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Interpretation Response #PI-70-004 ([American Meter Company] [H. F. Kruzan])

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: American Meter Company

Individual Name: H. F. Kruzan

Location State: CA Country: US

View the Interpretation Document

Response text:

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

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 shut-off 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:

  1. Some gases being distributed may contain excessive amounts of sulfur compounds.
  2. Systems that were formerly operated on manufactured gas may contain tars, oils and dust.
  3. 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 this mean that it doesn't meet the requirements of this paragraph?

Answer: In Section 192.197(a)(1) the phrase "cable 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 6: 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.

Regulation Sections

Section Subject
192.3 Definitions