Comprehensive Odorization Glossary for Gas Pipeline Safety

Break-through: During pickling/conditioning, break-through is the point when increased odor levels are detected downstream in the system.

Conditioning: Conditioning, also known as "pickling" or pre-odorizing, is performed when a new gas pipeline is commissioned. The line continues to absorb odorant until saturated, leaving the gas with weak or no odor at the outlet. Conditioning accelerates this saturation process for safe operation.

Distribution Line: A distribution line is a pipeline responsible for distributing gas.

Disulfide: A disulfide refers to the structural unit composed of a linked pair of sulfur atoms.

Hydrotest/Hydrostatic Test: Hydrotest or hydrostatic test is a method to test pressure vessels, such as pipelines, using water for strength and leak testing.

Injection Rate: Injection rate, also known as odorization rate, is the ratio of the amount of odorant added to a known volume of gas.

Odorant: Odorant is a mixture of organic sulfur compounds with a strong, persistent, and unpleasant odor detectable at very low concentrations.

Odor Concentration: Odor concentration is the percent gas in the air at which gas odor is detected or recognized.

Odor Fade: Odor fade is the loss of odorant due to physical or chemical processes inside the pipeline or from an underground leak through surrounding soil.

Odor Intensity: Odor intensity is the perceived strength of an odor.

Odor-Intensity Test: Olfactory test with a gas dilution apparatus to satisfy periodic sampling requirements.

Odor Masking: Odor masking is a change or reduce the perceived presence of the gas odorant.

Odorant Concentration: Odorant concentration is the concentration of odorant molecules in a gas, expressed in lbs/MMSCF or ppm.

Odorization: Odorization is the act of adding odorant to gas pipelines.

Odorizer: An odorizer is equipment used to odorize gas.

Pickling: Pickling is synonymous with conditioning, the process of saturating a new gas pipeline with odorant during commissioning to eliminate the risk for odor fade.

Readily Detectable: Readily detectable refers to a condition where a person with a normal sense of smell can quickly discover gas in the atmosphere without hesitation or difficulty.

Secondary Containment: Secondary containment is used to contain odorizers and associated storage tanks and vessels.

Sniff Test: Olfactory test with a gas dilution apparatus to meet periodic sampling requirements of 49 CFR §192.625.