According to UNHCR, in any given year there are 30-50 million Internally Displaced People (IDPs), and around 5-10 million refugees crossing a border to escape conflict or disaster. These figures fluctuate, but the general trend continues to move upwards as population pressures and climate change incidents occur more frequently. Shelter is, perhaps, the most important part of the aid supplied, as it not only affords protection from the environment, it also creates communities and increases security – particularly important for women and children.

The quantity of shelters required can be very large, and examples from recent years include:
Haiti – required 135,000 transitional shelters after the earthquake of 2010.

Iraq – World Federation is planning to install around 1,000 transitional shelters in 2015, accelerating to 30,000 shelters over the next five years for southern Iraq alone.