11 Air Monitoring And Sampling Flashcards
What instrument can detect, identify, and measure all hazmat
Not one device can measure all
When can an operations level responder do air monitoring and sampling
With proper training, under direction of hazmat tech or allied pro, or with written sop
Air monitoring can be an important as peck of mitigation, assisting in the following tasks
ID hazards
Determine appropriate ppe, tools, equipment
Determine perimeter and scope of incident
Check effectiveness of defensive ops
Ensure efficacy of Decon
Detecting leaks
Monitor Decon runoff
Instrument reaction time
Elapsed time from air moving into device to reading provided
Monitoring must be done at different levels in the air because
Gasses vary in specific gravity, some lighter or heavier causing sinking or rising
Dose
Quantity of chem ingested or absorbed into body
Concentration
Quantity of chem inhaled, percentage of chem mixed in air or water
Parts per million measures concentration in what mediums
Water or air
Exposure limits may be expressed in terms such as
Threshold limit value TLV
short term exposure limit STEL
threshold limit values ceiling TLV-C
Permissible exposure limit PEL
Concentrations that are high enough to cause serious injury or death are expressed in terms of
IDLH immediately dangerous to life or health
The lower the exposure limit of a chemical…
The potentially more harmful it is
You should be safe from any toxic effects from an exposure if
Your exposure level never exceeds the lowest number indicated. I
What should be monitored for
O2, radiation, corrosives, flammables, oxidizers, explosives, toxics, exothermics
Many detection devices require what to function properly
Sufficient oxygen
It is important to document the detection finding, such as,
Time of reading
Level (height) the reading was taken at
Reading obtained
Instrument used
Issues to consider when selecting monitoring equipment
Mission- rescue or control Suspected hazards involved Portability and user friendliness Instrument reaction time Sensitivity and selectivity- how well and to what degree Calibration Training
Improperly maintained or calibrated instruments are a safety hazard because
Readings may be inaccurate or misleading
Devices should be calibrated, maintained and Deconed according to
Manufacturers directions
All devices and instruments have their strengths and
Limitations
PH should always be one of the first hazards monitored unless specific hazard is known because
A large percentage of hazmat incidents involve corrosives and can damage detection instruments and ppe
PH
Measurement of hydrogen ions in solution indicating strength.
Concentration
Reflects amount of acid or base mixed with water. Higher percentage, higher damage. 95 percent formic acid solution is 95 acid 5 water.
Each who,e ph value below 7 is how many more times acidic than the next highest value
10 times. 4 is 19 times more than 5 and 100 times more than 6
For each whole number above 7 how much more basic is it
10 times more than the previous. 10 is 10 times more than 9, 100 more than 8
Primary methods of determining ph
Ph meters and paper
Ph 0-3
Strong acids
Ph 7
Neutral, water
Ph 10-14
Strong base
Limitations of ph paper
Close proximity or contact with hazmat
Can’t detect concentration
Difficulty reading paper if contaminated or damaged by material being read
Most ph paper requires to be wetted with
Distiller water
Before using ph meter what must be done
Calibrated and prove rinsed with distiller water before and after use
Most reactive of all chem compounds
Fluorine, compounds with it are called fluorides
Hydrogen fluoride requires what level suit protection
Level a, extremely corrosive toxic and mildly reactive.
Fluoride test papers
Detects fluoride ions and gaseous hydrogen fluoride
Pink red paper turns yellow white.
Oxygen deficient atmosphere is be,ow what percent
19.5 percent
Oxygen enriched atmosphere is above what percent
23.5 percent
Normal air contains what gasses and percentage
20.9% O2
78.1% nitrogen
1% other or trace gasses
Any oxygen reading below 20.9 indicates
The presence of other contaminants displacing the oxygen.
Contaminants will displace oxygen proportionately, a 1% drop on oxygen is equivalent to
50,000 ppm of something else in the air.
Oxygen sensors degrade quickly, even when
Not in use, or in contact with oxidizers and co2
O2 meter limitations
Corrosives cause rapid failure
Strong oxidizers cause high readings, chlorine, bromine, fluorine
Sensors deteriorate over time and need replacing
Humidity, temp and atmospheric pressure affect monitors
Cgi
Combustible gas indicator
Aka lel meters
Cgi measures gas in three ways
Percent of lel
Ppm
Percent of gas by volume of air
Typically lel meters will alarm at what
10 percent the lel
Common calibration gases for cgi
Methane, pentane, propane, hexane
Conversion factors
Aka response curves, aka multipliers
Conversions from calibrated gas to gas being metered
When using cgi the atmosphere must have sufficient oxygen to render accurate reading because
A combustion chamber is used and oxygen variances will effect rare of combustion and reading.
Factors influencing cgi readings
Catalyst poisons Concentrations exceeding 100% lel Concentrations exceeding uel Chlorinated hydrocarbons Oxyacetylene mixtures
Limitations of cgi
Sensitive to battery life, loses responsiveness with power
Corrosive gas damage sensors
Meter response slow in cold weather
Cell phones, high voltage, other emf, interfere with readings
Oxygen sensitivity,
Toxicity is also a factor of exposure over
Time
Median lethal dose
Ld50
Lethal concentration
Minimum concentration of inhaled substance to cause death, 1-4 hrs
Typical four gas meter will detect
Lel, oxygen, co, hydrogen sulfide
Photoionization detectors
PIDs use uv lamp to ionize samples of gas to detect low concentrations of organic or inorganic vapors, can’t determine specific substance but indicate a contaminant is present.
Colorimetric tubes
Reagent in tube changes color when exposed to specific chemical or family.
Problems with colorimetric tubes
Determine presence of material but not unidentified products. Error rate of 25-35%
Curie
Ci
English system for radioactivity measurement. Indicating number of radioactive decays or disintegrations in a time
Large amount
Becquerels Bq
International radioactivity measurement, small amount
Amount of radiation exposure is expressed in
Rem (large amount of radiation) or Millirem
Roentgen
R
Measuring radiation exposure only for gamma and X-ray on US DOSIMETERS
r/hr
Radiation absorbed dose
RAD
Used to measure the amount of radiation absorbed by a material
Roentgen equivalent in man
REM
Absorbed dose equivalent in human body. All types of radiation. Takes energy absorbed in RAD and bio effect on body based on different types of radiation. Used to set dose limits.
Simplest and most affordable tool available for responders to detect radiation and contamination
Hand held portable survey instruments.
Three groups for radiological instruments
Measuring radiation exposure
Detect contamination
Dose monitoring and personal dosimetry
Contamination can emit what types of radiation
Alpha, beta, gamma, combination
Two types of radiation detectors
Gas filled
Scintillation
Gas filled radiation detector
Radiation ionizes gas in chamber, instrument measures number of ions made.
Common gas filled radiation detectors
Ion chambers
Geiger- mueller GM
Scintillation radiation detector
Radiation interacts with crystal, usually sodium iodide, cesium iodide, or zinc sulfide. Produce small flash of light. Electronics amplify flash to create signal. Detect small amounts of radiation
Dosimeters are useful for tracking accumulated radiation dose
Works like an odometer because
Measures total dose received over time
Dosimeters should be read how often
Before entering
15-20 min intervals inside hot zone
Upon leaving
