High alumina cement (HAC) concrete was used extensively in the UK from the 1950s to the early 1970s in the manufacture of pre-cast, pre-stressed concrete beams. Extensive research into the structural performance of HAC concrete construction led, in 1975, to publication of DOE's Building Regulations Advisory Committee of detailed guidance and recommendations on design-check procedures. This guidance (commonly known as the BRAC rules) is the best advice available and is still used to assess the structural performance of the many tens of thousands of buildings in the UK containing such pre-cast HAC concrete beams. This report incorporates the original documents, leaving out redundant information, with additional and revised information where relevant. 96 pages.