Combustion Analyzers Specifications

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Physical Specifications

	Mounting Type:
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	Handheld		Handheld instruments are specifically designed to be operated while being held in the user's hand.
	Portable		Portable instruments are designed to be easily carried or moved about.  They are typically battery powered.
	Fixed		Fixed devices are designed with the intent that all parts will be installed permanently. Products may be referred to as permanent, fixtured, or in-situ.
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	Application:
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	Personal Exposure Monitoring		Personal exposure monitoring (PEM) instruments check the air in a person's breathing zone in order to monitor exposure to a particular gas or gases. These devices are often handheld or portable (attached to the user) and may offer audible or visual alarms to alert the user about dangerous situations.
	Confined Space Monitoring		Confined space monitoring (CSM) instruments are designed to detect, monitor, or analyze gases in a confined space. A confined space is a large enough for a person to perform work and has a limited opening for entry or exit. A confined space is not designed for continuous occupancy.
	Continuous Emissions Monitoring		Continuous emissions monitors (CEM) are used to continuously measure emissions of SOx, NOx, and other particulates.  CEMs send emissions data to the utility's data acquisition system where it is compiled and submitted to the EPA.
	Ambient Air Monitoring		Ambient air monitors are used to monitor the atmosphere in the area where the gas detection system is located.
	Process Gas		Process gas instruments detect, monitor, and/or analyze gas or gases in process streams.
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	Analyzer Technology
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	Catalytic Bead Sensor		Catalytic bead sensors include a coil of wire that is coated with glass or ceramic material which is, in turn, coated with a catalyst. The coil is electrically heated to a temperature that burns or catalyzes the hydrocarbon being monitored. When burned, all hydrocarbons liberate heat proportional to the concentration of the hydrocarbon present. This heat increases the temperature of the wire coil, in turn increasing its resistance. The increase in resistance is measured electrically and is the source of the signal.
	Electrochemical		Electromechanical sensors are the most popular way to monitor toxic gases and oxygen. These simple, reliable, and relatively inexpensive devices are the best all-round sensors for ambient toxic gas monitoring, but are not suitable for combustible gas monitoring.  Electrochemical sensors are self-powered micro fuel cells. Each cell consists of a casing containing a gel or electrolyte and two active electrodes: the working electrode (anode) and the counter-electrode (cathode). The top of the casing has a membrane which can be permeated by the gas sample. Oxidization takes place at the anode and reduction at the cathode. A current is created as the positive ions flow to the cathode and the negative ions flow to the anode. Electrochemically reducible gases such as oxygen, nitrogen oxides and chlorine are sensed at the cathode. Gases that are electrochemically oxidizable, such as carbon monoxide, nitrogen dioxide and hydrogen sulfide, are sensed at the anode.
	Flame Ionization Detector		The flame ionization detector (FID) is a type of gas analyzer that detects hydrocarbons (e.g. solvents, benzene, methane, etc.) in gaseous media. They are used in applications such as threshold limit value (TLV) monitoring, continuous emission monitoring (CEM), and lower explosion limit (LEL) testing. The flame in an FID is produced by the combustion of hydrogen and air. When a sample is introduced, hydrocarbons are combusted and ionized, releasing electrons. A collector with a polarizing voltage located near the flame attracts the freed electrons, producing a current that is proportional to the amount of hydrocarbons in the sample. The signal from the flame ionization detector is then amplified and output to a display or external device.
	Infrared		Sensors optically absorb gases that fall in the infrared (IR), visible, or ultraviolet (UV) spectral ranges. These gases include carbon dioxide, methanol, hydrogen cyanide, chlorine, refrigerant gases and naphthalene. The essential components of an IR system include a source of IR radiation, a detector capable of seeing the IR radiation, and a path between the detector and the source open to the gas to be detected. Detector electronics are used to measure the difference between the dark (no light hitting the detector) and light (full energy hitting the detector) regions. When gas in the path absorbs energy from the source, the detector receives less radiation than normal. This reduction in radiation is used to measure the gas concentration. Note: Each chemical substance has a unique absorption of radiation in the infrared, visible and ultraviolet spectral regions. The absorption intensity is related to the concentration of the chemical substances according to the Beer-Lambert Law. Non-dispersive infrared absorbance (NDIR) sensors, non-dispersive ultraviolet (NDUV) sensors, and other optical measuring techniques are included in this sensor category.
	Photoionization Detector		Photoionization detectors (PID) use an ultraviolet (UV) light source to ionize components of the incoming sample. The compound entering the detector passes the UV lamp and is bombarded by high energy photons. Components that have a low enough ionization potential are ionized, producing free electrons that are directed to a polarizing electrode within the detector. The photoionization detector senses the electron stream as a current that is proportional to the amount of ionizable gases in the sample. The signal from the photoionization detector is then amplified and output to a display or external device. PIDs are used to continuously monitor hazardous and toxic gases or vapors in low parts per million (ppm) concentrations. Examples of these volatile organic compounds (VOCs) include benzene, butadiene, methylene chloride and vinyl chloride. Current and proposed permissible exposure limits (PEL) of these air contaminants require low ppm levels, often with resolution down to 0.1 ppm.
	Semiconductor		Semiconductor sensors are well-suited for monitoring toxic and combustible gases such as hydrogen sulfide (H2S) when sensitivity to low concentrations (ppm) is required. There are two types of devices: sintered bulk and solid-state thin film metal oxide. Both types use a ceramic substrate. With semiconductor sensors, a semiconducting material is applied to a non-conducting substrate between two electrodes. The substrate is heated to a temperature such that the gas being monitored can cause a reversible change in the conductivity of the semiconducting material. Under zero gas conditions, the oxygen (O2) molecules tie up free electrons in the semiconductor material by surface absorption, thereby inhibiting electrical flow. As H2S or CHC gas or vapor molecules are introduced, they replace the O2, releasing the free electrons and decreasing the resistance between the electrodes. This change in resistance is measured electrically and is proportional to the concentration of the gas being measured.
	Other		Other unlisted, specialized, or proprietary gas sensor technology.
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Measurement Type

