firth ecopave system Browns Bay Waterfront Auckland

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1 firth ecopave system Browns Bay Waterfront Auckland

2 FIRTH ECOPAVE SYSTEM Traditionally, land development has had a negative impact on the natural flow of rain, stormwater and nutrients. Runoff from impermeable surfaces not only increases demand on drainage systems during rain, but also starves adjacent vegetation and subsoil of water and nutrients and increases the rate of erosion. However, the effect of wetting the sub-grade needs to be considered carefully, and factored into the system design, if the paving area is to be used for vehicle traffic such as residential driveways and car parks. Should infiltration alone be inadequate it is recommended that an alternative method of discharge is included in the design (for example detention). Infiltration Example Councils now require steps to be taken to reduce the effects of development on natural patterns of water runoff, stormwater and drainage. The use of water-permeable surfaces not only maintains a natural water cycle, but places fewer restrictions on the potential use of developed land unlike solutions such as detention ponds. Firth s EcoPave System is a paving system that will help to maintain the natural water balance as part of a property development. Advantages of the Firth EcoPave System: Reduce rainfall runoff from hard surfaces, decreasing the demand on drainage systems. Reduce the need for retention structures (e.g. ground sumps, ponds or dams) and maximise land use by retaining water within the EcoPave System. Recharge natural groundwater and acquifers, when using the infiltration system. Improved hydrological management of stormwater peak flow by holding and releasing in a controlled manner. Detention In some circumstances stormwater can be detained in the storage medium and then gradually released into the storm water system. This will help prevent sudden water surges that can overload some drainage systems and cause flooding. By limiting the size of any outlet from the storage medium, the rate at which stormwater is released into the drainage system is controlled and reduces the peak flow. Detention Example May filter run off water by removing heavymetals such as zinc and copper through cationic exchange when using greywacke sub base drainage aggregates. The Firth EcoPave System The Firth EcoPave System consists of permeable paving overlaying a storage medium consisting of EnviroMix concrete or greywacke drainage aggregate. Geotextiles are used to separate the storage area from the bedding layer and the sub-grade. SYSTEM FEATURES Infiltration Where ground conditions are suitable, the rainfall can be allowed to infiltrate and recharge the ground-water. Applications Plastic tanking membrane Whichever method of water control is required, the choice of paver is determined by the end use of the installation. Each product performs differently depending on the amount of vehicular and foot traffic it will be exposed to.

3 Note: Base course thicknesses are indicative only and are provided to give an example of typical construction. This table does not replace the use of engineering advice. Base course Thickness and Filter Cloth Classification Loading Condition Sub Grade Classification (Soaked) Type of Paver Residential Pedestrian Patio / Pathway Weak CBR 5 Medium CBR 10 Strong CBR 15 EnviroPave 50mm PorousPave 60mm Class B Class A Grass Paver Residential Light Traffic Single Unit Residential Driveways 150mm Class D 125mm Class B EnviroPave 50mm PorousPave 60mm PorousPave FlowPave Grass Paver * Gobi Block * Residential Light to Medium Traffic Multi Unit Residential Driveways Specific Design 150mm 125mm PorousPave FlowPave Public Footpath Low and High Impact Class D Class D Class B Commercial Grade EnviroPave 50mm PorousPave 60mm Notes: 1) For small jobs NZS3116:2 suggests the following sub-grade assessment test which may be sufficient. Weather conditions can however significantly influence the test. The test should therefore be carried out under wet ground conditions: Weak - Walking leaves a strong foot imprint. Medium - Heel pressure leaves an imprint. Strong - No imprints. 2) For moisture sensitive soils (the soaked and unsoaked CBR s are significantly different i.e. clays). The thickness of the base course should be increased by at least 50mm above the values provided in the table above. 3) Where soils are known to be expansive (large volume change in wet and dry states), engineering advice should be sought. A solution sometimes adopted is to provide an impermeable liner above the expansive material. 4) Greater base course thickness than indicated above may sometimes be required for water storage or hydraulic requirements. 5) Specific design is required where soaked CBR is less than 5. However, a solution often used in very soft sub-grades is to provide a 150-mm layer of GAP40 below the drainage base course with a biaxial geogrid at the interface between sub-grade and GAP40. See installation guide for more detail. * Gobi and Grasspavers are suited to residential parking areas for light vehicles such as campervans, caravans and boats. To determine the on-site sub-grade CBR value use the Scala Penetrometer Test as per NZS 4402:1986 Te Atatu Peninsula Medical Centre

