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1、Hazardous Materials Incidentsby Chris Hawley,CHAPTER 6:Product Control and Air Monitoring,Chapter 6:Overview,IntroductionDefensive operationsAir monitoring for first respondersMeter methodologyOxygen monitorsCombustible gas indicatorsToxic gas monitorsOther detectorsCarbon monoxide incidentsSummary,
2、Defensive Operations,First responders should only use defensive methods to control releases of hazardous materials.Entering the hot zone to take“hands on”action is not allowed.You must have specific training to do other work.,Defensive Activities,AbsorptionDikingDammingDivertingRetention,DilutionVap
3、or dispersionVapor suppressionUse of remote shutoffs,Absorption,Material must be compatible.There is a variety of absorbing media available.Spilled material may still present risk(flammable).,Diking,Must be sufficient size to collect material.Minimum of three should be built.Start away from the spil
4、l and work toward the spill.Large spills require mechanical equipment.,Damming(1 of 6),There are two types.OverflowUnderflowAt least three should be built.Start away from spill and work toward spill.Use mechanical equipment for large spills.,Damming(2 of 6),Damming(3 of 6),Damming(4 of 6),Damming(5
5、of 6),Damming(6 of 6),Diverting,Commonly used to move a spill away from a risk areaCan use boomsFloating(absorbent)Solid(harbor boom),Retention,Retention is creating a hole to retain the spilled material.Large spills require mechanical equipment.Line hole with plastic or compatible material.,Dilutio
6、n,Solution to pollution is not always dilution.Non-soluble materials such as gasoline or fuelsSignificant amounts of water are needed to neutralize corrosives.May need several hundred thousand gallons for small spill,Vapor Dispersion,Creates water runoff issuesMay not eliminate vaporsJust moves them
7、Requires large quantities of water,Vapor Suppression,Foam usually usedMust be reapplied on a regular basisMust be compatible with the material,Remote Shutoffs,Tank trucks have emergency shutoffs.Most tank facilities have remote shutoffs.Responders should not endanger themselves to shut off valves.,A
8、ir Monitoring for the First Responder,Monitoring is essential to protect responders.Fire riskToxic riskCorrosive riskRadiation risk,Regulations,It is OSHAs intention that the worker(responder)be protected against workplace hazards.Air monitors are the only way to identify potential airborne hazards.
9、,Typical Configurations,Monitors usually have 3-5 functions.LEL sensorOxygen sensorCarbon monoxideHydrogen sulfideOther toxic material,Basic Principles of Air Monitoring&Detection Devices,Air monitorsPrimary protectionCan assist with determining the presence of risk materialsHelp provide a possible
10、identity of the material,Air Monitoring Strategies,Always use pH,LEL,O2,and PID as a minimum.Expand the use of other monitors as more information is available.The absence of readings does not mean that harmful materials are not present.Biological threat agents,Determination of Risk,CorrosivepH paper
11、OxygenOxygen sensorFireLEL or flammable gas detectorToxicPhotoionization detector(PID)RadioactiveRad pager and monitors,Meter Terminology,AccuracyAbility to produce findings close to actual quantity of gasPrecisionAbility to reproduce the same resultsFactors affecting precisionSensor technologyWeath
12、er,Accuracy and Precision,Known Amount=50 ppm Reading A&P P A N 1 50 30 50 39 2 51 29 40 49 3 49 31 50 21 4 50 29 51 93 5 51 30 40 31 6 50 29 49 74,Bump Test,Exposing monitor to known gases and allowing it to go into alarmAlso known as a field testIf insufficient response,conduct calibration,Time an
13、d Monitors,Lag timeReaction timeMonitors without a pump(diffusion)have a 15-30 second lag time.Monitors with a pump have a typical reaction time of 3-5 seconds.Add 1-2 seconds of lag time for each foot of extension hose.,Response Times,Photoionization=1-2 secondsLEL with pump=up to 7 secondsLEL w/o
