SharpEye 40/40 IR3

Four Variants, Three Questions

Three questions decide it. Is hydrogen part of the risk? That selects I or M. How far is the detector from the hazard? That sets the range you need. And does the risk develop or erupt? That selects C or D.

Why IR3 Reaches So Far

Hydrocarbon combustion produces carbon dioxide, and hot carbon dioxide gives off strongly in a narrow infrared band around 4.3 microns. That emission is powerful, specific to combustion, and travels well through air.

An IR3 detector watches that band along with other channels either side of it. A real fire produces a strong signal on the combustion channel and comparatively little on the reference channels, with the flicker frequency of a flame. A hot object produces broadly similar output across all channels, and no flicker.

Correlating the channels against each other delivers both advantages at once. The signature is strong enough to detect at a distance, and specific enough that hot exhausts, heaters, sunlight and welding arcs don’t look like it. Where UV/IR achieves immunity by requiring two different technologies to agree, IR3 achieves it by requiring several views of the same thing to agree.

That’s why the 40/40D-I reaches 90 metres, and why IR3 is the default specification for large open process areas.

Why a Standard IR3 Can’t See Hydrogen

This is the most important thing on the page, and it catches people out.

Hydrogen doesn’t contain carbon. Burning it produces water vapour, not carbon dioxide. So a detector watching the carbon dioxide band is looking for a signature a hydrogen fire never produces, and it will register a hydrogen fire as nothing at all.

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

The M variants exist for exactly this. They watch four infrared bands across a wider range, from 2 to 5 microns, adding detection of the hydrogen combustion signature. The 40/40D-M reaches 50 metres for hydrogen, and the 40/40C-M reaches 36 metres.

For any site with hydrogen, whether that’s a production facility, an electrolyser, a refuelling station, a battery room or a semiconductor process, the M variant is the specification, not the I.

Where IR3 Isn’t the Right Answer

It’s worth saying plainly, because it saves a wrong purchase.

IR3 detects fires through their combustion products. Metal fires such as magnesium, and inorganic fires generally, don’t produce the emissions these channels look for. No I or M variant will see them reliably.

Where metal or inorganic fires are part of the risk, the broad spectrum UV/IR variants are the right technology, specifically the 40/40C-LB and 40/40D-LB, which detect hydrocarbon, hydrogen, metal and inorganic fires. You give up some range in exchange for that coverage.

Range and Speed: C or D

The series decides several things together.

The C-Series is built for standard industrial applications. It responds in typically under 5 seconds, reaches 65 metres on the C-I, runs from -40°C to +75°C, and carries a 3 year warranty.

The D-Series adds ultra fast response and extends the range. The D-I reaches 90 metres, responds in under 2 seconds at 40 metres, under 1 second at 30 metres in ultra fast mode, and in 50 milliseconds to an explosion. It runs from -60°C to +85°C and carries a 5 year warranty.

Speed matters where the event is an ignition rather than a developing fire. A vapour cloud ignition doesn’t build over seconds, and a detector chosen for a growing pan fire will report the aftermath rather than the event. Where the detector sits in front of suppression that has to act before a fireball develops, the D-Series is the specification.

The Shared Platform

All four variants have heated optics, which stop condensation and ice from obscuring the window. An obscured optical detector is blind, not degraded, and in Australian conditions condensation is a more common problem than ice.

HART and RS-485 Modbus give real diagnostic information during installation and maintenance, so configuration and detector health can be read at commissioning rather than assumed. On detectors mounted at height across a large area, that turns a scheduled inspection programme into a targeted one.

Hazardous area certification covers ATEX, IECEx and UKCA, and FM and FMC, with CSA on stainless steel D-Series detectors, for Zone 1 installation. Both series are SIL 3 compatible.

Testing

The built in test confirms window cleanliness and detector operation, and a smart field of view integrity test checks the optical path. It doesn’t activate the alarm outputs, so it proves the detector can see, not what happens downstream.

Proving the relays, loop, wiring, panel, notification and any suppression release needs an external flame simulator. Spectrex lists the FS-1100 for the 40/40D-I and the FS-1400 for the M variants, and Gastech supplies them for purchase or hire.

Where It’s Used

Refineries and petrochemical plant. Oil and gas processing, wellheads and terminals. LNG production, storage and loading. Large open process areas where detection distance decides the detector count. Hydrogen production, storage and refuelling, using the M variants. Electrolyser halls. Offshore platforms and vessels. Turbine halls and enclosures. Aircraft hangars and fuel farms. Battery energy storage installations. Semiconductor facilities handling hydrogen. Compressor stations. Tank farms and loading racks.