Unit 3 Flashcards
T/F- Reagents in colorimetric tubes are designed to change to a specific color when exposed to a specific chemical.
True
T/F- Colorimetric tubes have an expiration date.
True
T/F- Reagents in colorimetric tubes will only change color when exposed the chemical they are designed to detect.
False
T/F- Reagents in colorimetric tubes can change an unexpected color when exposed to a chemical it might be cross sensitive to.
True
Name things that will contaminate a combustible gas detector.
Corrosive gases; liquids aspirated into the detector; silicone
T/F- A combustible gas detector can function properly in all types of atmospheres.
False
In order for the proper operation of a combustible gas detector the oxygen levels in the sampled atmosphere must be:
A.) Oxygen levels don’t matter
B.) The minimum oxygen levels varies from manufacturer to manufacturer
B.) The minimum oxygen levels varies from manufacturer to manufacturer
What will too high or too low oxygen levels in the sampled atmosphere do to the readings of the combustible gas meter?
A.) Give more accurate readings
B.) Give incorrect readings
B.) Give incorrect readings
What pH readings when read from a pH meter should be concerning?
Less than 2 (<2) and greater than 12.5 (>12.5)
The presence of which chemicals will give a false elevated oxygen reading?
Chlorine, Oxidizing chemicals
When a meter is set to parts per million (ppm) or parts per billion (ppb) the lowest reading you can get is?
1
pH paper is used to indicate the approximate strength of?
Acids and Bases
What types of chemical detection devices can be used to determine explosive atmospheres?
OVA- Organic Vapor Analyzer
PID- Photo Ionization Detector
Wheatstone Bridge Circuit (Traditional CGI)
1% by volume equals how much parts per million (ppm)
10,000 ppm
1% by volume equals how much parts per billion (ppb)
10,000,000 ppb
For an indoor natural gas release at what LEL threshold should you delineate your hotzone?
10% LEL
For an outdoor natural gas release at what LEL threshold should you delineate your hotzone?
20% LEL
Can Carbon Dioxide influence oxygen detected by oxygen detectors? Explain your answer.
Yes. High concentrations of carbon dioxide, or any other gas given the right situation, can physically displace the oxygen available in the area.
Does atmospheric pressure influence the amount of oxygen a oxygen detector sees?
Please explain.
Yes. Above sea level the atmosperic pressure begins to drop and as the atmospheric pressure drops the air becomes thinner so a oxygen detector will see less oxygen molecules passing in front of it.
Define Vapor Density
The weight of vapor contained in a container when compared to the weight of dry air in a container of similar volume.
Should the atmospheres of confined spaces be monitored prior to and during entry? Explain your answer.
Yes. For life safety reasons confined spaces should be monitored for several hazards including explosive, asphyxiant and toxic gases.
Can a carbon monoxide detector be used to determine the identity of a liquid product?
No
Which detection methods might be used to detect nerve agents?
M8/M9 paper
Surface Acoustic Wave (SAW)
What is the first priority of monitoring?
Safety
What is the first hazard a haz mat technician samples for?
Radioactivity
What are the radiation limits found at 1 meter from the outer package surface for the three levels of radioactive materials with intact packages and the associated color of their labels?
Level I = Almost none at 1 m; 0.5 mrem/hr @ surface, White label
Level II = max. 1 mrem/Hr @ 1 m; 50 mrem/hr @ surface, Yellow label
Level III = max. 10 mrem/Hr @ 1 m; 200 mrem/hr @ surface, Yellow label
Explain correction factor or relative response as it pertains to calibration gas for a combustible gas instrument (CGI).
The correction factor of a calibration gas is the ratio of how much hotter or colder a flammable gas burns in reference to the known calibration gas used on the instrument. This ratio can then be used to determine the percent of flammable gas that is present in the atmosphere being sampled.
T/F- Colorimetric tubes have a high margin of error.
True; +/- 25-30%
T/F- Colorimetric tubes are not designed to measure concentrations below 10,000 ppm
False
This method of detection consists of numerous piezoelectric crystals coated with a polymer film that specifically absorbs a particular class of volatile compound. The absorption of these volatile compounds to their specific piezoelectric crystal cause that crystal to vibrate differently than it normally would. By monitoring the vibrational changes across the different array of crystals a chemical pattern or fingerprint can be detected and used to identify the compound.
Surface Acoustic Wave (SAW)
In regards to radiatioactive packaging explain transport index (TI).
Transport index (TI) is the maximum radiation level in mrem/hr at a distance of one meter from the intact surface of the package.
EX: for a package with a TI of 3 the maximum radiation intensity that hould be measured 1 meter from the intact surface of the box should be 3 mrem/hr. A higher value indicates that contents may have shifted, shielding breached or an error in labeling the package may have occurred
This detector works by exposing the gas sample stream to an ultraviolet light of a wavelength with sufficient energy to ionize an agent molecule. If ionizable agents are present in the gas they become ionized. An ion detector then registers a voltage proportional to the number of ions produced and thus the concentration of the agent.
Photo Ionization Detector (PID)
This general purpose detector is used to determine the presence of volatile carbon-based compounds that are incinerated in a hydrogen-oxygen flame. When a carbonaceous compound burns an increase in the flames baseline ion current occurs and detection of a compound occurs. Unfortunately when used alone this detector is not specific and only detects the presence of a volatile carbonaceous compound.
Flame Ionization Detector (FID)
This detection system measures the absorbtion of infrared light by a sample. Different wavelengths of infrared light are absorbed by different chemical bonds as well as the stretching and bending of those chemical bonds. The different wavelengths absorbed and the amount of energy absorbed graphed provides a spectrum that can be used to identify chemical compounds.
Infrared Spectroscopy
This detection system uses a hydrogen flame to burn volatile chemical agents present in air. Compounds that contain phosphorous and sulfur produce hydrogen phosphorous oxygen (HPO) and elemental sulfur (S) respectively. At the elevated flame temperature the phosporous and sulfur emit light of specific wavelengths. These wavelengths are then detected and their intensity relates to their overall and relative concentration. This is important because the classical nerve agents all contain sulfur and phosphorous and this detection system allows for rapid detection.
Flame Photometry
This detection system ionizes components in air and passes them through a weak electric field toward and ion detector. The time it takes the ion to traverse the distance to the detector is proportional to the mass of the ionized chemical species and is used as a means of identification.
Ionization/Ion Mobility Spectrometry (IMS)
