| Gas detectors can be found in all walks of | | | | which a flammable substance can produce a |
| life, from food processing plants to parking | | | | fire or explosion when ignited. |
| garages, from airplanes to casinos. Any place | | | | |
| that can have a potential lack of oxygen or | | | | UEL (Upper Explosive Limit) is the maximum |
| presence of a toxic gas needs a gas detector | | | | concentration of gas in air that will burn. |
| present to monitor the safety of people. Some | | | | |
| common uses during field projects are: | | | | Each compound (gas) has a different LEL, or |
| confined space entry, well drilling, soil | | | | the point at which the compound will burn or |
| screening, area mintoring, worker safety, | | | | become explosive. |
| indoor air quality, and leak detection. Gas | | | | |
| detectors have a variety designs; pager size | | | | Most flammable compounds become explosive at |
| units, handheld datalogging units, Stand | | | | less than 5%(vol). |
| alone area monitors, and wall mount fixed | | | | |
| systems.Here are some gas detection basics: | | | | Each gas has a different LEL and UEL. |
| | | | |
| 1ppm is one part in 1,000,000 | | | | %Gas is the highest unit of measurement, |
| parts.Generally ppm (parts per million) is | | | | which is the amount of pure gas. |
| the lowest unit of measurement 10,000ppm = 1% | | | | |
| by Volume | | | | How Do Gas Detection Sensors Work? |
| | | | |
| LEL is the next unit of measurement. It is a | | | | The Oxygen Sensor is an electochemical |
| percentage of the explosive %(vol) level of a | | | | sensor. Any gas which can be oxidized or |
| compound. | | | | reduced electrochemically can be detected by |
| | | | means of a fuel based electrochemical sensor. |
| 100% LEL is the lowest concentration at | | | | |