AWWA JAW60845

Negative pressures have been documented in a varietyof distribution systems as a result of eitherunintentional (e.g., power outages) or intentional(e.g., pump stoppage or startup tests) circumstances.The production of transient low and negative pressuresin otherwise pressurized potable water supply distributionsystems creates the opportunity for contaminatedwater to enter the distribution system from externalenvironments. However, few systematic or long-termstudies have monitored real distribution systems for theoccurrences of transient low and negative pressuresunder field conditions. A comprehensive and lengthystudy was conducted to monitor the occurrence of low- andnegative-pressure transients and to evaluate theeffect of a variety of operational situations on the developmentof these events. The authors also compared theefficacy of electronic and mechanical pressure-monitoringdevices for detecting transient pressure surges.Because of the danger of contamination, the watersupply profession should be aware of the occurrenceand potential adverse effects of transient low and negativepressures. Water providers can use the informationin the article to aid in the design of a pressure-monitoringprogram to help determine their systems' susceptibilityto low and negative pressures. Such a programcould use hydraulic surge models to assess the potentialfor pressure transients to occur throughout the systemunder a variety of operating conditions. Study resultsalso point to the usefulness of high-speed electronicpressure monitors for detecting surge events. Includes 12 references, tables, figures.

Product Details

Edition:

Vol. 96 - No. 11

Published:

11/01/2004

Number of Pages:

15

File Size:

1 file , 510 KB