F-Guard IR3-H2

Why Hydrogen Needs Its Own Detector

Hydrogen fires are dangerous for two reasons that have nothing to do with how much energy they release.

The first is that you can’t see them. A hydrogen flame gives off almost nothing in the visible spectrum, so a serious fire can be burning in daylight with no visual sign at all. People have walked into them.

The second is that most flame detectors can’t see them either. Infrared flame detection works by watching the band given off by hot carbon dioxide, which is what hydrocarbon combustion produces. Hydrogen contains no carbon. It burns to water vapour. So a detector watching the carbon dioxide band is looking for a signature a hydrogen fire never produces, and it will report clean air while a fire burns in front of it.

That isn’t a sensitivity limit you can solve by mounting the detector closer. The detector is blind to it.

The F-Guard IR3-H2 is built for hydrogen and other energy transition fires, including methane, syngas and methanol. It uses the same improved IR3 platform as the hydrocarbon detectors, tuned to the signature hydrogen actually produces.

Detection Times

One thing to understand when comparing this with a hydrocarbon detector: the test fire here is a 0.8 metre hydrogen fire, not the 0.1 square metre n-heptane pan fire used to rate hydrocarbon detectors. The two figures can’t be compared directly, because you can’t test a hydrogen detector with heptane. Compare hydrogen detectors against hydrogen figures.

Forty Milliseconds

Hydrogen has a very wide flammable range and a very low ignition energy. A release is more likely to find an ignition source, and more likely to deflagrate than to burn steadily.

So the explosion response matters more here than with a hydrocarbon detector. Forty milliseconds is fast enough for the detector to sit in front of a suppression or isolation system that has to act during the event, rather than after it.

The detector handles the slower case as well, covering gradually developing fires alongside fast eruptions.

Two Variants

Replace the existing variant table with:

The HD variant matters more with hydrogen than with hydrocarbon, precisely because the flame is invisible. A responder arriving at an alarm can’t see where the fire is or how far it has developed by looking through a window. Video from a detector that can see it is the only way to know before going in.

Choosing Between This and the F-Guard UV/IR

The F-Guard UV/IR also detects hydrogen, alongside hydrocarbon, metal and inorganic fires, and responds to an explosion in 5 milliseconds. It has an ultraviolet channel, which is what gives it that broad fuel coverage.

The F-Guard IR3-H2 is infrared only, tuned for hydrogen and other energy transition fuels. Without an ultraviolet channel, it doesn’t rely on UV for detection. But it still needs care around welding: the manual says arc welding shouldn’t be done within 5 metres of the detector, and the system should be inhibited during welding.

So the decision comes down to the fuels and the environment. Where hydrogen and energy transition fuels are the main risk, the IR3-H2 is built for it. Where the risk spans hydrocarbon, metal and inorganic fires as well, the UV/IR. Gastech engineering will work through it against your area.

Certified for Hazardous Areas

The detector holds FM approval for both the United States and Canada, along with IECEx certification and a EUTEC certificate. The HD version is certified flameproof (db), dust ignition protection (tb) and increased safety (eb), so it suits both gas and dust hazardous areas. The Standard version is certified flameproof (db) only, for gas hazardous areas.

IECEx matters for Australian installations, since hazardous areas here are assessed under the Zone system, and hydrogen facilities are classified almost by definition. The detector is certified for hazardous locations, and can also be used in areas that aren’t classified as hazardous.

Window Heater and Self Test

A window heater prevents condensation and icing forming on the optics. An obscured optical detector is blind, not degraded.

The built in test runs automatically and can be triggered manually, checking window cleanliness and the overall operation of the detector, including its optics, electronics and software.

As with all flame detectors, the self test confirms the detector can see. It doesn’t activate the alarm outputs. Proving the relays, the loop, the panel and any suppression release needs an external flame simulator, and Gastech supplies an F-Guard simulator kit matched to this detector.

Welding: Design Around It

The manual says arc welding shouldn’t be done within 5 metres of the detector, and recommends inhibiting the system during welding. Gas welding always needs an inhibit, because the torch is an actual fire.

That’s worth designing around, rather than discovering during a shutdown. Where maintenance welding is routine in the protected area, either position the detector outside that radius, or plan for it to be inhibited during hot work, with the inhibit recorded and reversed.

Built for Harsh Sites

The housing is 316 stainless steel, rated IP66 and IP67, and NEMA 250 4X and 6P. It operates from -55°C to +85°C. Both variants carry a 5 year warranty.

Where It’s Used

Hydrogen production and electrolyser halls. Hydrogen storage and compression. Hydrogen refuelling stations. Ammonia to hydrogen cracking. Renewable energy and power to gas facilities. Methanol and syngas facilities. Battery and fuel cell manufacturing. Semiconductor facilities using hydrogen. Refineries and petrochemical plant with hydrogen units. Laboratories and test cells. Gas turbine facilities running hydrogen blends. Battery rooms where hydrogen builds up during charging.