METHODOLOGY FOR SMOKE DETECTION IN GRAIN AND HATCHERY APPLICATIONS Dave Boyack

Contents VESDA ASD in harsh environments How to Discussion-Grain applications

Risks Business continuity Deep seated fires Conveyor equipment High temperatures High air velocity Normal detection systems unsuitable Continue

Conventional detection is too late Smoke and fire damage occurs at stage 2

VESDA solves a problem Xtralis was contacted by major international agri-business company. They had a history of fires occurring in their grain hammer mills, undetected until operators smelled the fire. Brushes that clean heads are burning, not flour. Wanted automatic fire detection. Test burns were conducted on a live site, in their process. 9

Grain Hammer Mill Application/Test conditions Thirty (30) hammer mills exhausted into one bag house Bag house - 10 ft (3 m) diameter bag house. - 65 Southern Filter Media filter socks. - 100% Polyester. - Heat set, single one side. - 12 ounces per sq yard (400 g/m 2 ). - ~99.99% PM2.5 removal efficiency. Sample points inside 30 in (0.77m) diameter exhaust. 2,832 ft/min (863 m/min) air flow through exhaust duct. Natural brush bristles burned using hot plate. Smoke introduced into 1 of 30 hammer mills. Highly diluted smoke carried to exhaust duct on clean side of filter sock bag house. We detected 100% of test fires and an actual fire. Competitor s ASD failed to see any of the fires. Burned brush Sample probe installed across exhaust Smoke generator

Dust Collector VEU used on clean side of filter bag house. VEU detects incipient events. Can prevent explosions. Ember detectors used on dirty side. Embers are ignition sources. Embers have to pass by the ember detector. Clean side no contamination VEU Process side high levels of contamination Ability to detect on clean side of filter bag house increases detector life and reduces operational service and maintenance 11

Actual Fire Detected 1 Fire Detected 3 Decreased air flow reduces dilution, increases background 2 Decrease in VEU air flow caused when process flow shut off to investigate fire 13

RBCT Dry Bulk Terminal 14

Advantages of ASD 15 Filtration Active sampling Wide range of sensitivity settings..asd does not have to be high sensitivity Total coverage may not be required..consider where the smoke will go.

Advantages of ASD 16 Flexibility in pipe design Inverting detector Countersinking holes Selection of materials Horizontal and vertical sampling

Best practices: Backflushing 17 Backflushing is used to: Purge contaminants from the sampling pipes Reduce cleaning cycle Extend internal filter life Reduce maintenance costs. Low air pressure required As many backflush cycles as required can be accommodated ASD placed into standby during backflush cycle (typically 30 seconds) Can be manual or automated

Backflushing: 18

Best practices: External filters 19 External filters: Remove contaminants from sampled air before it enters the detector Extend the life of the internal filter/s Reduce maintenance costs Are not limited to dust. Are easily maintained Should not attenuate smoke

Best practices: External filters 20

External filter: Chemical 21

Reference Sampling Reference Detector Air Sampling External Source (Reference Zone) VESDA Zone 5 (Reference Zone) Sampling Pipes sampling Zone 2 VESDAnet Sampling Pipes sampling Zone 1 VESDA Zone 2 (Reference reading is subtracted) VESDAnet VESDA Zone 1 (Reference reading is subtracted) Sampling Pipes sampling Zone 3 Sampling Pipes sampling Zone 4 VESDA Zone 3 (Reference reading is subtracted) VESDA Zone 4 (Reference reading is subtracted)

How to: 30 https://www.xtralis.com/misc/industrialhowto.html

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