Civil Products

Civil Products Division Brochure (4.73MB)

Webforge supplies a complete range of Mild Steel Grates and Ductile Iron Access Covers in compliance with the load and permanent set requirements specified in AS3996-1992. Conformance certificates can be supplied upon request. Webforge are also capable of custom manufacturing Mild Steel Grates and Frames to suit specific client applications and load test according to AS3996-1992 if required.

Access Covers and Drainage Grates - General Information

Testing

Webforge manufacture and test in-house the Mild Steel Grates and Ductile Iron Access Covers to ensure compliance with the load and permanent set requirements specified in AS3996-1992.

AS3996
Strength classifications and the loading conditions applying to these classifications

Class A - Test Load 10kN
Footways and areas accessible only to pedestrians and pedal cyclists (Extra-light Duty).

Class B - Test Load 80kN
Footways that may be mounted by a vehicle or livestock, and light tractor paths (Light Duty).

Class C - Test Load 150kN
Malls and pedestrian areas open to slow moving commercial vehicles (Medium Duty).

Class D - Test Load 210kN
Carriageways of roads and areas open to commercial vehicles (Heavy Duty).

Other requirements of AS3996

In addition to strength, AS3996 has requirements for gas and water tightness, keyhole dimensions, grate bicycle safety, identification markings, frame dimensions, etc. All Webforge access covers and drainage grates comlpy with these requirements.

Specifiying access cover and drainage grate sizes.

The industry convention is to identify the size of access covers and drainage grates by specifying the interal clear opening dimensions of the frame. For circular covers this dimension is a diameter. For square and rectangular covers the width is taken as the frame dimension parallel to the side of the cover with two keyholes. For singlerow, multirow, and trench grates, the width is taken as the span of the trench

Frame clear opening dimensions

The frame clear openings of Webforge access covers and drainage grates are made to be 15mm larger than the norminal sizes of industry standard sized pits. These pits increase in size in increments of 150mm.

This has been done to allow frames to be placed over standard panel framework and cast in while pouring the pit walls. This speeds up installations and ensures the fram eis fully embedded in the concrete.

Optional Extras

Holding down bolts
Any cover can be supplied fitted with two or four M12304 stainless steel holding down bolts to provide resistance to backpressure or unauthorised opening. If two bolts are required in a square or rectangular cover the bolts are fitted in diagonally opposite holes. To determine the number of bolts required to resist a given backpressure (m head of water), please contact your nearest Webforge sales office.

Snap-Lok
Circular covers can be supplied with Snap-Lok as an alternative to Holding down bolts. Snap-lok is a pin and groove arrangement which also provides resistance to back pressure or unauthorised opening.