QUICK GAS FACTS:
Target gas specific information is included below for both Open Path Gas Detection and In-Situ Monitoring Applications.
Open Path Gas Detection
Setting Alarm Thresholds:
For Open Path Toxic Gas Detection, there are no standardized alarm thresholds like there are for combustible/flammable gases. There is a common assumption within the industry that:
- Within Enclosed or Congested Areas, it is assumed that the plume could be between 5-10 m (15-30 ft) in diameter by the time it passing through the Active Measurement Path.
- Within Open Areas, it is assumed that the plume could be between 10-20 m (30-60 ft) in diameter by the time it passing through the Active Measurement Path.
For Fixed Point Toxic Gas Detection, it would be common for end-users to set Alarm Thresholds at Exposure Based Concentrations based off of published NIOSH, OSHA, or IDLH levels. The end-user can utilize typical Exposure Based Thresholds to make them applicable to for Open Open Toxic Gas Detection by using the assumed plume size for your application.
To assist the end-user in determining a starting point, the table below shows the typical Exposure Based Thresholds multiplied the assumed Plume Size of 10 m to generate a Path Integrated Concentration (ppm-m) Alarm Threshold.
The table below shows how the example Alarm Thresholds fit within the Detectable Range for Open Path Gas Detection Applications.
For the sake of illustration and simplicity, we’ll assume that the concentration of the plume is homogeneous throughout. As the size of the plume increases, we’ll be able to see lower Path Average Concentrations – this is the same for the MDL, Sensitivity, and Full Scale.
Remote Point (RPX) Probe:
LASER BASED – FIXED POINT GAS DETECTION
To replace traditional Fixed Point Gas Detection measurements with all of the benefits of Laser Based Gas Detection, Boreal Laser has developed the Remote Point (RPX) Probe. The Remote Point (RPX) Probe has a 0.5m (1.5 ft) Active Measurement Path and has the following detection range.
Laser Based – Gas Monitoring and Analysis
Making measurements within a contained process is handled differently than those in Open Path/Line-of-Sight arrangements. It is often assumed that the concentration is more or less homogeneous for path lengths less than 5m (15ft).
As Path Length (and the length of the Active Measurement Path) changes, so to does the Detectable Range of the GasFinder.
The relationship between the Path Length and the Detectable Range for Path Average Concentrations is both inverse and proportional:
- If the Path Length increases then the Path Average Concentration Detectable Range (MDL, Sensitivity, and Full Scale) will decrease.
- If the Path Length decreases then Path Average Concentration Detectable Range (MDL, Sensitivity, and Full Scale) will increase.
The table below shows an example how the Minimal Detectable Limit (MDL) can change as the Path Length is increased and decreased.
Hydrogen Chloride (HCl):
For more information, please visit our Frequently Asked Questions (FAQ) Page: Click Here
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