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Published byWilfred Thornton Modified over 9 years ago
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1 Hazard Detection Equipment Critical Life Safety
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2 Flame Detectors - Past
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3 Flame Detectors - Present X2200 UV X3301 MSIR X3302 MSIR(H2) X5200 UVIR X9800 IR
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4 Flame Detection - The Reasons Actual loss/catastrophe Fire department/AHJ requirement Code requirement Recognition of risk/preventative measure
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5 Flame Detection - The Means
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6 The Basis of Optical Flame Detection
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7 Electro-Magnetic Spectrum
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8 Gasoline Flame Spectral Signature
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9 Optical Flame Detection - Advantages Rapid detection capability Detects from a distance Highly resistant to environmental conditions (wind, cold, rain) Self-check capability
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10 Optical Flame Detection - Limitations Useless on smoldering fires Requires “line of sight” Technically sophisticated Higher Cost
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11 The Customer Expectation Detect Fire Only Fire Anytime there is fire Anywhere there is fire Or annunciate a fault condition
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12 Optical Flame Detection - The Strategy Utilize features of flame emissions
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13 Consecutive gates UV Spectral Selection to Minimize Interference Terrestrial Solar Spectrum
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14 Consecutive gates IR Spectral Selection Pick a Bright Spot
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15 Consecutive gates IR Spectral Selection Minimize Solar Interference Mid-IR Flame Emission Band Terrestrial Solar Spectrum
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16 Consecutive gates IR Spectral Selection Minimize Solar Interference
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17 Optical Flame Detection The Methods UV Detection IR Detection UV/IR Detection Multi-IR Detection
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18 Optical Flame Detection The False Alarm Challenges UV - emitted by nearly all fires but... electrical discharge arc-welding, lightning, motors are also strong UV emitters. IR - fire has strong emissions but… so do hot objects. UVIR - improved false alarm resistance but… it is vulnerable to combinations.
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19 Consecutive gates Blackbody IR Emissions
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20 Fire “flickers” randomly. Non-flame IR –Tends to be static or –“flickers” with a regular period. No Fire Alarm Fire Alarm! Advanced Technology IR Temporal Features
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21 Consecutive gates Advanced Technology UV Temporal Features Fire produces continuous UV Many electrical discharges are momentary
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22 Consecutive gates Multi-IR Method
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23 Multi-IR - excellent false alarm resistance and flame detection but.. it is complex & hard to do well. –Fuels vary in IR emissions –Black body sources desensitize –IR filter band-pass “blue-shifts” off-axis Multi-IR Flame Detection The Challenges
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24 Fuel Type Emissions
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25 CO2 Emission Peak Patented wavelength criteria Wavelength X3301 4 microns5 microns
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26 From The Detectors Point Of View
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27 How Flame Detectors See the World Conically-shaped area extending from detector optics Center axis provides highest sensitivity Detection range depends on detector & fuel type Optimum protection leaves no gaps in COV layout
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28 Consecutive gates MIR Challenges Filter “Blueshift” RE F A
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29 Interference Desensitization FLAME SUN FLAME + SUN
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