FIRE RISKS WITH NEW SUSTAINABLE TECHNOLOGIES – AND HOW THEY CAN BE MINIMISED

There is an ongoing search for new and better options for how we can produce, store and use energy. Achieving the ambitious climate targets requires new technologies and rapid deployment, but new technologies entail not only new opportunities but also new risks.

The strongest pace of development of new technology on the Swedish market today is in the areas of solar cell technology, electric vehicle development and energy storage technology. All of these areas present new and unique fire hazards which, if they are left unmanaged, can cause total damage to a building.

Another side of the rapid technological development is that regulatory developments are not keeping pace. Rapid technological development, combined with a strong political will to promote renewable energy, has led to relaxed control and application processes. This in turn has resulted in an almost complete lack of regulation of this type of system today. However, as always, the responsibility lies with the owner of the property or facility.

There is an absence today of a lot of research and statistics necessary in order to obtain an overall picture of how the new technology affects and interacts with fire protection in our buildings. However, there are sufficient statistics available to take effective action to tackle the main risks. So what kind of measures are we talking about, and why are they not being implemented today?

PHOTOVOLTAIC POWER PLANTS AND PROTECTION MEASURES

Photovoltaic power plants are increasing rapidly in Sweden today [1], which is likely due to a combination of a higher level of ambition from both political and private sources, as well as increasing cost-effectiveness.

Many energy-intensive activities such as industries, refrigeration plants or food retailers are often constructed as large span buildings with large flat roofs. From an installation, efficiency and maintenance point of view, this type of roof is optimal for photovoltaics, but less optimal from a fire safety perspective. Flat roofs are predominantly constructed with combustible insulation, and in many cases also with combustible roofing. This is permitted under the building regulations, as the main purpose of fire protection of roofs is to prevent the spread to the roof itself in case of fire in an adjacent building [2]. There is therefore no requirement that the roof structure can withstand more than minor impacts in the form of heat radiation and aerial fires. Historically, the occurrence and development of a fire on the external roof itself has not been considered a likely scenario. There is thus a lack of evidence regarding the risks of these types of fires and a lack of regulation to manage them today. A photovoltaic system can pose such a risk. The incidence of fires in photovoltaic power plants is still low [3], but is likely to increase as the number of installations increases and as they age. New technologies and materials are also constantly emerging, which is a factor that contributes to an increased risk of installation errors.

Nevertheless, all the evidence suggests that if they are done correctly, photovoltaic power plants do not pose a significant fire risk. The risks that exist today are often manageable with relatively simple measures. Instead, the problem lies in the fact that they are never noticed, and that they can be significantly exacerbated by the existing conditions of the building stock we have today. Typically, this type of risk is raised and managed in the construction or application process. However, the requirement for a building permit/notification for solar cells was removed in 2018 to facilitate the expansion of solar energy at the national level. This means that all responsibility for managing fire risks falls on the property owner, with no risk awareness functions at all.

Until such functions are in place, there must be a shared responsibility, where contractors, consultants and developers jointly manage the risks. In principle, there are no existing buildings where a photovoltaic power plant can be installed on a roof without some type of fire safety measure being implemented. This is necessary in order to ensure the benefits of the photovoltaic power plant without disproportionate risks. It also ensures that cost estimates, calculations and the design of the plant are carried out in the correct manner. Last but not least, it ensures the possibility of a safe and efficient fire-fighting operation for the emergency services. Although the number of incidents so far is few, we cannot overlook the fire safety of our photovoltaic power plants. Because if the incidents increase, there is a risk that confidence in and the development of solar energy as part of our environmental transition will be cadastral reduced, which would be unfortunate.

CHALLENGES OF ENERGY STORAGE AND SUGGESTIONS FOR MANAGEMENT

One effect of solar cells and many other types of renewable energy is that production fluctuates. Production is dependent on conditions such as light intensity, wind speed and precipitation, all of which are beyond our control. Energy storage can be used in order to be able to use the energy when and where it is needed. There are many types of energy storage, such as impoundment lakes, pellets, biogas and hydrogen gas.

However, the greatest fire risks mainly exist in the newer energy storage devices in the form of batteries. This is partly because their energy density is high and is increasing all the time, but perhaps mainly because they are placed in, and even integrated into, buildings to a much greater extent than other forms of energy storage. As with photovoltaic power plants, technology is developing very rapidly and the cost-effectiveness of these solutions is improving. The increased energy density means that they take up less space, and this is largely what allows them to be both designed and located in a flexible way that, from aspects other than fire protection, does not require much of the building in which they are installed.

