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STRATOS HSSD, Technical Manual

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STRATOS HSSD Technical Manual Download Page 33

World Patents Pending  ©AirSense Technology Ltd. 1999

ISSUE 2.4

Page 33

T E C H N I C A L

.

M A N U A L

room resulting in an inverse exponential change of pollution within the room, as

previously explained.  Providing that the external pollution level is not exorbitantly

high, some trial and error adjustments around the setting of the “Reference back off

time delay (mins)” in function 8 will achieve good results.  Very good matching can be

obtained under most normal conditions and will be a very great improvement on using

an unmodified reference signal.

0

Time

D

Smoke Density

0

Modified Reference Signal

Pollution at Source

Time

D . K

Reference Signal

0

CALCULATED POLLUTION ADDED

Time

Density required for alarm

Smoke Density

0

Pollution at Outlet

Time

D (1-E)

Smoke Density

Fig. 6.

Summary of Contents for HSSD

Page 1: ...Technical Manual Issue 2 4 Quality system cert no 404 Assessed to ISO 9001 afp 813...

Page 2: ...22 Stratos detector referencing 32 Local and remote referencing 34 Terminal board jumper link connections 35 Apollo Series 90 Interface 35 Autronica BNX 3 36 Thorn AM521 37 Remote control software 38...

Page 3: ...ng when no fire occurs The problem of unwanted alarms is a major one for instance frequent call outs to deal with non existent fires can lead to a tendency for alarms to be ignored Unwanted alarms fro...

Page 4: ...is greater than a given amount it is assumed that this is due to a fire Unfortunately for general use the unwanted alarm conditions still occur even if not so readily as with the simple heat detector...

Page 5: ...accurate laboratory measurements The different principles of Optical detection are described below Asimplifiedadaptationofthelaboratorymeterdescribedaboveimmediatelybecomes interesting as a smoke dete...

Page 6: ...Scattering Detectors Most fires will generate light of one sort or another infrared light being the most prominent Extremely sensitive infrared cameras are available which could be used in an alarm sy...

Page 7: ...systems etc It normally indicates the signals it is receiving from the detectors by means of lamps but the use of special PC programmes to display more comprehensive information is becoming more comm...

Page 8: ...of these devices in an effort to reduce unwanted alarms Point detectors are usually set to give an alarm at a smoke density corresponding to between 2 and 4 obscuration per metre Although they are cap...

Page 9: ...ction of smoke at a very much earlier stage in the development of a fire and as a consequence this may reduce damage levels considerably This saving of time more than offsets the delay due to the tran...

Page 10: ...would detract from the appeal of the building Other important applications are found where their specific properties include museums art galleries warehouses telephoneexchanges penalestablishments du...

Page 11: ...h in a different manner One uses a Xenon flash bulb as its light source whilst two take advantage of the very reliable semiconductor laser in this application Mean Time Between Failure can be in exces...

Page 12: ...since either a very large particle or a very small particle will increase the count by one unit It is assumed that dust particles are larger than smoke particles and the particle counter can give a s...

Page 13: ...ending into very short wavelengths well below the visible spectrum The intensity of scattered light at these wavelengths is high but is only of use when a light sensor is used which is sensitive to th...

Page 14: ...ge this situation it is difficult to envisage that the effort required would be practical or cost effective when the alternative of a laser exists The semiconductor laser is at present the subject of...

Page 15: ...he background levels will vary according to the time of day and the particular activities in the protected area The requirement then is to find what are the appropriate levels to set the pre alarm and...

Page 16: ...ming a continual statistical analysis of the background pollution and continuously calculating the level at which a given probability of a signal occurring is acceptably low Such measurements and calc...

Page 17: ...period or historical period that is represented by the histogram it also sets the time which the histogram requires to become truly representative of the distribution The method for doing this is an...

Page 18: ...ferent levels of use These are usually day time and night time but for the sake of generality may be referred to as normal time and quiet time The problem of maintaining correct alarm trigger levels i...

Page 19: ...tos provides a very adequate solution For reasons of power economy and reliability a low power air impeller is required to draw air down the sampling pipes This leads to the problem that the bore of t...

Page 20: ...ings in the histogram give a warning that the filter is becoming fully loaded This progressive reduction in signal spread causes the detector to compensate thereby automatically maintain ing the sensi...

Page 21: ...illuminated continuously for the whole duration of the delay time in order to be signalled unless the signal has risen very rapidly to beyond full scale If this is the case then the time delays may b...

Page 22: ...ith the use of a reference detector and shows how special features of the STRATOS detector may be used in providing a solution When a room is to be protected with smoke detectors there are two prime c...

Page 23: ...easurements must track one another to within 1 Another is that the signal from a detector does not carry on rising indefinitely it reaches a ceiling where in spite of increasing pollution the output s...

Page 24: ...urs instantaneously Although this will not be realised in any practical case it will be closely approached An area is taken which either has filtered air fed into it from outside or has air being extr...

