Suppression: Alternative fuel for the fire

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Paul Trew, the newly appointed Alternative Fuels Co-ordinator at the Institution of Fire Engineers and former head of safety at London Fire Brigade, discusses his new role and explains the implications and potential risks alternative fuels pose for the fire industry

Whilst I joined Institution of Fire Engineers (IFE) as the technical support manager at the start of this year, I more recently took on the additional responsibility as the new dedicated alternative fuels coordinator. This comes at a crucial time with the world changing at a faster pace than ever before driven by the challenges raised by climate change and sustainability.

The adoption of alternative fuels has wide ranging implications for the fire industry including new and existing buildings, engineering and firefighting to name a few.  As the international professional body for those in the fire sector, I will work to help assess these changes, identify their impacts and educate our members.

Working with IFE members, volunteers and branches from around the world as well as external partners, my focus is on creating a valuable pool of knowledge to help members and the sector better understand the impact of alternative fuels and energy storage systems including hydrogen, electric vehicles, and lithium-ion batteries on fire safety and engineering.

The new resource will give members rapid access to the latest guidance and advice via technical updates and ensure IFE is at the forefront of consultations for the new standards and regulations needed to keep pace with change.

The IFE is committed to working with its members and other partners to help raise standards and ensure continued safety. With a dedicated resource in place to focus on alternative fuels, the IFE will provide a flow of knowledge which is critical to our sector and in turn will enable members to advance their knowledge, improve their competence and raise standards across the industry.

Alternative fuels

Our world is changing and innovations are constantly being introduced as we strive for a more sustainable future. With new investments in hydrogen infrastructure, renewable energy and other green technologies, come new risks. The rapid adoption of EVs around the world means it is critical for us to understand how to mitigate, manage and deal with lithium-ion battery fires.

Lithium-ion batteries are a popular technology for electric vehicles because they store a huge amount of energy in a very small space. However, if the battery is exposed to excessive heat, or there is a penetration in the battery case, then an internal short circuit causes heat that triggers a chemical reaction and a process called thermal runway which can lead to ignition, or in some cases even explosion. This impacts on where energy storage batteries are located in buildings, where EVs should be parked at home as well as multi story car parks and how first responders should deal with the additional risks.

For heavy vehicles and high heat demand in industry, hydrogen is becoming a major part of the decarbonisation roadmap for many countries. In Sweden they have already introduced hydrogen powered refuse trucks, Mercedes Benz has demonstrated how hydrogen can be used as an alternative to diesel to power HGVs and Japan and Australia are already collaborating on liquid hydrogen supply chain projects.

In the UK, JCB has announced plans to fuel heavy plant and equipment that is poorly suited to battery power, by hydrogen.  Mining giant Anglo American is also looking at powering its giant 220 tonne trucks with hydrogen.

Indeed, hydrogen is primarily being trialled as an alternative to diesel for buses and heavyweight trucks and this includes fire trucks.  This means changes to operational considerations when they become involved in fire.

Under the Transition to Zero Emission programme, Innovate UK  is funding HySPERT (HYdrogen Special Purpose Electric vehicle platform for Refuse collection and fire Trucks), which sees Liverpool-based ULEMCo, a specialist in the conversion of commercial vehicles to hydrogen power, working in partnership with Oxfordshire County Council (OCC) and its fire and rescue service (FRS) to develop a design for a zero-emissions fire truck that can operate continuously for up to 40 hours.

On the domestic front, hydrogen is also being lined up as part of the future energy mix for household boilers. Boiler manufacturers are working on a new ‘hydrogen-ready’ standard which will mean the UK can switch as easily as possible to 100% hydrogen much further down the line. The important thing to realise is that ‘hydrogen-ready’ boilers are still in development, whereas ‘hydrogen-blend ready’ boilers are widely available.

In May last year, IOSH  provided an overview of the risk of hydrogen fuel cells in vehicles that concluded that the two main hazards from fuel cell and hydrogen-powered vehicles are electrical shock and fuel flammability. Some fuel cell vehicle motors run on voltages exceeding 350V. With such high currents, the danger of electric shock is great, with 50V being high enough to stop the human heart.

Fuel flammability

Flammability is also an issue. Hydrogen has a flammability range between 4% to 75% in air, which is very wide compared with other fuels (gasoline is to 7.6%). Under the optimal combustion condition (a 29% hydrogen-to-air volume ratio), the energy required to initiate hydrogen combustion is much lower than that required for other common fuels (for example, a small spark will ignite it). However, hydrogen is about 57 times lighter than gasoline vapour and 14 times lighter than air. This means that if it is released in an open environment, it will typically rise and disperse rapidly. This is a safety advantage in an outside environment. Hydrogen also burns with an almost invisible flame, making it less noticeable and harder to firefight.

So, leakage can be a concern, especially when vehicles are stored in enclosed spaces as hydrogen can build up in roof spaces. Due to its small molecular size, hydrogen disperses quickly at normal atmospheric pressure. Therefore, it needs to be maintained at higher pressures (up to 10,000 pounds of force per square inch). The rupture of a pressure tank can cause high concentrations of hydrogen to form in the vicinity of the vehicle, as the turbulent flow rate of hydrogen is extremely high. Even though hydrogen disperses quickly, this emission will cause a combustible mix to form for a short period in the open.

All vehicles must be manufactured to minimum safety requirements, either nationally or internationally. The United Nations World Forum for Harmonization of Vehicle Regulations sets safety standards for motor vehicles. Standards for electrical safety, such as IEC 60664-1:2020 Insulation coordination for equipment within low-voltage supply systems – Part 1: Principles, requirements and tests, and ISO 19881:2018 Gaseous hydrogen – Land vehicle fuel containers, give minimum requirements for design specifications of components for electrical and fire safety. produced a paper based on the safety of hydrogen fuel cell cars. Researchers tested the electrical safety measures and leakage of hydrogen, both in use and post-crash. The electrical isolation and electrical continuity met the requirements in use and post-crash and no leakages from the tank were identified.

One of our largest special interest groups has a working group specifically looking at hydrogen vehicle infrastructure and transport. Legislation and regulations are piecemeal around the world and the aim is to bring learnings together to help shape a consistent approach that not only informs fire engineering professionals but can also help Governments, regulators and legislators develop statutory guidance that can keep everyone safe in a fast-changing world.

We have also been looking at the fire risks of solar panels, especially in relation to the fact that they remain live for as long as light reaches the panels, even when disconnected. Ultimately, the decarbonisation journey has been a catalyst for innovation and as fire engineers, we need to keep pace with the rapid technological and material changes that are being adopted around the world in transport, business and domestic settings.

The IFE’s strategy is focused on professional competency and sustainability, and we bring regular updates and technical articles to members through our journal, newsletters and CPD events. Our branches around the world are contributing to our knowledge base which will be hosted on our website. Our priority is to give members the tools and professional standards they need to navigate a more sustainable future.

Climate change events and the geopolitical landscape are both accelerating demand for alternative fuels with adaption happening at a rapid pace, in some cases more quickly than regulation so fire engineers have to adapt by staying at the forefront of knowledge, initiating research and sharing best practice.

This article was originally published in the September edition of IFSJ. To read your FREE digital copy, click here.

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