Safety and Waste Management of Asbestos Cement Pipes
Bibliographic record
Abstract
Asbestos cement (AC) water mains, generally considered as non-friable asbestos-containing materials (ACMs), are not believed to represent a significant hazard to public health in normal use. However, repair, rehabilitation and removal of AC pipes involve cutting, polishing, and demolition can release asbestos fibers into the air, posing risks to public health. Many water utilities in North America currently have significant portions of their water mains composed of AC pipes. A comprehensive survey was conducted with 20 water utilities in the United States of America and Canada to understand the existing conditions of AC water mains in North America and to determine current management practices related to AC pipe repair, rehabilitation, and replacement. The survey was conducted through questionnaires that covered various areas: pipe inventory; environmental working conditions; current practices in pipe repair, rehabilitation and replacement; and safety/health protection practices used in working with, and disposing of AC pipe. This paper focuses on the survey results related to safety and disposal issues, including existing regulations related to testing and concentrations of asbestos fibers in drinking water, AC pipe project management, worker protection measures, and existing disposal practices for broken AC pipes. Results indicate that some utilities do not have well-established procedures to provide suitable protection for workers and the general public during AC pipe projects. Some current practices can also lead to potential problems for future site development. For example, less than half of the utilities reported having a formal procedure specifically for dealing with AC pipe in water distribution systems. When replacing broken AC pipes, more than half of the utilities had abandoned broken pipes and buried them in place as their primary method of disposal. Standardized procedures, which can be critical for the safety of workers, the public and future site development, are needed by water utilities for handling AC pipes during the repair, rehabilitation, and replacement of AC water mains.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".