- Ultra Flo Steel Pipe



Armtec Ultra Flo is a storm sewer pipe with a unique external rib corrugation that provides a significant improvement in hydraulic performance over traditional corrugated steel pipe, reducing the Manning’s value to 0.013.


Ultra Flo pipe is produced by a continuous spiral seam method. Stiffness is provided by external box-shaped ribs, 19 mm x 19 mm, at 190 mm centres.

Ultra Flo performs as a flexible compression ring under load, redistributing pressure radially into the surrounding high-density soil. The unit pressure at the pipe invert can be as little as one-third of the unit pressure under a rigid pipe in identical loading conditions.

  • Fast installation
    Lightweight and long lengths with minimal joints
  • Durable
    Available in galvanized steel, aluminized steel, polymer-laminated and aluminum steel to suit environmental conditions
  • Nestable pieces
    Efficient shipping for remote locations
  • Value
    Lowest installed cost compared to large-diameter concrete storm sewer
  • Efficient Hydraulics
    Ultra Flo’s low “n” factor is equivalent to or less than the standard .013 usually used in storm sewer design
  • Efficient shipping for remote locations – pieces can be nested
  • Lowest installed cost compared to other large diameter storm sewer materials
  • Couplers provide mechanical pull-apart resistance – critical in soft soils
  • Variety of materials to match design service life to material service life

  • Municipal storm sewers, especially in large diameter in long runs
  • Highway median drainage
  • Industrial storm sewers
  • Large diameter culvert slip-lines
  • Stormwater detention tanks

Pipe Size:

  • Round Range – 450, 525, 600, 750, 900, 1050, 1200, 1350, 1500, 1650, 1800, 2000, 2200, 2400 mm
  • Pipe Arch – from 500 mm span x 410 mm rise to 1,850 mm span x 1,400 mm rise.
  • Length – up to 10 m (max)
  • Corrugation Wall Profile:
  • Corrugation – 19 mm x 19 mm x 190 mm
  • Wall thickness – 1.6 mm to 2.8 mm 


  • Conventional couplers available
  • H500 Hugger Band Couplers recommended for storm sewer applications

  • Canadian Standards Association (CSA) G401

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