Hydrant Unidirectional Flushing

Hydrant Unidirectional Flushing

Hydrant flushing plays an important role in water distribution system sustainability. Water quality can quickly deteriorate during delivery due to a number of controllable factors.

Unidirectional flushing
Unidirectional flushing services (UDF) from Wachs Water Services use water velocity to remove non-solidified pipeline deposits. Combining condition assessment techniques with engineering modeling, unidirectional flushing services (UDF) flushing thoroughly scours pipes and removes pipe tuberculation, increases water flow, minimizes water discoloration, and improves overall water quality. Unidirectional flushing (UDF) involves systematically opening and closing hydrants to force water at high velocity through connected pipes, and is typically performed in the warm-weather months, the process requires anywhere from 30 minutes to more than an hour.

Unidirectional flushing (UDF) differs from conventional flushing in that it involves the closing of adjacent valves, and the use of a single hydrant per flush for isolating individual sections of main. Wachs Water Services implements unidirectional flushing services (UDF) programs for several major water utilities and pipeline operators, delivering the full suite of unidirectional flushing services (UDF) services from hydraulic modeling to developing zones and sequences, testing water quality, and establishing program sustainability by training and supervising utility field crews in unidirectional flushing (UDF) methods and techniques.

Benefits of a water main hydrant flushing program include:

  • Confirmation of hydrant and valve operability
  • Improved water quality through removing accumulated sediment
  • Effective chlorine disinfection levels
  • Verification of proper pressure levels for fire protection
  • Unidirectional flushing programs use less water
  • Unidirectional flushing programs achieve higher scoring velocities
  • Unidirectional flushing programs provide a better knowledge of water network connection

Fire hydrant flushing
Conventional fire hydrant flushing services are also an effective way to remove accumulated sediment from pipes, but conventional fire hydrant flushing involves flushing multiple hydrants simultaneously, and does not include the "valving-off" of individual sections of main pipe that is typically performed in unidirectional flushing. Conventional fire hydrant flushing is used in areas of the city where fewer minerals build up in the mains, requiring less "scouring" efficiency achieved by unidirectional flushing.

Like unidirectional flushing services (UDF), conventional fire hydrant flushing services from Wachs Water Services help remove pipe tuberculation, increase water flow, minimize water discoloration, and help eliminate dirty or "rusty" water for improved overall water quality. Done in accordance with American Water Works Association recommendations, fire hydrant flushing is typically performed in the spring, summer, and fall months by schematically opening and closing hydrants, and permitting the water to continuously flow until all sediment is carried out and water appears clear.

Turnkey Service Solutions
Wachs Water Services has the experience and expertise to effectively plan and execute water main hydrant flushing and unidirectional flushing programs on-time and on-budget.

  • Assessment of water main valves to enable effective flushing programs
  • Generation of flushing sequences for the entire water distribution system or targeted regions
  • Identification of water main sections to be flushed, the hydrants to be used, the valves to be operated and the proper hydrant flushing timing
  • Execution of flushing programs working in close cooperation with utility crews

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Wachs Water Services is the leading provider of water distribution system asset management solutions that significantly improve efficiency and network control. Our specialized approach combines condition assessment and rehabilitation services for valves, hydrants and water mains with the capture and integration of critical water asset GIS information. We provide the expertise, equipment and personnel to locate, assess, operate and document virtually any water asset.