Table of Contents
Portable multi-gas detectors are considered to be highly accurate devices. Accordingly, they have been found to go a step beyond mere recognition of the existence of Volatile Organic Compounds to identifying them (Dressler, 1986). However, despite the prowess, there is a bigger challenge that faces them in terms of the quantity of the Volatile Organic Compounds (VOCs) that are present. The devices are not known to operate properly in areas with highly concentrated VOCs. Unlike the bulky Flame Ionization Detector (FID) the Photoionization Detectors (PIDs) do not portray linearity all the way through the entire range. That means their performances are limited to the areas that could only record low concentrations of VOCs.
As a result, the response to the leak will be faced with some level of challenges in the determination of the extent of the leakage. The risk here is accelerated as the fixed detector, which could easily determine the concentration rates, has broken down. Again, the range of the hand device is quite low in comparison to that of the Flame Ionization Detector. While the PID’s range is in between 5 ppb to 10,000 ppm, that of FID varies in between 1 ppm to 50,000 ppm (Sun & Ong, 2004). That means PID’s concentration is within the limits of FID. Thus, Flame Ionization Detector represents a better instrument for the monitoring and establishing the level of concentration than Photoionization Detector.
Therefore, when the leaked acetylene goes far beyond the limit of the multi-gas hand-held detector, then there will be no recording made from it. Similarly, should the rate of concentration fall below 5 ppb, the likely outcome is that the apparatus may fail to make the expected detection. As such, this could be a major concern in using the gadget.
The ionization of ethylene oxide occurs at electron volts (eV) of 10.57 (Photoionization Detector (PID) HUN, 1994). As such, the use of a Photoionization Detector (PID) with a lower eV would lead to the detection of gases that ionize at this level or below it. PID devices have the particular ability to measure the ionizations that happen at or below their electron volts. Since the used PID had a 9.5 eV lamp, then the expected ethylene detection at this moment could not arise. PID applies ultraviolet (UV) light as a source to ionize gas molecules, which can be recognized by the detector. UV light is usually higher in terms of frequency than that of visible light. UV light is used to identify and crash the Volatile Organic Compounds existing in the atmosphere into either positive or negative ions. It then uses the released ions in determining the charge present in the ionized gas. That happens when produced molecular ions get collected through the electrodes and create a measurable current. The concentration of the Volatile Organic Compounds is considered to have the charge as its function. Low-pressure inert gas is filled in the lamp. Then, the inert gas is empowered by means of energy with similar characteristics as the natural frequency of the molecules of that gas. As a result, an ultraviolet spectral radiation gets generated.
To distinguish the noted Volatile Organic Compounds, the electron volts of the compounds are measured (Meurant, 2011). The frequency of the ultraviolet rays varies depending on the amount of change that passes through, thus, making it possible to identify clearly the gas in question. However, where the electron volts capacity of the device is below that of the gas within the atmosphere, no identification can be made. That could be misleading and dangerous as could result in bigger exposure due to the wrong results being posted. To rectify the problem a device with a higherr electron volts potential should be used.
However, the use of an overly high electron volts device could also lead to the complications as it will raise the range in which the apparatus determines the gas (McNair, 2011). A more probable Photoionization device for that course could be like one containing krypton gas. Therefore, it is evident that with a 9.5 eV detector device, there will be no recordings made about the presence of the ethylene gas that has the ionization potential of eV 10.57.
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Draeger tube measures the presence and the amount of concentration of a given element within the environment. That is done via the use of the pH liquid that is filled in a calibrated tube. In the presence of the chemical element being tested, expectations are that there will be a color change to some level of the calibrated instrument (Arcilesi, 2007). The higher the measure of color change, the higher the level of concentration of the element in question.
In the case of the acetic acid, the pH liquid will be expected to have a color change from the original purple to yellow (Draeger. Draeger-tubes & CMS handbook: Handbook for short term measurements in soil, water, and air investigations as well as technical gas analysis, 2011). The length covered by the yellow coloration will indicate the concentration of the acetic acid in that particular environment. From our recorded results on the Draeger of the tests conducted at Occupational Safety and Health Administration (OSHA), the readings were 30 ppm. That figure is way above the OSHA’s Permissible Exposure Limit (PEL) that is recommended as 10 ppm. The indications are that the concentration of the acetic acid at OSHA has risen with between 15.5 ppm to 24.5 ppm considering that the Draeger tube allows up to 15 % variation in concentration for the measured units.