Gas detection for FCEVs

Dräger discusses safety technology crucial to ensuring the safety of heavy-duty fuel cell electric vehicles

The heavy-duty trucking industry stands on the brink of a transformative shift with the integration of fuel cell electric vehicle (FCEV) technology. Because of the growing potential for this zero-emission powertrain solution, it is important to consider its risks as well as the surrounding infrastructure and value chain. 

The inherent properties of hydrogen — colourless, odourless, explosive as well as highly flammable — pose unique safety challenges that must be meticulously managed. Safety incidents relating to hydrogen and humans aren’t uncommon. According to an analysis of the Hydrogen Incidents and Accidents Database (HIAD) conducted by the European Hydrogen Safety Panel, human error accounted for 29% of all reported incidents from the database’s creation up until 2021, with 66% of all incidents happening within normal business hours. 

Enhancing safety necessitates the development of a robust hydrogen detection system. With over a century of expertise in gas detection, Dräger advises that an effective stationary gas detection system should include a comprehensive network of essential components. Central to this system is a sensor housed within a gas warning transmitter, connected to a control unit. This unit plays a crucial role in triggering subsequent measures, such as activating alarms or operating ventilation systems.

THREE LANES OF STATIONARY DETECTION

Zooming in on the technology involved in stationary gas detection, there are three main components to consider: point gas detection, flame detection and ultrasonic gas leak detection. 

One layer for stationary detection is ultrasonic gas leak detection (UGLD), which utilises acoustic technology to rapidly detect hydrogen leaks within a radius of up to 15 metres from the source. This method is particularly effective in outdoor settings where wind may disperse hydrogen away from traditional point gas detectors. UGLD systems provide straightforward binary feedback, indicating either the presence or absence of a gas leak, making it a great early warning tool for areas prone to hydrogen leaks.

Another possible layer of stationary detection is flame detection. Flame detectors are designed to identify the electromagnetic radiation emitted by the reaction products of flames, such as CO2 or H2O, from distances up to 40 metres. For hydrogen flames, which emit a unique infrared (IR) radiation spectrum distinct from those of hydrocarbon flames, specialised hydrogen infrared flame detectors are necessary. Hydrogen flames are almost invisible during daylight and therefore these dedicated detectors are crucial for identifying hydrogen fires and should thus be implemented in any environment where hydrogen is used.

A third layer for stationary detection is point gas detection. A point gas detector operates by detecting gas at a specific location, requiring the gas to directly reach the sensor. This technology is particularly effective in environments where gas is prone to accumulate, such as confined spaces. It provides precise measurements of hydrogen gas concentration, quantified in the percentage of the lower explosive limit (LEL), ranging from 0-100% LEL. This capability makes it an essential tool for ensuring safety in areas where gas buildup could pose significant risks.

FAUN Umwelttechnik, a leader in the European market for waste collection and street cleaning vehicles, is pioneering the integration of hydrogen fuel cell technology into its fleet, used in the maintenance hangars at each FCEV parking space. Dräger PEX 3000 transmitters with catalytic bead sensors were installed in the roof area to detect any hydrogen that could rise quickly and collect under the ceiling in the workshop. These types of point gas detectors are mainly used for continuous area monitoring of the ambient air. They provide good long-term stability and a fast response time. 

In addition to stationary detection systems, mobile gas detection plays a crucial role in keeping workers safe when dealing with FCEVs and hydrogen leaks. FAUN Umwelttechnik integrates this approach by equipping technicians with Dräger X-am personal gas detectors (5000 series, sometimes 8000 series) during vehicle maintenance. This is advantageous as it provides flexibility and protection not only within FAUN’s service centres but also at customer locations where on-site maintenance is required.

For example, when a hydrogen-powered vehicle is brought into the workshop or a technician is dispatched to a site following a vehicle accident, portable Dräger X-am devices are employed for preliminary assessments. Technicians use these detectors in conjunction with a telescopic probe to methodically inspect the vehicle for potential leaks while it is still outside the workshop. This proactive measure ensures that any potential sources of danger are identified and addressed before the vehicle enters the facility, thereby preventing the formation of an explosive zone within the workshop environment.

TAILORED DETECTION FOR HEAVY-VEHICLE SAFETY

FAUN Umwelttechnik was able to find the right detection solution through careful advising, risk assessment and evaluation. Its work with Dräger gas detection experts was necessary because while there are plenty of options available for leak detection, there is no one-size-fits-all solution for a workshop or plant. A custom solution created by experts is the best way to maximise safety and ensure compliance with regulations. As FCEVs become widespread in more industries, Dräger advises that industry leaders plan ahead and make sure to not only consider the technology behind the powertrain or truck solution, but also how to ensure long term safety for facilities, workers and the environment.

Dion Stibany is segment manager industries Germany at Dräger.