dust explosions silo hopper fires

Dust Explosions Dust Explosions

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Dust Explosions Dust Explosions

Approx 50 explosion are reported each year

Resulting in hundreds of deaths

Yet are the least recognized Industrial hazard

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Dust ExplosionsDust Explosions

February 1999, Massachusetts February 1999, Massachusetts Iron Iron foundry foundry A small, primary A small, primary Resin dust Resin dust explosion within the ductworkexplosion within the ductwork,,fuelled a secondary explosionfuelled a secondary explosion,,powerful enough to lift the roof powerful enough to lift the roof and cause wall failures. and cause wall failures. 33 people were killed, and people were killed, and 99 were were injured.injured.

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January 2003 January 2003 –– North CarolinaNorth Carolina--Pharmaceutical plant that Pharmaceutical plant that manufactures rubber drug manufactures rubber drug delivery componentsdelivery componentsA A fire and a series of explosions fire and a series of explosions destroyed the plant with minor destroyed the plant with minor damage surrounding area damage surrounding area 66 people killed and 3people killed and 38 8 injured injured including 2 firefightersincluding 2 firefighters

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February 2003February 2003 -- Kentucky Kentucky insulation manufacturing plant. insulation manufacturing plant. Primary Primary blast was blast was ignited ignited by a by a small fire small fire while cleaningwhile cleaningA deadly cascade of dust A deadly cascade of dust explosions followed throughout explosions followed throughout the plant. the plant. 77 people were killed and 37 people were killed and 37 injured injured

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February 200February 2008 8 –– GeorgiaGeorgiaImperial Sugar refineryImperial Sugar refineryDust Explosions ripped through Dust Explosions ripped through the plant destroying 2 silos and the plant destroying 2 silos and 1 building 1 building Seven days to extinguishSeven days to extinguish1313 people were killed and people were killed and 117 7 injuredinjured

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Dust ExplosionsDust ExplosionsUS Chemical Safety Board (US Chemical Safety Board (CSBCSB) identified 281 ) identified 281 dust fires & explosions between 1980 & 2005 dust fires & explosions between 1980 & 2005 In the USA alone, Dust explosions in the last 25 In the USA alone, Dust explosions in the last 25 yrs killed 119 workers and injured 718 others.yrs killed 119 workers and injured 718 others.Wood & Coal Dust explosions are by far the Wood & Coal Dust explosions are by far the leading sources for Explosionsleading sources for ExplosionsDust Collection/ Hopper systems are the leading Dust Collection/ Hopper systems are the leading equipment type for Explosionsequipment type for Explosions

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Can occur anywhere combustible dust is Can occur anywhere combustible dust is producedproducedCan be almost any organic material Can be almost any organic material An Explosion be initiated by any energy An Explosion be initiated by any energy source.source.Sparks, Friction, Open Flames, HeatSparks, Friction, Open Flames, HeatUsually results in secondary explosionsUsually results in secondary explosions

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Dust Explosion PentagonDust Explosion Pentagon

Dust Explosion Pentagon

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Rules for dust explosions.Rules for dust explosions.Must be combustible.Must be combustible.Dust cloud must be confined.Dust cloud must be confined.Capable of becoming airborne.Capable of becoming airborne.Size & distribution = flame spread.Size & distribution = flame spread.Explosive range 50g/m3 to 23kg/m3Explosive range 50g/m3 to 23kg/m3

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Dust / Powders that CAN ExplodeDust / Powders that CAN ExplodeNatural Organic materials (grains, linen, Natural Organic materials (grains, linen, sugar, coal, peat)sugar, coal, peat)Synthetic Organic materials (pesticides, Synthetic Organic materials (pesticides, plastics, resins)plastics, resins)Metals ( aluminum, zinc, iron)Metals ( aluminum, zinc, iron)Any Unstable OxideAny Unstable Oxide

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Dust / Powders that WILL NOT ExplodeDust / Powders that WILL NOT ExplodeSilicates, SulphatesSilicates, SulphatesNitrates,Carbonates,PhosphatesNitrates,Carbonates,PhosphatesCement, Sand, limestoneCement, Sand, limestoneAny Stable OxideAny Stable Oxide

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Glass breaks at 50 kpa (7 psi.)Glass breaks at 50 kpa (7 psi.)Wood frame at 56Wood frame at 56--70 kpa (870 kpa (8--10 psi.)10 psi.)Reinforced concrete 70Reinforced concrete 70--85 kpa (1085 kpa (10--12 psi.)12 psi.)

