We introduce this subject matter in our Gas Detection Applications Primer. OSHA has promulgated PELs (Permissible Exposure Limits) for many substances, and—unlike the ACGIH TLV®s—these have the force of law behind them. In general, the PELs are 8-hour time weighted averages, but ceiling limits have been established for some chemicals. 29 CFR 1910.1000 Table Z-1…
Especially when doing low range work, it is important to make sure that your instrument is properly zeroed. Ideally, zeroing should be performed with a certified zero gas. However, mostly since it adds another step to the calibration process, this practice has somewhat fallen out of favor. The alternative to a zero gas requires that…
One of our salespeople was demonstrating a portable hydrogen sulfide analyzer to a prospect, who told us he needed to be sure that there was “no” H2S in the ambient air—caused by a leak from a scrubber installation. Our analyzer showed a fairly consistent reading of 0.2 ppm, whereupon the prospect pulled out his nifty…
For a good introduction, first read this Knowledge Base article. Then, if you really want to get techie, we present an article (3.7 MB) entitled “Generating Calibration Gas Standards with OVG-4 and Permeation Tubes,” from our friends at Owlstone.
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…
Fair question. How would you respond to such a query, if pressed by an employee? In fact, this sort of thing does come up, and here’s an example: 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…
Everyone in the safety field knows that carbon monoxide is the “silent killer.” So, you might find it interesting that CO is used in an important test of lung function—the test for lung diffusing capacity. That is, how well do the lungs transfer gases to and from the bloodstream? (Oxygen and carbon dioxide) Carbon monoxide…
This one is courtesy of our friends at the American Chemistry Council A part-per-million can be thought of as: A credit card lying in the middle of a football field One step, on a 568–mile (914 km) walk One minute, in a two-year span A part-per-billion can be thought of as: One thousand times smaller…
Most likely, your earliest exposure to “formaldehyde” involved some sort of biological specimen, preserved in a clear liquid. This liquid was probably identified as “formaldehyde.” And, if you were in elementary school or junior high, you didn’t give it a second thought. But, if you were to study organic chemistry, you would learn that formaldehyde…