	Measurement Type:
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	%LEL		The lower explosive limit (LEL) or lower flammable limit (LFL) of a combustible gas is the smallest amount of the gas that supports a self-propagating flame when mixed with air (or oxygen) and ignited. In gas-detection systems, the amount of gas present is specified as a percentage (%) LEL. Zero percent (0 %) LEL denotes a combustible gas-free atmosphere. One hundred percent (100 %) LEL denotes an atmosphere in which gas is at its lower flammable limit. The relationship between percent LEL and percent by volume differs from gas to gas.
	%Volume		Percent by volume is the concentration of a gas in a particular volume (%v/v).
	Trace		Trace is expressed in units of concentration: parts per million (ppm) or parts per billion (ppb). One percent exposure equals 10,000 ppm or 10,000,000 ppb.
	Leakage		Leakage is the prevailing fluid flow through a leak at existing conditions. The leakage rate is typically specified in units of flow, such as milliliters per minute (ml/min).
	Density		Density is expressed as mg/m^3.
	Signature or Spectra		The measurement type is a spectral signature of the gases present.
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	Number of Gases Sensed
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	Single Gas		Instruments are designed to detect a single gas.
	Multi Gas		Instruments are designed to detect multiple gases.
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Gas Type

	Specific Gas Types
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	Aerosols		Aerosols are particles suspended in the atmosphere. They range in size from about 10-3 µm to about 20 µm. They are produced by natural processes or man's activities. They include volcanic dust, sea spray and its particulate products, wind generated dust, smoke from natural forest fires, and particles emitted during combustion
	Ammonia (NH3)		Ammonia (NH3) is toxic and corrosive to some materials and has a pungent odor.  Ammonia is used in the production of fertilizers, explosives, polymers, and household cleaners
	Arsine (AsH3)		Arsine (AsH3) is both flammable and toxic. Synonyms include arseniuretted hydrogen, arsenous hydride, arsenic trihydride, and hydrogen arsenide.
	Bromine (Br2)		Bromine (Br2) is a toxic, brownish-red element that has a bleach-like suffocating odor. Inhaling bromine gas can cause coughing, breathing difficulties, headache, irritation of the mucous membranes inside the mouth and nose, dizziness, and watery eyes.
	Carbon Dioxide (CO2)		Carbon dioxide is a common chemical compound that is often called by its formula name, CO2.
	Carbon Monoxide (CO)		Carbon monoxide (CO) is flammable, toxic, colorless, and odorless. It is a major byproduct of combustion.
	Chlorine (Cl2)		Chlorine (Cl2) is a diatomic gas that is yellow-green in color.  It is a halogen that combines easily with nearly all other elements.  Chlorine irritates the respiratory system and mucous membranes. It is fatal in amounts of 1000 ppm or more. Prolonged exposure at lower, non-fatal levels weakens the lungs.
	Chlorine Dioxide (ClO2)		Chlorine dioxide (ClO2) is a synthetic, yellowish-green gas that is used in water purification, sanitation applications, and the paper industry. It is made stable in an aqueous solution. Chlorine dioxide is a heavy, explosive gas.
	Diborane (B2H6)		Diborane (B2H6) is a colorless gas with a repulsive, sweet odor.  It mixes easily with air and will ignite spontaneously in humid air at room temperatures.  Diborane is a respiratory irritant.  Symptoms can occur immediately or be delayed for up to 24 hours after exposure.
	Fluorine (F)		Fluorine (F) is a poisonous, pale, yellow-green gas that is the most chemically reactive of all the elements. It is highly dangerous in its pure form, and can cause severe burns if it comes into contact with the skin.
	Germane (GeH4)		Germane (GeH4) is a flammable, toxic, colorless gas that reacts with oxidizers and halogens.
	Hydrocarbons		Hydrocarbons are organic compounds made primarily of hydrogen (H) and carbon (C) atoms. Natural gas is a mixture of hydrocarbons.  Examples of hydrocarbons include methane (CH4), ethane (C2H6), propane (C3H8), butane (C4H10), pentane (C5H12), benzene (C6H6), hexane (C6H14), and heptane (C7H16).
