Electro-Optical Fire Detection “A History”
-
Upload
cullen-hutchinson -
Category
Documents
-
view
63 -
download
0
description
Transcript of Electro-Optical Fire Detection “A History”
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 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 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
Early Electro-Optical UV/IR Fire Detectors
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 Electro-OpticalMulti-Spectrum Fire Detectors
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
Modern Electro-OpticalMulti-Spectrum Fire Detectors
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 Electro-OpticalMulti-Spectrum 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
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00
100.00
10
20
112
0
12
20
13
20
14
20
15
20
16
20
17
20
18
20
19
20
20
20
21
20
22
20
23
20
24
20
25
20
26
20
27
20
28
20
29
20
30
20
31
20
32
20
33
20
34
20
35
20
36
20
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
Per
cen
tag
e o
f To
tal R
adia
nt
En
erg
y
Wide Band Detector
Narrow Band 4.3 micron IR
Percentage of Total Radiant Energy - Wide Band v. Narrow Band
Modern Electro-OpticalMulti-Spectrum Fire Detectors
T otal R adiant Energy as a Function of a Fire's T emperature
1.00
10.00
100.00
1000.00
1020
112
0
12
20
13
20
14
20
15
20
16
20
17
20
18
20
19
20
20
20
21
20
22
20
23
20
24
20
25
20
26
20
27
20
28
20
29
20
30
20
31
20
32
20
33
20
34
20
35
20
36
20
Temperature of Fire in K degrees
Tota
l Rad
ian
t E
ner
gy
(wat
ts/c
m2)
Modern Electro-OpticalMulti-Spectrum Fire Detectors
Times More Wide Band Radiant Energyvs. Narrow Band 4.3 micron IR
0
50
100
150
200
250
300
1020
1140
1260
1380
1500
1620
1740
1860
1980
2100
2220
2340
2460
2580
2700
2820
2940
3060
3180
3300
3420
3540
Temperature of a Fire in K degrees
Tim
es M
ore
Wid
e B
and
En
erg
y
Modern Electro-OpticalMulti-Spectrum Fire Detectors
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
Modern Electro-OpticalMulti-Spectrum Fire Detectors
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
Modern Electro-OpticalMulti-Spectrum Fire Detectors