What are Safe Temperature Sensors for Hydrogen Applications?

Safe temperature sensors for hydrogen applications are sensors specifically designed to withstand hazardous conditions, resist hydrogen embrittlement and deliver accurate measurements in environments where hydrogen is produced, stored or transported. Because hydrogen is highly flammable and can permeate certain materials, temperature sensors used in these applications must meet strict safety and performance requirements.

As industries continue exploring hydrogen as a cleaner energy source, selecting the right temperature instrumentation has become increasingly important for safe and reliable operation. 

For decades, Ashcroft has supported hydrogen and alternative energy applications with temperature instrumentation designed for demanding industrial environments. Read this article to learn about the challenges of hydrogen applications, the safety requirements for temperature sensors and the key features to consider when selecting sensors for hydrogen systems.

Why are temperature sensors important in hydrogen applications?

Hydrogen is used in a growing range of applications, including fuel cell vehicles, backup power systems, semiconductor manufacturing, pharmaceutical processing, and fertilizer production.  Temperature sensors, including resistance temperature detectors (RTDs) and Thermocouples, help maintain safe operating conditions, improve process efficiency and protect equipment from hazardous failures during production, compression, storage, and transportation.

Common hydrogen applications that use temperature sensors include:

• Failsafe generators for large facilities

• Fuel systems for light-duty and specialty vehicles

• Combined heating and power systems

• Semiconductor manufacturing

• Pharmaceutical blending processes

• Fertilizer production for agriculture

Because hydrogen environments are often classified as hazardous locations, temperature sensors must provide consistent and reliable measurements under demanding operating conditions.

How is hydrogen produced as a clean energy source?

Hydrogen can be produced as a clean energy source through electrolysis, a process that separates water into hydrogen and oxygen without generating CO2 emissions.

During electrolysis, water molecules are split into pure hydrogen and oxygen gases using electricity. Once separated, the hydrogen is compressed and stored for transport or later use, while oxygen is released into the atmosphere. This process can significantly reduce greenhouse gas emissions compared to traditional fossil fuel production methods.

As hydrogen adoption grows, reliable temperature measurement becomes increasingly important throughout production, storage and distribution systems.

What challenges do temperature sensors face in hydrogen applications?

Hydrogen is highly flammable and requires extremely reliable sealing and measurement systems to maintain safe operation. Temperature sensors used in these applications must withstand hazardous environments, material degradation and demanding operating conditions. Even a minor leak or seal failure can create dangerous conditions for personnel and equipment.

Because of these risks, hydrogen environments are typically classified as hazardous locations. Temperature sensors used in these areas often require approvals such as:

• FM
• ATEX
• IECEx
• Intrinsic Safety approvals
• Non-incendive safety approvals

These certifications help verify that the instrument is suitable for operation in hazardous environments.

What is hydrogen embrittlement?

Hydrogen embrittlement occurs when hydrogen molecules penetrate certain materials and reduce their strength and durability over time.

Because hydrogen molecules are extremely small, they can permeate materials such as high-strength steel, titanium and aluminum alloys. Over time, this exposure can reduce elasticity, ductility and load-bearing capacity, negatively affecting instrument stability and repeatability. 

Figure 1. Hydrogen embrittlement illustration

Selecting materials that resist corrosion and embrittlement is critical for maintaining long-term sensor performance in hydrogen systems. Learn more. 

What features should temperature sensors have for hydrogen applications?

Temperature sensors used in hydrogen applications should provide accurate measurements, hazardous location protection and resistance to corrosion and embrittlement. They should be designed to maintain stable performance in harsh operating environments while supporting system safety and process control. For more information read, Choosing Pressure Transducers for Hydrogen and Hazardous Locations. 

Temperature sensor features include:

• 316L stainless steel wetted materials for corrosion resistance
• Resistance to hydrogen embrittlement
• Hazardous location approvals such as FM, ATEX or IECEx
• Flexible mounting configurations
• Optional digital displays
• High accuracy and repeatability
• Durable construction for harsh industrial environments

What mounting options are available for hydrogen temperature sensors?

Hydrogen temperature sensors are available in multiple mounting configurations to support different installation and environmental requirements.

• A direct-mount sensor attaches directly to the thermowell and typically includes a head or junction box mounted to the probe. An example is the Ashcroft® S50 industrial RTD, which is manufactured to IEC 60751 standards and is available with explosion proof, intrinsically safe and non-incendive design options for hazardous locations.

• A remote-mount thermocouple probe uses flex armor and configurable lead wire options to support installation flexibility and durability. For example, the Ashcroft® S80 Thermocouple Probe can be configured with or without extension lead wire and is available with PVC, silicone, PTFE or fiberglass insulation options depending on application requirements.
  
  

• A remote-mount RTD probe provides additional flexibility and durability for demanding industrial environments. The Ashcroft® S81 RTD Probe includes flex armor and is well suited for hydrogen applications exposed to environmental stressors such as industrial ovens and equipment manufacturing facilities.

What should you know before purchasing temperature sensors for hydrogen applications?

Before purchasing temperature sensors for hydrogen applications, it is important to evaluate connection requirements, certifications, temperature ranges, and lead wire materials. Here are a few questions you will need to answer: 

1. What kinds of connections do your hydrogen application sensors support? Each specific temperature sensor offers slightly different connection options, but the sensor needs to properly mounted to the hydrogen process. They are typically mounted in a thermowell or using hydrogen-rated compression fittings.
   
   
2. What kinds of industrial certifications should my sensors have? It depends on the specific applications you’re using. Some of the common certifications our sensors can meet include FM, ATEX, and IECEX.
   
   
3. What temperature range should my sensors have? The ideal range for your sensors will vary based on how extreme your application is. Ashcroft’s most durable instruments can withstand temperatures up to 1000 °C or down to -250 °C.
   
   
4. What lead wire materials do you use for your temperature sensors? PVC, silicone, PTFE or fiberglass depending on application requirements.

Ready to learn more?

Choosing safe temperature sensors for hydrogen systems requires evaluating hazardous location approvals, material compatibility, mounting requirements and environmental durability. Understanding the operating environment and instrumentation requirements is an important step toward selecting temperature sensors that can perform reliably in hydrogen production, storage and transportation systems.

If you have more questions, see the related resources below or contact us to speak to a product expert. In the meantime, download our guide to see how to avoid hydrogen hazards in your operations.