	Hydrogen (H2)		Hydrogen (H) is a colorless, highly flammable gaseous element.  It is used in the production of synthetic ammonia and methanol, in petroleum refining, in the hydrogenation of organic materials, as a reducing atmosphere, in oxyhydrogen torches, and in rocket fuels. Ordinary hydrogen gas is made of diatomic molecules (H2) that react with oxygen to form water (H2O) and hydrogen peroxide (H2O2), usually as a result of combustion.
	Hydrogen Chloride (HCl)		Hydrogen chloride is commonly known by its formula name, HCl.  It is a highly corrosive and toxic, colorless gas. White fumes form on contact with humidity. HCl often refers to hydrochloric acid, which is actually a mixture of hydrogen chloride in water.
	Hydrogen Cyanide (HCN)		Hydrogen cyanide (HCN) is a colorless, volatile, extremely poisonous, and flammable liquid that is miscible in water and used in the manufacture of dyes, fumigants, and plastics.
	Hydrogen Fluoride (HF)		Hydrogen fluoride (HF) is a colorless, fuming, corrosive liquid or a highly soluble corrosive gas used in the manufacture of hydrofluoric acid, as a reagent, catalyst, and fluorinating agent, and in the refining of uranium and the preparation of many fluorine compounds.
	Hydrogen Selenide (H2Se)		While free selenium is nontoxic, many of its compounds are extremely toxic and have modes of action similar to that of arsenic. Hydrogen selenide (H2Se) and other compounds are very toxic. H2Se is used to prepare metallic selenides and organoselenium compounds.  It is also used in doping gas mixtures for the preparation of semiconductor materials that contain a controlled amount of significant impurity.
	Hydrogen Sulfide (H2S)		Hydrogen sulfide (H2Se) is a colorless, flammable poisonous gas with a characteristic rotten-egg odor. It is used as an antiseptic, bleach, or reagant.
	Mercury Vapor (Hg)		Mercury (Hg) vapor is the vapor generated from elemental liquid mercury or compounds of mercury.
	Methane (CH4) / Natural Gas		Methane is a chemical compound with the chemical formula CH4. It is the simplest alkane, and the principal component of natural gas.
	Nitric Oxide (NO)		Nitric oxide is a gas with the chemical formula NO.  Nitric oxide is a toxic air pollutant produced by automobiles and power plants.
	Nitrogen Dioxide (NO2)		Nitrogen dioxide (NO2) is a red or orange/brown gas with a characteristic sharp, biting odor. Nitrogen dioxide is one of the most prominent air pollutants. Long-term exposure to concentration levels above 40 - 100 mcg/m³ causes adverse health effects.
	Nitrogen Oxides (NxOx)		Nitrogen oxides include dinitrogen oxide (N2O, nitrous oxide), dinitrogen trioxide (N2O3), dinitrogen tetroxide (N2O4), and dinitrogen pentoxide (N2O5).
	Oxygen (O2)		Oxygen (O2) is an atmospheric gas. The abundance of free oxygen is due to photosynthesis by plants.
	Ozone (O3)		Ozone is (O3) an unstable, poisonous allotrope of oxygen that is formed naturally in the ozone layer from atmospheric oxygen by electric discharge or exposure to ultraviolet radiation. It is also produced in the lower atmosphere by the photochemical reaction of certain pollutants. Ozone is a highly reactive oxidizing agent used to deodorize air, purify water, and treat industrial wastes.
	Phosphine (PH3)		Phosphine (PH3) is a colorless, spontaneously flammable, poisonous gas that has a fishy odor. It is used as a doping agent for solid-state components.
	Silane (SiH4)		Silane (SiH4) is a colorless gas that is both flammable and pyrophoric (i.e., capable of igniting spontaneously upon contact with air). It has a repulsive odor. Silane is used as a silicon source for the epitaxial deposition of single-crystal and polycrystalline silicon, for the low-temperature chemical vapor deposition of silicon dioxide, and for the chemical vapor deposition of silicon nitride films. It also is used for growth of amorphous silicon films.
	Sulfur Dioxide (SO2)		Sulfur dioxide (SO2) is a colorless, extremely irritating gas or liquid used in many industrial processes, especially the manufacture of sulfuric acid.
	Sulfur Hexafluoride (SF6)		Sulfur hexafluoride (SF6) is one of the most popular insulating gases (next to air). It is non-flammable, non-toxic, moderately inexpensive, and a good insulator because of its electronegativity. SF6 has breakdown strength of about three times that of air. At normal temperatures, it is non-corrosive and fairly inert; however, at temperatures above 500°C, SF6 decomposes. The decomposition products (i.e., fluorine) react with most substances, especially any water vapor.
	Water Vapor		Water vapor is water present in the atmosphere in gaseous form.
	Other		Other unlisted gas types.
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Electrical Outputs