Battery fires have many characteristics that make them difficult to handle, which increases the risks of placing them inside buildings near areas where people are present. On the one hand, the smoke produced is often highly toxic, and the protective equipment normally used by emergency services provides only limited protection compared to other fires. However, perhaps the greatest risk is that these types of fires can continue with little or no external oxygen supply [4]. How a fire develops depends on the battery chemistry, which can vary greatly and is constantly evolving, so fires are also difficult to predict. The combination of these characteristics means that normal measures such as fire cell division no longer have the expected effect. With the exception of fan rooms, mechanical rooms are often relatively small, and are often located in basements or other areas without windows. This normally means that any fire that occurs will consume the available oxygen in the space relatively quickly and then self-extinguish or continue with a very limited effect. This does not apply equally to battery fires, which can continue even after the oxygen in the room is largely exhausted. The effect is that the fire can continue to grow or continue with undiminished intensity. This drives a process in the fire compartment called thermal expansion, which occurs because hot smoke takes up more space than cold air. The increasing amount of smoke eventually has to go somewhere, and often the only way it can escape is through gaps at the door leading into the space. This is often a door that is positioned up to a communication area or escape route.

As with photovoltaic power plants, there are relatively simple measures when it comes to energy storage. For example, it is possible to place this type of energy storage outdoors. When placed indoors, consideration should be given to where they are placed and it should be ensured that no other combustibles are nearby. It is also recommended to provide the space with some type of automatic pressure relief or smoke ventilation. Again, the problem is rarely that the measure itself is unreasonable or particularly costly, but rather that there is an absence of awareness of the risks and that regulation is still lacking.

The risk of total damage may not be as great as it could be with an improperly designed photovoltaic power plant, but the risk of personal injury can often be greater. There is also an awareness today in many emergency services of the risks to responders arising from this type of fire, which means that a response can be considerably more complicated and time-consuming than it would need to be if it was designed correctly. Naturally, a prolonged process increases the risk of the smoke spreading to many adjacent spaces and causing much greater material damage. In addition, the risk of water damage during the extinguishing and cooling of the fire is greatly increased. Similar to the solar cell installation, there is a lack of clear regulation and examples of specific measures in the regulatory framework. Getting the safety of the plant right therefore depends entirely on bringing in the right skills at the right stage.

CHARGING STATIONS FOR ELECTRIC VEHICLES AND PROBLEM DEPICTION

Naturally, the energy produced and stored by solar cells and battery storage can be used in many ways. However, there is a high probability that at least part of it will be used to power the ever-growing number of electric vehicles in Sweden. There are big goals for transition in the automotive sector and electric vehicles are part of the solution to achieve them. More and more parking spaces with charging points will be required as the number of these vehicles increases.

With regard to fire risks, electric vehicles are essentially a battery on wheels, so the same problems exist in terms of a fierce and very difficult to extinguish fire scenario with noxious smoke. The difference so far has been that fires in electric vehicles have largely occurred outdoors. This makes the problem of smoke much less problematic and allows the fire to be extinguished and cooled from all sides and, if necessary, the vehicle can be moved to avoid igniting other nearby objects. However, with the increasing proportion of car parks with charging points, we will eventually see more and more of them moving into our multi-storey car parks and underground garages. Fires in this type of environment can often be protracted and difficult to manage even today, yet historically they have been relatively predictable. With the introduction of electric cars, these conditions are changing. Naturally, it will not be possible to prevent electric vehicles from parking anywhere, but the development of a fire in batteries is directly dependent on how much charge they have, so the location of the charging points can still often determine how serious the fire has the potential to be. They also represent a potential risk of fire in themselves, given the current and power required for charging and the consequences if something were to go wrong. The most effective measure so far is to place the charging stations correctly. A location on the same level as the entrance to the garage and as close as possible to the entrance from the open air is preferred. This makes them easier to protect or transport away in the event of a garage fire, facilitates a possible response by the emergency services and increases the possibility that the smoke can be ventilated out.

In order to ensure that the impact of a fire is not too serious, charging points should also be avoided altogether in garages that are not adequately open or have smoke ventilation. Locating them in underground garages is often inappropriate unless fire safety is specifically incorporated into the design, and it is often difficult to achieve the type of measures required in existing buildings. Where possible, placement should always be in the open or where the garage floor is as open as possible.

NEW SUSTAINABLE TECHNOLOGIES – HOW RISKS CAN BE MINIMISED

I am one of those who believe that a faster transition to achieve the climate goals than we can foresee is actually possible. If trends continue in such a way that market forces move in the same direction as society’s desire to shift to sustainable solutions, there will be no real barriers any more. But it is also critical that we do not create our own barriers, for example by building unmanaged risks into the technology necessary to achieve our goals.

We must continue to let these kinds of technologies represent solutions to our problems and not the beginnings of new ones. Achieving this will require a different approach from what we are used to. We can’t wait for the regulatory framework to evolve. Instead, we as property owners, contractors, investors and consultants have to highlight and manage the risks ourselves. The right expertise, measures and design must be in place at the right time. This is how we ensure that we ourselves become part of the solution, and not part of the problem.

Author:

Mattis Arnqvist