4 THE Firth ecopave system Product Selection Firth PorousPave Number per m²: 50 Manufactured in 60mm and Firth FlowPave Number per m²: 50 Manufactured in Firth FlowPave Firth FlowPave Numb er per m²: 50 Number m²: 50 Manufactper ured in Manufactured in 60 or Gobi Block Grass Paver 400mm mm mm 400mm THE FIRTH ECOPAVE SYSTEM Typical Cross-Section (Using EcoPave)

5 Firth EcoPave System Design Every job is different in terms of site layout, topography and the extent of development in the area. At the planning stage please consult your council with regards to their requirements for the control and handling of rainwater. These requirements can be used to establish the most effective layout to control runoff. Some local bodies and councils are in the process of developing design guidelines for permeable paving. Please check with your local body or council if they have such guidelines. For a list of installers in your area, contact Firth Customer Service on or go to and follow the Envirorange System link. Refer to the Firth EcoPave Systems Installation Guide. Storage Media Storage media are the collection points for water absorbed by the Firth EcoPave System. It is critical to the overall functionality of the design, and is comprised of Firth EnviroMix concrete or a specifically designed Winstones drainage aggregate. This material allows collected water to move between interconnected open space, hence maximising water storage space and reducing pressure on the drainage system. A sloping site will have less storage capacity than a level site as water will resurface at the lowest point. This can be overcome by encouraging cross flow (through the installation of weirs) or concentrating storage capacity at the lowest point of the design. Permeable paving is not suitable where high sediment loading is expected as this will cause the permeability to rapidly reduce. Permeable paving may not be suitable where: Dirty water discharges onto the paving. Windblown fine silt accumulate. Leaves accumulate and mulch on the paving. Firth s Installation Guide is available through Firth Customer Service on or visit Construction When using Firth s EcoPave Systems, Firth recommends the use of an experienced paving contractor to ensure the system functions as designed effectively. Maintenance A properly designed, located, and constructed concrete block pavement will perform well for many years. A combination of regular inspection and light maintenance will ensure long term durability and performance. Typical maintenance is limited to the control of weeds and replacement of lost joint sand. However, materials such as clay and silt can build up over time and reduce the permeability of the paving. Blocked paving is best overcome by low-pressure waterblasting and vaccuming. This will remove unwanted materials from the paving surface as well as contaminated joint sand. Jointing sand can be replaced simply by sweeping new sand over the paving surface with a broom. In extreme circumstances, the blocks can be lifted and re-laid.

6 CBI 8211, 8231 September 2011 The Firth EcoPave System Firth EcopavE system installation guide enviropave PorousPave is a complete paving system that will help to maintain the natural water balance as part of a property development. FlowPave gobi Block grass Paver Te Atatu Peninsula Medical Centre SustainabilitY: The Firth Concrete & Concrete Masonry sustainability lifecycle n 4 Environmentally compliant manufacturing plants n 4 Surplus water and some aggregates recycled n 4 Low transport impacts n 4 Leftover concrete returned from construction sites n 4 Passive solar heated thermal mass makes completed buildings more energy-efficient n 4 Most wash water returned from construction sites n 4 Highly durable, low maintenance buildings and no rot n 4 High degree of noise control n 4 Inherent fire resistance n 4 Overall longer effective building life n 4 Demolished concrete can be recycled as hard fill or aggregate For more on Firth s contribution to building a sustainable tomorrow today, visit or call us on for our free brochure. Copyright Firth 2011 Oct 2011 Chalis FIR21198 Available in Available in PRODUCTSPEC