Long Range Flame Simulators

What the Self Test Doesn’t Cover

Most Spectrex optical flame detectors have an automatic built in self test, covering ultraviolet, UV/IR, single band infrared, triple infrared and multi infrared types. It checks window cleanliness and sensor operation.

What it doesn’t do is activate the alarm outputs, and rightly so, because a detector firing its relays several times an hour would be unusable.

So the self test answers one question and leaves the rest open. The detector can see. But whether the relay contact still closes, whether the cable is intact, whether the panel input is still connected, whether the notification devices work and whether the suppression release is armed are all unanswered. A detector can pass its own test for a year while any of those has failed.

What Actually Gets Tested

A flame simulator produces a signal the detector accepts as a real fire, so the outputs fire and the whole system responds. That single action verifies:

The detector’s sensors and internal electronics. The alarm activation software. The cleanliness of the viewing window and lens. The integrity of the wiring. The actual relay activation. And the correct function of any other outputs in use, whether 4-20 mA, RS-485 or HART.

Beyond the detector, it tests the cabling and connections back to the panel, the fire alarm panel itself, and the alarm notification. If you choose to leave it armed, it also proves the suppression release, though that has to be a decision made at the panel beforehand, not a surprise.

Line of Sight, Which Nothing Else Checks

This one is easy to overlook, and it’s the reason to test annually rather than only after a change.

A detector’s built in test confirms the window is clean. It can’t tell you whether something has been placed in the field of view. Racking gets moved, a partition goes up, scaffolding is erected, a new vessel is installed, a pipe run is added. Any of those can block the view of the area the detector is meant to watch, and the detector will keep reporting itself healthy throughout.

Triggering the detector from the position a fire would actually start proves the path is clear. That’s a different test from anything the instrument can do on itself.

Four Models

Matching the simulator to the detector matters. 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, which wastes a day and undermines confidence in the system.

Testing at Distance

Range is the practical constraint on this equipment. Flame detectors are routinely mounted high, in classified areas and in positions that are hard to reach, which is exactly why testing gets put off.

The FS-1100 and FS-1400 reach 12 metres, around a third further than the previous generation. That lets a technician test from ground level or an accessible platform, rather than arranging access equipment.

Testing distance depends on the detector’s sensitivity setting. At 12 metres, the detector needs to be set to its 60 metre sensitivity. At lower sensitivity settings, the simulator has to be closer: 9 m at 45 m sensitivity, 6 m at 30 m, and 2 m at 15 m. Plan the test positions around the settings on site.

Approved for the Area You’re Testing In

It’s worth stating, because it isn’t obvious until you think about it. The detector you need to test is usually inside a hazardous area, so the test equipment has to be certified to go in there with it.

Spectrex flame simulators are ATEX and IECEx approved, certified Ex d ib op is IIB + H2 T5 Gb for gas, and Ex ib tb IIIC T135°C Db for dust. They can be taken into the area with you, rather than the detector being removed or the area declassified for the test.

Lighting a real fire isn’t an option. It’s not permitted in a hazardous area and it’s dangerous in a non hazardous one, which leaves a simulator as the only safe way to do a full end to end test.

Annual Testing

Spectrex recommends a full system loop test at least once a year. Where the detector forms part of a SIL rated safety function, periodic proof testing is a requirement of the safety lifecycle, not just good practice.

That makes a simulator a recurring need, not a commissioning tool. The lithium ion battery gives up to 1,000 activations between charges, and recharges in about two hours, which covers most sites in a single visit.

Buy or Hire

For most operations, hiring makes more sense than owning.

Testing comes round once or twice a year. A simulator sitting in a store for the other eleven months still needs its battery maintained and its own condition checked, and it’s an asset earning nothing. Gastech supplies these for purchase where a site tests often enough to justify it, and through the hire fleet where it doesn’t.

Where testing is the problem rather than the equipment, our field service team carries out functional testing as part of a service programme.