Naylor Drainage - Metrotunnel

METROCELL
	Attenuation
	Infiltration
	Structural Design Criteria
	Installation & Maintenance

METRODRAIN

METROTUNNEL
	Domestic Soakaway
	Installation

NAYLOR PAVING SYSTEM
	Installation
	Accessories

RAINWATER HARVESTING

LEGISLATION

BROCHURE

Metrotunnel - Installation - Planning of Percolation Ditches
With the Naylor Percolation Tunnel
The Naylor Percolation Tunnel is a system which has been specifically designed for the percolation and retention of rainwater. The structure of the modules allows a space-saving installation close to the surface. For larger projects dimensioning according to ATV - A 138 or corresponding, country specific technical regulations. In order to avoid silt accumulation a silt trap must be installed.

Volume	300 litres
Length	1,200mm (incl. End plates)
Width	800mm
Height	500mm
Connectors	End: 100, 150, 200, 300mm Top: 100, 200mm
Weight	approx. 11 kg
Material	100% made of recycled material polypropylene (PP)

Choice of position
Tunnel installation needs to be at least 5 metres from adjacent buildings. For the best possible percolation performance, the Naylor Percolation Tunnel has to be installed at least 1 metre above groundwater. Tunnels should not be installed under the crown of any trees.

Installation of the feed and vent pipes:
Feed pipes should be connected at the front of the end plates using the circular cutouts provided . The feed pipes must extend approximately 20 cm into the tunnel modules. To ensure water enters into the modules in a controlled way. In the case of multi-line installations it is essential that every percolation line is equipped with its own feed pipe. Use the connection on the upper side of the module for the vent / inspection pipe (1 vent / inspection pipe per line).

Installation of the Naylor Percolation Tunnel

1. Excavate the hole to receive the percolation tunnel, creating a flat level base and cover the bottom of the trench with 10cm of granulated material (8-10mm).

2. Lay the percolation modules on the gravel bed and connect them to each other in lines (lengthwise).

3. To protect the percolation modules from dirt etc, wrap them with a geotextile fleece to separate them from the filling material. The filter fleece should overlap the end of the modules by at least 30 cm.

4. Backfill the excavation in layers.

5. If a lawn is planted on top of the percolation surface, cover the system with a waterproof film, as otherwise the lawn above the percolation system may dry faster than the rest of the lawn. Maximum earth covering and installation depth
Percolation Tunnel:

Load capacity	Max, 7.5 +/m² temporarily Max, 3.5 +/m² for long term
Min, earth covering without traffic load	250 mm
Max, installation depth (lower edge)	2,500 mm

Suitable for light duty applications only. eg domestic garden and landscape areas.

Top View

Sectional view

Sectional view of open swale percolation ditch