Siphonic Drainage Solution to for Dublin Waste to Energy Centre

Dublin Waste Facility Poolbeg - Drainage

Dublin Waste to Energy Project

  • Client
  • Design Team
    PM Group
  • M&E
    Mercury Engineering
  • Technology
    Primary & Secondary Siphonic Drainage
  • Scope
    Design, Pre-fabrication, Installation & Certification


The Dublin Waste-to-Energy project at Poolbeg was of national significance at the time of commissioning and construction and was led by Dublin City Council in conjunction with Covanta, a world leader in sustainable energy.  It was a large-scale project which, due to the height, scale and access requirements, posed some difficulties for installation and design of a rainwater roof drainage system.


Capcon was faced with numerous challenges when it came to designing the most effective rainwater roof drainage solution. These included:
  • External wall designed with a 12 degree gradient
  • Heavily congested environments requiring detailed coordination
  • Fixing pipework in an extremely corrosive environment
  • Installation at heights of up to 50m

Siphonic Solution Reduced Materials & Cost

Through extensive coordination our specialist design team were able to design the most effective and efficient system by bringing the siphonic drainage from roof outlet all the way to ground level. This solution gave Capcon Engineering the winning edge over other competitors. The other proposals involved breaking the siphonic system (siphon action)  half-way up the building, thereby significantly reducing the efficiency of the solution. 

Using siphonic from roof level to ground level meant we could greatly reduce the amount and size of pipework required for the project helping to reduce cost by over 20%. In addition to reduction materials cost, less pipework requires less labour and time on site.

The pipework was designed to be installed at a 12⁰ gradient whilst still performing to Siphonic Standards EN 12056-3:2000 and BS 8490:2007. This highly complex install allows the system to operate at maximum capacity.

The Valsir Rainplus Siphonic Drainage System was chosen and implemented over 9 x primary and 9 x secondary systems. 

Installation at Challenging Heights

The scale and height of the structure required consideration in regard to constructability and access to the rainwater system in a restricted area. To overcome these challenges the design solution proposed alternative positioning of pipework within structure to ensure ease and safety of installation and accessibility. 

The installation phase involved installing over 2km of HDPE Pipework at heights ranging from of 28m to over 50m.

An unusual aspect of the project was the corrosive environment in some areas caused by the incinerating process. In order to install a system that could withstand the extreme environments we utilised all stainless steel brackets and fixings with our HDPE pipework which is naturally corrosion resistant. 

  • 2000m of Pipework
    Over 2000m of pipe work designed, manufactured and installed
  • 18 x Siphonic Systems
    9 x primary and 9 x secondary systems were designed and installed
  • 12⁰ Degree Gradient
    Vertical pipework installed at 12⁰ gradient to suit building design