Glossery

Term Main definition
Accessories

Auxiliary equipment, not inherent to the task but used to better perform the task in certain circumstances. Accessories can range from carrying, testing, calibrating and storing equipment to specialised filters, dedicated communication equipment and software, or equipment to perform detection duties in special circumstances. Examples are: filters, hoses, ball floats, automated bump test and calibration stations, calibration gas cylinders, cylinder valves, demand flow regulators, rapid deployment kits, carrying cases, wireless reception stations, etc.. While many accessories are standard issue or made by the original equipment manufacturer, 7Solutions also develops or adapts its own accessories to fit gas detection equipment to specialised detection applications.

Air speed meters
A precision instruments to measure air speed. They are frequently used to analyse air circulation and draught, and can also be used to predict propagation of hazardous chemicals in environmental incidents.
Alarm Only Instrument
A gas detector designed to serve only as an alarm in case of danger; does not provide real time concentration values. Alarm only instruments are normally disposable single gas detection devices, coloquially known as "beepers".
Alarm Set Point
The concentration of a specific gas at which an alarm is triggered.
Alcohol meter
An instrument to analyse breath alcohol, giving an indication of intoxication by alcohol consumption, especially in companies or environments with strict policies regarding alcohol intoxication. Also known coloquially as breathalyser.
Ambient Air
A term for air normally found in the environment, roughly 20.9% oxygen, 78% nitrogen and 1.1% other compounds (argon, carbon dioxide and trace gases), excluding water vapour (the concentration of which varies by location, altitude, temperature, weather and which is normally constant enough to be disregarded for gas detection purposes). In gas detection, ambient air is used to give instruments their zero calibration or fresh air calibration, provided they are free of contaminants.
Ammonia (NH3)
A colourless alkaline gas with a characteristic pungent smell. Ammonia is an important substance in agricultural, pharmaceutical and industrial cleaning environments. It is considered a hazardous substance because of its toxicity at low concentrations and prolongued exposure to even low concentrations should be prevented. Ammonia is measurable with a wide range of colorimetric detection tubes, electrochemical sensors (only suitable for low concentrations: at high concentrations, the expensive ammonia sensor is depleted quickly) and even with PID instruments (suitable and more cost effective at high concentrations as PID sensors are not depleted and are unharmed even in high concentrations of ammonia. This, and their quicker response time, makes PID instruments suitable for ammonia leak detection).
Approved
A term for a gas detection instrument or accessory to signify that it meets criteria regarding (intrinsic) safety or appropriateness. Examples are: ATEX, UL&cUL, EMI/RFI, Marine Equipment Directive ("Wheel Mark") and many others, mostly according to local laws and regulations.
Asphyxiant Gas
Any gas that has a tendency to replace the air in a given environment, presenting a choking hazard more than a poisoning hazard.