Frequently Asked Questions

Calibration gas cylinders should be stored upright in a secure, well-ventilated area away from heat sources, direct sunlight, ignition sources, and corrosive chemicals. Keep cylinders capped when not in use, clearly labeled, and separated by gas type if required. Storage temperatures should remain within the manufacturer’s recommended range to maintain gas stability and accuracy. It’s also important to regularly inspect cylinders for damage, leaks, expiration dates, and proper pressure levels.

When handling pressurized gas cylinders, always secure cylinders upright to prevent tipping, use the correct regulator and fittings for the gas type, and keep protective valve caps in place during storage or transport. Cylinders should be stored away from heat, flames, and impact hazards in a well-ventilated area. Never drag, roll, or lift cylinders by the valve, and always inspect for leaks or damage before use. Proper labeling, employee training, and following OSHA and manufacturer guidelines are also essential for safe handling.

The shelf life of a typical calibration gas cylinder depends on the gas mixture and cylinder type, but most calibration gases last between 12 and 36 months. Reactive gases, such as hydrogen sulfide or chlorine, generally have shorter shelf lives, while non-reactive gases can remain stable longer. Always check the cylinder label or certificate for the expiration date, as expired calibration gas can affect accuracy and compliance.

Calibration gas standards and certification requirements ensure that calibration gas mixtures are accurate, traceable, and compliant with industry regulations. Most certified calibration gases are produced according to standards such as ISO 17025 and ISO 17034, with traceability to organizations like National Institute of Standards and Technology (NIST). Certificates of Analysis (COAs) typically include gas concentration, accuracy tolerance, expiration date, and traceability information to verify reliability for safety, industrial, and environmental monitoring applications.

Colorimetric gas detection tubes contain a chemical reagent that reacts with a specific gas or vapor. A measured volume of air is typically drawn through the tube using a compatible sampling pump. If the target gas is present, the reagent changes color, and the concentration can be read from the calibrated scale printed on the tube. Instrument Depot offers gas detector tubes and sampling systems from manufacturers such as Gastec and Draeger for quick, on-site gas measurements.

Portable gas detection tubes are useful for quick spot measurements. They require no batteries or electronic calibration and are generally economical and easy to transport. Electronic gas detectors use sensors to provide continuous or repeated real-time monitoring and may include audible or visual alarms when concentrations exceed established limits. For occasional testing or measuring a particular contaminant, detector tubes may be appropriate; for continuous monitoring and immediate alarms, an electronic detector is generally more suitable.

Colorimetric tubes use a chemical reaction to produce a visible color change indicating the concentration of a specific gas or vapor. They're typically single-use and well suited to spot measurements. Digital gas detectors use electronic sensors and can provide continuous readings, alarms, and, depending on the instrument, monitoring for multiple gases. Tubes offer simplicity, portability, and no battery requirement, while digital instruments are generally better suited to applications requiring ongoing monitoring and immediate hazard notification.

Handheld gas detector tube systems can measure hundreds of gases and vapors, depending on the manufacturer and tube selected. Instrument Depot carries tubes for substances including carbon monoxide, carbon dioxide, ammonia, chlorine, hydrogen sulfide, benzene, acetone, hydrocarbons, sulfur dioxide, ozone, and many others. Instrument Depot offers gas detector tubes and pumps covering more than 600 gases, vapors, and aerosols, making tube systems useful across industrial hygiene, manufacturing, HazMat, environmental, and workplace safety applications.

Gas detection tubes have manufacturer-defined expiration dates and should not be used beyond those dates. Shelf life and measurement performance vary by tube, target gas, and manufacturer, so there isn't one lifespan or accuracy specification that applies to every detector tube. Accuracy can also be affected by sampling volume, temperature, humidity, interfering gases, and proper pump operation. For reliable results, use an unexpired tube within its specified measurement range and follow the manufacturer's sampling instructions and any applicable correction factors. Instrument Depot provides specifications for its Gastec and Draeger gas detector tubes to help users select the appropriate tube for the application.

When purchasing gas detection tubes, look for products from established manufacturers with documented measuring ranges, sampling procedures, expiration dates, and quality-control information. The tube should be specifically designed for the contaminant and concentration range being tested, and the sampling equipment should be compatible with the tube manufacturer. For example, Instrument Depot notes that Gastec gas detection tubes are manufactured in ISO 9001-certified facilities and that expiration dates and lot numbers are printed on Gastec tubes. Always consider the specific occupational or regulatory requirements that apply to your workplace and application rather than relying on a certification alone.

Gas detectors should generally be calibrated every 30 to 180 days, depending on the manufacturer’s recommendations, the operating environment, and the type of gas being monitored. Detectors used in harsh conditions or critical safety applications may require more frequent calibration. Regular bump testing between calibrations is also recommended to confirm the detector is responding properly.

Common errors during gas detector calibration include using expired or incorrect calibration gas, applying the wrong gas concentration, failing to allow enough stabilization time, and using damaged regulators or tubing that can cause leaks. Other mistakes include calibrating in contaminated environments, skipping bump tests, and not following the manufacturer’s recommended calibration procedures or intervals.

For a typical short-term detector tube, break the sealed ends using an appropriate tube-tip breaker, insert the tube into the compatible pump in the specified direction, and draw the required volume of air through it. After the specified sampling period, read the color-change endpoint against the tube's calibrated scale. Because procedures differ among tubes, always follow the manufacturer's instructions for the specific tube being used. Used tubes contain broken glass and chemical reagents, so they should be handled carefully and disposed of according to the manufacturer's instructions and applicable workplace and local waste regulations.

Start by identifying the exact gas or vapor you need to measure and the concentration range you expect to encounter. Then select a gas detector tube designed for that substance and measurement range, checking for potential interfering gases, required sampling volume, number of pump strokes, sampling time, and correction factors. You should also make sure the tube is compatible with your sampling pump. Instrument Depot carries Gastec and Draeger gas detector tubes covering hundreds of gases and multiple concentration ranges, allowing the tube to be matched more closely to the specific testing application.

Replacement pump parts and accessories are available from Instrument Depot for supported gas detector pump systems. For example, Instrument Depot offers a Draeger Accuro Spare Parts Kit containing common wear components including a tube socket, indicator membrane, and exhaust valve discs. The site also carries Draeger pump accessories as well as Gastec pumps, pump kits and accessories. When ordering replacement parts, match the component to the exact pump manufacturer and model.