14、pump=up to 30 secondsCO and H2S sensors=20 secondsIon mobility=up to 1 minutesRadiation monitors=up to 1 minutes,Correction Factors(Relative Response),A meter calibrated to methane is only accurate and precise for methane.The meter will respond to any other flammable gas.How well it responds is dete
15、rmined by the relative response.,Correction Factors for LEL Sensors,LEL sensors are typically calibrated for methane gas.The LEL of methane is 5%.When the meter reads 100%in a methane environment,there is 5%methane by volume in the room.,Example LEL Correction Factors,Propane=1.82Hexane=2Turpentine=
16、2.9Acetone=2.2Ammonia=0.8Phosphine=0.26,Correction Factors(1 of 4),Gas Meter A Meter B Meter CAcetone 0.9 1 0.45Hydrogen 0.5 0.6 0.8Methane 0.5 0.6 1Methanol 0.6 0.7 0.7Propane 0.8 0.9 0.55Meters calibrated with pentane to pentane,Correction Factors(2 of 4),Meter C has a CF of 0.45 for acetone.You e
17、nter an area and the meter reads 60%of the LEL.Take the meter reading(60%)times the CF(0.45)and the actual meter reading is 27%of the LEL for acetone.,Correction Factors(3 of 4),Meter A has a CF of 2.5 for the chemical EMUC.The reading on the meter(calibrated to pentane)is 45%of the LEL.The actual m
18、eter reading(AMR)is 112.5%and you are in the flammable range.,Correction Factors(4 of 4),Acetone is being used in a process.Correction factor for acetone is 2.2.In the building,the meter reads 5%of the LEL.Meter is calibrated to methane.Multiply 5%times 2.2=11%.The meter should be reading 11%.,pH De
19、tection,Used for corrosive materialsShould be one of the first items down range at a chemical releaseUse of multi-range pH paper most common method,Oxygen Monitors,Normal air contains 20.9%oxygen.Less than 19.5%oxygen is considered oxygen deficient.LEL readings are off.Greater than 23.5%oxygen is ox
20、ygen enriched.LEL readings are off.,Oxygen Sensor,Oxygen Sensor Limitations,Most oxygen sensors will only last 1-2 years.Chemicals with additional oxygen in their molecular structure hurt the sensors.Optimal temperature is between 32-120F.,Flammable Gas Indicators(FGIs),Also referred to as combustib
21、le gas sensors or LEL sensorsUsed to measure the lower explosive limit(LEL)of the calibration gasMajority calibrated to methane(natural gas),using pentane gas as the calibration standardWhen calibrated for methane,the sensor will read up to the LEL of methane.,Common Flammability Ranges,LEL UELMetha
22、ne 5%15%Propane 2.2%9.5%Acetone 2.6%12.8%Ammonia 16%25%Carbon monoxide 12.5%74%Ethylene oxide 3%100%Hydrogen sulfide 4.3%46%,Catalytic(Pellistor)Bead Structure,LEL Sensor Types(1 of 2),The basic principle of LEL sensors is that a stream of sampled air passes through the sensor housing causing a heat
23、 increase and conversely creating an electric charge,causing a reading on the instrument.,LEL Sensor Types(2 of 2),Catalytic bead Round piece of heated metal strung between a wireQuick reaction time and precise sensorMetal oxide sensor(MOS)A semiconductor in a sealed unit that has a Wheatstone bridg
24、e in it surrounded by coating of a metal oxide,Infrared Gas Detectors,Detectors use infrared light beams and a series of mirrors to detect flammable gases.Each different type of gas blocks a specific amount of light.Sensor does not require O2 to function.It cannot be poisoned by overexposure.Most un
25、its switch from%LEL to%by volume,when it reaches the LEL.,Flammable Gas Sensors,Toxic Gas Monitors,Toxic sensors are available in a variety of gases.Carbon monoxideHydrogen sulfideChlorineAmmoniaSulfur dioxideHydrogen chlorideHydrogen cyanideNitrogen dioxideMany others,Toxic Sensors,Most are electro
