Negative pressures in pumping mains – A problem?
Yes!
It is not commonly appreciated that a far higher proportion of surge pressures identified by hydraulic modelers as requiring addressing, are negative and NOT positive.
Negative pressures are equally destructive as positive due to the extreme high pressures created as the vacuum collapses.
Negative pressures in Potable water mains directly contravene the Drinking Water Inspectorate (DWI) regulation of maintaining a positive pressure at ALL times.