Acceptance Limits for Subsurface Voids in HDPE Piping
Bibliographic record
Abstract
Mandatory Appendix XXVI in Section III of the ASME Code (2015 Edition) includes the requirements for the construction of Class 3 high density polyethylene (HDPE) pressure piping. Currently, there are no acceptance limits for subsurface voids in HDPE piping included in the Code. Data from recent EPRI tests conducted to determine the rate of growth of flaws in HDPE piping can be used to develop acceptance criteria for subsurface voids. The tests exposed specimens with surface flaws to sustained loads under elevated temperature and stress conditions. No failures were observed in the tests. Therefore, the results are useful to establish lower bound lifetime estimates for flawed piping under the maximum allowable temperature and stress conditions for buried pipe. The HDPE material has considerable ability to resist crack growth at temperatures well above the maximum allowable service conditions permitted in Appendix XXVI. The test data were used to establish allowable subsurface void sizes in HDPE piping. Correlations for rupture time that are based on the applied stress intensity and net section stress were used to determine an allowable subsurface void size. Because the creep failure mechanism in HDPE piping is time-dependent, an allowable void size was developed to ensure HDPE pipe integrity at the void location for a 50-year service life. The allowable flaw sizes can be used for the disposition of void indications identified in piping both before and after installation.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.012 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.008 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".