Category: Solar System Safety & Maintenance

By Antonio Molina

The growth of photovoltaic installations poses challenges in fire safety. A very serious mistake is not to recognise panels as an installation or accessible roofs as work areas, which prevents the adoption of mandatory measures and, therefore, generates non-compliance and problems for all actors in the sector. In addition, the lack of protection affects the sustainability and image of the sector.

The 10 breaches and tips to take into account

These are the common non-compliances in fire protection when installing a photovoltaic system:

1. Failure to assess and determine the new level of risk

Problem:

Installing solar panels on industrial roofs can increase the risk of fire due to combustible materials and direct current (DC) generation. If the new level of risk is not properly assessed, the installation could fall outside the required safety parameters.

Regulations:

• RSCIEI (Royal Decree 2267/2004) – Article 3 and Article 6: Requires an assessment of the level of risk in modifications of industrial establishments.
• CTE DB-SI: Requires that any changes to the structure or facilities of a building be evaluated in terms of safety.

Key actions:

Prior to installation, it is key to conduct a risk study to adapt existing fire safety systems. This includes a standardised initial assessment, documentation of ignition hotspots, analysis of the impact on existing safety, development of a mitigation strategy and planning of periodic reviews.

2. External propagation and protection

Problem:

Photovoltaic systems can spread fires from the roof to the interior of the building due to improper wiring, electric arcs, openings such as skylights, and heat build-up on the roof or supporting structure.

Regulations:

• CTE DB-SI, RSCIEI Annex II, section 5.4: Requires the installation of protective barriers to prevent spread.
• UNE-EN 13501-2: Fire resistance regulation of construction materials.
• UNE-HD 605: Requirements for fire-resistant electrical cables.

Applicable requirements:

To reduce the development and spread of fire, fire-resistant cables and conduits should be used, cable passages should be sealed, safety distances should be maintained with roof edges and skylights, and fireproof mounting materials should be used.

3. Impact on sectorisation

Problem:

An inadequate installation of photovoltaic panels can affect or compromise the sectorization of the building and the compartmentalization of fire, facilitating its spread.

Regulations:

• RSCIEI – Art. 13 and Annex II: Requires that fire sectors be independent and not affected by new installations.
• CTE DB-SI: Requires that sectorization is not compromised with additional installations.

Essential Measures:

Separations must be left, strips and fire barriers must be implemented, as well as fire-resistant seals must be used between sectors.

4. Emergency plan or self-protection

Problem analysis:

The installation of a photovoltaic system changes the conditions for evacuation and firefighting, which makes it necessary to update emergency and self-protection plans.

Regulations:

• Royal Decree 393/2007 (Regulations on Self-Protection Plans).
• Regional and local fire protection regulations.

Required Measures:
Update the Emergency Plan with procedures for roof fires; new evacuation routes and periodic drills. Implement measures for the intervention of firefighters, signpost access routes, install emergency stop systems and guarantee the availability of documentation at entry points.

5. Training

Problem:

Maintenance and intervention personnel must be trained to work safely in environments with a risk of fire and electrocution.

Regulations:

• Law 31/1995 on the Prevention of Occupational Risks and RD 1215/1997: Requires training to be provided on the specific risks of the workplace.

Recommendation:

Implement specific training on risks in photovoltaic systems, work at height with electrical risk, firefighting and emergency response, in addition to the use of extinguishing equipment.

6. Provision of means of protection

Problem:

On roofs accessible with photovoltaic systems, it is necessary to have additional means of protection, such as fire extinguishers or others.

Regulations:

• RIPCI (RD 513/2017): Requires that the facilities have adequate fire protection measures.
• UNE 192005: Specifications for the review and maintenance of fire protection systems.

Required Equipment:

Specific fire extinguishers for electrical fires, fire and arc fault detection systems, emergency stop mechanisms and personal protective equipment.

7. Personal Protective Equipment

Problem:

Workers and emergency equipment must have specific personal protective equipment (PPE) to reduce the risks of burns and those of a damaged photovoltaic installation (electrocution and/or arcing).

Regulations:

• RD 614/2001: Regulation of protection against electrical risk.

Essential points:

Provide complete personal protective equipment, including face shields, insulating gloves, fireproof clothing, and harnesses. Implement safe disconnection procedures and use specific products such as PVSTOP, which eliminates arcs (not possible with fire extinguishers) and hazard factors for safe and effective interventions.

8. Compliance with specific regulations of the site or activity

Regulations:

• REBT ITC-BT-40: Establishes the electrical requirements for low-voltage generating installations.
• Regional and local fire protection regulations.

Recommendation:

Ensure compliance with PCI and electrical regulations, as well as site-specific regulations such as special hazard premises, ATEX, etc.

9. Notification to the insurance of the aggravation of the risk

Problem:

Insurance companies must be informed about the installation of photovoltaic systems, as it can affect the conditions and coverage of the insurance.

Regulations:

• Insurance Contract Law: Requires the insurer to be informed of any change that increases the insured risk.

