Natural gas odorant systems must comply with federal regulations under 49 CFR 192.625, which mandates that natural gas be odorized to provide a distinctive odor detectable at concentrations as low as one-fifth of the lower explosive limit. Additional compliance requirements include regular odor intensity testing, proper documentation of odorant injection rates, and maintenance of odorant detection equipment. State and local regulations may impose additional requirements for gas odorization services. Burgess Pipeline Services ensures full regulatory compliance for all natural gas odorization projects, providing documentation and testing services that meet federal, state, and local requirements for safe natural gas operations.

Natural gas is odorized through a variety of mercaptan blends: tertiary butyl mercaptan, tetrahydrothiophene, isopropyl mercaptan, dimethyl sulfide, and methyl ethyl sulfide.

Common suppliers of odorant are Arkema's Spotleak blends and Chevron Phillips Scentinel gas odorants.

Odor fade can be overcome by pickling, conditioning, pre-odorization, or odor fade remediation of the natural gas pipeline. Burgess Pipeline Services uses two methods to overcome the odor fade phenomenon by Static Pickling or Dynamic Pickling.

Natural gas should be odorized so that gas is readily detectable by a person with a normal sense of smell at a concentration in air of one-fifth of the lower explosive limit. A combination of tests can be used to determine the concentration needed for injection. These test include sniff tests, sulfur analyzers or gas detector tubes.

§ 192.625 Odorization of gas.

(a) A combustible gas in a distribution line must contain a natural odorant or be odorized so that at a concentration in air of one-fifth of the lower explosive limit, the gas is readily detectable by a person with a normal sense of smell.

(b) After December 31, 1976, a combustible gas in a transmission line in a Class 3 or Class 4 location must comply with the requirements of paragraph (a) of this section unless:

(1) At least 50 percent of the length of the line downstream from that location is in a Class 1 or Class 2 location;

(2) The line transports gas to any of the following facilities which received gas without an odorant from that line before May 5, 1975;

(i) An underground storage field;

(ii) A gas processing plant;

(iii) A gas dehydration plant; or

(iv) An industrial plant using gas in a process where the presence of an odorant:

(A) Makes the end product unfit for the purpose for which it is intended;

(B) Reduces the activity of a catalyst; or

(C) Reduces the percentage completion of a chemical reaction;

(3) In the case of a lateral line which transports gas to a distribution center, at least 50 percent of the length of that line is in a Class 1 or Class 2 location; or

(4) The combustible gas is hydrogen intended for use as a feedstock in a manufacturing process.

(c) In the concentrations in which it is used, the odorant in combustible gases must comply with the following:

(1) The odorant may not be deleterious to persons, materials, or pipe.

(2) The products of combustion from the odorant may not be toxic when breathed nor may they be corrosive or harmful to those materials to which the products of combustion will be exposed.

(d) The odorant may not be soluble in water to an extent greater than 2.5 parts to 100 parts by weight.

(e) Equipment for odorization must introduce the odorant without wide variations in the level of odorant.

(f) To assure the proper concentration of odorant in accordance with this section, each operator must conduct periodic sampling of combustible gases using an instrument capable of determining the percentage of gas in air at which the odor becomes readily detectable. Operators of master meter systems may comply with this requirement by -

(1) Receiving written verification from their gas source that the gas has the proper concentration of odorant; and

(2) Conducting periodic “sniff” tests at the extremities of the system to confirm that the gas contains odorant.

[35 FR 13257, Aug. 19, 1970]

Pipeline pickling is a specialized conditioning process that pre-treats new natural gas pipelines with odorant before they go into service. This process prevents odor fade by saturating the pipeline walls with mercaptan, ensuring consistent odor detection throughout the pipeline's operational life. Burgess Pipeline Services offers both static and dynamic pickling methods to optimize pipeline safety and regulatory compliance.

Odor fade occurs when odorant molecules are absorbed into new pipeline walls, react with mill scale and metal oxides, or are diluted by pipeline materials. This phenomenon is most common in newly installed pipelines and can compromise safety by reducing leak detectability. Professional pipeline conditioning and pickling services prevent odor fade before it becomes a safety concern.

Static pickling involves filling a pipeline with odorized gas while the line is offline, allowing extended contact time for odorant absorption. Flowing pickling injects odorant while gas flows through the pipeline during commissioning. Both methods effectively condition pipeline walls to prevent odor fade, with the choice depending on project timeline, pipeline configuration, and operational requirements.

Federal regulations require periodic sampling to ensure proper odorant concentration. Testing frequency varies by system type and location, but typically ranges from monthly to annually. Methods include sniff tests and analyzers. Regular monitoring ensures compliance with safety regulations and maintains effective leak detection capability.

Distribution pipelines always require odorization for public safety. Transmission pipelines in Class 3 and 4 locations must also be odorized unless specific exemptions apply. New pipeline installations, pipeline extensions, and systems experiencing odor fade all benefit from professional odorization services to ensure safety and regulatory compliance.

A mercaptan injection system is specialized equipment used for natural gas odorization that precisely controls the injection of mercaptan odorant into gas pipelines. The system typically includes injection pumps, flow meters, and control valves that ensure accurate mercaptan injection rates according to 49 CFR 192.625 compliance standards. These systems are essential for pipeline odorization services as they maintain consistent odorant levels for effective gas leak detection. Burgess Pipeline Services provides comprehensive mercaptan injection system installation, calibration, and maintenance to ensure optimal natural gas pipeline safety.