PRESSURE RELATED STANDARDS AND PERFORMANCE OF WATER DISTRIBUTION SYSTEMS
Notice bibliographique
Résumé
The standard design approach of water distribution systems requires that pressure at any point in the system is maintained within a range whereby the maximum pressure is not exceeded so that the likelihood of a pipe burst is reduced and the minimum pressure is always maintained or exceeded to ensure adequate flows for satisfying expected demands. High pressure systems tend to cause more frequent pipe breaks and an increase in energy use and leakage. Low pressure systems cause consumer complaints, make the system more susceptible to negative pressures, and possibly to the ingress of contaminants during transient events. The overall goal of establishing pressure standards is to balance these opposing tendencies to achieve a safe, reliable, and economic operation of the system. Yet, there are no universally acceptable or established rules or guidelines for establishing a pressure standard for water distribution system design, and few studies have considered whether the traditional standards are still applicable in modern systems. This study has made a critical appraisal on what pressure standards mean, where they are violated, and where they need revision to achieve a comprehensive picture about what the pressure standards really mean. The research also highlights the inter-related issues associated with pressure criteria. Assessment of the relationships governing water pressure, leakage, energy use and economics is realized via the analytical investigation of single pipes and the simulation of representative networks using the steady state analysis software EPANET 2. The role of minimum pressure standards, storage, pumping strategy, and resource prices on the energy and water loss of systems is analysed and assessed. In anticipation that pressure contributes to pipe break rates, a probabilistic approach considering uncertain water demand and pipe’s roughness modeled with a Monte Carlo simulation (MCS) algorithm is presented. This study also explores how the minimum pressure standards affect transient pressures and reviews how destructive transient pressures may be controlled to limit reduced pressure surges within acceptable limits even when the minimum steady state pressure is relatively low. In order to place the research in practical context, this study develops a surge limit control algorithm for the design of a portable device for limiting the down-surge pressures by creating a pressure control boundary in a pipe system during hydrant operations. This boundary is established using the portable control device to safely operate a hydrant in a water distribution system. This study also highlights the notion that high level of pressure standards may lead to a troublesome squandering of water and energy and may disrupt the performance of water distribution systems. Given the too often degraded nature of water supply infrastructures, the on-going challenges of urban growth, and the increased stress on natural resources, the significant benefits of better controlling water pressure are not only welcome but urgently needed.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,005 | 0,026 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,002 | 0,002 |
| Études des sciences et des technologies | 0,001 | 0,001 |
| Communication savante | 0,004 | 0,004 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».