A personal gas detector is a device that is made for the detection of one or more types of gases. The word personal indicates that the detector is handheld and made to travel around with a person, rather than being installed in a specific location. These detectors can be used for home security, mine safety, or for industrial applications. If the detectors have advanced features, they may be referred to as personal gas detectors and monitors.
Personal gas detectors are capable of locating a variety of gases. Single-gas detectors may register the toxic gases carbon monoxide, nitrogen dioxide, or hydrogen sulfide. Carbon monoxide readers may be made less sensitive to hydrogen, in which case it is referred to as being CO minus H. Alternatively, detectors may monitor for oxygen or sulfur dioxide. Multiple gas reading models may include some, or all, of these, as well as methane, isobutene, and hydrogen.
The use of the personal gas detector is governed by the gas or gasses that it measures. In mining, the detector can both predict danger and assist workers in getting out of harm’s way, but it is not universally used. These objects which are small enough to be held in the palm of one's hand may be carried by the miner.
Fire and emergency rescue workers can benefit from the use of personal gas detectors. They are also used in industries that treat or deal with hazardous materials, such as petrochemical refineries and wastewater treatment plants. People also use them to check their homes.
Readings available on a personal gas detector vary with the sophistication of the device and the gas being detected. Typical displays in the US, Australia, and Britain, are parts per million (PPM) and lower exposure limit (LEL. Additional readings for carbon monoxide and hydrogen sulfide include a time weighted average (TWA) — a measure of exposure over time, and short-term exposure limit (STEL) — the maximum amount that should exist on average over a period of 15 to 30 minutes.
There are a variety of features that not all detectors include. More advanced models include memory capacity to enable data logging. Microprocessors may also be included to control the sensor and alert the user to problems with operation, such as a low battery. Some have alarms may be given visually, audibly, and/or by vibration. Others have large buttons designed for use by a person wearing gloves. Many models are designed to be water and dust resistant.