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	Analog Current		Analog current levels (transmitters) such as 4 – 20 mA are suitable for sending signals over long distances. A current is imposed on the output circuit proportional to the measurement. Feedback is used to provide the appropriate current regardless of line noise and impedance.
	Analog Voltage		Analog voltage outputs are simple, usually linear functions of the measurement.
	Frequency		Frequency or modulated frequency outputs include amplitude modulation (AM), frequency modulation (FM), sine waves, and pulse trains.
	Switch		The output is a change in state of a switch or an alarm.
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General Features and Functionality

	Number of Channels		This is the number of channels.
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	Response Time		Response time is the time required for a sensor to read a certain percentage of a full-scale reading after being exposed to a full-scale concentration of a given gas.
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	Display
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	Analog		Data is displayed with an analog meter or simple visual indicator.
	Digital		Data is presented on a numerical or application-specific display.
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	Features
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	Audible or Visual Alarms		Instruments have audible or visual alarms to alert users to dangerous conditions.
	Controller		Instruments have or receive sensor inputs, provide control functions (e.g., limits, PID, logic etc.), and output a control signal.
	Data Logger		Instruments have integral or on-board data storage capability.
	Interchangeable Probes		Instruments are supplied with interchangeable probes for measuring different types of gases.
	Hazardous Environments		Instruments are rated for use in hazardous environments. They may be flameproof or waterproof.  This category does not include intrinsically safe devices.
	Intrinsically Safe		Intrinsically safe (IS) is an adjective for equipment and wiring which is incapable of releasing sufficient electrical or thermal energy under normal or abnormal conditions to cause ignition of a specific hazardous atmospheric mixture in its most ignited concentration. IS terminations and wiring may be brought into any hazardous location of any group classification for which it is accepted, without requiring explosion proof housing or other means of protection.
	Sampling Pump		The sample draw method causes the deliberate flow of the atmosphere being monitored to a gas-sensing element, typically called a sniffer.
	Self Calibration		Instruments are capable of self calibration for different types of gases.
	Sensor Array		A sensor array is a group of sensors working together to detect gases. Typically, the array is comprised of one or more sensors of the same technology and type.
	Temperature Measurement		The sensor or instrument measures and outputs temperature in addition to the measurement of gas variables.
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Environment

	Operating Temperature:		This is the full-required range of ambient operating temperature.
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	Operating Humidity:		This is the full-required range of ambient operating humidity.
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