Interpretation Response #PI-86-005 ([Memo: Internal])
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
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Response text:
ROUTE SLIP
August 4, 1986
Ivan, Can you explain what they mean in this response? Ed
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Yes, If during the period 7/65 - 7/70, the pressure at C.S. "A" = P1 and at downstream C.S. "B" pressure = P2, the MAOP of the line from "A" to "B" is not P1. The MAOP will vary with the actual pressure imposed at any point at the time the line was operated at the subject pressures.
Ivan
10-13-87
From: Frank Fulton
Clarification of Questions and Answers to Ivan Huntoon's Interpretation Request - 192.619(c) (Questions by Ivan - Answers by Frank Fulton and Buck Furrow)
Q. Is it the intent of the regulations that the pressure gradient be ignored in determining the MAOP and that the MAOP for the entire line from A to B be established at 850 psi?
A. No, the intent of .619(c) is to allow old safe operations to continue, but not be exceeded. Thus, pressure gradient would have to be continued. The MAOP of an element inside the segment could not exceed its old operating level.
Q. Are we to consider the "segment of pipeline" to be that length from A to B; and since it was operated at 850 psi at A, the entire segment is qualified for 850 psi?
A. In the final rule "segment" replaced "section" or "portion", but it has no definite beginning or end. If A and B mark a segment the MAOP of the segment under .619(c) would vary according to past operation and not be uniform as it would under .619(a).
Q. Is the MAOP established at 850 psi because of the probability that at some time during the five year period the line was packed to 850 psi from A to B?
A. No
Q. Is it necessary for the pressure at B to have been 850 psi to qualify the entire line for an MAOP of 850 psi?
A. Yes
Q. As an inspector, must I verify that the entire line from A to B was subjected to 850 psi sometime during that five year period?
A. Yes
Q. Is it adequate to assume that it was because the line was frequently operated at a discharge pressure of 850 psi at A?
A. No
Q. Do the regulations require that the operator have records to substantiate the pressures used to establish the MAOP per 192.619(c)?
The regulations do not require "records", however, enforcement personnel have to apply judgment as to what they will accept to substantiate the operator claim. A violation would have to be clearly obvious in order to be enforceable.
Records (i.e., pressure recording charts, compressor station records, flow calculations from a substantiated point, dispatcher records, etc.), sworn statements by the operator, etc., would be means that the operator could use to establish the highest pressure for the 5 year period.
ROUTE SLIP
August 4, 1986
To: Ivan Huntoon
Can you explain what they mean in this response?
Ed -----------------------------------------------------------------
Yes! If during the period 7/65 - 7/70, the pressure at C.S. "A" = P1 & at downstream C.S."B" pressure = P2, the MAOP of the line from "A" to "B" is not P1. The MAOP will vary with the actual pressure imposed on at any point at the time the line was operated at the subject pressures.
From: Frank
Date: April 12, 1985
Subj: Intent of 192.619(c)
From: Ivan A. Huntoon, Staff Engineer, DMT-14
To: Frank Fulton, Chief, Pipeline Safety Enforcement, DMT-13
During our telephone conversation on April 5, 1985, I questioned the intent of the "grandfather clause", 192.619(c). As I am not certain that I satisfactorily stated the situation, it is stated in this memo, as are the questions which arose.
I would like to have our position clarified in regard to this matter. Please call if you have any questions.
The "grandfather clause", 192.619(c), states that an operator may operate a segment of pipeline found to be in satisfactory condition, considering its operating and maintenance history, at the highest actual operating pressure to which the segment was subjected during the five years preceding July 1, 1970...subject to the requirements of 192.611.
My concern lies with the intent of the regulations as related to consideration of pressure gradient in the pipeline. Possibly it revolves around "segment of pipeline". Consider the following example.
I have a gas transmission line. The maximum allowable operating pressure (MAOP) between compressor stations A and B is established by 192.619(c) to be 850 psi. By the other criteria of 192.619, the MAOP would be 650 psi. The 850 psi MAOP is established on the basis of one day's operation in April of 1970 (or any other day during the five years preceding July 1, 1970) when the discharge pressure at A, the upstream station, is 850 psi at some time during that day. The suction pressure at station B corresponding to the 850 psi at A is 450 psi. Consider the line section to be entirely in a Class 1 location from A to B.
Is it the intent of the regulations that the pressure gradient be ignored in determining the MAOP and that the MAOP for the entire line from A to B be established at 850 psi?
No, the intent of .619(c) is to allow old safe operations to continue but not be exceeded. Thus pressure gradient would have to be continued. The MAOP of an element inside the segment could not exceed its old operating level. In the final rule "segment" replaced "section" or "portion" but it has no definite beginning or end. If A and B mark a segment, the MAOP of the segment under .619(c) would vary according to past operation and not be uniform as it would under .619(a).
Are we to consider the "segment of pipeline" to be that length from A to B; and since it was operated at 850 psi at A, the entire segment is qualified for 850 psi?
Is the MAOP established at 850 psi because of the probability that at some time during the five year period the line was packed to 850 psi from A to B? NO
Is it necessary for the pressure at B to have been 850 psi to qualify the entire line form an MAOP of 850 psi? YES
{As an inspector, must I verify that the entire line from A to B was subjected to 850 psi sometime during that five year period,} YES {or is it adequate to assume that it was because the line was frequently operated at a discharge pressure of 850 psi at A?} NO
Do the regulations require that the operator have records to substantiate the pressures used to establish the MAOP per 192.619(c)?
The regulations do not require "records", however, enforcement personnel have to apply judgement as to what they will accept to substantiate the operator claim. A violation would have to be clearly obvious in order to be enforceable.
Records*, sworn statements by the operator, etc., would be means that the operator can use to establish the highest press. for the 5 year period.
*Press. recording charts compressor sta. press. records flow calculations from a substantiated point dispatcher records etc.