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    Updated: 10 May 2020


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Startpage > Products > Smoke Detection > Fire Gas Detector

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The FCO Smoke Detector
This detector provides very early detection.
The FCO Smoke detector is a new concept for early warning of smoke detection.

The system has a number of CO detectors;
00-50 ppm, which allows one to tailor the system for all possible systems.

The system may include one or more detectors, with or without display, relay outputs and bus functions such as Modbus RTU connected to a communications system.

It can also be connected to external systems, like control- and monitoring systems for building automation.


  • Detects most carbon based fires

  • Provides very early warning of slow smoldering fires

  • Ideal for stealthy hotbeds

  • Insensitive to false alarms

  • Can be placed at several different locations

  • Compatible with existing control- and building automation systems

  • Environmentally friendly Halogen-free enclosure

The FCO is a new series of smoke detectors for carbon monoxide measurement that is unique within the fire detection industry.

The FCO can be used in many applications and the detectors are especially useful in smoldering fires.

De Luxe - Duct Design, IP65




Protection Class








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Wall design, IP65

To be used up to 10 m/s in
ventilation duct




Carbon Monoxide
Carbon Monoxide is a toxic gas produced by fires and isresponsible for a high proportion of fire fatalities.

Carbon Monoxide is odourless, colourless and tasteless making it almost impossible for people to be aware of its presence.

Exposure to relatively low levels of Carbon Monoxide for just one or two minutes can lead to permanent brain damage or death. Lower levels of Carbon Monoxide can cause disorientation and collapse during physical exertion thus hampering the ability of victims to escape.

For many years it has been known that Carbon Monoxide can be used as a means of providing early warning of fire, especially in slow developing and smouldering fires where Carbon Monoxide is produced significantly before before traditional detectable smoke (aerosols and particulates).

In these situations, using Carbon Monoxide fire detectors, detection occurs significantly earlier than ion-chamber or photo-electric smoke detectors operate.

Because Carbon Monoxide is a gas and more mobile than smoke, detector positioning relative to the seat of a fire is less critical, giving a higher likelihood of early detection.


Slow Smouldering Fires
A disproportionate number of fatalities are caused by fires that start slowly.

Fires, typically the result of discarded cigarettes account for only around 18% of all fires, but more than 42% of all deaths, mainly due to inhalation of poisonous gas.

By detecting these fires early the Carbon Monoxide fire detector ensures evacuation takes place before the effect of the poisonous gases take their toll and before the means of escape is blocked.

Typical applications include:

  • Hotels and apartment blocks

  • Hospitals and Rest Homes

  • Cruise liners

  • Schools, colleges and Universities

  • Office blocks and Shopping precincts

Flexible Detector Positioning
Smoke movement is constrained by convection currents created by the fire, whereas Carbon Monoxide being a gas is much more mobile than smoke and also moves by diffusion.

The advantage of the Carbon Monoxide fire detector is that it allows a high tolerance on where the detectors can be located.

Typical applications:

  • CO detectors will detect fire from outside the closed door of a cupboard, bedroom or cabin before spreading outside the room.
    This helps to detect fires whilst the means of escape is still clear.

  • CO detectors will continue to detect even if incorrectly mounted on a wall or under floor.

  • CO detectors will operate where thermal barriers inhibit smokemovement such as hot roof spaces in atria and metal roofed buildings. CO detectors will operate on beamed ceilings which present obstructions to possible smoke flow.

Flexible Detector Coverage:
Carbon Monoxide fills a space evenly and the CO fire detector is far less sensitive to the point where the fire started.

Thus, CO Detectors spaced in the same way as conventional detectors would provide far better protection and early warning in large areas where the potential seat of any fire is difficult to predict.

Applications include:

  • Warehouses and large covered areas

  • Large foyers, halls and reception areas

  • Cinemas, theatres, concert halls

  • Sports halls and large waiting areas

False Alarm Immunity
A key advantage of the CO fire detector is its resistance to the false alarms that affect smoke detectors because smoke detector false alarm sources do not generate CO.

Careful design of the detector thresholds means that false alarm sources which do contain CO are below the predefined threshold levels. If the CO levels from false alarm sources rise above this threshold it should be a cause for concern.

Typical applications include:

  • Hotel rooms and changing rooms where steam and water mistcan cause problems

  • Manufacturing facilities where large quantities of dust areproduced

  • Production facilities where chemical vapours cause traditional detectors to false alarm

  • Kitchens and restaurants where burnt toast and similar causes of false alarm are prevalent. In these circumstances the alarm threshold will only be reached once the toast is actually burning.

  • Farm buildings with high levels of dust and other airborne materials

Resistance to Dust and Dirt
The Carbon Monoxide fire detector FCO is less prone to reduced performance due to becoming dirty by the ingress of dust and dirt.

Even if the detection element becomes very dirty, the fact that CO is a gas means that it can penetrate dirt, provided that dirt has not produced an impervious coating.

Unsuitable Applications
Some fires generate little or no Carbon Monoxide and as such are not suitable for protection using the Carbon Monoxide fire detector.

Such fires include the early stages of electrical fires and burning cable where aspirating systems are more suitable.

Other non-carbon fires such as pure metal fires would not be detected by CO fire detectors.

CO fire detectors are also unsuitable for protection of areas where fast burning chemical fires represent the main hazard.

In this case ion-chamber or flame detectors are more suitable.

CO fire detectors will only operate in situations where combustion takes place, it will not detect smoke and fumes alone.

Designing Systems
Most detector fire tests which currently exist, such as those defined in EN54:Pt9 are intended for ionisation and optical detectors.

Thus, it is not possible to test CO fire detectors against existing standards around the world.

Nevertheless extensive tests with real fires show that the CO detector can detect most types of fires.

The nature of CO means that in principle less CO detectors may be needed to cover an area than traditional ionisation and optical detectors, however, fire detection systems using only CO detectors should be designed with the same coverage as traditional detectors.

When a certified fire alarm system is needed CO detectors should be regarded as additional detectors and be placed in high risk spaces according to above.

















Warning Siren for fire gas detectors


Combined warning siren and flash light for
fire gas detectors


ATEX Gas detectors are available for 2 explosion classes as follows:

Zone 1 is available with or without display.

Gas detectors for ATEX Zone 1 are located in a flameproof enclosure, EEx d

The shell is such that ignition and combustion within the shell of a potential explosive gas mixture is not propagated to the explosive mixture outside the enclosure and the enclosure can thus endure the resulting explosion pressure without damage.

In Zone 1, one can expect an explosive atmosphere to occur during normal operation but the presence of it is relatively short.

The equipment shall not be a source of ignition in normal operation or when an error occurs.

Gas detectors for ATEX Zone 2 are of the design Non-sparking EEx nA

EEx nA is a non-sparking piece equipment.

In Zone 2, you need not count with an explosive atmosphere to occur during normal operation, and if it should occur, which is probably rare it is of short duration.

The equipment shall not be a source of ignition during normal operation.











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EEx-d ATEX Protection Class


EEx-n ATEX Protection Class


E-mail: lars@fjellcom.se     

Phone: +46(0)31-287202

Mobile: +46(0)706-755561



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