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1
- #1
yudhichen
Mechanical
- Aug 22, 2013
- 53
Dear folks,
i'd like to ask your opinion.
recently i did some hydrostatic pressure test for wellhead equipment and record it under pressure chart (barton chart).
the graph were taken had a very slightly drop which drive me to think about allowable pressure drop tolerance.
i'm confused about what is acceptable and what is not acceptable when i look at those chart result.
As i look at API 6A, it doesn't mention 'allowable pressure drop' to qualify accepted test result.
API 6A on annex F.1.1.10 b) about hold period mention:
"Pressure shall be considered stabilized when the rate of change is no more than 5 % of the test pressure per hour
or 3,45 MPa/h (500 psi/h), whichever is less. Pressure shall remain within 5 % of the test pressure or within
3,45 MPa (500 psi), whichever is less, during the hold period."
on the other hand,
API 6A annex F.1.6.3 about pressure integrity mention:
"The hydrostatic test at room temperature is passed if no visible leakage occurs during the specified pressure hold
periods of the test. The pressure change observed on the pressure-measuring device during the hold period shall
be less than 5 % of the test pressure or 3,45 MPa (500 psi), whichever is less."
my case: the test pressure is 1,000PSI hold for 15 minutes (after stabilize).
1. if i look at annex F.1.1.10, it means pressure are allowed to change 50PSI/hour or 12.5PSI/15min.
2. if i look at annex F.1.6.3, it means pressure are allowed to change 50PSI.
so far, i think the logical acceptance criteria is following F.1.6.3.
i look it from engineering measurement perspective, the smallest scale that can only barton chart mention is 50PSI.
i couldn't say anything if the pressure drops less than 12.5PSI since it shows in analog.
My question:
1. does anybody has experience dealing with similar situation? and which of those 2 statements in API 6A apply for allowable pressure drop?
2. what does API mean for "pressure integrity"? can we say for example, seal test, as an integrity, so that we can take annex F.1.6.3 as a limitation?
Thank you in advance
yudhi
i'd like to ask your opinion.
recently i did some hydrostatic pressure test for wellhead equipment and record it under pressure chart (barton chart).
the graph were taken had a very slightly drop which drive me to think about allowable pressure drop tolerance.
i'm confused about what is acceptable and what is not acceptable when i look at those chart result.
As i look at API 6A, it doesn't mention 'allowable pressure drop' to qualify accepted test result.
API 6A on annex F.1.1.10 b) about hold period mention:
"Pressure shall be considered stabilized when the rate of change is no more than 5 % of the test pressure per hour
or 3,45 MPa/h (500 psi/h), whichever is less. Pressure shall remain within 5 % of the test pressure or within
3,45 MPa (500 psi), whichever is less, during the hold period."
on the other hand,
API 6A annex F.1.6.3 about pressure integrity mention:
"The hydrostatic test at room temperature is passed if no visible leakage occurs during the specified pressure hold
periods of the test. The pressure change observed on the pressure-measuring device during the hold period shall
be less than 5 % of the test pressure or 3,45 MPa (500 psi), whichever is less."
my case: the test pressure is 1,000PSI hold for 15 minutes (after stabilize).
1. if i look at annex F.1.1.10, it means pressure are allowed to change 50PSI/hour or 12.5PSI/15min.
2. if i look at annex F.1.6.3, it means pressure are allowed to change 50PSI.
so far, i think the logical acceptance criteria is following F.1.6.3.
i look it from engineering measurement perspective, the smallest scale that can only barton chart mention is 50PSI.
i couldn't say anything if the pressure drops less than 12.5PSI since it shows in analog.
My question:
1. does anybody has experience dealing with similar situation? and which of those 2 statements in API 6A apply for allowable pressure drop?
2. what does API mean for "pressure integrity"? can we say for example, seal test, as an integrity, so that we can take annex F.1.6.3 as a limitation?
Thank you in advance
yudhi