Commonly Used Terms for Gas Detection Applications PPM: Part(s) Per Million A unit of concentration, pertaining to a gas mixture, defined as the ratio between the volume of an individual component Vi and the total volume Vtotal : 10,000 parts per million equals one percent. Other concentration units are discussed here. LEL: Lower Explosive Limit The lowest…
Background Gas detection instruments must often be used or installed in areas considered to be “hazardous locations.” Generically, all sorts of hazards might be recognized in a particular environment, but the term “hazardous locations,” as it applies to electrically-operated equipment refers to provisions established by the National Fire Protection Association (NFPA), and various other organizations.…
While Sensor Resource’s products are primarily concerned with toxic gas detection, many of our end-users are also involved with flammable and combustible compounds, so we are pleased to provide this material.
In accordance with the Clean Air Act, nitrogen dioxide (NO2) is a criteria air pollutant. Thus, it has always been of interest to the gas detection community. But, what about dinitrogen tetroxide (N2O4), a name heard primarily within the aerospace community? In that field, N2O4 is a hypergol (or hypergolic propellant). Hypergols are used in…
“Minimum Detectability” is one of those instrumentation terms that is used frequently, but is seldom defined. Indeed, even though you will encounter this term on many data sheets, its definition does not appear in any of the usual learned references, including Process Instrumentation Terminology, ANSI/ISA—51.1—1979(R1993) and Standard Terminology Relating to Sampling and Analysis of Atmospheres,…
This is a follow-up to our earlier article on Using Common Sense and Science in Expressing Gas Concentrations, inspired by a real-life adventure of one of our sales engineers. As our hero was slogging through some e-mail inquiries, he came upon two units of measurement he had not seen before: ppmv and µg/Nm3 ppmv…
A complete list of nitrogen oxides would include… Nitric oxide, aka nitrogen monoxide (NO), nitrogen(II) oxide Nitrogen dioxide (NO2), nitrogen(IV) oxide Nitrous oxide (N2O), nitrogen(−I,III) oxide Nitrosylazide (N4O), nitrogen(−I,0,I,II) oxide Oxatetrazole (N4O) Dinitrogen trioxide (N2O3), nitrogen(II,IV) oxide Dinitrogen tetroxide (N2O4), nitrogen(IV) oxide Dinitrogen pentoxide (N2O5), nitrogen(V) oxide Trinitramide (N(NO2)3 or N4O6), nitrogen(0,IV) oxides Of primary…
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. 1. Owing to…
Here are some dynamic converters —featuring a handy set of tools to convert between various gas concentration units of measurement. Several other goodies are also included. The gas concentration unit converters are said to be the best on the Web, and have garnered hundreds of thousands of visits. Check out our Tech Center articles on…
Go directly to conversion calculators Early on, in our first chemistry classes, we learn about solutions, and different ways of expressing their concentrations. Since a solution is any homogeneous mixture of two or more substances, gas mixtures are indeed solutions. In the world of gas detection, we tend to be concerned with combustible or toxic…