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Guide to selecting the proper gas detector

1) What gases do I need to detect? OSHA mandates monitoring of combustible, toxic, oxygen-deficient/enriched gases in confined spaces.

Common Gases

(Combustible / %LEL): Many combustible gases such as Natural gas (Methane), propane, and hydrogen can be detected when using the proper gas sensor. Methane gas is commonly found in landfills, wetlands, sewers, agriculture, biofuels, and oil refining.

Oxygen (O2): Oxygen levels in the atmosphere are usually at 21%. However, in confined spaces, other gases can displace oxygen. When oxygen levels drop below 19.5%, it can pose a health risk.

Hydrogen Sulfide (H2S): Organic materials and wastes produce hydrogen sulfide. H2S gas can result from various human activities such as petroleum/natural gas drilling and refining, wastewater treatment, landfills, coke ovens, tanneries, and Kraft paper mills.

Carbon Monoxide (CO): When fuels like gas, oil, coal, and wood burn incompletely, carbon monoxide is produced. Common sources of carbon monoxide are vehicles, boilers, gas-driven machinery, water heaters, and cookers.

Toxic gases: While CO and H2S are frequently monitored, OSHA mandates that any gas that endangers health must be monitored. Gas meters are available with a variety of gas combinations. If you cannot find the combination you need, please reach out to our technical team for help.

2) What features and options do you need?

Sampling Pump: A pump can be used to test the air quality of a confined space before entering. It is important to test the entire space since some gases are lighter than air and others are heavier. Please specify the length of hose required to test the entire space. A pump with a hose and probe is useful for leak detection around valves and fittings.

(Size) Large or small? Generally the larger the meter the more robust it is. Although larger gas meters are more expensive, they are designed for heavy-duty use. If your application is demanding, then you should consider a lunchbox-style meter like the RKI Eagle or Eagle 2. For personal monitoring, it is advisable to use smaller meters. The ideal solution is to provide the entrant with a compact meter and the standby with a sample draw meter.

Batteries: Rechargeable or Replacement Alkaline batteries. Most meters provide 8-12 hours of operation from each new set of Alkaline batteries. Due to this, most end users purchase rechargeable batteries. The downside of rechargeable batteries is that if you forget to charge the batteries the meter will not work. Many of the meters we sell can be supplied with both options so that if you forget to charge the batteries you can insert Alkaline batteries.

Data-Logging: Most meters we sell are available with data-logging. Data logging allows the user to record daily gas readings with time and date stamps for record-keeping requirements. Most meters can record over a week’s worth of readings.

3) What sensing technology is best for my application? This is where our in-house technical group can assist you the most. Some gases may damage a gas sensor. For example, a Catalytic-style combustible sensor can be damaged by Chlorine and Halogenated gases. If this is the case then an (IR) infra-red sensor may be the answer. Some gases present a toxic hazard well before a gas become flammable. If this is the case you need to monitor this gas in the low ppm or PPB range. A (PID) Photo-ionization detector can detect organic vapors in the very low PPM and PPB range.

Limitations: If the environment you intend to monitor is too harsh to support life then the meter will not survive that environment. These meters are designed to detect gas in low concentrations and should never be exposed to conditions outside of their specifications. Please see the meter specifications which detail the temperature, humidity, and gas range of the meter prior to purchase. If you are not sure the meter is correct for your application, please contact our technical group for assistance.

Featured Products

Smallest 4-gas meter in the world

GX-3R – Size of a pager; a vibration alarm calls your attention to the meter in high noise environments, add on sample pump for remote sample capability, 2-year warranty. Great for climbing ladders and entering tight spaces.

Rough and Tough

Eagle 1 & Eagle 2 – For heavy-duty use. Takes abuse that smaller portable meters can’t survive in. Too many features to list – Please see the specifications for details.

Broad Range Sensitivity

GX-6000 – Detects VOCs in the ppm gas range. When a gas is toxic, before it becomes flammable, this is the meter for the job. This meter detects a broad range of gases. Please contact our technical group for assistance in picking the correct GX-6000 meter for your application.

Responsibility for the use of any information contained in this e-mail is strictly and solely that of the user.

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