The BS EN124 standard provides a general guide to product stability and sets out test load parameters for the various classes of products in terms of static load tests.

However, it provides little specific information on dynamic loads imposed by the wide variety of traffic conditions found on modern road systems.

Product selection in most cases is a simple matter, but long association with specifiers has convinced us that there are certain conditions which dictate a little extra care in making a selection. The diagram illustrates vulnerable spots where products may be subjected to extreme loading.

With BS EN124 offering little or no guidance on selection of products under dynamic loads, BRISCOVER has developed a portfolio of products incorporating the Interaction range of covers and gratings which, when complemented with the selection guidance software, enables the specification engineer to make the right choice with confidence.

1. Dual Carriageways
Speed of traffic increases the impact loading on castings and deceleration areas at roundabouts can be particularly aggressive.

2. Roundabouts
Turning vehicles encourage movement between cover/grate and frame and can increase wear. Gully grates are particularly vulnerable at clipping points.

3. Hard shoulders
Changes in traffic flow necessary to accommodate maintenance work or emergencies, can result in units being required to accept loadings and conditions for which they may not have been intended.

4. Traffic lights
Acceleration, deceleration and turning all increase the stress on road ironwork.

5. Bus routes
The pulling into the kerb or lay-by and braking of buses result in gratings being required to accept loadings not experienced through normal traffic.

6. Traffic calming
The installation of traffic islands and narrowing of roads to slow traffic will increase the vulnerability of gully grates to clipping.

7. Narrow lanes
Width restrictions can lead to road castings being heavily trafficked, particularly on bend clipping points. Gully grates are particularly vulnerable.