FORCE FROM DUST EXPLOSIONS FORCE FROM DUST EXPLOSIONS CAN EXCEED 700 kpa or 100 PSICAN EXCEED 700 kpa or 100 PSI

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Hopper FiresHopper Fires

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Hopper FiresHopper FiresCharacteristics.Characteristics.

Funnel Shaped Funnel Shaped On legs or stiltsOn legs or stiltsLoaded from the Loaded from the toptopUnloads from Unloads from the bottom.the bottom.

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Hopper FiresHopper Fires-- Incident CommandIncident Command

Be aware of the Be aware of the potential for potential for explosions explosions Initial Defensive Initial Defensive StrategyStrategyEstablish large Establish large ““Hot ZoneHot Zone””Evacuate civilians Evacuate civilians to safe distanceto safe distance

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Hopper FiresHopper Fires-- Incident CommandIncident CommandProtect exposures Protect exposures including the including the building the hopper building the hopper servesservesEstablish water Establish water supply sufficient supply sufficient volume for worst volume for worst case scenariocase scenarioLock out / Tag Out Lock out / Tag Out each power sourceeach power source

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Hopper FiresHopper Fires-- Incident CommandIncident CommandI/C Size UpI/C Size Up

Built in Suppression Built in Suppression systemssystemsExplosion venting Explosion venting systems / access systems / access doorsdoorsLoading / Unloading Loading / Unloading systemssystemsType & level of Type & level of product product Expert adviceExpert advice

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Hopper FiresHopper Fires-- Incident CommandIncident CommandI/C Action PlanI/C Action Plan

Utilize built in Utilize built in Suppression systemsSuppression systemsActivation may trigger Activation may trigger an explosionan explosionNo personnel on /near No personnel on /near the hopper when the the hopper when the suppression system is suppression system is activatedactivatedOperate system till Operate system till fire is extinguishedfire is extinguished

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Hopper FiresHopper Fires-- Incident CommandIncident CommandI/C Action PlanI/C Action PlanAccess doors Access doors -- OpenOpen

Probability of Dust Explosion Probability of Dust Explosion is reduced is reduced Access Doors could be used Access Doors could be used to position Aerial Ladder for to position Aerial Ladder for low pressure fog stream low pressure fog stream Raise Aerial to similar height Raise Aerial to similar height and set pump pressure for and set pump pressure for low pressure fog stream low pressure fog stream Use minimum number of Use minimum number of personnelpersonnel

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Hopper FiresHopper Fires-- Incident CommandIncident CommandI/C Action PlanI/C Action PlanAccess doors Access doors -- ClosedClosed

Opening Access doors is an Opening Access doors is an extremely Hazardous extremely Hazardous OperationOperationLimit personnel when Limit personnel when opening access doors or opening access doors or explosion relief panelsexplosion relief panelsUse least dangerous method Use least dangerous method possible possible ( tie a rope to handle and use elevated ( tie a rope to handle and use elevated device to unlatch door)device to unlatch door)

FLOOD HOPPERFLOOD HOPPER ( low press fog)( low press fog)

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Hopper FiresHopper Fires-- Incident CommandIncident CommandI/C Action PlanI/C Action PlanUnloading a HopperUnloading a Hopper

