19/03/2020Từ Gioi thieu Siphonic (EN)

From the days when our forefathers began draining roofs, gravity drainage has been the used to move the rainwater from the roof to the ground.

However, our 21st century technology offers a superior alternative to cater for the storm profiles that today’s changing climate brings us. It’s available now –

The Technology is
 HydroMax™ Siphonic (Syphonic) Roof Drainage System.

Siphonic Drainage offers a unique technology whereby you can achieve many Technical and Commercial Benefits.

Through the use of a siphonic roof drain to eliminate air ingress into the pipework, the horizontal pipes prime full of water which then accelerates down the vertical downpipe inducing a negative pressure flow – hence the siphonic or syphonic name.

This results in high flow velocites that self cleanse the pipework and extremely efficiently removes the rainwater from the roof.

Contrary to common misconception, our siphonic roof drainage systems are self draining after a storm event and advanced inducer design result in low ponding on the roof during rainfall events (refer to our flow graphs from testing to BS 8490:2007 and ASME A112.6.9:2005) and .


Comparison between Gravity and HydroMax Siphonic Drainage
  • Cost effective with typical savings of 20% to 45%
  • High level carrier pipes installed horizontal without gradient (eases co-ordination with other services)
  • High velocity flow ensures that systems are self cleaning
  • HydroTechnic™ Design configures optimised drainage solution
  • Fewer collector pipes can convey water to the perimeter of the building or other preferred locations which frees up valuable building space
  • Drainage below the floor of the building can be eliminated
  • Small bore pipework reduces space taken up and
    imposes less load on the structure
  • Engineered solution that allows controlled flow and or controlled discharge
  • Reduced Construction build-program due to less ground works, less pipework, etc.

Rainwater Downpipe Routed to Chosen Location

  • Fewer internal downpipes
    (less restrictions on building space usage).
  • Environmental benefits because HydroMax™ makes routing to Harvesting/Retention/Attenuation easier. Less ground disturbance, fewer Raw materials, etc.
  • Fewer Roof penetrations due to high performance roof drains
  • Lower ponding depths than Gravity Drains

Deli Factory in Vietnam (Design & Build by HICON M&E):