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12 Cards in this Set
- Front
- Back
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combustible gas indicator (CGI)
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1. an instrument used to detect flammable and combustible vapors; a CGI is characterized by a wheatstone bridge, which burns present vapors and may indicate lower and upper explosive limits
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Explosimeter
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electronic device that detects gas in the air
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roentgen equivalent man (REM)
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REM relates the absorbed dose in human tissue to the effective biological damage of the radiation; not all radiation has the same biological effect, even for the same amount of absorbed dose
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Oxygen deficient or enriched:
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This is when the oxygen content is less than 19.5% or greater than 23.5%.
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Radiation action levels
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The NRC recommends an action level of 2mR/h (millirem per hour) while EPA recommends an action level of 1mR/h.
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Flammable atmospheres:
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When the concentrations of flammable materials are greater than 10% of the Lower Explosive Limit (see Lesson 2), the environment is considered IDLH.
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Toxic
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Concentration levels which are consider hazardous will depend on the specific chemical involved in the incident. Some examples include:
· Carbon Monoxide values of 35 ppm or greater are considered toxic by first responders. The OSHA permissible exposure limit is 50 ppm and the IDLH value is 1200 ppm. · Hydrogen Sulfide values at or above 10 ppm are considered hazardous by OSHA. The IDLH value is 100 ppm. The most common toxics monitored in the field are CO and H2S |
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Corrosives
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Corrosive liquids and vapors are damaging to human flesh and must be identified in order to protect the first responder.
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Acording to OSHA 29 CFR 1910.120, paragraph h,
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“Air monitoring shall be used to identify and quantify airborne levels of hazardous substances and safety and health hazards in order to determine the appropriate level of employee protection needed for site entry.”
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colorimetric
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methods include pH paper strips, spill classifier strips, and detector tubes. In each of these cases a chemical reaction is allowed to take place between the atmosphere and a detection media. The detection media (such as a tube of silica, pH paper, or classifier strip) changes color as a result of the chemical reaction. It is than matched up to a chart to determine pH value.
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post-incident w/ detectors
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○ decontaminate as necessary and following the manufacturer’s recommendations
○ purge: allow instrument to purge in a clean environment; simply let the instrument run and allow readings to return to zero; in sensor based instruments, if the instrument fails to return to initial settings this may provide early indication that sensors have been fouled or failed ○ return to ready state: the instrument should have batteries recharged or replaced (if applicable) and an operational check completed prior to return to service |
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Monitoring Methodology
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-turn on, zero, and calibrate instruments which require this operation in clean environments
-approach a possible release area from an upwind and upgrade location which is a safe distance from the incident - allow the instrument the proper time frame to obtain results -document results -set zones -consider using multiple instruments to verify readings when possible |