Unloading kept to a Unloading kept to a minimum with light water minimum with light water fog played on product exit fog played on product exit When hopper gates are When hopper gates are closed wet down the area to closed wet down the area to reduce the possibility of dust reduce the possibility of dust in the airin the airFirefighters should Firefighters should commence carefully commence carefully removing the product from removing the product from the area the area Repeat until the Hopper is Repeat until the Hopper is emptyempty

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Hopper FiresHopper Fires-- Incident CommandIncident CommandSafetySafety

If the risk of Explosion is too If the risk of Explosion is too great great –– Defensive positionDefensive positionMaintain an awareness of Maintain an awareness of the Hopper weight due to the Hopper weight due to water added during water added during firefighting operations firefighting operations Minimize any actions that Minimize any actions that disturb the dust in the disturb the dust in the HopperHopperTreat all Fires in Dust Treat all Fires in Dust Collectors / Hoppers as Collectors / Hoppers as Potential Severe Explosion Potential Severe Explosion HazardHazard

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Hopper FiresHopper Fires-- Incident CommandIncident Command

Dec 21 2005 Salisbury Maryland

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Silo Fires / ExplosionsSilo Fires / Explosions

Significant Fires and Explosions.Significant Fires and Explosions.AlabamaAlabamaCaliforniaCaliforniaOhioOhioNew YorkNew YorkNova Scotia Nova Scotia –– Halifax 2003Halifax 2003Georgia Georgia –– Imperial Sugar Imperial Sugar –– 13 Killed13 KilledOntario Ontario –– 2006 Perth, 2008 Woodbridge2006 Perth, 2008 Woodbridge

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Fire Fighter Serious Injuries / Deaths.Fire Fighter Serious Injuries / Deaths.Georgia 1993 Georgia 1993 –– 2 FF killed2 FF killedTexas 2000 Texas 2000 –– 1 FF Killed1 FF KilledNorth Carolina 2001 North Carolina 2001 –– 3 FF injured3 FF injuredNebraska 2002 Nebraska 2002 –– 13 FF injured ( shredded 13 FF injured ( shredded Rubber Silo)Rubber Silo)Missouri 2005 Missouri 2005 –– 2 FF killed2 FF killedOhio ( Twice) Ohio ( Twice) –– 1985 & 2003 1985 & 2003 –– 5 FF killed 5 FF killed

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Firefighter Injuries / DeathsFirefighter Injuries / Deaths

August 27August 27thth 1985 Marshville Ohio.1985 Marshville Ohio.Three Firefighters killed, 4 injured.Three Firefighters killed, 4 injured.Concrete Oxygen limiting silo.Concrete Oxygen limiting silo.50 minutes into fire operations.50 minutes into fire operations.10,000 liters of water applied.10,000 liters of water applied.

SILO EXPLODEDSILO EXPLODED

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Firefighter Injuries/ DeathsFirefighter Injuries/ Deaths

October 1October 1stst 2003 New Knoxville Ohio.2003 New Knoxville Ohio.Two FFTwo FF’’s Killed s Killed –– 8 injured8 injuredConcrete Modified Oxygen Limiting Silo.Concrete Modified Oxygen Limiting Silo.2.5 hours into firefighting operations.2.5 hours into firefighting operations.30,000 liters applied. 30,000 liters applied.

SILO EXPLODEDSILO EXPLODED

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Firefighter Injuries / DeathsFirefighter Injuries / DeathsDecember 21December 21stst 1997 Iredell 1997 Iredell

County N.C.County N.C.Three Firefighters severely Three Firefighters severely injured.injured.Metal Oxygen limiting silo. Metal Oxygen limiting silo. 2.5 hours into firefighting 2.5 hours into firefighting operations.operations.40,000 liters of water applied.40,000 liters of water applied.SILO EXPLODEDSILO EXPLODED

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Silo Classifications.Silo Classifications.Conventional.Conventional.Oxygen limiting.Oxygen limiting.Modified Oxygen Modified Oxygen Limiting.Limiting.

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Conventional Silos

Characteristics.Most common type.Reinforced Concrete or Concrete staves wrapped in steel bands.Domed roof ( metal ).Top unloading.Unloading chute.

