FG | Self-operating Flood Guard for Air Valves


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The FG, flood guard attachment, protects potable water systems from external contamination caused by floodwater overflow. The contaminated water fills the manhole and enters the pipeline via the air & vacuum (kinetic) discharge outlet. The FG seals at zero pressure, guaranteeing a leak-tight seal and preventing the water from entering the air valve.

The effective intake and discharge flow rates of the air valve are maintained and not affected by the flood guard attachment.

Note: Under flooding conditions, when the FG is sealed, the air valve will not intake air in the event of negative pressure (vacuum) conditions.

Product Features

  • Efficient - full flow intake and discharge of air
  • Hygienic - prevents contamination during flooding
  • Self-operating float - no auxiliary power required
  • Adaptable - mountable on various types of valves
  • Retrofitting - easily installable on existing products
  • Simple to use - few parts and easy handling
  • Economic - effective emergency measure for failing manholes
  • Zero sealing pressure - new seal concept; closes drip-tight immediately
  • Non-corrosive - all parts made of composite materials and stainless steel
  • Lightweight - 3 kg total weight
  • Minimum maintenance – periodic examination of screen integrity (intact and clean of debris).

Application Range

  • Pressure rating:
    Zero sealing pressure requires only buoyant force
    Seals up to 10M water column head
    Negative pressure cannot seal the float
  • Sizes: 2”, 3”, 4” (male thread)
  • Adaptable Products: D-060 + NS (2" - 4"), D050 (2" - 4")


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Last Updated on: Sunday, 26 February 2023