Apollo Discovery 58000-300 Carbon Monoxide Detector

Summary

Discovery CO fire detectors contain a long-life electro-chemical carbon monoxide sensor which is tolerant of low levels of common vapours and household products. The sensing technology is fast, accurate and needs only very low power. The detection capabilities are enhanced by a rate-sensitive response. Fast rises in the carbon monoxide level are often associated with hot fires and the detector will respond earlier under these conditions. The analogue reply from the detector is rate limited to remove nuisance alarms resulting from short-term high levels caused by sources such as pipe smokers or gas flame ignition.

About Apollo Discovery

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

The  Discovery  CO  detector  has  five  operating  modes,  each  having  a  set combination  of  sensitivity  and  response  delay,  which  the  user  can  select  for  any  given  application.

Application

CO  detectors  do  not  detect  smoke  particles  or  heat  and  are  not  universal replacements for smoke detectors.

Apollo does not endorse the use of CO detectors  as  the  main  method  of  fire detection if:

• the protected area is an escape route.
• there is a requirement to detect overheating of electrical equipment or cables.
• the protected area is exposed to sources of CO such as vehicle exhausts, or to hydrogen or to high levels of alcohol vapour as emitted by some cleaning agents.
• there is a requirement to detect fires involving flammable liquids.

CO  fire  detectors  are  particularly  suitable  for  supplementing  smoke detection when there is:

• a deep seated smouldering fire risk.
• a risk of fire starting in an enclosed space.
• a likelihood of stratification taking place Carbon  monoxide  detectors  may  be  used  as  the  primary  fire  detector  in  areas  where  the  following conditions  exist.
• the main risk is smouldering fires.
• optical smoke detectors are deemed unsuitable (see ‘FALSE ALARMS’ below).
• the fire compartment is not greater than 50m2.

Typical  applications  include  hotel  bedrooms, halls of residence, sheltered accommodation and hospital wards.

Communication

Discovery uses a digital communications protocol which has been developed from the XP95 protocol but differs in that it allows communication in three different modes: (Normal, Read and Write) to allow a more extensive exchange of information and commands than previous analogue addressable ranges. In addition, Discovery can store data in non-volatile memory.

The Normal mode is identical to the XP95 protocol with the exception that the five additional analogue value bits in the XP95 protocol extension have been re-defined so that the fire control panel is able to distinguish between Discovery and XP95 devices.

The Read mode is used to check information stored in the non-volatile memory of each detector. It is accessed by using a simple extension to the Normal mode communication method from the fire control panel to the detector.

In Write mode the fire control panel is able to write information to the detector by extending the communication method in the same way as in Read mode. During Read or Write modes a detector can signal an alarm by means of the alarm flag and alarm address bits.

Discovery detectors are compatible with XP95 and Soteria. It should be noted, however, that Discovery features will not be available when Discovery is used with XP95 fire control panels. Fire control panels with drift compensation algorithms should disable the algorithms when communicating with Discovery.

For fire control panels running CoreProtocol, please refer to the fire control panel manufacturer’s operating instructions.

Maintenance & Service

The  electrochemical  cell  used  in  the  Discovery CO fire detector has a more limited  life  than  would  normally  be  expected  from  a  smoke  detector.  In  a  typical environment, the life of the cell is five years.

High  temperature  or  low  relative  humidity  can,  however,    reduce  the  life significantly. The limits given in the section  ‘TECHNICAL  DATA’  overleaf  should be carefully observed.

It  is  essential  that  systems  using  CO  fire  detectors  be  correctly  maintained  and  that  the  maintenance  schedule  include  functional  testing  of  the  CO  fire detectors.

CO  fire  detectors  will  not  respond  to  the  aerosol  testers  commonly  used  for  the  in-situ  testing  of  smoke  detectors.    The  Apollo  (No  Climb)  detector  tester  with  a  CO  test  gas  canister  can  be  used to test CO detectors.

If there is any doubt over the sensitivity of  a  Discovery  CO  fire  detector  it  should  be  returned  to  Apollo  for  servicing and calibration.

Detector siting

CO fire detectors should be sited using the recommendations from BS 5839-1 (or other applicable code).

In  the  development  of  a  fire,  smoke  and  CO  in  the  smoke  plume  is  spread  by  convection  to  a  fire  detector.  As  CO  is  a  gas,  it  further  spreads—like  smells—by  diffusion.  For  this  reason  CO  may  reach  a  detector  faster  than  smoke would. This potential advantage can be exploited when designing a fire protection  system  and  CO  detectors  may  be  used  for  supplementary  detection.    Equally,  the  opposite  effect  might  occur,  with  CO  moving  away  from a detector. 

The  behaviour  of  CO  is  therefore  unpredictable and  diffusion  should  not be relied on when designing a fire protection system.

False alarms

Carbon  monoxide  detectors  are  less  susceptible  than  smoke  detectors  to  false alarms from sources such as toast, steam,  cooking,  plumbing  work  and  hair spray.  They may therefore be used in some applications  in  which  smoke  detectors  would  be  usceptible  to  unwanted alarms. Conversely,  they  may  be  more  susceptible  than  smoke  detectors  to  false  alarms  from  fumes  containing  CO,  such  as  vehicle  exhausts,  open  fires and gas appliances.