Natural Gas Odorant Concentration Testing Methods
Updated: 5 days ago
Odorant testing methods answer different questions and have method-specific limits. Results depend on the target compound, sampling point, tube or sensor range, calibration status, interferences, environmental conditions and procedure. This article compares common concentration-testing approaches, including length-of-stain detector tubes, without treating one result as proof of systemwide detectability or compliance.
Understanding Testing Standards and Recommendations
ASTM Standards
ASTM publishes test methods with defined scopes, apparatus, procedures and limitations. A project should use the current edition of the selected method and confirm that it applies to the compound, sample, measuring range and decision being made. Citing a test method does not by itself establish regulatory applicability or compliance.
Length-Of-Stain Detector Tubes (Stain Tubes)
Length-of-stain tubes can provide compound-, tube- and range-specific field estimates when used under the applicable instructions. They should not be labeled universally as the least or most accurate method because performance depends on the selected tube, sample conditions, interferences, user technique and comparison method.
Operation
To use stain tubes, the operator breaks both ends of the tube and draws the test gas through it using a calibrated hand pump. The resulting stain length correlates with the concentration, which can be read from markings on the tube.
Advantages and Disadvantages
Advantages:
Speed
Low cost
Simplicity
Disadvantages:
Low accuracy (±25 percent)
Potential interferences from other gas constituents
Limitations in detecting trace-level measurements
Accuracy Considerations
Select a tube whose stated range and target compound fit the expected sample, then follow the current manufacturer and method instructions for sample volume, timing, reading and any applicable environmental correction. Do not apply a universal center-of-range accuracy rule unless the selected tube documentation supports it.
Disposal Considerations
Do not assign used tubes, sorbent, rinse water or packaging a disposal method from a generic webpage. Review the current manufacturer instructions and safety data, characterize the waste as required, and follow the approved site and jurisdictional waste procedure. Do not soak or neutralize tubes unless the applicable instructions and waste plan specifically authorize it.
A defensible testing program documents why the method was selected, where and when the sample was taken, the instrument or tube range, calibration or lot information, environmental conditions, corrections, uncertainty and result. Concentration measurements can support troubleshooting and trending, but they do not independently establish perceived odor intensity, systemwide performance or compliance.
At Burgess Pipeline Services, we are committed to providing top-notch solutions for natural gas odorization. Contact us today to learn more about our services and how we can support your operations.
Related Reading
Portable Odorant Analyzer
Concentration Testing Support
Comparable concentration records should identify the sample location and time, test method, instrument range and calibration status, reported units, and relevant operating conditions. See Pipeline Operations & Maintenance for field monitoring and documentation support.
