Discovery Marine Ionisation Smoke Detector

Product code: 58000-500MAR

58000-500MAR - Discovery Marine Ionisation Smoke Detector
The Discovery Marine Ionisation Smoke Detector uses a low-activity radioactive foil to detect fires by irradiating the air in the smoke chamber and causing a current flow. If smoke enters the chamber, the current flow is reduced leading to an alarm.
Full Details

Application Environments


Large vessels



Brand Information

Discovery Marine analogue addressable fire detectors are suitable for larger vessels. The high specification range has been developed to meet the requirements of sophisticated systems. Discovery gives you total reassurance in installations where it is necessary to adapt detection to different operating environments and where protection against unwanted alarms is paramount.

Brand Features

Approved for use in the marine environment Five response modes for environmental adaptation Day/night switching for increased flexibility Drift compensation for false alarm reduction User programmability for data XPERT card addressing for increased security


The Discovery Marine Ionisation Smoke 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 control panel when the device is polled.

Device Addressing

For details refer to datasheet PP2479.



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.

Additional Information

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.

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 Regulations 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: Environmental Agency Swift House Frimley Business Park Frimley GU16 7SQ Outside the UK, please contact the relevant national agency.

Environmental Characteristics

The Discovery Marine 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 (200ft/min) the change in analogue value will not exceed 5 counts. Continuous operation in wind speeds greater than 2m/s (400ft/min) is not recommended. However, wind speeds up to 10m/s (2000ft/min) can be tolerated for short periods and will not under any conditions increase the probability of false alarms.

Product Information

The Discovery Marine Ionisation Smoke Detector uses a low-activity radioactive foil to detect fires by irradiating the air in the smoke chamber 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 Remote test feature Rejection of transient signals

  • Bedrooms
  • Large vessels
  • Marine
  • Restaurants
Fire TypeFast burning, flaming fires
Warranty10 year
Analogue value nominal0
Analogue value (- tolerance)4
Analogue value23 +0/-4
Alarm level analogue value55
Chamber typeChevron
Protocol voltage (min)5V
Protocol voltage (max)9V
Protocol voltage5 to 9V peak to peak
Power-up surge current 1mA
Maximum power-up time10 seconds
Quiescent current300μA
Quiescent current tested at24V dc
Terminal functions +R+R Remote indicator positive connection
Terminal functions -R-R Remote indicator negative connection
PolarityL1 & L2 are polarity insensitive
Humidity (min)0% RH
Humidity (max)95% RH
Humidity Noteno condensation or icing
Humidity0% to 95% (no condensation or icing)
Operating temperature (min)-30°C
Operating temperature (max)70°C
Operating temperature-30 to 70°C
IP rating ValueIP44
Effect of wind speedLess than 20% change in sensitivity at speeds up to 10m/s
StandardsEN 54-7
  • BV
  • DNV.GL
  • ABS
  • KRS
  • ESC
  • LR
  • MED
  • LPCB
  • CPR
Materials housingPolycarbonate
Materials terminalsNickel plated stainless steel
Product length42mm
Product diameter100mm
Detection principleIonisation chamber.
Sensor configurationTwin compensating chambers using one single sided ionising radiation source.
How to Order

Apollo is dedicated to ensuring that our customer service is aligned with your expectations. This includes making our order, service and delivery process a seamless and hassle-free experience.

Full details of our service standards can be downloaded here.

Existing customers

Please email your order to us at: or tel: 023 9245 6530.

New customers

Please email your order to us at: or tel: 023 9244 2700.


Despite our best efforts, mistakes sometimes happen. Please contact us at: if you have any difficulties placing your order.

Please note…

Remember to quote your account number and purchase order number on any order correspondence.

All orders must be over £50.00 (excluding carriage). Any orders received under the minimum order value will be returned to sender for revision.