Gas detection certifications give customers the assurance that the equipment and devices they purchase are reliable in their industry and application. With hazards present across a variety of industries and applications, customers need assurance that their safety systems can withstand those hazards and alert personnel of dangerous conditions at a specific location.
Locations are classified by their type of combustible risk and the likelihood of it being present in the area. Classifications are determined by standards set by the National Electric Code (NEC) in the United States and internationally by the International Electrochemical Commissions (IEC).
A hazardous area is defined in one of two ways: either the Class/Division system in North America or the Zone system which is recognized internationally. The Class/Division certification system will occasionally use a Minimum Ignition Current (MIC) ratio when measuring. The MIC ratio is the least amount of current generated from an inductive spark required to ignite the easiest concentration of methane in the air. This is important because it is necessary to ignite the easiest concentration of the target gas in the air by the minimum current from an inductive spark.
The organization of classes consists of three types: gas (I), dust (II) and fibers (III). Divisions are split into two categories: a hazard likely to be present during normal operating conditions (I), and a hazard present during abnormal conditions like a spill or leak (II). Group definitions (A through G) identify the particular hazard of concern. Group A refers to acetylene, while Group B refers to hydrogen, butadiene, ethylene oxide, propylene oxide, acrolein, and other gases with a MIC ratio of less than 0.40. Group C consists of ethyl ether, ethylene, acetaldehyde, cyclopropane, and other gases with a MIC ratio greater than 0.40 but less than 0.80.
Group D contains acetone, ammonia, benzene, butane, ethanol, gasoline, methane, natural as, naphtha, propane, and other gases with a MIC ratio greater than 0.80. Combustible metal dusts including aluminum, magnesium and alloys of aluminum and magnesium are all gathered into Group E, while combustible carbonaceous dusts containing more than 8% volatile compounds such as carbon black, coal, and coke dust make up Group F. Lastly, Group G has combustible dusts such as flour, starch, grain, wood, plastic, chemicals, and other combustible dusts not included in groups E or F
A more modern international system defines areas by zones, the likelihood of a hazard to be present, and groups, which tell you the particular type of hazard. Zone 0 indicates the hazard is present continuously and for long periods of time. Zone 1 indicates the hazard is likely to be present in normal operating conditions. And Zone 2 indicates the hazard is not likely to be present in normal conditions for an extended period of time.
Group I will determine whether the hazard is specific to the mining industry, while Group II will have a subset telling you the hazard is gaseous in nature, as indicated below. Group III consists of dusts and other subsets by particle size and material type.
- A: methane, propane, and other similar gases
- B: ethylene and gases that present similar hazard risk
- C: acetylene, hydrogen or other similar hazards
There are also logos on the labels of gas detectors to show which association has tested and evaluated the equipment to ensure its safety based on a set of applicable standards. While safety is imperative to all certifications, customers should still want to understand what circumstances their gas detector(s) is certified to face. The IECEx logo shows that this detector is certified to IEC and ATEX standards, and the CE Mark is a universal marking for Europe similar to the UL logo in the United States. These marks indicate that the gas detector meets certain safety, health and environmental protection requirements. Underwriters Laboratories, certifiers using the UL symbol, identify many different types of electrical equipment. Other familiar markings include CSA (Canadian Standards Association) and MSHA (The U.S. Mine Safety and Health Administration).
A device marked with the CSA logo and a marking that it has been certified to standard 22.2 No.152 indicates that the part of a device that detects combustible gas is up to Canada’s performance standards required for a combustible gas detector. Similarly, the MSHA logo and a label stating that it is a permissible methane detector indicates the device has been certified to United States performance and safety specifications established for methane detectors.
Otis Instruments offers a variety of Wired and WireFree easy-to-use, robust and configurable gas detectors. Made in the USA, our high-quality products are capable of detecting both toxic and non-toxic gases for diverse applications. If you would like more information about gas detection solutions for your application, implementing Otis Link services, or have a question for us, contact our team today.