Apollo XPander Combined CS Heat Detector & Sounder (XPA-CB-14018-APO)

The XPander Combined Sounder and Detector is wireless and designed to provide one point detection and notification.

Operation

Heat detectors have an open-web casing which allows air to flow freely across a thermistor which measures the air temperature every 2 seconds. A microprocessor stores the temperatures and compares them with pre-set values to determine whether a fixed upper limit–the alarm level–has been reached.

In the case of rate-of-rise detectors the microprocessor uses algorithms to determine how fast the temperature is increasing.

Static heat detectors respond only when a fixed temperature has been reached. Rate-of-rise detectors have a fixed upper limit but they also measure the rate of increase in temperature.

A fire might thus be detected at an earlier stage than with a static detector so that a rate-of-rise detector is to be preferred to a static heat detector unless sharp increases in temperature are part of the normal environment in the area protected by the heat detector.

XPander sounders are ceiling mounted and use a bi-directional monitored radio platform to communicate. They feature 4 tone pairs, including the Apollo tone, and a self test which causes a fault signal to be sent if the sounders fail to operate.

Device Addressing

The address of a sounder or a combined sounder/visual indicator is set at the commissioning stage by means of a DIL switch. The sounder address is plus one of the address set. The sounders and combined sounder/visual indicators are powered by two packs of batteries, one with three “AA” and one with three “C” size alkaline batteries which provide a working life of typically 3-5 years. The five-year life includes weekly tests and a half-hour sounding in a fire condition.

Radio Communications

Fire detection systems are life-saving systems and must, therefore, be highly reliable in use. Radio communications have been developed to a point where high reliability can be guaranteed, provided that the rules for the design of radio systems and installation are carefully observed.

Radio communication technology in the detection has matured to the point where a standard has been drawn up as part of the EN54 family of standards for components of a fire detection system. The standard is EN54 Part 25.

Frequency

The frequency used by XPander is 868MHz which is the harmonised European radio frequency.

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