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Conventional SiloConventional Silo


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Conventional SiloConventional Silo


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Oxygen Limiting SilosOxygen Limiting SilosCharacteristics.Characteristics.

Reinforced concrete, Reinforced concrete, or metal or metal (blue, green)(blue, green)

Design limits amount Design limits amount ofof oxygen in silo.oxygen in silo.Flatter roof than a Flatter roof than a conventional silo.conventional silo.No exterior openings No exterior openings or unloading chutes.or unloading chutes.Unloads from the Unloads from the bottom.bottom.

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Oxygen Limiting SilosOxygen Limiting Silos

Characteristics.Characteristics.Reinforced concrete, Reinforced concrete, metal metal ( blue, green )( blue, green )Design limits amount of Design limits amount of oxygen in silo.oxygen in silo.Flatter roof than a Flatter roof than a conventional silo.conventional silo.No exterior openings or No exterior openings or unloading chutes.unloading chutes.Unloads from the Unloads from the bottom.bottom.

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Top unloader to Top unloader to center chutecenter chuteNo exterior No exterior openings or openings or unloading chutes.unloading chutes.Unloads from the Unloads from the bottom.bottom.

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Flatter roof.Flatter roof.Venting valves.Venting valves.Airtight Hatch Airtight Hatch Cover.Cover.Hatches will be Hatches will be sealed with sealed with gaskets / clampsgaskets / clamps..

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Oxygen Limiting SiloOxygen Limiting Silo

Satin Finish Flooring200 Fenmar Dr

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Modified Oxygen Limiting SiloModified Oxygen Limiting SiloModified from Conventional Modified from Conventional to Oxygen Limiting to Oxygen Limiting

Bottom unloading.Bottom unloading.No external chute.No external chute.

Oxygen Limiting to Oxygen Limiting to Conventional.Conventional.

Top / bottom unloading. Top / bottom unloading. Top unloading Top unloading --external external unloading chute and hatches.unloading chute and hatches.

Always Treat as Always Treat as Oxygen LimitingOxygen Limiting

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Modified Oxygen Limiting SiloModified Oxygen Limiting Silo

Satin Finish Satin Finish FlooringFlooring8 Oak St.8 Oak St.

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Modified Oxygen Limiting SiloModified Oxygen Limiting Silo

Satin Finish Satin Finish FlooringFlooring8 Oak St..8 Oak St..Modified from Modified from Oxygen Limiting Oxygen Limiting to Conventional to Conventional SiloSilo

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FirefightingFirefighting-- SilosSilos

Personal Protection Equipment.Personal Protection Equipment.S.C.B.A.: smoke, gasses, oxygen deficiency.S.C.B.A.: smoke, gasses, oxygen deficiency.I.M.S.: large hot zone, Safety Officer, R.I.T..I.M.S.: large hot zone, Safety Officer, R.I.T..Fall arresting devices: heights.Fall arresting devices: heights.Confined space: avoid entering.Confined space: avoid entering.

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FirefightingFirefighting--SilosSilosDisconnect power Disconnect power sources: lock / tag sources: lock / tag out.out.Protect exposures: Protect exposures: embers, adjacent embers, adjacent buildings.buildings.Extent / location of Extent / location of fire.fire.

Amount of heat, smoke Amount of heat, smoke and flames.and flames.Thermal imaging Thermal imaging camera.camera.Drier concrete shades.Drier concrete shades.

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FirefightingFirefighting--Conventional SilosConventional Silos

Generally slow Generally slow burning, deep burning, deep seated fires.seated fires.Contain the FireContain the FireUsually near the Usually near the unloading doors. unloading doors. Normally within the Normally within the top 10 feet of the top 10 feet of the silage. silage.

