Surface Stiffness Modulus testing shall be carried out using a Dynamic Plate Test device, which has been properly calibrated to the manufacturer’s specification; this includes the Falling Weight Deflectometer (FWD) as well as lightweight devices. The FWD may be more appropriate for the higher Foundation Classes. The equipment shall be capable of delivering a load pulse of peak magnitude in the range 4-15kN of total duration 15-60msecs to a rigid circular plate of 300mm diameter. Both the applied load and the transient deflection, measured directly on the tested surface, shall be measured. The deflection measurement transducer shall be capable deflections up to 2000 microns. The test is followed HD 73/09 and IAN 26/06.