F-Guard UV/IR

Two Versions, and the Choice Isn’t Only About Video

Two things in that table matter more than the video.

The HD version has a narrower vertical field of view, 75 degrees against 90. On a detector mounted high, looking down across a process area, that changes the coverage footprint, and may change how many detectors a site needs. Check it against the mounting geometry, rather than assuming the HD is the same detector with a camera added.

The response times also cross over. The standard version is quicker inside 15 metres, while the HD is considerably quicker beyond it. So the better choice depends on how far the detector sits from the risk it’s watching.

Hydrogen as Well as Hydrocarbon

Most flame detectors are built around hydrocarbon fires, which make up most of the risk on most sites. Hydrogen is the harder problem.

A hydrogen flame is close to invisible. It gives off very little in the visible spectrum, and very little in the infrared bands a hydrocarbon detector watches. A detector tuned for a diesel fire can look straight at a hydrogen fire and see nothing.

The F-Guard UV/IR detects both, along with visible and non visible hydrocarbon fires. As hydrogen projects in Western Australia move from proposal into construction, that’s becoming a specification requirement rather than a nice to have.

Five Milliseconds

The detector handles two very different fire behaviours.

Slow growing fires are the conventional case, and the detector responds in about a second at close range. Fast eruptions are the other case. An ultra fast detection mode responds to a fireball or an explosion within 5 milliseconds.

Those are different events needing different logic. A detector optimised only for a growing pan fire will be too slow for a vapour cloud ignition. One optimised only for speed will alarm on things that aren’t fires. Having both modes is what lets the detector cover both risks.

What the Video Actually Changes

The HD version streams high definition video of the monitored area, with clear imaging of a fire and of personnel at up to 30 metres.

The value isn’t the picture. It’s that someone responding to an alarm can see the situation before entering the hazardous area: whether the fire is where the detector says it is, whether anyone is in there, and how far it has developed. Those are decisions currently made by walking in and looking.

It also records automatically, capturing one minute before the alarm and up to three minutes after. For an incident investigation, that’s the difference between reconstructing events from a log file and watching them.

Video integrates over ONVIF Profile S on a standard IP network, so it goes into an existing security or control room video platform rather than needing its own. A composite video output (NTSC or PAL) is also available.

Configurable Detection Mode

The detector can be configured to run as UV/IR, UV alone or IR alone.

That flexibility matters, because the right mode depends on what else is in the field of view. UV/IR gives the best false alarm rejection, because both sensors have to agree. UV alone is faster where false alarm sources are absent or controlled. IR alone suits installations where ultraviolet sources, such as arc welding, are routine.

Because the mode can be changed on site, a detector can be re-tuned when an area changes use.

Heated Optics and Self Test

A window heater stops condensation and ice forming on the optics. A blinded detector isn’t a partly working detector. It’s a non working one. In Australian conditions, the problem is more often condensation on a cool morning than ice.

The built in test runs automatically and can be triggered manually. It checks window cleanliness and the overall operation of the detector, across both the UV and IR channels.

It’s worth understanding what the self test doesn’t do. It confirms the detector can see, but it doesn’t activate the alarm outputs. Proving the relays, loop, panel and notification needs an external flame simulator, which Gastech supplies for purchase or hire.

Integration

Outputs cover 4-20 mA in three wire and four wire isolated configurations, sink or source, with HART 7, Modbus RTU over RS-485, and Ethernet. Relays are volt free contacts rated 2 A at 30 VDC, with alarm available normally open or normally closed, and fault normally closed.

An alarm delay of 0 to 30 seconds is configurable. Alarms, faults and other relevant events are written to non volatile memory, so the detector holds its own history rather than relying on the panel to log it.

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 +75°C as standard, with a high temperature option to +85°C. The tilt mounting bracket fits above or below the detector. Both versions carry a 5 year warranty.

Where It’s Used

Hydrogen production, storage and refuelling. Oil and gas processing and terminals. LNG facilities. Turbine halls and enclosures. Refineries and petrochemical plant. Offshore platforms and vessels. Fuel storage and loading. Aircraft hangars and fuel farms. Semiconductor facilities handling hydrogen and silane. Battery energy storage installations. Compressor stations. Mine site fuel storage and workshops.