Alarmline Linear Heat Detection
Linear Heat DetectionTemperature Related Risk Protection
• Data supplied by fire insurance companies indicates that most industrial fires are caused by
- Friction heat & sparks
- Overheating of equipment
- Spontaneous combustion
- Oil & oil fired equipment.
What is Linear Heat Detection?
• Continuous heat detector in the form of a cable
- Alarmline Analogue: averaging heat detector
- Alarmline Digital: fixed temperature heat detector
What is Linear Heat Detection?
• Cable-type Sensor– “Point of Risk” Detection Method
• Detects Heat From Fire– Last stage of fire
• Typically used where smoke, flame or other detectors are not an option
Stages of Fire
Analogue LHD Cable
• Definition:
- Multi-conductor cable containing insulators whose resistance varies proportionately to changes in temperature
- Re-settable provided temperature does not exceed burn-off point of PVC coating
- Alarm level adjusted via controller.
- Allows testing without damaging cable
Alarmline Analogue LHD Cables
• High resistance - standard applications
• Nylon extruded - chemical resistance
• Bronze braided - increased mechanical protection over standard high resistance cable
• Stainless Steel braided over nylonextruded cable - offshore applications.
AlarmLine Construction
• 4 conductor 0-46 mm dia copper cable– Two conductors for heat sensing– Two enameled conductors for continuity– Twisted at 30 turns per foot to cancel potentially high
voltage inductance
How Does AlarmLine Work?
• Sensor cable has negative
temperature coefficient
insulation
• Temperature increase
exponentially lowers cable
resistance PROTECTIVE INSULATIONHIGH TEMPERATURE PVC
SENSOR CONDUCTORWIRE
NEGATIVE TEMPERATURECOEFFICIENT (NTC)
Alarmline LHD 4 Controller
Alarmline LHD 4 Controller
- Alarm level adjusted via moveable link
- Open circuit and closed circuit fault monitoring
- Fire and fault output to conventional fire alarm panels
- Volt-free relay option for analogue addressable fire alarm panels
- Eurocard 19” rack option.
- Allows quick system adjustments without cable or hardware change.
AlarmlineNomogram- Select the sensor cable
length being used (D)100m
- Mark the Max Temperature where an alarm must not be given (B) 45 degrees
- Draw a line from point on “D” through point on “B” to the switch setting line (A). This is the switch setting that will not give a false alarm at the Max ambient temperature.
AlarmlineNomogram-In the event of a hot spot
occuring, it can be shown how hot this would need to be to give an alarm for a given length
- 10 metre length = 83 degrees
- 1 metre length =120 degrees.
Intrinsic Safety Barriers
• For Class 1, Div 1, Groups A, B, C, D classified areas
• Each IS Barrier handles two conductors
• Use two IS Barriers per sensor cable
• Use enclosure to insure grounding
Intrinsic Safety Barriers
Safe area Hazardous area
Inte
rface
Mod
ule
Junction BoxIS Barrier
Reference: AlarmLine Manual
Up to 255devices
PSD
Typical Intelligent Application
Addressable RxTx Loop~1000 Metres26 Ohm, 0.25uF
AlarmLine Sensor
AI AOCPD
LHD LHD LHD
AO AO AO
24v PSU 24ov
Standard 4 core cable
Hazard
2 WireInterfaceModule
Typical Conventional Application
AlarmLine Sensor
KiddeControlPanel
Standard 2 core cable
Max (1,000 m)
JunctionBox
Alarmline LHD - Advantages
• Flexibility
- Mechanically
- Electrically
• Durability
- Wide range of casings / braiding within both analogue and digital cables.
- Operating range -65º to +200º C
- Unaffected by operating environment.
Digital LHD Cable
• Definition:
- A cable which contains an insulator which melts at a specific temperature
- Switch output provided once alarm temperature is reached
- Not re-settable.
Alarmline Digital LHD Cables
• Polythene braid 70º C (158º F )
• Nylon over sheath 70º C (158º F )
• Polythene braid 90º C (194º F )
• Nylon over sheath 90º C (194º F)
• PVC 105º C (221º F )
• PVC 174º C (346º F )
• Fluoropolymer 227º C (440º F )
Internal
Internal / External
Internal
Internal / External
Internal / External Protected
Internal / External Protected
Internal / External
LHS Digital Cable Construction
Alarmline Digital Control Units
• Firebeta conventional panel with optional extinguishant release module
• Any other conventional fire alarm panel and/or extinguishant release module (retrofit).
• Any analogue addressable control system
Addressable vs. Hard-WiredZONE A ZONE B ZONE C
MPMP
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nti
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MP
To
Ad
dit
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al Z
on
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LHS
Hard-Wired System
Addressable vs. Hard-Wired
ZONE A ZONE B ZONE C
MPMP
To
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ga
Sy
stem
MP
To
Ad
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AILHS
RxTxLine
Addressable System
Analogue & Digital Comparison
Alarmline Analogue Alarmline DigitalAnalogue DigitalRecoverable Non-recoverableOpen & Short Circuit Fault Detection Open Circuit Fault DetectionMin operating temperature -65 C Min Operating Temperature -65 CMin Alarm Temperature 35 C Min Alarm Temperature 61 CMax Alarm Temperture 105 C Max Alarm Temperture 238 CMax Re-coverable Alarm Tempurature 150 C N/AMax Length 1000m Max Length 10,000m
°
°°
°
°°
°
International Approvals
Alarmline (Analogue) Alarmline (Digital)
UK power generation- 5117 P 11- EPA 022/215
Factory Mutual- OB 9A2.AY- OR 5A4.AY
Chinese Fire Officers- MAAL 96652
Chinese Power Generation- NSTCFEPQ (Appr) 92005
German VdS (1995)
UK power Generation- EPA 019-021- EPA 206/220
Factory Mutual- OD 6A9.AY- 300 5155- 300 3834
Chinese Fire Officers- MAAL 96652- 300 8312- 300 8933
Alarmline - The Competition
• Digital systems
- Protectowire (USA)
• Analogue systems
- Patol Firesense (UK)
• Fibre optic systems (UK)
- York Sensors
- Siemens.