In the past it was common for granular raw materials to be supplied to site in large sacks. These sacks, weighing either 25kg or 50kg, were manually packed and stacked on a pallet. The recipient would then empty the sack in what was traditionally known as a ‘rip and tip’ operation. In the late 1980s this process was gradually replaced by people preferring to use semi-bulk packaging in the form of large versatile polypropylene bags, known today as bulk bags. This was the beginning of the decline of the use of the sack—whether made of paper, polythene or PP—in first world countries. So why did people prefer to switch to bulk bags?