F-Guard Flame Simulators

The F-Guard Already Tests Itself Two Ways

It’s worth stating up front, because it changes what the simulator is actually for.

All F-Guard flame detectors run an automatic self test covering their optics, windows, electronics and software. Separately, an F-Guard detector can be put into alarm manually, either through the FGD communicator software, or by short circuiting the Manual BIT terminal to the 24 VDC negative terminal for one second.

That second method is genuinely useful, and often overlooked. A technician with a screwdriver can put the detector into alarm and prove the relay works, the cable is intact, the panel receives the signal and the notification devices activate. For a routine loop check, that’s enough, and it costs nothing.

So the honest question is what a simulator adds.

What Only an External Source Proves

Both internal methods trigger the detector from the inside. They tell you the detector’s electronics work, and that everything downstream of it works. What they can’t tell you is whether the detector can see.

An external simulator produces a signal that has to travel through the air, through the detector’s window and into its sensors. That proves three things nothing else can.

That the optics are clear enough to detect a real fire, not just clean enough to pass a self test. That the line of sight to the protected area is unobstructed. And that the detector is still aimed where the design intended.

Those last two matter more over time than most people expect. Racking gets moved, partitions go up, scaffolding is erected, a new vessel is installed, a pipe run is added. Any of those can put something between the detector and the area it’s watching, and the detector will keep reporting itself healthy throughout. An internal test will pass. A fire wouldn’t be seen.

So the two methods answer different questions. Use the manual BIT for a routine loop check. Use a simulator at commissioning, after any change to the protected area, and for periodic checks that the detector still sees what it’s meant to.

Three Models

Matching the simulator to the detector isn’t optional. A simulator produces a specific spectral signature, and a detector tuned for hydrogen won’t respond to a source built for hydrocarbon flames. The wrong model produces a failed test on a detector that’s working correctly.

Seven Metres, and When That’s Enough

The simulators work at up to 7 metres from the detector (6.5 metres for the UV/IR model), which is shorter than the long range Spectrex units reach.

Testing distance also depends on the detector’s sensitivity setting. At extreme sensitivity, the IR3 and IR3-H2 simulators reach 7 m. At high sensitivity, that drops to 5 m. At medium, 3 m (4 m for the UV/IR). At low, 1 m.

Whether that matters depends on the installation. In a plant room, compressor house, turbine enclosure, workshop or skid, 7 metres reaches most detectors from an accessible position. On a large open process area with detectors mounted high on structure, it won’t, and the Spectrex long range simulators are the right tool.

It’s worth checking against your actual mounting positions and sensitivity settings before ordering, since the whole point is reaching the detector without arranging access equipment.

Designed to Be Used, Not Stored

This is the practical detail that decides whether periodic testing actually happens.

The simulators are inexpensive, lightweight and simple to use. At 1.8 kg, with a modern ergonomic design and alignment markers, they allow accurate, fast and convenient testing. That combination matters, because test equipment that’s heavy, awkward or intimidating gets left in the store, and the testing gets put off.

A 3 colour LED shows the simulator’s status, and the rechargeable lithium battery charges in up to 3 hours. Each kit contains the simulator, a carrying case and strap, a battery charger, the user manual, an Allen key and a tool for removing the rear cover. Nothing else needs sourcing before the first test.

Approved for Hazardous Areas

The simulators are ATEX approved for use in hazardous Zones 1, 2, 21 and 22. They’re certified Ex db ib op is IIC T6 Gb for gas, and Ex tb ib op is IIIC T85°C Db for dust, so they can be taken into the area with the detector without a hot work permit. The LM25 aluminium enclosure is rated IP65 (NEMA 4X) and operates from -20°C to +50°C.

Buy or Hire

For a site with a large installed base and a regular testing programme, owning a simulator makes sense.

For a site with a handful of detectors tested once a year, hiring usually works out better. A simulator sitting in a store for eleven months still needs its battery maintained and its own condition checked, and it earns nothing in the meantime. Gastech supplies these for purchase and through the hire fleet, and our field service team carries out functional testing as part of a service programme, if you’d rather not do it yourselves.