This paper discusses fires in informal settlements (otherwise known as slums, ghettos, shantytowns, etc.), which are regularly ravaged by fire in South Africa. Initially an overview of the problem is presented, highlighting the factors that contribute to the frequent, large conflagrations that occur. Details have been based on research conducted in Cape Town, South Africa, although the research is applicable to settlements worldwide. Data from recent fires where up to 4500 people were left homeless is included, highlighting aspects regarding fire spread and fire dynamics. Thereafter, preliminary results from a pilot study are presented where full-scale burn tests have been carried out on informal settlement dwellings, or “shacks”. Results from (a) a smoldering fire test, (b) 25 kg/m2 wood fire load test and (c) a ‘representative’ shack fire test are presented. For flaming fires it is shown that flashover in these small dwellings can occur in as little as one minute (depending on the fuel source), which is consistent with observations from professional firefighters in the field. Photoelectric smoke detectors, ionization, and rate-of-rise heat detectors were included during fire tests, to evaluate their performance in such confined spaces, as these are currently being either used or being considered for use in settlements. Activation times are reported for the different tests conducted.