire may encroach upon the solar panel system and compromise safety. In these scenarios, it is just as important to isolate the power from the solar panel system as it is to isolate mains power from the grid. Up until now this has proven problematic for firefighters, and in many cases defensive tactics have been employed because solar panel systems could not be easily or reliably isolated.
Solar solutions
There is currently a range of electro-mechanical solutions available on the market including isolation switches, micro-inverter systems and DC-optimising equipment, but all of these options operate downstream of the panels and do not isolate the power produced by the panel itself. An Australian innovation, PV Stop, has recently been developed and is now used as a reactive solution to safely isolate the power produced by solar PV systems. It acts as a liquid tarp that can be sprayed over solar panels to block light from hitting the panels, which isolates the power produced by the system in seconds and eliminates the risk of high voltage DC electrocution.
A critical consideration for fire and emergency services agencies when adopting a new product is the assurance that the product is safe for their personnel, the community and the environment. PV Stop, which was awarded the FPA Australia’s Innovative Product and Technology Award in 2018, was tested by the NSW Environment Protection Agency for harmful elements and has been deemed safe for the environment and personnel working in the vicinity of solar panels. This is just one example of the industry’s step toward adapting to more environmentally friendly practices and products that do not limit our ability to embrace clean energy solutions.
PV Stop eliminates electrocution risk from solar panels. Photo: PV Stop International Pty Ltd
Working toward a cleaner future
As technology continues to evolve at its current rapid rate, it is critical that safety innovations keep pace to ensure the fire and emergency services sector can maintain its commitments to emission reductions and environmental protections, without sacrificing the safety of personnel. Actions during the December 2018 hailstorms in Sydney show the sector needs to do more to adapt to emerging technologies and their associated risks, but proactive fire and emergency service agencies can continue to address these knowledge and resource gaps by seeking information, continually improving their practices and driving the development of innovative new safety technologies.
2020 was a bumper year for solar power in Australia. More solar PV systems were installed in the first nine months than in all of any previous year.
Almost one in four Australian houses now have rooftop solar panels. But the number of solar panel incidents reported by fire and emergency services has increased too.
The exponential growth in solar PV and associated problems has attracted media and political attention.
In 2018, federal Energy Minister Angus Taylor warned his state counterparts lives were at risk from substandard solar panel installations. An audit of the Clean Energy Regulator by the Australian National Audit Office found there were potentially tens of thousands of badly installed and even unsafe rooftop systems. The regulator had inspected just 1.2% of rooftop installations.
It’s a nationwide problem
State and territory regulators are responsible for electrical safety. Only Victoria mandates an inspection of each installed system.
Last October, Fire and Rescue NSW Superintendent Graham Kingland said:
Over the last five years we have seen solar panel related fires increase five-fold. It is not uncommon to see solar panels cause house and building fires.
On Christmas day, ACT Fire & Rescue attended a fire at a home in Theodore where the solar panels caught alight. Coincidentally, the location was Christmas Street!
Components such as DC isolators and inverters, rather than the actual panels, are the cause of most solar-related fires. A DC isolator is a manually operated switch next to a solar panel array that shuts off DC current between the array and the inverter. It was intended as an extra safety mechanism, but the switches have caused more problems than they have solved – particularly when not installed correctly or when poor-quality components are used.
Solar is cheaper in Australia but poorly regulated
A recent report rated Australia as one of the cheapest per kilowatt for solar PV, but it questioned our safety standards. Most solar systems sold in Australia use DC voltages that can pose a serious fire risk.
Unfortunately, Australia has been slow to adopt safer solar regulations. In contrast, the United States has had safety standards preventing the installation of conventional DC solar systems since as early as 2014.
It’s more difficult for lower-voltage, microinverter-based systems (requiring no DC isolator switch) to catch fire, but it’s not impossible.
An amendment to the DC isolator standard (AS/NZS 5033:2014) to improve product datasheets and ensure isolators can withstand the harsh Australian climate took effect on June 28 2019. By then, over 2 million systems had been installed on Australian rooftops.
Added to issues such as flammable cladding, dodgy electrical cable and other “grey imports” (products not sourced from approved manufacturers) in the building industry, we are now playing a game of catch-up.
Poor-quality solar rooftop components have led to an expanding list of product recalls. The latest Australian Competition and Consumer Commission (ACCC) recall list includes installations managed by industry giants such as Origin and AGL.
One notable recall in 2014 reported a risk of “arcing” and “eventual catastrophic failure, resulting in fire”. It listed no fewer than nine traders operating nationally as having used this failed product. The recall noted that the product supplier, Blueline Solar Pty Ltd, was insolvent.
What should consumers do? The ACCC said:
Owners should immediately shut down the PV system following the standard shutdown procedure.
If a consumer suspects they have one of the affected units, they should have an electrician inspect and replace the DC isolators.
Solar systems do not fall under the National Construction Code unless an ancillary structure is being created. Most systems are simply fixed with rails to an existing roof. If the code covered rooftop solar, this would require private certification and a compliance check on any system, as is the case overseas.
Research has shown consumers’ knowledge of solar systems is poor. Many owners have little idea if their system is working properly, or even at all.
And how would a consumer know what kind of DC isolator is on their roof or how to shut down the system in the event of a fire?
Solar panel systems are a growing incident category for firefighters. Yet even among firefighters there is some confusion on procedures to deal with a fire on live solar panels.
Even some firefighters aren’t clear about how to deal with fires on live solar panels. riopatuca/Shutterstock
Solar panel fires have yet to make it onto a top 10 list of domestic fire causes (statistically, your Christmas tree lights are a greater risk). But the sheer volume of installations and ageing components in uninspected older systems are increasing the risks.
One Aussie inventor has developed a product PVStop — “a spray-on solution to mitigate solar panel risks by reducing DC output to safe levels to offer homeowners and emergency personnel peace of mind”.
The latest update on Clean Energy Regulator inspections completed to June 30 2020 shows a negligible 0.05% decrease in substandard systems. Roughly one in 30 systems (3.1%) have been deemed unsafe and another 17.9% substandard.
Without adequate solar PV industry standards, tools, inspection regimes, procedures or training, dangerous scenarios may increasingly put lives at risk. The high uptake of solar is very good news for reducing household electricity bills and carbon emissions, but safety issues undermine these positives.
The surge in installations, the introduction of batteries, the ageing of panels and components together with more extreme weather events mean solar panel incidents are likely to continue increasing.
Australia prides itself on being a world leader in household solar but until now we have not fully appreciated the safety risks. Fire authorities would do well to update fire safety guides that omit specific information on solar. And system owners should ensure they understand the risks and shut-down procedures.
The team at PVStop are very excited and proud to announce that they have won the FPA Australia, Fire Protection Industry Awards in the category of “Innovative Product & Technology for 2018!”
The Innovative Product & Technology Award is a new award category for 2018, so it is an even greater privilege to be the inaugural winner of this new award category.
The award recognises the outstanding contribution from an organization, for the development of leading edge industry products and technology solutions for the purpose of progressing the fire protection industry in Australia and acknowledges the commitment to providing solutions to existing threats / issues, currently facing the fire protection industry and community.