26、chemical sensors with electrodes(two or more)and chemical mixture sealed in a sensor housing.The gases pass over the sensor causing a chemical reaction within the sensor.Electrical charge is created which causes a readout to be displayed.,Electrochemical Toxic Sensor,Electrochemical SensorCross Sens
27、itivity,Photoionization Detectors(PID),Can detect a wide variety of gases in small amountsWill not indicate what materials are presentCan identify potential areas of concern and possible leaks or contaminationSensitivity from 0.1-2,000 PPMPart per billion unit available,PID Technology,Technology use
28、s an ultraviolet(UV)lamp to ionize any contaminants in the air.When contaminant particles become ionized,they carry an electrical charge which can be read.Gas that is sampled must have ionization potential(IP).,What Does a PID Measure?(1 of 2),What Does a PID Measure?(2 of 2),Organics:Aromatics Benz
29、eneEthyl benzeneTolueneXylene Ketones&aldehydes AcetoneMEKAcetaldehydeAmines&amides Diethyl amine Chlorinated hydrocarbons Trichloroethylene(TCE),Sulfur compounds MercaptansCarbon disulfideUnsaturated hydrocarbons Butadiene Isobutylene Alcohols Ethanol Saturated hydrocarbons ButaneOctaneInorganicsAm
30、monia Arsine,What PIDs Do Not Measure,RadiationAirNitrogenOxygenCarbon monoxideWater vaporToxicsCarbon monoxideHydrogen cyanideSulfur dioxide,Natural gasMethane Ethane AcidsHydrochloric acidHydrofluoric acidNitric acidOthersFreonsOzone,Example PID Correction Factors,Benzene=0.53Toluene=0.5Acetone=1.
31、1Nitrobenzene=1.9Diesel fuel=0.7Gasoline=1,Toluene CF with 10.6eV lamp is 0.5 If PID calibrated to isobutylene reads 100 ppm in a Toluene atmosphere,then the actual concentration is 50 ppm Toluene units.0.5 x 100 ppm=50 ppm,CF Example:Toluene,Problems with PIDs,The lamps are affected by dirt and dus
32、t and require cleaning.Higher levels of methane(natural gas,swamp gas,landfill gas)may suppress some readings.Extreme humidity plays a role in the reading.,Colorimetric Sampling Types,Standard tubesMultiple-test systemChip measurement system,Standard Colorimetric Systems,Glass tubes filled with a re
33、agent material change color when exposed to the intended gas.Air sample is drawn across the tube in a specific quantity.The tube changes color in the presence of the contaminant the tube is intended to detect.,Standard Tubes,Cover standard chemical familiesUsed to sample for identified and unidentif
34、ied materialsUsually available in various sensitivitiesSome bundled together in a manifold for simultaneous multiple sampling,Colorimetric Sampling,Chip system involves the use of bar-coded sampling chips.A sampling chip is inserted into a pump.The pump recognizes the chip in use and provides the co
35、rrect amount of sample through the reagent.A reflective measurement provides an accurate reading of the gas that may be present.,Carbon Monoxide(CO),Colorless,odorless,and tastelessOnly detectable through the use of air monitorsYour nose is not effective at all at detecting CO,no matter what odor ma
36、y be present.,CO Symptoms,Exposure can present flu-like symptoms,headache,nausea,dizziness,confusion,and irritability.Exposure to high levels can cause vomiting,chest pain,shortness of breath,loss of consciousness,brain damage,and death.Amounts in the 9 ppm range have killed unborn babies in the wom
37、b.,Exposure Levels,OSHA provides that less than an average of 50 ppm for an 8-hour period is acceptable.NIOSH states 35 ppm for 10 hours.ACGIH uses less than 25 ppm average for 8 hours.,Sources of CO,Furnaces(oil and gas)Hot water heaters(oil and gas)Fireplaces(wood,coal,and gas)Kerosene heaters(or
38、other fueled heaters)Gasoline engines running inside(basements or garages)Barbecue grills burning near the residence(garage or porch)Faulty flues or exhaust pipes,Summary,Defensive operationsAir monitoring for first respondersMeter methodologyOxygen monitorsCombustible gas indicatorsToxic gas monitorsOther detectorsCarbon monoxide incidents,
