Designed to form a continuous or semi-continuous narrow opening in a pavement, the SlimDrain™ pavement system is designed to help alleviate ponding traditionally associated with continuous gullies and pits while providing excellent hydraulic characteristics, and a robust design. SlimDrain™ is manufactured from pipe which has a 2 hour fire rating.
The SlimDrain™ system consists of a galvanized steel ‘box’ section fitted into a fibre reinforced concrete pipe. Several configurations of SlimDrain™ system are available including the standard metal grate with shimming adjustment capability, and a polystyrene foam option that forms the void between the grate and the pipe. The SlimDrain™ metal grate meets ‘bike safe’ standards.
The system consists of fitting a riser, and a 'bikesafe' surface grate 'box', into a fibre reinforced concrete pipe.
The pipe is bedded in screenings to the spring line, then concreted into place up to the surface, to form a smooth continuous pavement.
The SlimDrain™ drainage system is available in 225mm to 750mm diameters - the pipe diameter should be chosen by the designer to suit the hydraulic requirement of the system.
The standard grate length is 2m (two lengths per standard 4m length of FRC™ pipe). Pipe size can be increased to accommodate additional flow as the surface area increases, and wider grates can be supplied for severe flow cases.
Hydraulic Performance
The SlimDrain™ drainage system has excellent hydraulic characteristics and will usually operate as a weir for most flow depths. The NSW Roads and Traffic Authority (RTA) 'Bridge Deck Drainage Guidelines' calculate the weir flow from the following equation:
Q= 1.66p(d)1.5
Where: p= perimeter of grate
d= overall depth of ponding
Q= flow into grate
There are a number of commercially available hydraulic software programs available to design the length of the SlimDrain™ drainage system for individual site parameters.
Configuration
Several configurations of the SlimDrain™ drainage system are available to meet clients' budgetary and performance requirements.
The design incorporates a metal grate with a standard grate opening width of 48mm, or an optional 65mm opening available on request (at additional cost). The standard 48mm opening will be supplied with two longitudinal bars with an approximate opening of 15mm.
An economy version of the system incorporates polystyrene foam to form the void between the grate and the pipe. The polystyrene foam option is applicable where the grade on the surface varies from the pipe grade, or the surface is in excess of 150mm above the top of pipe (standard height).
| 
