In most cases, the goal is to establish some sort of ventilation control, such that a balance can be achieved between energy conservation and guarding against toxic exposure. Carbon monoxide is usually chosen as the target analyte, unless the vehicular traffic will be largely diesel. While diesel engines do emit CO, it is less than…
In most cases, gas monitoring applications focus on a single gas. There may well be interest in detecting this compound at several points, but the end-user has determined that it has one particular target analyte. Sometimes, though, there will be two gases of interest. Common examples are hydrazine and nitrogen tetroxide; and carbon monoxide and…
Sometimes it is necessary to transport sample from some distance to the analyzer. There is no inherent problem in doing this, unless the sample is subject to condensation (see “Sample Conditioning” article); the analyte is unstable; or the interconnect tubing material might exhibit chemisorption properties. System lag time, reflecting the time for gas sample to…
The term “sample conditioning” simply means the preparation of the gas sample containing your analyte to render it suitable for introduction into your gas analyzer. This is usually less of a consideration in ambient air monitoring applications than in source monitoring applications. When sampling from a source such as an industrial process, utility stack, or…
Back in the 1970s, many multi-point systems were being deployed, for monitoring carbon monoxide in parking garages and vehicular tunnels. Since long and otherwise exposed sample tubing runs needed to be installed, copper tubing was used. Because CO is not very reactive, and copper tubing is both flexible and robust, this was a preferred choice.…
In the field of gas detection, an “interference” is an unwanted response on your instrument, caused by some chemical other than the target analyte. Generally speaking, no analytical method—using any technology—is completely specific. Thus, it is important for instrument manufacturers to document these interferences to the best of their ability. Here at Interscan, we…
Fair question. How would you respond to such a query, if pressed by an employee? In fact, this sort of thing did happen, back in the day. In the early days of instrumentation-based toxic gas detection, the steel industry was a major part of the business, and carbon monoxide was the biggie. Large amounts of…
Very simply, since no two toxic gas detection applications are the same. We admit that this concept has been obscured under the quite false rubric that “All gas detection is confined entry.” Certainly, a goodly percentage of all portable gas detection instruments are designed as if they are intended for the confined entry app. These…
A detector tube is a graduated glass tube filled with a chemical reagent that will produce a color change, when exposed to the gas in question. It is used with a hand pump that will draw a sample into the tube. The tubes are generally supplied in packages of ten, and are sealed at both…
First, let’s define the terms: “Continuous” monitoring means that each sampling point is being monitored all the time, and in most cases, the concentration displayed reflects what is truly happening at the point in real time. There are certain exceptions to this involving instrument techniques that run batch analysis, but that is beyond the scope…