Infiltrated (Conventional) vs Evacuated Drainage Systems

Infiltrated (Conventional) versus an Evacuated Drainage Design Solution

 

A straight forward explanation of differences in the design and the cost savings provided between an infiltrated (Conventional) under-field drain sub-base and the Vertical-To-Horizontal (Evacuated) drainage design which we – TargaPro, Inc. - recommend as the primary choice in the installation of the EcoGreen66 artificial sports turf.

 

Fallacy versus Truth

 

Typical base designs and under field drain systems for infill turf surfaces are saddled with an inherent engineering conflict between rate of infiltration and grade stability with no ability to guarantee that the system will perform as designed, specified or built.  Some competitors will insist that drainage is secondary and seemingly out of the control of the turf installer. This is yet another fallacy in the industry and nothing could be further from the truth.

 

Drainage and base preparation should be the primary design concern, if the intent of the system owner is to install a multi-seasonal, all-weather surface.  Improper base design can be problematic for any infill system and is often not addressed by the turf company simply because they cannot solve the engineering conflicts it presents.

 

In a conventional (infiltrated) drainage system the designer (or the turf company) must pay the most attention to the infiltration rate of the stone base while trading off the stability of that base as infiltration rates become more demanding.  This design trade off in a conventional system is much more relevant than the flow rate through the turf system. 

 

Dilemma or Solution

 

This drainage system dilemma has been addressed and solved by TargaPro through the design of an alternative drainage system which circumvents the problematically unstable stone base as a conductive median for the water.  By this design, evacuation rates can be pre-determined and thus be assured (and hence guaranteed) that they exceed a 50 year, one-hour storm intensity.

 

Our solution combinesthe unique benefits of the GSE GeoMax Replicated Grass turf with an advancedand patented Vertical-To-Horizontal drainage design through the use of the GSEProDrain dynamic drainage and shock attenuation blanket as shown in the following edge detail and base cross section inside an existing track.

 

The use ofthe TargaPro EcoFlo drain pad is the first vertical-to-horizontal drainage designfor in-filled synthetic turf which incorporates the following benefits – 

 

  • Reduces the risk factor associated with poor subsurface soils while eliminating the added costs usually associated with stabilizing sub-surface soil conditions.

  • Provides significant cost reduction associated with the requirement to remove 135,000 cubic feet of spoils (for a 90,000 sq foot installation) and then replace those spoils with the aggregates required for the under field drain system.

  • Provides added cost savings through the reduction of the construction schedule by a number of weeks.

  • Provides permanent improvement in G-Max performance and uniformity as well as a lower sustained G-Max without producing a ‘soft’ or ‘spongy’ underfoot feel.

 

The TargaPro Guarantee

 

Finally, with respect to how each company addresses the drainage issues it is imperative to require a guaranteed infiltration rate for the full term of the warranty.   TargaPro will provide – and suggest that the specification require - that a guarantee which meets the following definition be incorporated in every request for proposal.

 

Proper drainage is defined as: there being no visible puddling or any accumulation of water in the infill materials sufficient to cause visible splashing from ball impacts, foot falls, or other bodily impacts, either during or after storm events, where the rainfall does not exceed two inches per hour. Furthermore, under such conditions, the accumulation of water in the infill materials shall not cause such infill to float, move, or dislodge or in any way redistribute within the field area or beyond, at any time during the full term of the guarantee. The surface shall at all times, during or after the aforementioned weather events, remain functional and playable.