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The Great A15 Debate

One of the most common queries we get as a drainage product and access cover manufacturer is - “can I use an A15 product on a driveway?” or (all too often) put another way - “I have an A15 product on my drive that’s broken, how come??”

The confusion is caused by interpretation of the A15 loading i.e. 1.5 tonnes.  To the untrained eye this equates to less than the weight of their car so the incorrect conclusion is drawn that an A15 product is suitable for their driveway.

However, the static mass of a vehicle and the loads it exerts through its wheels to the ground is very much different to the dynamic loads applied when the same vehicle is turning and braking, as is often the case on driveways.  In such circumstances the loads exerted are several times the level when static so even a small hatchback car with a static mass of, say, 1.2 tonnes will exert much more through its outside wheels when turning, and even more through its outside front wheel when braking at the same time.  In extreme cases the load exerted through a single wheel can be 3 or 4 times the static mass of the car!

All of this was thought of by the committee of clever chaps who put together the load rating classification standards, and hence on initial glance each loading class seems to be over-specified but in reality they have been defined so as to accommodate the effects of dynamic loads that pedestrians, cycles, motorbikes, cars, vans and lorries exert when either moving at speed and/or turning & braking.

To conclude – an A15 product, is suitable for pedestrian areas only.  For driveways B125 loading class is recommended as a minimum, and if the driveway in question is subject to occasional trafficking by dustbin lorries, delivery vehicles, removals vans, etc, then a C250 loading class product should be considered.  If in doubt, install a higher loading class than you think!

- Uploaded 29/04/2014