Interpretation Response #PI-70-015
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Mr. H. F. Kruzan
Chief Engineer Regulators
American Meter Company
300 North Gilbert Avenue
Fullerton, California 92633
Dear Mr. Kruzan:
Thank you for you letter of October 28, 1970, requesting an official interpretation of certain sections of 49 CFR, Part 192. The interpretation requested are furnished herewith:
Question 1: Section 192.145 and others: Are pressure regulators to be classified as valves?
Answer: Generally speaking pressure regulators are valves and as such must meet the general requirements of this section. The requirements of API-6A and API-6D are limited to steel gate valves, plug valves, ball valves and check valves 2" and larger in size and MSS-SP-52 is limited to cast iron gate valves, plug valves and swing check valves 2" and larger in size. The omission of specification for other types of valves does not exempt them from the general requirements of this section.
Question 2: Section 192.195(b)(1)(2): Distribution System. What is the intent of the special requirement for Distribution Systems? What type of installation will meet this requirement: Monitor, Parallel Stand-By Regulator, or What?
Answer: The intent of Section 192.195(b). Additional requirement for distribution systems is to prevent subjecting a distribution system to pressures above the maximum allowable operating pressure of the distribution system. For example, this could be accomplished by use of a monitor type of installation, by a series cut in pressure where the pressure ahead of the downstream regulator is less than the MAOP or the distribution system or by use of relief or automatic over pressure shut-offs. The relief or automatic shutoff may be either built in to the regulator or separate units.
Question 3: Section 192.197(a)(6): Please define the term "Control Line." It is synonymous with static line? There are certain pilot loaded pressure regulators that do not require a static line, but do require a pilot inlet supply line. If this line is broken, the regulator will close. An overpressure condition cannot be experienced due to breakage of this line. Please comment.
Answer: The term "Control Line" used in paragraph 192.197(a)(6) is considered synonymous with "Static Lines." This is taken verbatim from the B31.8 - 1968, paragraph 845.51(f). A pilot supply line may be necessary to the operation of a pilot controlled regulator but is not considered as prohibited by this paragraph.
Question 4: Section 192.197(b): Concerns gas content of materials that could interfere with the operation of a service regulator. Question: Does this mean normal content, or is the operator responsible for any abnormal interpretation, this could mean the end of service regulators that are not equipped with an approved type safety device, could it not?
Answer: In Section 192.197(b) the phrase "or if the gas contains materials that seriously interfere with the operation of service regulators" is meant only to apply to those conditions that can be reasonably anticipated. As examples:
- Some gases being distributed may contain excessive amounts of sulfur compounds.
- Systems that were formerly operated on manufactured gas may contain tars, oils and dust.
- If new lines are not cleaned before being placed in service they may contain foreign materials that were introduced during construction.
Question 5: Section 192.197(a)(1): Paragraph specifies a regulator "capable" of reducing distribution pressure, etc. If such a regulator also has the capability of being adjusted for higher pressures, does the mean that it doesn't meet the requirements of this paragraph?
Answer: In Section 192.197(a)(1) the phrase "capable of reducing distribution line pressure to pressures recommended for household appliances" is in no way a restriction on the capability that may be designed into a regulator.
Question: Section 192.201(c) and Others: The deletion of 2 psig W.P. so as to conform to "performance type specifications, leaves interpretation of "safe pressure" wide open. There will undoubtedly be many opinions as to the proper pressure limitation. On what basis will DOT determine compliance?
Answer: The phrase "the safe operating pressure for any connected and properly adjusted gas utilization equipment" in Section 192.201(c) is intended to place the burden on the operator to prevent unsafe conditions. There are some appliances that may be adjusted for normal operation at 4 to 6 inches water column that would be dangerous with a 1-1/2 to 2 psig inlet while some others would take 4 to 5 psig and be safe. The operator must determine the maximum safe operating pressure and install appropriate relief devices.
Question 7: Section 192.63 Marking of Materials: Please elaborate on this requirement. Examples would be of help. Does this apply to any and all pressure regulators; service, appliance, etc., small and large? Is the intent to identify casting material per ASTM specification, etc., or to identify the complete product with a given specification?
Answer: In Section 192.63 the intention is to require positive identification of the equipment or component and thus assure that it is not subjected to operating and conditions exceeding those for which it was designed. Where the requirements of MSS SP-25 apply they should be followed. Under the definition of "service line" presently contained in Section 192.3 the standards of Part 192 do not apply downstream of 192.3 the standards of Part 192 do not apply downstream of the customer's meter, therefore, house piping and appliances do not have to be marked.
Question 8 : Section 192.275(e): May cast iron valves or filters be made with flanges not cast integrally, but assembled to the valve or filter body with retaining rings? Is this requirement different if these cast iron valves or filters are installed in steel pipe?
Answer: Section 192.275(e) is a rewording of the B31.8, subparagraph 842.15(d) and clearly requires flanges or flanged joints to be integrally cast with the pipe, valve or fitting. This does not prohibit the connection of cast iron flanges to flanges of other materials.
Question 9: Section 192.509(b): Are "conversion" operations affected by this requirement, or are they wholly governed by Subpart K - Uprating?
Answer: It is assumed that by the term "conversion" you are referring to increasing operating pressure on a gas system from low pressure (see definition in Section 192.3). Section 192.509(b) applies to new construction and does not apply to uprating.
Question 10: Section 192.145(c)(2) Ductile Iron: Is welding of any type an acceptable method of casting salvage? In our area, foundry suppliers have been quite successful in this procedure.
Answer: Section 192.145(c)(2) is taken directly from the B31.8, 1968 edition, paragraph 831.11(b) and prohibits such welding. This may be considered for a possible proposal of rulemaking.
If your have further questions, do not hesitate to ask.
Joseph C. Caldwell
Office of Pipeline Safety
|§ 192.195||Protection against accidental overpressuring|