Discovery Ionisation Smoke Detector

Brand Information

Discovery® is a range of high-specification, analogue addressable fire detectors and alarm devices. Discovery detectors offer effective false alarm management by a combination of EN 54 approved operating modes and sophisticated algorithms. Drift compensation further reduces the likelihood of false alarms caused by a build-up of dust in the sensing chamber. In addition to the familiar smoke and heat detectors, the Discovery range features two multisensor detectors. One is an optical/heat multisensor which can be used to protect against many types of fire risk. The other is a carbon monoxide/heat multisensor which protects against both smouldering fires and those generating heat.

Operation

he Discovery Ionisation Detector uses the same outer case as the optical smoke detector and is distinguished by the red indicator LEDs. Inside the case is a printed circuit board which has the ionisation chamber mounted on one side and the signal processing and communications electronics on the other. The ionisation chamber consists of a reference chamber contained inside a smoke chamber.The outer smoke chamber has inlet apertures fitted with insect resistant mesh. At the junction between reference and smoke chambers, the sensing electrode converts variations in chamber current into voltage changes. When smoke particles enter the ionisation chamber, ions become attached to them with the result that the current flowing through the chamber decreases. This effect is greater in the smoke chamber than in the reference chamber, and the imbalance causes the sensing electrode to become more positive. The analogue voltage at the sensor electrode is converted to a digital format which is processed to provide an analogue value for transmission to the fire control panel when the device is polled.

Communication

Discovery, XP95 & CoreProtocol compatible

Maintenance & Service

Detectors should be maintained according to BS 5839-1 or other locally applicable code. Test equipment can be ordered from Apollo for testing smoke and heat detectors. Detectors should not be cleaned in the field except for careful removal of exterior dirt with a damp cloth. For cleaning and recalibration detectors should be returned to Apollo Fire Detectors or to the local distributor.

EMC Directive 2014/30/EU

The product complies with the essential requirements of the EMC Directive 2014/30/EU, provided that it is used as described.

Construction products regulation 305/2011

The product complies with the essential requirements of the Construction Products Regulation 305/2011.

Safety Note

In the United Kingdom, ionisation smoke detectors are subject to the requirements of the Environmental Permitting Regulations 2010 and to the Ionising Radiations egulations 1999 made under the provisions of the Health and Safety at Work Act 1974. The detectors, independently tested by the Health Protection Agency (HPA), conform to all the requirements specified in the 'Recommendations for ionisation smoke detectors in implementation of radiation standards’ published by the Nuclear Energy Agency of the Organisation for Economic Co-operation and Development (OECD) 1977.There is no limit to the number of ionisation smoke detectors which may be installed in any fire protection system. Storage regulations depend on local standards and legislation, but, in the UK, up to 500 detectors may be stored in any premises, although there are stipulations on storage facilities if more than 100 ionisation detectors are stored in one building. At the end of their recommended working life of ten years, ionisation smoke detectors should be returned to Apollo for safe disposal. Guidance on storage and handling can be given by Apollo Fire Detectors and full details can be requested from: UK Environment Agency Old Crest House Alice Holt Lodge Farnham Surrey GU10 4LH Outside the UK, please contact the relevant national agency

Environmental Characteristics

The Discovery Ionisation Detector, like all ionisation detectors, has some sensitivity to air movement (wind). The extent to which the analogue value will change depends on the wind speed and on the orientation of the detector relative to the wind direction. Relatively small changes in wind direction can cause significant changes in analogue value. For wind speeds up to 1m/s the change in analogue value will not exceed 5 counts. Continuous operation in wind speeds greater than 2m/s is not recommended. However, wind speeds up to 10m/s can be tolerated for short periods and will not under any conditions increase the probability of false alarms. Ionisation smoke detectors are supplied in individual packing with a red lid serving as a dust cover which can be left in place after fitting to prevent ingress of dust and dirt until commissioning of the system takes place. At this point the covers must be removed.

Product Information

The Discovery Ionisation SmokeDetector uses a low activity radioactive foil to detect fires by irradiating the air in the smoke chambers and causing a current flow. If smoke enters the chamber, the current flow is reduced leading to an alarm.

Key Features

Responds well to fast-burning, flaming fires Designed to operate in a variety of environments Resilient to dust Five response modes Remote test feature