A portable gas detector is a handheld device, usually battery-operated, that senses the presence of a toxic or combustible gas. In the home, a natural gas detector can be used to check for gas leaks around stoves and furnaces to ensure that all connections are sealed properly. Carbon monoxide detectors are also commonly used in the home, particularly around furnaces, to alert occupants of any build-up of this potentially fatal gas. Portable gas detectors are used extensively in all kinds of commercial and industrial settings, where gasses are produced as a by-product of manufacturing, refining, mining, or other commercial activities. Gas detectors may be calibrated to check for one type of gas, or they be set for a wide-spectrum to test for the presence of several different gasses.
Gas detectors are generally designed to test for either toxic gasses or combustible gasses. Combustible gasses are those which can cause an explosion or fire if they are exposed to a spark. These would include natural gas, propane, and oxygen, among others. A toxic gas is any gas that can cause illness or death in concentrated amounts. Carbon monoxide, chlorine, and ammonia are all classified as toxic gasses.
In a residential setting, a portable gas detector can save lives and prevent property damage and loss due to fire. Natural gas has no odor of its own, but mercaptan is often added to the gas so that leaks can be detected by the unpleasant "rotten-egg" smell. A gas detector is more effective than relying on smell, because it can detect much smaller leaks, and many natural gas detectors can also detect propane leaks. Nearly every appliance installation professional uses a portable gas detector to ensure a safe, leak-free installation of any new gas or propane appliance. Municipal inspectors also use these devices when turning on gas service to a home or business where service had previously been disconnected.
Carbon monoxide is another gas that can build up inside homes and offices. It is produced by the incomplete combustion of natural gas, wood, coal, and other fuels. Carbon monoxide is colorless and odorless, and can be fatal if it accumulates in an enclosed area. Some portable gas detectors can sense the presence of carbon monoxide. More commonly, carbon monoxide detectors are installed close to a fuel-burning appliance, and emit a loud alarm signal when the gas is detected.
Within industrial settings, many potentially toxic gasses can be produced as a by-product of manufacturing. A portable gas detector can be worn on a worker's clothing or on a harness to continuously monitor the levels of toxic gas in a workspace and sound an alert if levels become too high. Oxygen deficiency gas monitors work slightly differently, because they alert workers of low oxygen levels within a workspace. These are commonly used in laboratories and pharmaceutical manufacturing plants, where leaks of cryogenic materials, such as liquid nitrogen, can deplete the oxygen in the surrounding workspace.
Homeowners may purchase a portable gas detector at a local home improvement store, hardware store, or from an online retailer. Workplace gas monitors are often integrated into a larger system installed by workplace safety professionals. Batteries should be checked regularly, and some units also require regular calibration to ensure proper functioning. Users should always read and follow the manufacturer's instructions regarding the care and use of a particular model.