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FirefightingFirefighting--Conventional SilosConventional SilosKnock down surface burning Knock down surface burning first.first.DonDon’’t flood: will not withstand t flood: will not withstand lateral pressure.lateral pressure.Do not apply water to Do not apply water to exterior of silo.exterior of silo.Minimal chance of structural Minimal chance of structural collapse from heatcollapse from heatExtinguish pockets with Extinguish pockets with straight streams, piercing straight streams, piercing applicators.applicators.

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FirefightingFirefighting--Conventional SiloConventional Silo

Early stagesEarly stagesExtinguish surface Extinguish surface fire.fire.Locate hotspots.Locate hotspots.Inject water. Inject water. directly into hotspotdirectly into hotspotOpen hatches above Open hatches above to allow for venting.to allow for venting.

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FirefightingFirefighting--Conventional SilosConventional Silos

Advanced Fires.Advanced Fires.Leave to burn themselves out.Leave to burn themselves out.Product is unsalvageable.Product is unsalvageable.Fires in concrete silos do little harm.Fires in concrete silos do little harm.Protect exposures to prevent spread of fire.Protect exposures to prevent spread of fire.Unload silo to ensure complete Unload silo to ensure complete extinguishmentextinguishment

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FirefightingFirefighting--Conventional SiloConventional Silo

Do Not flood the silo.Do Not flood the silo.Water follows path of Water follows path of least resistance.least resistance.Water will run down Water will run down the walls, passing the walls, passing most of the hot most of the hot silage.silage.Inject water directly Inject water directly into hot spots.into hot spots.

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FirefightingFirefighting--Oxygen Limiting SiloOxygen Limiting SiloAnticipate an Anticipate an Explosion. Explosion. Establish a large Establish a large Explosion Zone.Explosion Zone.Water supply for a Water supply for a worst case scenario.worst case scenario.Do nothing to Do nothing to increase the level of increase the level of oxygen in the silo.oxygen in the silo.DO NOT USE WATER / DO NOT USE WATER / FOAM. FOAM.

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FirefightingFirefighting--Oxygen Limiting SiloOxygen Limiting Silo

If Silo is quiet If Silo is quiet and no smoke / and no smoke / steam. steam. Seal unloading Seal unloading doors if possible.doors if possible.close topclose top--hatch. hatch. Do not latch top Do not latch top hatch cover.hatch cover.

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FirefightingFirefighting--Oxygen Limiting SiloOxygen Limiting Silo

May require May require injection of Liquid injection of Liquid Nitrogen or Carbon Nitrogen or Carbon Dioxide. Dioxide. (trained professionals).(trained professionals).

Seal silo for up to Seal silo for up to three weeks.three weeks.

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FirefightingFirefighting--Modified Oxygen Modified Oxygen Limiting SiloLimiting Silo

Always treat a Always treat a ModifiedModified Oxygen Oxygen Limiting Silo as Limiting Silo as an Oxygen an Oxygen Limiting Silo.Limiting Silo.

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FirefightingFirefighting-- SilosSilos

PrePre--plan silos in your Command.plan silos in your Command.Type, age, and contents.Type, age, and contents.Fire suppression systems (sprinklers).Fire suppression systems (sprinklers).Information site personnel, Experts.Information site personnel, Experts.Have time to review and confirm preHave time to review and confirm pre--plans.plans.

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Silo GasesSilo Gases

Carbon Monoxide (CO).Carbon Monoxide (CO).Carbon Dioxide (CO2).Carbon Dioxide (CO2).Nitrogen Dioxide (NO2) Nitrogen Dioxide (NO2) –– Silo gas.Silo gas.

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It is essential that the incident commander It is essential that the incident commander determines the type of silo, whether the determines the type of silo, whether the Silo is a Conventional, Oxygen Limiting, or Silo is a Conventional, Oxygen Limiting, or modified oxygen limiting. modified oxygen limiting. NEVER proceed with extinguishing NEVER proceed with extinguishing procedures until you are certain the type procedures until you are certain the type of Siloof SiloThe contents of a Silo are never worth The contents of a Silo are never worth putting a firefighterputting a firefighter’’s life at risks life at risk

dust explosions silo hopper fires

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