Complying with odorization regulations

A question often posed concerning odorization is “Why odorize?” There are two basic answers to that question: regulations and liability. The first answer, regulations, is an easy one. Pipeline safety regulations promulgated by the Department of Transportation, Pipeline and Hazardous Materials Safety Administration, Office of Pipeline Safety (OPS) contain specific requirements in 49 CFR §192.625 that gas contain an odor. So, by law, operators are required to deliver odorized gas.

The second answer, liability, also seems easy. Odorization of a gas system is done with a single purpose in mind: provide the public with an effective warning device to alert them when there is a possible problem. Difficult to document, yet it continues to prove itself effective as gas companies continue to receive odor complaints on a regular basis.

Now that the easy answers are identified, let’s explore some of the more complicated issues behind each one.

49 §CFR 192.625 – Odorization of gas

Section 192.625(a) requires that “(a) A combustible gas in a distribution line must contain a natural odorant or be odorized...” Two critical issues are addressed here. First, all distribution lines must be odorized. There are no exceptions to this requirement. OPS reinforced this with an interpretation written on September 10, 1980, when questioned about a service line connected to an unodorized transmission line. OPS stated:

Section 192.625(a) requires that gas in distribution lines have a natural odor or be odorized to the limit prescribed. Since service lines are distribution lines, they are subject to the odorization requirements of §192.625(a). The exception from odorization provided by §192.625(b) for some transmission lines does not affect the requirement to odorize gas in distribution lines connected to an unodorized transmission line.

Second, this statement does not leave any latitude for lapses in odor in a distribution line. Operators must provide continuous odorization, 24 hours per day, 7 days per week, 365 days per year.

Note that this regulation does not require odorant be added to the gas. If the gas contains a natural occurring odor and meets the requirements of this paragraph, odorization is not required. OPS confirms this in an interpretation written on April 14, 1975.

If, however, a combustible gas is itself a natural odorant and can be smelled at the requisite concentration of gas in air, the requirement that the gas be odorized would not apply. At the same time, the other requirements in paragraphs (c)-(f) of Section 192.625, applicable to the odorant in combustible gases, must be met.

Section 192.625(a) continues with “…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.” This level of intensity must be met at all times. For odor recognition to be effective, the levels must be consistent, within reason, to avoid confusing the public and creating an excess or lack of complaint calls.

What does readily detectable mean? Using the Merriam-Webster Dictionary, on-line edition, “readily” is defined as “in a ready manner: as a) without hesitating: willingly b) without much difficulty…” “Detectable” is defined as “1: to discover the true character of 2: to discover or determine the existence, presence, or fact of…” Putting these two definitions together a definition can be developed of a “readily detectable odor” similar to the following:

Readily detectable odor – an odor that can be discovered, determined or whose existence can be identified in a ready manner, without hesitating or much difficulty.

How do operators ensure their personnel understand this concept, so as to be able to report correctly when testing odor intensities? Perhaps a better way of understanding this idea of readily detectable is to put it in a different perspective. “The odor of gas should be one that a spouse, family, or member of the general public would quickly recognize, prompting them to take appropriate action.”

All this must be at a concentration of one-fifth of the lower explosive limit (LEL), generally considered to be one percent gas-in-air. It would be prudent on the part of operators to include a definition of the lower explosive limit in their operations and maintenance manuals and training material. Consideration should also be given to including a definition or example of readily detectable in these documents.

Finally, there is the issue of a person with a “normal sense of smell.” Using numerous personnel to conduct odor tests is suggested. This allows for a range of olfactory sensitivities to be used to determine the odor intensity. Testing or “qualifying” a person’s sense of smell as part of an operator qualification program should be considered, as the results of the odor concentration tests will be used to prove compliance with §192.625.

Section 192.625 (b) requires that gas in transmission lines in Class 3 and 4 locations be odorized, but provides for a number of exceptions. One that must be closely reviewed is §192.625(b)(1), allowing gas in these locations to be exempt from odorization if at least 50% of the downstream piping is in Class 1 or 2 locations.

Operators are required under section 192.613 Continuing Surveillance, to monitor their system for changes in class location. If a class location change occurs along a segment of a transmission pipeline, further study of the odorization requirements is necessary. If a previously unodorized Class 3 or 4 location now requires odorization, it must be done within some time period. On February 6, 1979, the OPS wrote the following interpretation regarding time period allowed to implement odorization:

This is in response to your recent letter asking how much time is permitted under Part 192 to make system changes (in particular odorization) necessitated by class location changes…While §192.613(a) requires an operator to make necessary changes, no time period for compliance is specified.

However, a similar provision under §192.611(c) requires confirmation or revision of MAOP within 18 months after a change in class location. In view of this similarity, it appears that an 18-month compliance period is appropriate to apply under §192.613(a). In a previous interpretation, we have stated that the 18-month period begins to run upon completion of a structure which results in a new class location (see May 12, 1978 memo to DMT-213.)

Confirmation or revision of the MAOP is now in §192.611(d), which was amended in 2004 to allow operators 24 months for this task. It may be reasonable to assume that the logic in the above interpretation would continue to be applicable to this time period.