Page 25: ...me towards X and in theory never actually reach it This effect is illustrated in Figs 3 4 Plant Room A A Filter Air Inlet 0 Pollution at Inlet as seen by reference detector Transport delay through duc...

Page 26: ...ted in Fig 1 may have an effect in reducing the amount of pollution in the incoming air Its efficiency is shown as E in Figs 3 4 If it is 100 efficient then E 1 and there is no apparent need for refer...

Page 27: ...Density 0 CALCULATED POLLUTION ADDED Time Density required for alarm Smoke Density D 1 E It is a common error made by many people that the time scale for pollution increasing in a room is different fr...

Page 28: ...building via an air filter which is 30 efficient at removing pollution and travels 25 metres down an air duct 2m2 area to the room A reference detector is placed after the air filter to provide refere...

Page 29: ...ficant compared to them and they illustrate very clearly a very large problem It can be argued that a step change in the external pollution will never occur and represents the worst case This is true...

Page 30: ...m but all other data remained the same then the filling time constant T would be 12 minutes instead of 120 minutes The alarm level would be exceeded for 42 7 minutes instead of 427 minutes The same w...

Page 31: ...Outlet Inlet Outlet Inlet Outlet Inlet Outlet Inlet Plant Room The ability to vary the air conditioning in one of the rooms can effect the flow into all the rooms Air ducts will become long with the...

Page 32: ...t is to modify the reference signal such that modified sig representing signal representing signal representing pollution entering the area pollution leaving the area pollution added from within the a...

Page 33: ...error adjustments around the setting of the Reference back off time delay mins in function 8 will achieve good results Very good matching can be obtained under most normal conditions and will be a ver...

Page 34: ...L A V E D E T E C T O R TM Master 1 Local y Remote n Slave loop Reference Slave H I G H S E N S I T I V I T Y S M O K E D E T E C T O R TM ISOLATE TEST RESET S M O K E D E N S I T Y AUX FIRE PRE ALAR...

Page 35: ...minal board to configure the line connections for different interface boards These links need to be connected to bring the line connections from the interface board out to the back box Given below are...

Page 36: ...chnology Ltd 1999 ISSUE 2 4 Page 36 T E C H N I C A L M A N U A L Autronica BNX 3 Master 3 Slaves Master 2 Slaves Master 1 Slave Single Master Line in ve Line 1 Line out ve Line connections Line 2 Lin...

Page 37: ...Technology Ltd 1999 ISSUE 2 4 Page 37 T E C H N I C A L M A N U A L Thorn AM521 Master 3 Slaves Master 2 Slaves Master 1 Slave Single Master Line in ve Line 1 Line in ve Line connections Line 2 Line o...

Page 38: ...nd date The time and date must be set correctly for the event log and chart recorder log The time is set in 24 hour format HH MM and the date set in DD MM YY Typing an invalid time or date causes an e...

Page 39: ...enu is not possible if the flow is currently being set up During flow set up the aspirator is cycled through it s different speeds and a note is taken of the flow readings The flow limits are set eith...

Page 40: ...This screen graphically displays the operation of the ClassiFire function The detector to display can be selected by pressing F1 F4 4 Chart recorder log Stratos has the facility of storing a chart rec...

Page 41: ...error rate Interference on the slave loop can cause corruption of the data passed between a master and it s slaves This is compensated for by the Stratos master but too much interference could indicat...

Page 42: ...te Alarm level Slave 2 byte Detector level Slave 2 byte Alarm level Master byte Detector level Master byte Alarm level Slave 2 byte Detector level Slave 2 byte The format of the chart recorder data as...

Page 43: ...r see following list for types byte number of detectors or 0x00 byte 0xff word 0x01 word 0xff word Fast histogram data 32 words obscuration 100 or 0x00 word detector number or 0x00 byte period DAY NIG...

Page 44: ...ow Fault LED flag 0 off 1 high 2 low 254 flash n bytes Head fault LED flag 0 off 1 on 254 flash n bytes Isolated LED flag 0 off 1 on 254 flash n bytes Separator LED flag 0 off 1 on 254 flash n bytes B...

Page 45: ...mum string length is 30 characters Exceeding these limits will result in strings being lost or ignored In addition the time between the first character and the terminating CR must be less than 33 mS S...

Page 46: ...a multiple detector system all detectors have their readings stored The maximum duration is divided by the number of detectors n Changing the sample rate will clear the data in the chart log NB Setti...

Page 47: ...he extremely high air flow characteristics of the Stratos Aspirator PipeCAD is incompatible with other aspirating smoke detection system types The pipe design software for the Stratos system requires...

Page 48: ...64 Gebouw C3 2741 EZ Waddinxveen Nederland Telephone 31 1825 635696 Facsimile 31 1825 635691 e mail conrad airsense nl AirSense Oy Ukonkellonkatu 19 Karhula 48800 Finland Tel 358 9 400 652131 Fax 358...

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