The project is concerned with the acquisition of reliable data from large-scale silos, and in particular data relating to pressures imposed on the silo by the stored material. For the purposes of the study a square plan-form steel silo was used, and the stored material was Leighton Buzzard sand. The experimental work was carried out in the environmentally controlled conditions of the laboratories at Building Research Establishment, Watford, United Kingdom. The project adopted the pressure cells designed by V. Askegaard. Both wall cells and embedded cells were used to measure pressure at the interface of the wall and stored material and within the stored material, respectively. For the embedded cells, it has been shown that the installation procedure is critical in obtaining reliable results. Preliminary tests were carried out in small-scale models until confidence in repeatability of the placement method was achieved. Even then there was some variation in results, and to ensure confidence each large-scale test was repeated five times. Pressures measured by both wall and embedded cells were compared to obtain calibration factors, and then the overall vertical equilibrium of the model was checked and found to be within the bounds of experimental error. The authors are confident of the accuracy of data which can now be achieved provided care is taken with both installation procedures and calibration checks. Key words : pressure measurement, silos, granular media, pressure cell calibration.