Sections 192.625(c) and (d) specify certain properties that odorant must have if it is used to impart an odor to gas. If the operator relies on a naturally occurring odorant, then it must also meet these requirements. Section 192.625(e) requires the odorant be introduced without wide variation. Again OPS has stepped in with an interpretation, written on October 31, 1973:

An acceptable range for variation of odorant concentration would be within a range no lower than a concentration which is readily detectable at one-fifth of the lower explosive limit by the typical person in Comment 1. The intent of the regulations is that the operator would not make variations in odorant concentration that could cause unwarranted public reaction. For the most part, each gas operator has determined the range of odorant concentration needed in its system for compliance with regulatory standards.

Section 192.625(f) states that operators must conduct periodic sampling to assure the proper concentration of odorant. While the word “odorant” is used in this paragraph, the intent is to assure that the gas meets the odor levels prescribed in §192.625(a).

Merriam Webster’s Dictionary provides a definition to assist in determining what period or time interval would be appropriate. “Period(ic)” is defined as “1: occurring or recurring at regular intervals.”

Considering that gas, where odorization is required, must be continuously odorized, the testing period should be selected to ensure that continuous odorization can be proven. Annually is certainly too long a time interval between tests, as is quarterly. Monthly may be acceptable if other data, such as leak call frequency, injection rates and random tests are done daily, or every other day at least.

A basic rule of thumb for testing is to conduct one test per 1,000 meters per month, or at least two tests per week, whichever is the greatest number of tests. An upper limit for tests might be one to two tests per day, from different areas of the system. Random testing on service calls is a good method to fill in additional tests beyond the baseline schedule.

Choosing the proper test points is critical to the success of the odorization process. A test point just downstream, in sight of the odorizer, will not give much useful information on how the odorant is carried throughout the system, mixing with other gas flows and inputs.

Certainly, endpoints of the system need to be considered as test locations. If the odor carries to the end of the system, then it is reasonable to assume that there is adequate odor at all points in between. However, changing flows, areas of low flow, types of pipe and entrained liquids can have an effect on odor quantity and quality. Test points should also be chosen throughout the system, to test the odor levels on as many types and conditions that exist in the system.

These test points should be developed as a baseline of information that is tested on a regular basis. Additional random testing should also be done, to catch that aberration that occurs. This testing can be done on service calls, which occur throughout the system at random locations. Observing the readings taken at standard test points and random locations will indicate if the entire system is protected.

A final rule published in 2003 (Amdt. 192-93, 68 FR 53895, Sept. 15, 2003) amended §192.625(f) to require odor tests be conducted “using an instrument capable of determining the percentage of gas in air at which the odor becomes readily detectable.” The “sniff” test, smelling a small release of gas, referenced in §192.625(f)(2) is a qualitative test that applies only to master meter systems if they are provided with additional documentation about odorization from their gas supplier.

The testing procedure, schedule, selection of test points, and reporting of results should be included in the operator’s operations and maintenance plan. Procedures should be specified for additional action when high or low odor intensities are determined (gas is not readily detectable at or below one-fifth of LEL.)

Odorization liability

How does the assignment of liability for odorization attach to a gas operator? Some courts have held that gas is dangerous if it is not confined. Odor detection levels, odorant quality, and periodic tests to assure proper odor levels are specified in the pipeline safety regulations. These court opinions and regulations impose a duty on the operator, a duty to exercise a high degree of care. Odorization, providing a warning to the public, is one means for exercising such care.

When an incident occurs the operator may be held liable for its actions leading to the incident. Even if the operator is in compliance with §192.625, there may be allegations of breach of duty to exercise a high degree of care. Often a claim is made of insufficient odor. One must remember that just because the plaintiff did not smell the gas, that does not mean the gas was not odorized.

If an operator has good records, this and other claims can be easily countered. Substantial documentation will be needed to refute “no odor” claims and the records must be accurate, dated appropriately and legible. The operator needs to show:

• Repeated odorization
• Injection rates
• Monitoring
• No evidence of fade
• Odor tests complying with §192.625
• Leak calls
• Tests made on service calls
• Type of odorant used
• Age of system and stability of odorant.

One method to identify liability exposures and documents available to refute odorization failure allegations is to audit the operator’s program. Conducting the audit is like putting a puzzle together. Each piece of the program, or topic element, must be examined to determine its effectiveness, and then it must be added to the whole system to evaluate its overall success.

Once all these pieces have been looked at, it is time to put the puzzle together. Can the operator answer the question – has the odorization program been continuous, consistent and operating as designed? If the answer is yes, then they must also answer the larger question – is the public provided with an effective warning device? If these questions cannot be answered satisfactorily, then the program needs to be changed.

Finally, in terms of liability exposure, an audit of the system verifies the operator’s knowledge of the odorization program. They will be able to prove they are experts in gas odorization, that the program meets its goals, and that as conditions change, they respond to those changes. This provides proof the gas operator is serious about the safety of the public and the gas system, and that the moral and legal duty is addressed with integrity and honesty.