Electro-Optical Fire Detection “A History” “World Leader in Electro-Optical Flame Detection...

Electro-OpticalFire Detection

“A History”“World Leader in Electro-Optical Flame Detection Technology”

Electro-Optical Fire DetectorsUsed in many Industries: Oil & Gas Exploration and Production Gas Transmission Automotive Semiconductor Aviation All Types of Manufacturing

Electro-Optical Fire DetectorsFires are detected by: Smell Sound Sight Heat

Electro-Optical Fire Detectors Different types of Fire Detection are: Smoke Detectors Heat Detectors Fusible Links Manual Call Points Linear Heat Detectors Electro-Optical Fire Detectors

Electro-Optical Fire DetectorsA Typical Fire requires: Source of Ignition Fuel Oxygen or an oxidant

Electro-Optical Fire DetectorsHydrocarbon Fires produce:

Water and Carbon DioxideHeat, (radiant infrared energy)

Typical combustion of a hydrocarbon

C3H8 + 5O2 = 3CO2 + 4H2O

(propane + oxygen = carbon dioxide + water)Incomplete combustion produces more Carbon Monoxide (CO)

Electro-Optical Fire DetectorsAdvantages of Electro-Optical Fire Detectors: Fast - detects fire in the early stages Area Coverage, not a point detector. Does not

have to be located directly at the fire event Detects electro-optical radiant energy from the

fire, (moves at the Speed of Light)

Electro-Optical Fire DetectorsElectro-Optical Energy includes: Infrared (IR) radiant energy Ultraviolet (UV) energy Visible Light (VIS)

Modern Electro-Optical Fire Detectors use all or a combination of these three

light spectra to detect a fire

Early Electro-Optical IR Fire Detectors

Early Fire Detectors use IR sensors developed during WWII

Designed to respond to near IR Some discrimination by using “flicker” amplifiers Could be fooled by non-fire events such as

shimmering water, vibrating manifolds, etc.

Early Electro-Optical UV Fire Detectors

Alternative technology using UV Tubes: Fast response Solar blind Could be fooled by non-fire events emitting short

band UV energy, such as lightning, quartz halogen lights and arc welding

Prone to physical damage due to tube design Expensive to maintain

Early Electro-Optical UV/IR Fire Detectors

UV Tubes combined with Narrow Band IR sensors:

IR sensors use Narrow Band Interference filters at 4.3 microns (CO2 “Spike”)

Some discrimination by using “flicker” amplifiers Attempted to reduce alarms to non-fire events by

using “AND” gates


Disadvantages: Will only respond to hydrocarbon fires CO2 “spike” is unpredictable Real world fires have incomplete combustion,

producing more CO, less CO2

Narrow Band IR sensor detects less than 1% of radiant IR energy from the fire

Old Analog technology

Modern Electro-OpticalMulti-Spectrum Fire Detectors

Developed from Military Missile Warning Systems Multi-sensor array using UV/WIR & VIS Solid state, digital electronics Real time, digital signal processing Fire Event data storage for postulating the cause

of a fire Responds to all types of fires


Modern UV Tubes have: Long glass to metal seal to prevent leakage and

damage from vibration Machine-made to ensure constant high quality Anode & Cathode made from steel to prevent

vibration


Wide Band Infrared (WIR) sensors: Respond to IR between 0.7 & 3.5 microns and detect

over 88% of a fire’s radiant energy Sees all types of fires Does not use optical interference filters Fast acting “Quantum” effect sensor, same as used in

military applications Easier to detect a small fire & track it as it grows and/or

gets hotter

Modern vs. Early Electro-Optical UV/IR Fire Detectors


4.3 micron IR.7 to 3.5 micron Wide Band IR

Wavelength in Microns

RelativeRadiantEmittance

.1 1.0 10

Blackbody Curve for a 2500K degree fire showing Wide Band IR Coveragecompared to the Narrow Band Spike at 4.3 microns

P e r c e n t a g e o f T o t a l R a d i a n t E n e r g y

W id e B a n d S p e c tr a l D e te c to r v s . N a r r o w B a n d 4 .3 m ic r o n IR

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T e m p e r a tu r e o f a F ir e in K d e g r e e s

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Wide Band Detector

Narrow Band 4.3 micron IR

Percentage of Total Radiant Energy - Wide Band v. Narrow Band


T otal R adiant Energy as a Function of a Fire's T emperature

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Temperature of Fire in K degrees

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Additional Features: Visible Sensors, (Blue & Yellow), reject non-fire

radiant energy events such as lightning, quartz halogen lights and arc-welding

Temperature Transducer and programmable software provide stable WIR sensor sensitivity baseline


Solid State Digital Design Digital signal processing of Real Time data by

sophisticated software algorithms Fire Event spectral data stored in non-volatile

memory Real Time data available through PC software Digital communications allows for addressable,

smart devices


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Electro-Optical Fire Detection “A History” “World Leader in Electro-Optical Flame Detection...

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