Gas Sampling From A Distance

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…

Sample conditioning

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…

Recommendations on sample tubing

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.…

Understanding Interferences In Gas Detection

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 provide…

When I’m buying a toxic gas detection instrument or system, why do I need applications engineering?

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…

Detector Tubes And When To Use Them

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…

Is there a OSHA/DOT or any guideline/regulation that tells me how many ammonia detectors are required in ammonia storage/vaporizer and unloading area?

While guidelines may exist that mandate monitoring of an area for any number of toxic compounds, no official government recommendations are made as to the detailed design of such a monitoring system. In practice, the design of a toxic gas area monitoring system results from a collaboration between the end-user, consultant(if any), monitoring system vendor,…