XP95 Heat Detector Standard

Brand Information

The XP95 range of analogue addressable fire detectors uses tried and trusted technology to give the best performance, and has unique features that benefit the installer and the end user. It is suitable for medium-to-large applications with simple installation requirements.

As it operates using digital communication, XP95 has a high immunity from corruption, and is, therefore, often preferred in a large system where life safety is critical. XP95 products are frequently used in commercial, industrial, financial, government, IT/telecoms and healthcare applications.

Electrical Considerations

The detectors are designed to be connected to a two wire loop circuit carrying both data and a 17V to 28V dc supply.

The detectors are connected to the incoming and outgoing supply via terminals L1 and L2 in the mounting base. A remote LED indicator requiring not more than 4mA at 5V may be connected between +R and -R terminals. An earth connection terminal is also provided.

When a device is energised the ASIC regulates the flow of power and controls the data processing. The thermistor provides an output over normal operating ranges that is proportional to the external air temperature. This voltage output is processed in the A/D converter and stored by the communications ASIC. It is transmitted to control equipment when the device is interrogated. When a count of 55 is exceeded the alarm flag is initiated and the device address is added to the data stream every 32 polling

Operating Principles

The XP95 heat detectors have a common profile with ionisation and optical smoke detectors but have a low air flow resistance case made of self-extinguishing white polycarbonate.

The devices monitor heat by using a single thermistor network which provides a voltage output proportional to the external air temperature.

The standard heat detectors, 55000-400 and 55000-420, respond to increasing air temperature in such a way that they are classified as an A2S device. Both devices will give 55 counts at 55°C.

A high temperature CS heat detector, 55000-401, which can be installed in a typical ambient temperature of 55°C is available. This device will give 55 counts at 90°C.

Application

The choice of detector from the XP95 range follows the well established principles of system design. That is, the optimum detector type will depend on the type of fire risk and fire load, and the type of environment in which the detector is sited.

For general use, smoke detectors are recommended since these give the highest level of protection. Smoke detectors from the XP95 range may be ionisation, optical or multisensor types. It is generally accepted that ionisation types have a high sensitivity to flaming fires whereas optical detectors have high sensitivity to smouldering fires. As a result of this, ionisation types are widely used for property protection, and optical types for life protection. These general principles still apply to XP95 detectors although the availability of a multisensor in the range offers more choice to the system designer.