Recommendation:

• Inform the insurance company and review if it is necessary to adjust the insurance policies.
• Verification of coverage.
• Claims management protocols.

10. Arc Risk Assessment

Problem:

Photovoltaic systems pose an arc flash hazard, dangerous to people and with the potential to cause fires if not properly controlled

Regulations:

• REBT ITC-BT-24 and UNE 50110: Regulations on the risk of electric arc.
• UL1699B and IEC 63027 standards for the detection and mitigation of arc faults.

Recommendation:

Implement arc fault detectors, minimize connection points, install remote/rapid shutdown systems, use predictive maintenance software, and employ specific products – such as PVSTOP – for added safety.

Real sustainability of photovoltaic systems

In short, it is crucial that all actors in the photovoltaic sector know and implement these measures to avoid legal, business and security problems. Fire protection is essential to achieve the real sustainability of the facility.

Its priority application guarantees the safety of personnel, property and the environment, while also preserving the good image of the sector.

Antonio Molina

I am an Industrial Chemist and Chemical Engineer from the University of Murcia. In addition, I have several master’s degrees in disciplines or topics, such as Quality, Environment and Sustainability, I am a Senior Technician in ORP (Safety, Industrial Hygiene and Ergonomics).

A large part of my professional career has been developed in the product manufacturing sector, where I have been lucky enough to collaborate in the research and development of some innovative products or solutions. Currently, I hold the position of Technical and Product Development Director of Extinction Against Fire and Safety SL (Extinction).

I am also a member or collaborator in important associations in the sector and director of the Innovation project ‘Novel devices for specific applications’, awarded by the Ministry of Science and Innovation.

I have been lucky enough to patent some devices (photovoltaic, fire, etc.) and to be part of groups or companies that promote innovation. I am passionate about security as well as technological advancements. My goal is to disseminate all these developments and transfer them to the sector, in order to improve safety and the environment.

Solar energy continues to gain popularity as a sustainable and efficient solution to reduce carbon emissions. However, with its expansion have also increased the risks associated with the installation and maintenance of photovoltaic systems . In this context, an Australian startup called PVStop has launched an innovative solution: a temporary coating that quickly turns off solar panels , eliminating the risk of electrocution.

Using solar energy and its risks

In Australia, more than 3.3 million households have already adopted solar energy . Despite the benefits of this technology, solar systems do present certain risks, especially when not installed or maintained properly. Solar hazards, such as electrical faults that can lead to fires, are becoming more common as panels age . Growing concern about these incidents has led the community to seek effective solutions to ensure the electrical safety of photovoltaic systems.

To address these issues, New South Wales-based startup PVStop has developed a first-of-its-kind temporary coating. This product enables photovoltaic systems to be disabled in seconds by blocking the light received by the solar panels.

Its operation is simple: just cover between 40% and 100% of the surface of the panels with the coating , which prevents the generation of dangerous energy. The process is quick and easy, and can be carried out from a safe distance of up to 10 metres, making it an essential tool in emergency situations.

Key benefits of temporary coating

The PVStop coating is distinguished by several features that make it a unique and safe option:

• ISO Certification: The product is backed by certifications that guarantee its reliability and effectiveness in sun protection.
• Immediate safety: Instantly deactivates solar systems, preventing accidents and electrocution risks.
• Non-conductive and fire retardant properties: Increases safety both during installation and in case of emergency.
• Easy removal: The coating can be removed without damaging the solar panels, allowing them to be reactivated once the emergency situation has been controlled.

Application in emergency situations

One of the key advantages of PVStop is its ability to be used in critical situations. According to Alex Keane, PVStop’s EMEA sales and marketing manager, the product can be applied at a number of different times – before a fault turns into a fire, during an incident, or after the fire has been controlled, preventing it from reigniting. This significantly reduces property damage and improves the safety of emergency workers and solar system owners.

The startup also plans to incorporate an innovative drone delivery solution. This technology, which is already used in the agricultural sector, is adapted to be used in hard-to-reach areas or in high-rise buildings. The incorporation of artificial intelligence will allow emergency services to apply the coating autonomously , further increasing the effectiveness of the product in critical situations.

Use and characteristics of the coating

The coating is applied easily using a sprayer, similar to a fire extinguisher. The product is available in 9 and 4.5 litre versions, which discharge in 70 and 35 seconds respectively. Once applied, it dries quickly, forming a latex film that can be easily removed from smooth surfaces.

In short, PVStop is an indispensable tool for those looking to enhance security in the installation and maintenance of solar systems. Its effectiveness in disabling photovoltaic systems and its ability to protect both people and property make it a key ally for those who rely on solar energy.

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!

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!

For more information, go to www.pvstop.com.au

Jim Foran

05/01/2017116 views

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.

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 Power

Photovoltaic (PV) Photo = Light, Voltaic = Electricity

Photovoltaic = Light Electricity

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.

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.

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.

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.

For more information, go to www.pvstop.com.au

by Jim Foran (PV Stop)

May 6, 2019

Categories:

AFAC Newsletter

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.