Why does the Advanced Multi-Criteria Fire Detector need four sensing elements?

Carbon monoxide (CO), infrared light, heat and smoke — each of which is represented by a separate sensor within the detector — are all found in real fires. Fires vary greatly by how they begin and what they consume, which affects how much CO, light, heat and smoke they generate. By relying on a combination of these sensing elements to make an intelligent decision, the Advanced Multi-Criteria Fire Detector can quickly tell the difference between a true fire and a nuisance condition.

The detector includes a CO sensor, so can the device be used as a CO detector?

“It does detect CO, but it’s an important distinction that this device is using that CO sensor as an element of the fire determination decision only,” said Alford. “While it has the same electro-chemical cell that we’re using in our other CO devices, in this case, it’s part of the alarm decision criteria. It is not a listed, CO life safety-type application.”

Don’t CO sensors have a limited life? If so, what happens when the CO sensor fails?

The CO cell has an expected lifespan of about six years. Be assured, however, that the detector’s onboard intelligence will know when the CO cell has discontinued and that the remaining three sensors will adjust and continue to operate without it.

Response: The infrared sensor quickly recognizes the condition and its reading spikes on the composite screen. Over time, the lamp generates some heat and the thermal sensor starts up. The detector, sensing a lack of particulate, recognizes that these levels are not indicative of a real fire, ignores the condition and allows the readings to drop off without triggering the alarm. In addition, the internal logic of the detector has been preprogrammed to recognize common conditions such as welding flash in order to enhance the immunity to nuisance alarms.

Result: Nuisance condition, no real fire

Response: As the current heats the wick, the wick slowly generates smoldering smoke, and the photoelectric sensor is the first element to sense trouble. As smoke builds in the chamber, the amount of CO output also increases, which the CO sensor begins to detect. The detector, seeing the troubling combination of the two sensing elements that are consistently delivering accelerated readings, doesn’t even bother to go into pre-alarm mode. The detector knows these readings are indicative of a real fire. It feeds the combination signal to the control panel, pushing the detector straight into full alarm mode.

Result: True fire condition worthy of full alarm