Whilst the IR2 and IR3 types of Flame Detector can still work with contamination (from dust or dirt for example) on the sensor window, their working range and sensitivity can be reduced.

Cleaning the Flame Detector, if it is high off the ground, may be difficult and or expensive, this is where the Flame Detector Air Purge kit comes in.

By connecting an Air Line or Compressed Air Cylinder to the Air Purge hose, the pressurized air can be used to clean the Flame Detector’s sensor window. This can be done as and when required, depending of the levels of contamination on the site to keep the Flame Detector working at its maximum capability.

Whilst both IR2 & IR3 Flame Detectors can still function, the UV/IR2 is a different matter. Because Ultra Violet cannot pass through various types of contamination, like dust and dirt, this means that the UV/IR2 Flame Detector may not pick up a fire if the sensor window is dirty, this makes regular cleaning essential if the UV/IR2 is to work at its maximum capability.

The Fireray 3000 ExD is an End to End Beam detector which is designed to be used in a Hazardous Area (Zone 1 and Zone 2).

Zone 1 is defined as: ‘An area where ignitable concentrations of flammable Gasses, Vapours or Liquids are likely to exist under normal operating conditions’.

Zone 2 is defined as: ‘An area where ignitable concentrations of flammable Gasses, Vapours or Liquids are not likely to exist under normal operating conditions’.

The Fireray 3000 ExD Beam is an ExD version of the existing Fireray 3000 Beam which uses proven End to End technology and is capable of covering distances from 10M to 100M. End to End Beams have a Transmitter at one end, sending out an Infra-Red signal which is detected and analysed by the Receiver and System Controller. If appropriate signal loss is detected the Fireray 3000 will signal a Fire or Fault.

The Transmitter (TX) and Receiver (RX) are mounted in ExD housings and can be placed in the Hazardous Area (with the appropriate ExD glands to route the cables to the Non-Hazardous Area), the System Controller MUST be placed OUTSIDE the Hazardous Area.

The Fireray 3000 ExD can be aligned by one person as there are LEDs in the RX to indicate the signal strength during commissioning, but if these are not visible, a second person can monitor the signal strength at the System Controller during the commissioning. Two pairs of Beams can be supported by one System Controller and there is a Fire and Fault relay for each pair of Beams.

The Fireray 3000 ExD has Light Cancelling Technology (LCT), this means it will not false alarm if the Sun (or another strong Infra-Red source) shines directly onto the RX.

As with all beam smoke detectors the following is good practice when installing the Fireray 3000 ExD.

1. The ExD housings are heavy, so it is very important to mount them to a solid structure which will not move. If either the TX or RX moves (due to poor installation) once it has been aligned, this can cause false alarms and or faults to occur.
2. There must be a clear line of sight (no obstructions) down the whole of the path of the Beam’s run. If anything can move into and break the Beam’s path, this must be taken into account when installing the F3000 ExD.
3. The Fireray 3000 ExD must be suitable for the environment it is protecting. A site with lots of airborne contamination and or extreme temperature swings may not be a suitable site.

Many industries have the potential to be affected by dust explosions. The processing of foodstuffs, natural fibres, metals and even electronic components can all generate dusts capable of exploding if they are mixed with air in the right proportions inside a vessel or duct. The same processing equipment can also generate sparks due to dry bearings, faulty machinery or a build-up of static charge, especially if recommended maintenance regimes are not followed.

When it comes to dust explosions, there is a lot to be said for adopting the approach that prevention is better than the cure. Although systems exist that can effectively extinguish a dust explosion after it starts to develop, FFE advocates systems that detect the occurrence of sparks and then take steps to prevent them initiating an explosion in the first place. The options include diverting the process flow away from the spark hazard, injecting an agent (such as water or carbon dioxide) to extinguish the sparks, or simply shutting down the process immediately. The choice depends on the preferred approach identified by your risk assessment.

Central to any explosion prevention system is the rapid and reliable detection of sparks. Devices like FFE’s Talentum® Spark use infrared radiation detectors to record the presence of a spark very rapidly, even before it has reached a sufficiently high temperature to visibly glow. They are designed to respond to flickering signals to avoid false alarms from continuous infrared sources such as sunlight or artificial lighting. These devices are well-suited for fitting to ducts in your system close to potential sources of sparks, and their signals can easily be fed back to a control panel and used to activate the appropriate response. They are therefore ideal for retrofitting to an existing process to strengthen your protection against dust explosions, perhaps following an audit from a health and safety consultant or an insurance agent’s appraisal.

If you manage a process that handles and moves dust, it is well worth taking a fresh look at the risks of dust explosions. They can be devastating to people and property, and can constitute such a significant hazard that countermeasures are often justifiable even if the probability of an explosion occurring is relatively low. The good news is that these measures need not be excessively complicated to be effective. A spark detection system provides the ever-watchful eye needed to stop sparks in their tracks and keep your process operating safely.

Handling dusty materials in industrial processes is a tricky business, raising numerous safety and housekeeping concerns that need to be handled by plant managers. One aspect of dusts that can easily be overlooked goes far beyond being a mere nuisance – it could jeopardise the existence of your factory and the lives of your workers. It’s the threat of dust explosions.

Many common materials react with the oxygen in air, which is the basis of combustion. Some, such as iron and aluminium, form a layer of oxide on their surfaces at ambient temperatures. Pieces of natural fibres such as wood or cotton will burn if heated strongly, but only fairly slowly. However, materials that can react with oxygen will do so increasingly quickly as they become more and more finely divided, because the surface area of the material that is exposed to the air sharply increases.

In most cases, this effect reaches its climax when the material exists as a fine dust dispersed in a stream of air within a confined space such as a vessel or duct. At this point, a relatively weak ignition source such as a spark can, under the right conditions, cause the material to burn extremely rapidly. This releases heat to the surrounding gases in the air, which then expand and cause an enormous increase in pressure – and a dust explosion occurs.

Dust explosions can be highly destructive and often occur completely without warning. They can almost instantly increase the pressure inside a chamber by eight or nine times normal atmospheric pressure, far exceeding the resistance of most vessels. In addition to the shockwave from the explosion, operators are then at risk from fire and the shrapnel from fragmented vessel walls. Furthermore, the explosion fireball can travel along interconnecting pipes and cause an even more violent explosion in another vessel downstream.

Image source: US Chemical Safety and Hazard Investigation Board